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frank3phyl(at)comcast.net
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 Posted: Sat Jul 01, 2023 12:03 pm Post subject: Excessive Amperage |
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Upon starting my IO360 (only 12 hrs on engine) I noticed the “Low Voltage” warning light did not go out (typically I get a flashing lite when battery relay is activated and light goes out when alternator kicks in after engine start). I checked voltage and it was about 12.5v and the amperage was 37 amps. Increasing RPM from 1k RPM idle the "Low Voltage” light went out at 1.5K but the amps went up to 40.
Turning off switches/loads made no difference in amperage.
Inactivating the alternator brought amps down to 0.
I have a B&C 40 A alternator with the B&C OV controller.
Is this likely a starter issue (Skytec—also 12 hrs) and what’s the likely fix?
Thanks much
Frank
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art(at)zemon.name
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| Posted: Sat Jul 01, 2023 12:33 pm Post subject: Excessive Amperage |
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Frank,
Maybe your alternator is just charging your battery. 37 amps of load from a 40 amp alternator is OK. Do you have a reason to believe that something is wrong?
-- Art Z.
On Sat, Jul 1, 2023 at 3:14 PM Frank McDonald <frank3phyl(at)comcast.net (frank3phyl(at)comcast.net)> wrote:
| Quote: |
Upon starting my IO360 (only 12 hrs on engine) I noticed the “Low Voltage” warning light did not go out (typically I get a flashing lite when battery relay is activated and light goes out when alternator kicks in after engine start). I checked voltage and it was about 12.5v and the amperage was 37 amps. Increasing RPM from 1k RPM idle the "Low Voltage” light went out at 1.5K but the amps went up to 40.
Turning off switches/loads made no difference in amperage.
Inactivating the alternator brought amps down to 0.
I have a B&C 40 A alternator with the B&C OV controller.
Is this likely a starter issue (Skytec—also 12 hrs) and what’s the likely fix?
Thanks much
Frank
|
--
My blog: CheerfulCurmudgeon.com
Wrinkles mean you laughed. Grey hair means you cared. Scars mean you lived.
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email(at)jaredyates.com
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| Posted: Sat Jul 01, 2023 12:45 pm Post subject: Excessive Amperage |
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This is normal behavior especially with a lithium battery.
On Sat, Jul 1, 2023, 16:42 Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:
| Quote: | Frank,
Maybe your alternator is just charging your battery. 37 amps of load from a 40 amp alternator is OK. Do you have a reason to believe that something is wrong?
-- Art Z.
On Sat, Jul 1, 2023 at 3:14 PM Frank McDonald <frank3phyl(at)comcast.net (frank3phyl(at)comcast.net)> wrote:
| Quote: |
Upon starting my IO360 (only 12 hrs on engine) I noticed the “Low Voltage” warning light did not go out (typically I get a flashing lite when battery relay is activated and light goes out when alternator kicks in after engine start). I checked voltage and it was about 12.5v and the amperage was 37 amps. Increasing RPM from 1k RPM idle the "Low Voltage” light went out at 1.5K but the amps went up to 40.
Turning off switches/loads made no difference in amperage.
Inactivating the alternator brought amps down to 0.
I have a B&C 40 A alternator with the B&C OV controller.
Is this likely a starter issue (Skytec—also 12 hrs) and what’s the likely fix?
Thanks much
Frank
|
--
My blog: CheerfulCurmudgeon.com
Wrinkles mean you laughed. Grey hair means you cared. Scars mean you lived.
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user9253
Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan
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| Posted: Sun Jul 02, 2023 4:56 am Post subject: Re: Excessive Amperage |
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Below is from https://earthxbatteries.com/faqs/
I just installed my EarthX battery in my aircraft and started the engine and my charging amps was really high, is this normal?
.
Yes, this is normal. A lithium battery can and will accept a much higher charging current than an equal size lead acid battery.
If your battery is not fully charged, your alternator can potentially output a current equal to
or slightly above the alternator’s rating for a few minutes to top the battery off.
. . .
You must use a lithium battery that is designed to handle the current from the alternator
or you can damage the battery, cause premature failure or possible even cell rupture.
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Joe Gores |
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skywagon185(at)gmail.com
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| Posted: Sun Jul 02, 2023 10:18 am Post subject: Excessive Amperage |
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Battery....Lithium
Joe makes a very good point about the potential of Lithium base batteries to potentially cause charging problems.
The other side of this combo is that when a "normal" alternator is running at idle speeds the Lithium is able to handle receiving a very heavy current charge rate such that the alternator could easily overheat and burn some internal part due to lack of cooling for such a heavy current draw. There are gizmos made to take control of the charge rate such that it stays under the alternators design limits.
The marine and RV folks use these controllers to safeguard their expensive stuff.
David
On Sun, Jul 2, 2023 at 6:02 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Below is from https://earthxbatteries.com/faqs/
I just installed my EarthX battery in my aircraft and started the engine and my charging amps was really high, is this normal?
.
Yes, this is normal. A lithium battery can and will accept a much higher charging current than an equal size lead acid battery.
If your battery is not fully charged, your alternator can potentially output a current equal to
or slightly above the alternator’s rating for a few minutes to top the battery off.
. . .
You must use a lithium battery that is designed to handle the current from the alternator
or you can damage the battery, cause premature failure or possible even cell rupture.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=511019#511019
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N509RV(at)eckenroth.com
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| Posted: Fri Jul 07, 2023 1:43 pm Post subject: Excessive Amperage |
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DavidYou refer to gizmos made to take control of the charge rate such that it stays under the alternators design limits. Can you be more specific as to what these gizmos are. I have been looking for something like this to try and keep the stator in my Revmaster engine from burning up again. I believe that controlling the output is the key.
Thanks
Paul
On Sun, Jul 2, 2023 at 2:19 PM skywagon185guy <skywagon185(at)gmail.com (skywagon185(at)gmail.com)> wrote:
| Quote: | Battery....Lithium
Joe makes a very good point about the potential of Lithium base batteries to potentially cause charging problems.
The other side of this combo is that when a "normal" alternator is running at idle speeds the Lithium is able to handle receiving a very heavy current charge rate such that the alternator could easily overheat and burn some internal part due to lack of cooling for such a heavy current draw. There are gizmos made to take control of the charge rate such that it stays under the alternators design limits.
The marine and RV folks use these controllers to safeguard their expensive stuff.
David
On Sun, Jul 2, 2023 at 6:02 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Below is from https://earthxbatteries.com/faqs/
I just installed my EarthX battery in my aircraft and started the engine and my charging amps was really high, is this normal?
.
Yes, this is normal. A lithium battery can and will accept a much higher charging current than an equal size lead acid battery.
If your battery is not fully charged, your alternator can potentially output a current equal to
or slightly above the alternator’s rating for a few minutes to top the battery off.
. . .
You must use a lithium battery that is designed to handle the current from the alternator
or you can damage the battery, cause premature failure or possible even cell rupture.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=511019#511019
===========
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Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
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FORUMS -
eferrer" target="_blank">http://forums.matronics.com
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errer" target="_blank">http://wiki.matronics.com
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b Site -
-Matt Dralle, List Admin.
="noreferrer" target="_blank">https://matronics.com/contribution
===========
|
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Ceengland
Joined: 11 Oct 2020
Posts: 381
Location: MS
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| Posted: Fri Jul 07, 2023 6:30 pm Post subject: Excessive Amperage |
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Assuming it's a 'dynamo' (permanent magnet) style alternator, and assuming that the rectifier/regulator is not a 'shunt' type regulator, then just about any switching style current regulator should do the job as long as it's designed to handle the level of current you want. The one in the link below is rated for 300 watts, which would be around 20A (at)14.7 volts. I'd derate it to lower than that to ensure some level of reliability, and I'd certainly provide forced air cooling.
https://www.amazon.com/Anmbest-Converter-Adjustable-Regulator-Protection/dp/B07R832BRX/ref=asc_df_B07R832BRX/?tag=hyprod-20&linkCode=df0&hvadid=366402536789&hvpos=&hvnetw=g&hvrand=712971344780976433&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9013892&hvtargid=pla-786421359827&psc=1&tag=&ref=&adgrpid=75347436439&hvpone=&hvptwo=&hvadid=366402536789&hvpos=&hvnetw=g&hvrand=712971344780976433&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9013892&hvtargid=pla-786421359827
On 7/7/2023 4:42 PM, Paul Eckenroth wrote:
| Quote: | David You refer to gizmos made to take control of the charge rate such that it stays under the alternators design limits. Can you be more specific as to what these gizmos are. I have been looking for something like this to try and keep the stator in my Revmaster engine from burning up again. I believe that controlling the output is the key.
Thanks
Paul
On Sun, Jul 2, 2023 at 2:19 PM skywagon185guy <skywagon185(at)gmail.com (skywagon185(at)gmail.com)> wrote:
| Quote: | Battery....Lithium
Joe makes a very good point about the potential of Lithium base batteries to potentially cause charging problems.
The other side of this combo is that when a "normal" alternator is running at idle speeds the Lithium is able to handle receiving a very heavy current charge rate such that the alternator could easily overheat and burn some internal part due to lack of cooling for such a heavy current draw. There are gizmos made to take control of the charge rate such that it stays under the alternators design limits.
The marine and RV folks use these controllers to safeguard their expensive stuff.
David
On Sun, Jul 2, 2023 at 6:02 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Below is from https://earthxbatteries.com/faqs/
I just installed my EarthX battery in my aircraft and started the engine and my charging amps was really high, is this normal?
.
Yes, this is normal. A lithium battery can and will accept a much higher charging current than an equal size lead acid battery.
If your battery is not fully charged, your alternator can potentially output a current equal to
or slightly above the alternator’s rating for a few minutes to top the battery off.
. . .
You must use a lithium battery that is designed to handle the current from the alternator
or you can damage the battery, cause premature failure or possible even cell rupture.
--------
Joe Gores
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 Virus-free.www.avast.com[url=#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2] [/url]
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Charlie |
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skywagon185(at)gmail.com
Guest
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| Posted: Sat Jul 08, 2023 2:06 pm Post subject: Excessive Amperage |
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Paul,Check out the various YouTube videos that deal with RV travel with the solar market.
Many have converted to lithium batteries for their solar storage and great power capacity.
They have the same problem, namely stock alternators burning up trying to supply max amperage at idle speeds.
Resulting in too little air cooling.
Companies like Victron, Renegy, etc., etc., make "Charge controllers" to safeguard the alternators from overheating.
On Fri, Jul 7, 2023 at 2:49 PM Paul Eckenroth <N509RV(at)eckenroth.com (N509RV(at)eckenroth.com)> wrote:
| Quote: | DavidYou refer to gizmos made to take control of the charge rate such that it stays under the alternators design limits. Can you be more specific as to what these gizmos are. I have been looking for something like this to try and keep the stator in my Revmaster engine from burning up again. I believe that controlling the output is the key.
Thanks
Paul
On Sun, Jul 2, 2023 at 2:19 PM skywagon185guy <skywagon185(at)gmail.com (skywagon185(at)gmail.com)> wrote:
| Quote: | Battery....Lithium
Joe makes a very good point about the potential of Lithium base batteries to potentially cause charging problems.
The other side of this combo is that when a "normal" alternator is running at idle speeds the Lithium is able to handle receiving a very heavy current charge rate such that the alternator could easily overheat and burn some internal part due to lack of cooling for such a heavy current draw. There are gizmos made to take control of the charge rate such that it stays under the alternators design limits.
The marine and RV folks use these controllers to safeguard their expensive stuff.
David
On Sun, Jul 2, 2023 at 6:02 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Below is from https://earthxbatteries.com/faqs/
I just installed my EarthX battery in my aircraft and started the engine and my charging amps was really high, is this normal?
.
Yes, this is normal. A lithium battery can and will accept a much higher charging current than an equal size lead acid battery.
If your battery is not fully charged, your alternator can potentially output a current equal to
or slightly above the alternator’s rating for a few minutes to top the battery off.
. . .
You must use a lithium battery that is designed to handle the current from the alternator
or you can damage the battery, cause premature failure or possible even cell rupture.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=511019#511019
===========
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Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
="noreferrer" target="_blank">https://matronics.com/contribution
===========
|
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user9253
Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan
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| Posted: Sat Jul 08, 2023 2:07 pm Post subject: Re: Excessive Amperage |
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Attached is a picture of a circuit which will limit the battery charging current.
It might be desired to limit the charging current to a lithium battery that is
too small to accept the full alternator output. Or it might be desired to limit
the charging current to avoid overheating the alternator. Choose diodes that
will drop about a volt and that can carry the expected current. Since the
charging voltage is one volt less, the charging current will also be less.
The bypass switch can be closed to charge the battery at full Voltage.
An on-delay relay could be used instead of the switch to reduce pilot workload.
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Ceengland
Joined: 11 Oct 2020
Posts: 381
Location: MS
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| Posted: Sat Jul 15, 2023 11:14 am Post subject: Excessive Amperage |
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On Jul 8, 2023, at 6:44 PM, skywagon185guy <skywagon185(at)gmail.com (skywagon185(at)gmail.com)> wrote: | Quote: | Paul,Check out the various YouTube videos that deal with RV travel with the solar market.
Many have converted to lithium batteries for their solar storage and great power capacity.
They have the same problem, namely stock alternators burning up trying to supply max amperage at idle speeds.
Resulting in too little air cooling.
Companies like Victron, Renegy, etc., etc., make "Charge controllers" to safeguard the alternators from overheating.
On Fri, Jul 7, 2023 at 2:49 PM Paul Eckenroth <N509RV(at)eckenroth.com (N509RV(at)eckenroth.com)>
wrote:
| Quote: | DavidYou refer to gizmos made to take control of the charge rate such that it stays under the alternators design limits. Can you be more specific as to what these gizmos are. I have been looking for something like this to try and keep the stator in my Revmaster engine from burning up again. I believe that controlling the output is the key.
Thanks
Paul
On Sun, Jul 2, 2023 at 2:19 PM skywagon185guy <skywagon185(at)gmail.com (skywagon185(at)gmail.com)> wrote:
| Quote: | Battery....Lithium
Joe makes a very good point about the potential of Lithium base batteries to potentially cause charging problems.
The other side of this combo is that when a "normal" alternator is running at idle speeds the Lithium is able to handle receiving a very heavy current charge rate such that the alternator could easily overheat and burn some internal part due to lack of cooling for such a heavy current draw. There are gizmos made to take control of the charge rate such that it stays under the alternators design limits.
The marine and RV folks use these controllers to safeguard their expensive stuff.
David
On Sun, Jul 2, 2023 at 6:02 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Below is from https://earthxbatteries.com/faqs/
I just installed my EarthX battery in my aircraft and started the engine and my charging amps was really high, is this normal?
.
Yes, this is normal. A lithium battery can and will accept a much higher charging current than an equal size lead acid battery.
If your battery is not fully charged, your alternator can potentially output a current equal to
or slightly above the alternator’s rating for a few minutes to top the battery off.
. . .
You must use a lithium battery that is designed to handle the current from the alternator
or you can damage the battery, cause premature failure or possible even cell rupture.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=511019#511019
===========
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Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
="noreferrer" target="_blank">https://matronics.com/contribution
===========
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nuckolls.bob(at)aeroelect
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| Posted: Mon Jul 17, 2023 11:00 am Post subject: Excessive Amperage |
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Sorry for the long 'silence' . . . sorta overbooked with
pressing issues . . .
At 01:17 PM 7/2/2023, you wrote:
| Quote: | Battery....Lithium
Joe makes a very good point about the potential of Lithium base
batteries to potentially cause charging problems. |
Where is this premise documented? The lithium battery
market offers a constellation of products with and
without 'battery management systems'. I'm not aware
of any such product that does not claim plug-n-play
compatibility with most vehicular storage batteries.
Ever since generators were bolted to the earliest
vehicles, battery recharge currents after engine
cranking understandably 'spiked' for some duration
needed to replenish energy removed from the battery
since the engine ran last. This 'used' energy included
cranking, operating loads with the engine off and
self-discharge unique to the battery technology
and condition.
Battery technology has evolved from flooded,
lead acid, wood separator, rubber cased
devices to contemporary offerings with a
variety of chemistries and fabrication
techniques. Lithium and Lead-Acid are the
big kids on the block these days.
Over the years, power generation has evolved
from 3-brush generators with virtually no
current limiting up to contemporary 3-phase,
externally excited and some permanent magnet
alternators. Every successful example of an
engine driven power source has been tailored
to deliver a known amount of energy within
operating limits for temperature and rpm.
While generators have NO inherent current
limiting qualities, a skillfully designed
alternator is inherently limited by its
magnetics. This is why, unlike regulators
for generators, regulators for externally
excited alternators are not fitted with
alternator current sense and limit
features.
This tells us that the adequately cooled
wound field alternator is essentially
invincible when operated within well known
conditions.
The PM alternator is a little different
breed of critter. While they CAN be
designed and cooled to exploit the
magnetically defined, current limiting
qualities, they tend to be optimized for
size, weight and cost of the consumer
(garden tractors) and hobby aviation
(small engine) applications.
To my knowledge, B&C's latest PM
regulator product is the ONLY such
device fitted with alternator output
current sensing with the goal of
protecting an alternator with a
lower degree of robusness.
| Quote: | The other side of this combo is that when a "normal" alternator
is running at idle speeds the Lithium is able to handle receiving
a very heavy current charge rate such that the alternator could easily
overheat and burn some internal part due to lack of cooling for such
a heavy current draw. |
Let's unpack this assertion a bit: I'm aware
of no contemporary alternator installation
capable of rated or more-than-rated output
at idle speeds. Indeed, the legacy wound-
field alternators can be operated with belting
ratios that offer greater output than
a generator but this is only because they
easily tolerate the resulting high cruise rpm
. . . over 10,000 rpm is not uncommon on
a Lycoming installation. This would buzz-off
the brushes in a generator in an unacceptably
short period of time.
For PM alternators that drive at crank-shaft
speeds, one is saddled with very constraining
design trade-offs. Put enough turns of wire
on it to get nice taxi-rpm output and the
cruise voltage is going to be very difficult
to manage with the legacy, pass-thru, rectifier-
regulator designs.
| Quote: | There are gizmos made to take control of the charge rate such that it
stays under the alternators design limits. The marine and RV
folks use these controllers to safeguard their expensive stuff. |
How does any alternator become loaded 'beyond
design limits' . . . under what conditions?
How long would such conditions be expected to
last? Can you cite any examples of such
protective 'gizmos' and how they function
in the system?
I just captured the current version of this posting
on the EarthX website:
<b>[url=??]I just installed my EarthX battery in my aircraft and started the engine and my charging amps was really high, is this normal?[/url]
Yes, this is normal. A lithium battery can and will accept a much higher charging current than an equal size lead acid battery. If your battery is not fully charged, your alternator can potentially output a current equal to or slightly above the alternators rating for a few minutes to top the battery off. Your fuse, breaker, or current limiting device should be sized approximately 20% above the alternator rating. Example, if you have a 40 amp alternator, use a fuse, breaker, current limiter set to 48 amps (or 50amps).</b>
I'm mystified by the EarthX response to this question.
Yes, the internal impedance of a lithium cell is lower
than that of an SVLA cell of the same 'size'. But the
questioner's observations are not quantified. How big
is 'really high'? I presume that the observation
was made at idle rpm . . . and while it might understandably
be higher than previously observed recharge current
than a previous, perhaps worn-out SVLA . . . was
(1) the current 'alarming' with respect to alternator
ratings and (2) for how long did it persist?
For an institution presumably competent in the design,
manufacture and marketing of a plug-n-play battery,
their reply is painfully lacking in understanding of
battery/alternator dynamics. It's not physically
possible to load an alternator at idle. Further,
the advice on 'current limiting' by sizing the
b-lead protection is waaayyy out in left field!
To my way of thinking, this advice from EarthX
shoots their plug-n-play philosophy right
between the eyes!
There's more to offer on this thread but I
just received notice of a family crisis
250 miles from here. Need to saddle up
and boogy . . .
Bob . . .
////
(o o)
===========o00o=(_)=o00o=========
< Go ahead, make my day . . . >
< show me where I'm wrong. >
=================================
In the interest of creative evolution
of the-best-we-know-how-to-do based
on physics and good practice.
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nuckolls.bob(at)aeroelect
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| Posted: Wed Jul 26, 2023 10:27 am Post subject: Excessive Amperage |
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Sorry to bug out on you last week.
Had a death in the family that needed our
attention. Been 'off line' for a few days.
>Upon starting my IO360 (only 12 hrs on engine) I noticed the Low Voltage warning light did not go out (typically I get a flashing lite when battery relay is activated and light goes out when alternator >kicks in after engine start). I checked voltage and it was about 12.5v and the amperage was 37 amps. Increasing RPM from 1k RPM idle the "Low Voltage light went out at 1.5K but the amps went up to 40.
>Turning off switches/loads made no difference in amperage.
>Inactivating the alternator brought amps down to 0.
>I have a B&C 40 A alternator with the B&C OV controller.
I suggest that when questioning such behaviors
of a B&C product, the FIRST, BEST source of
technical assistance is with B&C. They are
most willing and able to work with you by
phone or email and will be best able to
ask the right questions to sort through
your concerns.
Questions they might ask at the outset:
What's the make/model of your battery?
Was the battery in a state of full charge
when you started the engine?
What was your observed alternator current
at engine idle?
How fast was the engine turning at the
highest observed readings?
Over what period of time were these
observations made?
What is a 'new' experience with
battery recharge currents and durations
with this configuration. I.e. were
pervious behaviors more benign?
Analysis:
The fact that you saw 12.5v system
voltage at low rpm and low voltage light
still on suggests the battery was seriously
discharged and chemically primed to accept
a high rate of recharge.
The fact that your alternator current 'topped
out' at 40 indicates that the alternator is
functioning as expected (they inherently
self limit their output current).
The fact that your low volts warning went
out at higher rpm reinforces the suggestion
that the battery was significantly low
in state of charge.
With information currently in hand, I
deduce no anomalies in your electrical
system's behavior.
==== <correction for last post> ======
| Quote: | It's NOT physically
possible to OVERLOAD an alternator at idle. |
=======================================
Further, a properly integrated alternator
should be bullet-proof with respect to
damaging overloads. So if there's anything
to be concerned about with respect to
battery recharge currents after engine
start, damage to an alternator is not
one of them.
>There are gizmos made to take control of the charge rate such that
>it stays under the alternators design limits.
>The marine and RV folks use these controllers to safeguard their expensive stuff.
>Check out the various YouTube videos that deal with RV travel with the solar market.
>Many have converted to lithium batteries for their solar storage and great power capacity.
>They have the same problem, namely stock alternators burning up trying to supply max amperage at idle speeds.
>Resulting in too little air cooling.
>Companies like Victron, Renegy, etc., etc., make "Charge controllers" to safeguard the alternators from overheating.
Solar charge controllers? I agree that Youtube
CAN be a valuable resource for tapping the experience
of others before launching off on your own
'adventure'. I used it heavily but find that
perhaps 1/4 of the information concerning
physics is factually correct.
In your particular case, I suggest YouTube will
be of no value since virtually ALL presentations
will focus on fixing a problem you don't have.
Virtually no one publishes videos on things that are
working okay.
I presume we're talking about a lithium battery.
There have been suggestions for limiting recharge
current with connection of two diodes back-to-back
in series with the battery.
This is NOT a current limiting technique. It
serves only to insert a VOLTAGE DROP in the
battery connection of approximately 0.8 volts.
One can achieve the same result by adjusting
the regulator set point down by the same
amount of voltage (see below). The notion that adding
diodes is an appropriate prophylactic against
alternator damage is in error.
Experience demonstrating reduction in
alternator failure by the addition of these
diodes HIGHLIGHTS a deficiency in alternator
design, fabrication or installation.
If the lithium battery featured in this
thread is promoted as a plug-n-play substitute
for an SLVA or even a flooded battery,
then under normal circumstances there are
no concerns for damaging an alternator.
We're not in possession of sufficient
information to completely resolve the ORIGINAL
query prompting this thread. At the same
time, there are individuals experiencing
alternator failures which in my opinion are
improperly diagnosed as to root cause. These
failures are popularly attributed to the
quality or style of battery installed.
Repeat: A judicious alternator design and
installation can't care less about the type
of battery installed. If changing a battery
increases likelihood of alternator failure,
it's NOT a fault of the battery. I.e.
the alternator is crippled.
Although a battery supplier's fondest wish
is to assume plug-n-play compatibility
of their lithium offering, I suggest
that competent literature suggests that
recharging stress can be lightened by simply
turning down the regulator set point. See
https://www.powerstream.com/lithium-phosphate-charge-voltage.htm
I have repeated and confirm assertions offered
in this article.
Note that LiFePO4 cells will achieve essentially
full charge at any voltage above 3.4 volts per
cell (or 13.6 volts bus). When your system is
fitted with a remote bus voltage sense feature
(like the B&C products), TARGETING an operating
setpoint of 13.8-14.0 volts is not a bad thing
to do.
Bob . . .
////
(o o)
===========o00o=(_)=o00o=========
< Go ahead, make my day . . . >
< show me where I'm wrong. >
=================================
In the interest of creative evolution
of the-best-we-know-how-to-do based
on physics and good practice.
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user9253
Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan
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| Posted: Wed Jul 26, 2023 6:00 pm Post subject: Diode Limits Charging Current |
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Bob, read this https://earthxbatteries.com/dual-bus-lithium-battery-design/
by EarthX. A diode does indeed limit lithium battery charge current. Quote from EarthX:
"When a diode is used to connect the main bus to the essential bus, a .5V drop
across the diode lowers the charge voltage, thus limiting the charge current."
.
I was just offering a way to lower the charging current to solve the OP's perceived problem.
Of course it seems that the consensus is that there is no problem.
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Joe Gores |
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Eric Page
Joined: 15 Feb 2017
Posts: 243
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| Posted: Fri Jul 28, 2023 12:07 pm Post subject: Re: Excessive Amperage |
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Is anyone else confused by Figures 2, 3 and 5 in the EarthX article that Joe linked above?
https://earthxbatteries.com/dual-bus-lithium-battery-design/
They appear to show a battery charge cycle, with voltage and current both rising over the four hour period of the graph. This makes no sense, as charge current should go down as state-of-charge increases, not up.
The only way those graphs make any sense to me is to ignore the Time axis across the bottom and read the graphs as a best-fit plot of instantaneous charge current at various applied voltages, with battery state-of-charge held constant at either 80% (Figure 2) or 20% (Figures 3 and 5).
Does the Time axis have some meaning that I'm missing?
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dj_theis
Joined: 28 Aug 2017
Posts: 56
Location: Minnesota
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| Posted: Sat Jul 29, 2023 5:46 am Post subject: Re: Excessive Amperage |
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…….Is anyone else confused by Figures 2, 3 and 5 in the EarthX article that Joe linked above?……..
Yes, at a minimum it’s unclear what they are trying to convey and certainly misleading.
I’m always suspicious when the axis labels are missing units (Time is in….”Time” units).
It looks like the marketing department took control of the web page from the engineering staff.
Dan
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Dan Theis
Scratch building Sonex #1362
Still working on the Revmaster Alternator improvement |
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Ceengland
Joined: 11 Oct 2020
Posts: 381
Location: MS
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| Posted: Sat Jul 29, 2023 9:56 am Post subject: Re: Excessive Amperage |
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Looks like nonsense to me, too. Of course, I've been less than impressed with EX since they 1st started hyping their stuff on the VAF forum; it was obvious that their spokesperson knew a whole lot less than they pretended.
1st question about the graphs in question: Why is the supply voltage changing, if we're talking about an aircraft (or car, or motorcycle, etc) charging system? If properly sized, the alternator output voltage isn't going to vary in normal operation.
Makes me wonder if they were really trying to show the relationship between charge voltage and charge current, which should have been plotted as x/y, without time on the graph at all.
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nuckolls.bob(at)aeroelect
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| Posted: Sun Jul 30, 2023 1:59 pm Post subject: Excessive Amperage |
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At 12:56 PM 7/29/2023, you wrote:
| Quote: | --> AeroElectric-List message posted by: "Ceengland" <ceengland7(at)gmail.com>
Looks like nonsense to me, too. Of course, I've been less than impressed with EX since they 1st started hyping their stuff on the VAF forum; it was obvious that their spokesperson knew a whole lot less than they pretended.
1st question about the graphs in question: Why is the supply voltage changing, if we're talking about an aircraft (or car, or motorcycle, etc) charging system? If properly sized, the alternator output voltage isn't going to vary in normal operation.
Makes me wonder if they were really trying to show the relationship between charge voltage and charge current, which should have been plotted as x/y, without time on the graph at all. |
We'll probably never know . . . and the document
raises more questions than answers.
I have no doubt about that itty-bitty battery's
ability to sink 30A . . . but that's a condition
that would probably occur only if the battery
were severely discharged and then hit with
an energetic alternator of some loosely defined
setpoint.
The article suggests that dropping the charge
potential to the standby battery by ~0.6V would
prevent this deleterious inrush. The lithium
battery's ability to draw such currents is
based in part on its internal resistance. Hmmmm . . .
if 0.6 volt reduction is a 'magic' endeavor
what would happen if we put some small resistance
in series with the battery . . . say something
on the order of 50 milliohms.
Okay, try to stuff 30A thru 50 milliohms would
get you a drop of 30 x 0.05 = 1.5 volts!
That suggests any potential for 30A inrush just
evaporated.
Now, after the battery approaches full charge and
recharge load drops to say less than 1A, then
the drop becomes 0.05 volts . . . okay, no big
deal. Even with our resistor in place, the battery
WILL become full charged.
What would one expect for a voltage drop
in an 'emergency' situation? 6AH battery . . .
endurance load of what? 4A? That would give
you approximately 90 minutes endurance when
the battery is new . . . 70 minutes at end of
life. Okay 4A draw through 0.05 ohms is 0.2
volts . . . again, no device wanting power
from that battery would care.
Where does one get a 0.05 ohm power resistor?
How about 5 feet of 20AWG wire at 0.010 Ohms per
foot? It's certainly 'beefy' enough to carry
expected normal loads with negligible effect
on system performance while ADDING series
resistance to the battery thus corralling it's
willing to self destruct when charged from a
'stiff' source.
But let's further examine a fundamental
premise of that article: TWO batteries?
If we've learned anything over the past
30 or so years here on the List is that
TWO engine driven power sources beat TWO
batteries by a light year or so.
A second, seldom-if-ever-used s/b battery has
the same preventative maintenance burden
as the main battery. You are sorta obligated
to do periodic cap checks to confirm ability
to meet design goals. Oh, yeah, that's not too
hard on a long cross country, you could provide
a means by which that battery and its precious
loads are cut loose . . . then see how long
it takes for the voltage to drop into the
'worrisome' range.
But that also means that you're going to
recharge the same TOTALLY dead device over the
remainder of your trip . . . then is when
that 50 milliohm resistor comes in real
handy.
Yeah, not every engine will support two
power sources. So fine, have an separate
ENDURANCE bus that can be drawn into service
should the ONLY alternator fail.
NOW . . . you've got a ROBUST s/b battery
probably 3 or 4 times bigger than any itty-bitty,
fussy-fragile lithium device and a much simpler
system more like that described here on
the List about 30 years ago with ancestors
to Z-11.
Short answer, the EarthX article cited is
short on physics and practical realities
of robust system design. I suggest it's
safe to ignore it.
Bob . . .
////
(o o)
===========o00o=(_)=o00o=========
< Go ahead, make my day . . . >
< show me where I'm wrong. >
=================================
In the interest of creative evolution
of the-best-we-know-how-to-do based
on physics and good practice.
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