Today's Message Index:
----------------------
1. 05:32 AM - Re: Re: Revmaster engine with EarthX battery (Paul Eckenroth)
2. 06:21 AM - Re: Revmaster engine with EarthX battery (dj_theis)
3. 06:38 AM - Re: Re: Revmaster engine with EarthX battery (Paul Eckenroth)
4. 08:42 AM - Re: Revmaster engine with EarthX battery (dj_theis)
5. 08:49 AM - Re: Revmaster engine with EarthX battery (dj_theis)
6. 09:07 AM - Re: Revmaster engine with EarthX battery (dj_theis)
7. 10:22 AM - Re: RG400 with RG58 (Dan Fritz)
8. 11:17 AM - Re: Revmaster engine with EarthX battery (user9253)
9. 12:16 PM - Re: Rotax install (meat_ball)
10. 12:31 PM - Smoker Problem (Art Zemon)
11. 01:38 PM - Re: Re: Revmaster engine with EarthX battery (Robert L. Nuckolls, III)
12. 02:27 PM - Re: Re: Revmaster engine with EarthX battery (Charlie England)
13. 06:24 PM - Re: Re: Revmaster engine with EarthX battery (Robert L. Nuckolls, III)
14. 07:19 PM - Re: Re: Revmaster engine with EarthX battery (Ken Ryan)
15. 08:16 PM - Re: Re: Revmaster engine with EarthX battery (Robert L. Nuckolls, III)
16. 08:43 PM - Re: Re: Revmaster engine with EarthX battery (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Revmaster engine with EarthX battery |
Dan
your schematic as depicted is exactly how my Onex is wired. I would
caution you to use a lead acid battery if you can unless a good solution
materializes that will keep the generator from developing full throttle. I
think the B&C regulator is essential since it has adjustable voltage output.
Paul.
On Fri, Aug 7, 2020 at 7:05 PM dj_theis <djtheis58@gmail.com> wrote:
>
> >B&C has a new product that MIGHT be a
> >solution . . . albeit an unfortunate
> >'band aid' on the Revmaster's shortcomings.
>
> I own the Revmaster R2300 with the same alternator. (I've asked for
> advice from the forum on my project the past.) I also considered using the
> B&C regulator to provide an adjustable voltage regulator in a more robust
> package than what Revmaster provides. One thing that makes me pause is
> this thought process:
>
> 1) the original R/R is a half wave recitifer design.
> 2) The noted problem is an underdesigned PM alternator unable to reject
> heat produced with both sides running. So, what's recommended is to run
> only one side at a time.
>
> Isn't running one PM alternator with full wave rectification about the
> same current / heat level as two regulators, each with a half wave
> rectifier?
>
> Attached is my simpified sketch of the revmaster's PM alternators (for
> reference) with a design I cleaved from Bob's Z16 drawings, including
> overvoltage protection and switching (overvoltage not shown). I think my
> drawing is finding it's way around the "net," which is fine. I'm pretty
> sure it depicts the R2300 alternator accurately.
>
> BTW, I do like the current limiting idea, despite it's possible drawback
> with added complexity.
>
> Dan Theis
>
> --------
> Scratch building Sonex #1362
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=497570#497570
>
>
> Attachments:
>
> http://forums.matronics.com//files/revmaster_voltage_regulators_516.pdf
>
>
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| Subject: | Re: Revmaster engine with EarthX battery |
[quote]Dan
your schematic as depicted is exactly how my Onex is wired. I would cautionyou
to use a lead acid battery if you can unless a good solution materializes that
will keep the generator from developing full throttle. I think the B&C regulator
is essential since it has adjustable voltage output.
Paul.[/quote]
Thanks Paul,
I appreciate the advice and am doing exactly that (using the Oddesey PC680)
I like the idea of the variable regulator, as noted by you and Bob, offered by
B&C. It would take a little fanagling to wire two PMAs through a single regulator
but certainly possible (i.e., I'm suggesting using a single B&C RR wired
through relays so only one PMA is active at at time. All this to avoid the space,
weight and cost of two regulators).
I am planning (hoping) on adding temperature sensors to the stators on my engine,
before I modify the circuit with a different regulator. My thought is that
in many instances, (Glen Bradley's Thatcher, for example) the R2300 has ran for
many hours (again, 600 plus in Glen's case) without any issue. Again, in Bradley's
case, he had an event where (I think likely) the stars aligned and his
alternator went up in smoke. He had been running with both PMAs active up until
then and I suspect the charging system worked hard to re-charge the battery,
one too many times.
Whatever the source of trouble (low battery internal resistance, low battery charge
or simply poor heat rejection) the PMAs cannot be run together and possibly
cannot be run at their "natural" current limit without the risk of self destruction.
I'll eventually have data on the internal temperature characteristics of the alternator
and [b]DO[/b] plan on upgrading the RR if needed to address the problem.
As my previous note mentions, I have to ask if putting a full wave rectifier (the
B&C design) will effectively put the PMA into a similar overheating condition?
I look forward to hearing how your RR change works out.
Dan Theis
--------
Scratch building Sonex #1362
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497595#497595
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| Subject: | Re: Revmaster engine with EarthX battery |
Dan
According to Revmast, even the Odyssey may cause problems. They want you
to use the old lead anchor. lead acid. The difference in weight especially
considering lithium is dramatic.
Paul
On Sun, Aug 9, 2020 at 9:24 AM dj_theis <djtheis58@gmail.com> wrote:
>
> [quote]Dan
>
> your schematic as depicted is exactly how my Onex is wired. I would
> caution you to use a lead acid battery if you can unless a good solution
> materializes that will keep the generator from developing full throttle. I
> think the B&C regulator is essential since it has adjustable voltage output.
>
>
> Paul.[/quote]
>
>
> Thanks Paul,
> I appreciate the advice and am doing exactly that (using the Oddesey PC680)
>
> I like the idea of the variable regulator, as noted by you and Bob,
> offered by B&C. It would take a little fanagling to wire two PMAs through
> a single regulator but certainly possible (i.e., I'm suggesting using a
> single B&C RR wired through relays so only one PMA is active at at time.
> All this to avoid the space, weight and cost of two regulators).
>
> I am planning (hoping) on adding temperature sensors to the stators on my
> engine, before I modify the circuit with a different regulator. My thought
> is that in many instances, (Glen Bradley's Thatcher, for example) the R2300
> has ran for many hours (again, 600 plus in Glen's case) without any issue.
> Again, in Bradley's case, he had an event where (I think likely) the stars
> aligned and his alternator went up in smoke. He had been running with both
> PMAs active up until then and I suspect the charging system worked hard to
> re-charge the battery, one too many times.
>
> Whatever the source of trouble (low battery internal resistance, low
> battery charge or simply poor heat rejection) the PMAs cannot be run
> together and possibly cannot be run at their "natural" current limit
> without the risk of self destruction.
>
> I'll eventually have data on the internal temperature characteristics of
> the alternator and [b]DO[/b] plan on upgrading the RR if needed to address
> the problem.
>
> As my previous note mentions, I have to ask if putting a full wave
> rectifier (the B&C design) will effectively put the PMA into a similar
> overheating condition?
>
> I look forward to hearing how your RR change works out.
>
> Dan Theis
>
> --------
> Scratch building Sonex #1362
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=497595#497595
>
>
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| Subject: | Re: Revmaster engine with EarthX battery |
> According to Revmast, even the Odyssey may cause problems. They want you to
use the old lead anchor. lead acid. The difference in weight especially considering
lithium is dramatic.
Excellent point Paul, I had forgotten that but now recall that (anecdotal) warning
from Revmaster.
If the issue that Joe (Revmaster founder) is worried about is battery charge current
due to the low internal resistance, how about just adding an artificial
resistance to the charging circuit. From professor Nuckolls book, (chapter 2,
page 7). A comparison of the RG versus a wet lead acid battery internal resistance
is 11.5 vs 4 milliohms, respectively. Adding 6.5 milliohms (total of 11.5
milliohms) would bring the RG to a similar effective battery resistance and,
im assuming, similar charge current.
Coincidentally, two 100 milliohms shunt resistors rated at 20 amps continuously,
would add the 6.6 milliohms. Finally, a justification for adding shunt resistors!
You can monitor your charge current, not once but on redundant, in-line
circuits!!
https://shunts.com/collections/shunts/products/mka?variant=6973635067959
All kidding aside, what-ya think?
Dan Theis
--------
Scratch building Sonex #1362
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497598#497598
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| Subject: | Re: Revmaster engine with EarthX battery |
Oops,
> ...comparison of the RG versus a wet lead acid battery internal resistance is
11.5 vs 4 milliohms, respectively......
>
I reversed the comparison. The RG has (of course) the lower internal resistance
of 4 milliohms.
Dan Theis
--------
Scratch building Sonex #1362
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497599#497599
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| Subject: | Re: Revmaster engine with EarthX battery |
Double oops.
I meant to do my math correctly and hope Matt adds math-check to the spell-check
feature soon.
7.5 added to he RG battery's 4 milliohms would be 11.5.
Adding two 3.3 milliohm resistors would bring it to 10.6 milliohms.
Dan Theis
--------
Scratch building Sonex #1362
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497600#497600
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| Subject: | Re: RG400 with RG58 |
Thanks very much for the help. Looks like I have a way forward.
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497601#497601
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| Subject: | Re: Revmaster engine with EarthX battery |
Why not follow the battery manufacturer's recommendations?
https://earthxbatteries.com/dual-bus-lithium-battery-design
Based on extensive testing, the maximum charge rating will never be
exceeded using this simple and reliable diode isolation design.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497602#497602
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| Subject: | Re: Rotax install |
Hello everyone. Ive taken my first stab at the wiring diagram. I based this off
of a Rotax 914 because that drawing has the turbo charger electrics depicted.
The one thing it doesnt show is the electronic ignition wiring so I had to go
it alone on that part...hopefully Ive done it correctly.
After looking at the system a bit more in depth, I realized they were a few things
I left off the initial list of Consumers. The most significant thing I had
forgotten was the cabin heater. That will put me over the edge for electrical
usage as far as a single alternator goes. There is a 15 amp external alternator
which will sufficiently handle the extra loads so I plan on wiring that for
constant use along with the internal generator. I have the essential bus in
the top left corner of the drawing but am unsure how/where to connect it. Also,
I would like to add the crowbar unit but dont completely understand how that
would work in this setup. As I understand it, it measures bus voltage and removes
the alternator from the bus if that voltage is too high. The way I have it
wired, how would it know which is the offending alternator since theyre both
in an always-connected-to-the-bus-state? would I need one for each alternator?
Will some of you be so kind as to take a gander and offer your input?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497604#497604
Attachments:
http://forums.matronics.com//files/31a0fbad_a831_4f6a_81db_9858d7b83d6d_308.png
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Do you remember my electric smoker, the one that was tripping the GFCI? The
one that I said was pretty new so I was sure that there couldn't be a
problem inside the smoker. Well it quit working the other night. I think I
found the problem in the heating element connector.
[image: IMG_20200809_140723.jpg]
My wife always teases me (baselessly, I might add) that I have no clue
about time. Maybe I've had this smoker longer than I realized.
-- Art Z.
--
https://CheerfulCurmudgeon.com/
*If I am not for myself, who will be for me? If I am only for myself, what
am I? If not now, when?*
Message 11
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| Subject: | Re: Revmaster engine with EarthX battery |
>BTW, I do like the current limiting idea, despite it's possible
>drawback with added complexity.
I've been pondering the current limiter idea. It wouldn't
have to dissipate much energy. We're only talking about
a 1 to 2 volt drop at what . . . 18 amps?
A SIMPLE limiter requires a current-sense resistor
that will drop 0.6 volts in the limit-mode . . .
(0.033 ohms) not a big deal since we're wanting to toss off
a volt or so anyhow. But that same resistor is
in series with the alternator's output 100% of
the time . . . so it will drop as much as
0.033 x 17 = 0.56 volts in the non-limit
mode.
Just might be 'tolerable'.
I did a little sharp pencil work on a concept.
Cartoon attached. I'll see if I can refine
it to the prototype fabrication stage.
This is FAR preferred to down-adjusting the
alternator. I'm finding that 4-cell stacks
of LiFePO4 cells are just barely charged
when floated across our legacy 14.4v bus.
A maximally charged LiFePO4 needs a 4.2
volt supply. Stack four cells in series and
you now need a 16.8v bus!
Take a peek at the capacity vs. charge voltage
plots. A 3.6 volt charge (14.4v bus) would
charge an LiFePO4 to about 25% of its
potential chemical potential capacity.
Reducing the bus voltage to mitigate battery
charge limitations on the alternator only
exacerbates the problem. Tailoring the
alternator system to the battery makes
more sense.
Bob . . .
Message 12
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| Subject: | Re: Revmaster engine with EarthX battery |
On Sun, Aug 9, 2020 at 3:48 PM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> BTW, I do like the current limiting idea, despite it's possible drawback
> with added complexity.
>
>
> I've been pondering the current limiter idea. It wouldn't
> have to dissipate much energy. We're only talking about
> a 1 to 2 volt drop at what . . . 18 amps?
>
> A SIMPLE limiter requires a current-sense resistor
> that will drop 0.6 volts in the limit-mode . . .
> (0.033 ohms) not a big deal since we're wanting to toss off
> a volt or so anyhow. But that same resistor is
> in series with the alternator's output 100% of
> the time . . . so it will drop as much as
> 0.033 x 17 = 0.56 volts in the non-limit
> mode.
>
> snipped
>
> Reducing the bus voltage to mitigate battery
> charge limitations on the alternator only
> exacerbates the problem. Tailoring the
> alternator system to the battery makes
> more sense.
>
> Bob . . .
>
What about active current management? More complicated from a total parts
count, but might be dirt simple to implement, for less than $20. Something
like:
current limited supply
<https://www.ebay.com/itm/Constant-Voltage-Current-Synchronous-Rectificatio
n-Power-Supply-Module-300W-20A/174357694784?_trkparms=ispr%3D1&hash=ite
m2898874940:g:jxwAAOSwUgxfI1WV&enc=AQAFAAACgBaobrjLl8XobRIiIML1V4Imu%2Fn%
2BzU5L90Z278x5ickkSG%2BOFgrj2Yvbvmrj2TAdM76LofUMQeMK2Ee3X6QhJRX4Y3cccU0joQD
t13UZbKs8eAsqWmyrwYXRdVtSO0GjEsRYG%2BMZApAyQIat3Xhtd4XpT9qVw2yQcQ70wFeNDxdM
bSsZXcsNEVTrjRaJdbRkol9N747%2BQp443fPIaBUmH%2Fg%2FG1fsVGe4ZR%2BTt9pKR%2BlLi
mC%2B%2FqWzTFTq2Nu4Wi5Iq4EQkGhFQGug%2F90PAr7mblYzeP%2Bi9AYy%2BAavwb9fGdoNCT
qsmO4DWvgWDE6vN5pFU6iIAr1dC40MRrHW2lRJ0gCuKp8fUnA4sxJGfQMWLYpt0JBYoJEuzug9J
9%2BO0a2tqHlIsULwTSCBXabLsEtTUkTdiKAKbxudOhDc%2FFL8aW4LSPnTbT7b5gd3PnBzh4Di
S7pmx2zCMxBkY3kCycN9NES5KHEGxDBfjh8ucv6X%2FDP7n7WoT6ZvyGa5%2BJW0aVR%2BelXth
Fh4BhGpnxF12f9taD3zNmSkfR5we40%2FdHSPl3LfsVMhhhZXGr5d5LVbv%2BO%2BTRekUuyiZ5
S7p%2BwfmtO4FDH%2B95aRUCoq1U3OtcwQ4el%2FK3wWE2%2FSJ7z25Ty%2Fhvl0iCGORrZeXJy
tFitaM5RPrbcZuPTG2aIZ3Xyaf%2F3M4gxUHz%2FRCuF7dPunvp0M9qhEK%2BA2uneTIpLpAO%2
FM6zW2m95MauKikF%2F86zA5PB5XCoqvy0pMpJO%2BuDclszeCyuYq3CmaOdiNoPh7W0lbpDzA9
%2B%2BW87bmyTQ24ZTfnJNbt8rWXHqatajyAqA4wUO7poJA%2BLJ%2BgrCIG%2Bvo3oQMev3Hwy
I%3D&checksum=174357694784f3a36e753b0943a1aeba196045a20f64>
Charging lithium tech batteries is right there in their product
description. This was the 1st one I hit on when I searched, and it's
limited to 15A continuous (20A peak), but the alt in question isn't
surviving at higher currents, anyway. Set its current limit for whatever
current the alternator can survive at, and the system can't draw more than
that from the alternator/regulator pair.
The questionable thing about some of these 'switchers' is that some have
functional limitations if input & output grounds are common in the
circuit, and those limitations are sometimes lost 'in translation' in the
sales documents. That issue would need to be explored, of course.
Incorporating something similar to this into the BMS is something that
companies like the big EX *should* have done from the outset. Boost between
alt and battery, to allow full charge of the lithium tech, and buck on the
output, to return battery voltage to a safe level. Then
their somewhat buried alternator size limit could go away, since the BMS
would *truly* manage the battery, instead of just pretending. Would require
a 3 terminal battery, of course.
Charlie
Message 13
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| Subject: | Re: Revmaster engine with EarthX battery |
At 01:14 PM 8/9/2020, you wrote:
>
>Why not follow the battery manufacturer's recommendations?
>https://earthxbatteries.com/dual-bus-lithium-battery-design
>Based on extensive testing, the maximum charge rating will never be
>exceeded using this simple and reliable diode isolation design.
Are we talking about the same 'victim'? The
limiting hardware are the stator windings
in the PM alternator. The typical rectifier/regulator
for these systems has no electronic current
limiting . . . and unlike the inherent
limits set by the physics of a wound-field
alternator, the PM alternator CAN be
over-loaded.
In this case, the antagonist 'load' is not
made up of electro-whizzies but the battery
itself. In a low state of charge, battery
recharge loads combined with ship's loads
are too much for the alternator's stator
windings.
Reducing available charge voltage to the
battery will most certainly reduce its
demands during recharge but at a cost
of giving up capacity.
It seems a more reasoned approach to fix
the charging system as opposed to starving
the battery.
Bob . . .
Message 14
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| Subject: | Re: Revmaster engine with EarthX battery |
But lithium batteries prefer to be stored at less than a full charge, so in
that regard not filling them up is a plus. Why not use the diode and use
whatever size battery provides required capacity? Battery will be happy,
generator will be happy, and weight will be controlled.
On Sun, Aug 9, 2020 at 5:30 PM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 01:14 PM 8/9/2020, you wrote:
>
>
> Why not follow the battery manufacturer's recommendations?
> https://earthxbatteries.com/dual-bus-lithium-battery-design
> Based on extensive testing, the maximum charge rating will never be
> exceeded using this simple and reliable diode isolation design.
>
>
> Are we talking about the same 'victim'? The
> limiting hardware are the stator windings
> in the PM alternator. The typical rectifier/regulator
> for these systems has no electronic current
> limiting . . . and unlike the inherent
> limits set by the physics of a wound-field
> alternator, the PM alternator CAN be
> over-loaded.
>
> In this case, the antagonist 'load' is not
> made up of electro-whizzies but the battery
> itself. In a low state of charge, battery
> recharge loads combined with ship's loads
> are too much for the alternator's stator
> windings.
>
> Reducing available charge voltage to the
> battery will most certainly reduce its
> demands during recharge but at a cost
> of giving up capacity.
>
> It seems a more reasoned approach to fix
> the charging system as opposed to starving
> the battery.
>
>
> Bob . . .
>
Message 15
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| Subject: | Re: Revmaster engine with EarthX battery |
At 09:15 PM 8/9/2020, you wrote:
>But lithium batteries prefer to be stored at
>less than a full charge,=C2 so in that regard not
>filling them up is a plus. Why not use the diode
>and use whatever size battery provides required
>capacity? Battery will be happy, generator will
>be happy, and weight will be controlled.
Apples and grapefruit . . .
Airplanes are not battery storage facilities . . .
Legacy design rules call for:
(1) battery to start engines and
(2) operate most useful electro-whizzies after
alternator failure in accordance with design
rules for endurance.
Look at the charge volts vs. capacity curves
again . . . dropping the bus to 13.4 (3.35 volts
per cell) or even 13.0 (3.25 volts per cell)
leaves you with a battery that is essentially
useless for (2) above.
The endurance bus grew out of a concern for
PLANNING and MAINTAINING alternator-out
performance. I've had readers craft airplanes
that capable of running out a full
tank of fuel during battery-only ops.
For years the FAA had a number pulled
from some dark place calling for 30 minutes
minimum endurance in battery-only ops . . .
Every try to get down from 41,000 feet
in a Beechjet in less than 30 minutes?
I can personally attest to the agonies
of meeting even the 30 minute rule without
adding 25 more pounds of lead to the airplane.
The point is that we need to keep a grip
on the fundamentals of our craft. All
engineering stands on the three-legged
stool of properties of materials, management
of energy, refinement of processes.
The folks at Revmaster are having problems
with their obviously tippy engineering stool.
Elegant system integration is refinement
of process to meet (1) and (2) above.
Bob . . .
Message 16
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| Subject: | Re: Revmaster engine with EarthX battery |
>
>What about active current management? More complicated from a total
>parts count, but might be dirt simple to implement, for less than
>$20. Something like:
><https://www.ebay.com/itm/Constant-Voltage-Current-Synchronous-Rectification-Power-Supply-Module-300W-20A/174357694784?_trkparms=ispr%3D1&hash=item2898874940:g:jxwAAOSwUgxfI1WV&enc=AQAFAAACgBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkSG%2BOFgrj2Yvbvmrj2TAdM76LofUMQeMK2Ee3X6QhJRX4Y3cccU0joQDt13UZbKs8eAsqWmyrwYXRdVtSO0GjEsRYG%2BMZApAyQIat3Xhtd4XpT9qVw2yQcQ70wFeNDxdMbSsZXcsNEVTrjRaJdbRkol9N747%2BQp443fPIaBUmH%2Fg%2FG1fsVGe4ZR%2BTt9pKR%2BlLimC%2B%2FqWzTFTq2Nu4Wi5Iq4EQkGhFQGug%2F90PAr7mblYzeP%2Bi9AYy%2BAavwb9fGdoNCTqsmO4DWvgWDE6vN5pFU6iIAr1dC40MRrHW2lRJ0gCuKp8fUnA4sxJGfQMWLYpt0JBYoJEuzug9J9%2BO0a2tqHlIsULwTSCBXabLsEtTUkTdiKAKbxudOhDc%2FFL8aW4LSPnTbT7b5gd3PnBzh4DiS7pmx2zCMxBkY3kCycN9NES5KHEGxDBfjh8ucv6X%2FDP7n7WoT6ZvyGa5%2BJW0aVR%2BelXthFh4BhGpnxF12f9taD3zNmSkfR5we40%2FdHSPl3LfsVMhhhZXGr5d5LVbv%2BO%2BTRekUuyiZ5S7p%2BwfmtO4FDH%2B95aRUCoq1U3OtcwQ4el%2FK3wWE2%2FSJ7z25Ty%2Fhvl0iCGORrZeXJytFitaM5RPrbcZuPTG2aIZ3Xyaf%2F3M4gxUHz%2FRCuF7dPunvp0M9qhEK%2BA2uneTIpLpAO%2FM6zW2m95MauKikF%2F86zA5P
B
>5XCoqvy0pMpJO%2BuDcls>current limited supply
Man, if you don't scan the offerings every
week in that venue, you'll miss some new
gizmo! Thanks for the heads-up.
Your find reminds me of a bench study I
did on similarly 'upgraded' rectifier/
regulator philosophy for pm alternators
a couple years ago. Didn't find any
really attractive options . . . then.
But the item you've cited suggests a
further look is called for. It's getting
late . . . I'll sleep on it and do some
'asphalt engineering' on it tomorrow.
Need to drive into Wichita for remodeling
materials.
Re: my post of a few minutes ago.
I've got a stable of flashlights and tools
that use LiFePO4, 18650 cells. The chargers
for ALL of these cells tops off at 4.2 volts.
This doesn't seem to put the cell in any
manner of overcharge stress. The charging
currents fall to 1 milliamp or below at 4.2
volts.
I've got EarthX and AeroVoltz batteries on
the bench now that have been getting characterized.
Based on what's been gathered so far, both products
do indeed get your engine started . . . but when
charged at 14.2-14.4 volts, their discharge curves
look very similar to the plots I've been
getting on energy-starved, individual cells.
I'm thinking that BOTH products have untapped
chemical potential that is not available for
operating an airplane during alternator out
conditions. I think this shines a spot-light
on early lithium marketing claims for "lead
acid equivalency" and "engine starting battery".
Both terms sort of hat-dance around the capacity
issues forsaken in a quest for the holy-grail
of lighter weights.
To acquire the SAME capacity as a PC680 by
replacing it with THREE or FOUR AeroVoltz
AVAI-270 or TWO EarthX ETX36D.
Not a problem if your design goals for alternator
out endurance are approaching zero.
Bob . . .
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