Today's Message Index:
----------------------
1. 05:32 AM - Re: Revmaster engine with EarthX battery (user9253)
2. 06:12 AM - Re: Re: Revmaster engine with EarthX battery (Robert L. Nuckolls, III)
3. 06:51 AM - Re: Smoker Problem (Christopher Cee Stone)
4. 06:54 AM - Re: Re: Revmaster engine with EarthX battery (Ernest Christley)
5. 10:34 AM - Re: Re: Revmaster engine with EarthX battery (Robert L. Nuckolls, III)
6. 02:00 PM - Re: Re: Revmaster engine with EarthX battery (Ernest Christley)
7. 02:24 PM - Re: Re: Revmaster engine with EarthX battery (Ken Ryan)
8. 05:54 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 |
Whether the victim is the battery or the generator, the object is to reduce the
current. A diode will do that. If a regular diode limits the current too much,
perhaps a Schottky will work. It will not hurt to experiment. Once the battery
has been
recharged to a certain level, a relay could be automatically energized to short
out the diode.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497618#497618
Message 2
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| Subject: | Re: Revmaster engine with EarthX battery |
At 07:31 AM 8/10/2020, you wrote:
>
>Whether the victim is the battery or the generator, the object is to
>reduce the
>current. A diode will do that. If a regular diode limits the
>current too much,
>perhaps a Schottky will work. It will not hurt to experiment. Once
>the battery has been
>recharged to a certain level, a relay could be automatically
>energized to short out the diode.
But we've established that the battery is
already in an energy-starved state for
charging posed by the LiFePO4 chemistry.
While 'reducing' the current may indeed
fix the burning alternator problem, it
will also reduce the already suppressed
energy content of the battery.
In all fairness, if design goals for this
installation are simply to get the engine
started . . . then perhaps an experiment
to add the suggested diode is worth
exploring. But if there are ANY goals for
battery only endurance, then adding the
diode will be counter-productive in an already
precariously compromised condition.
Discussions in other threads are suggesting mods
to the charging system to make it more robust.
Assuming time and costs are attractive,
improving robustness is never a bad thing.
Further, it may well go toward
RAISING the bus voltage to a more common
14.2 to 14.4 range thus greatly increasing
stored energy in the battery . . . a win-win,
no?
I've expanded the annotation on the charge volts
vs. energy stored plots I posted previously. These
further emphasize that when operated 'per
manufacturer's recommendations', the battery
will contain perhaps 25% of it's potential
storage for the LiFePO4 chemistry.
If anyone has information to the contrary, I'd
be pleased to know it! I'd really like to be
wrong about this . . .
Bob . . .
Message 3
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| Subject: | Re: Smoker Problem |
Root cause determination is satisfying no matter the route taken to get
there!
.chris
On Sun, Aug 9, 2020 at 12:39 PM Art Zemon <art@zemon.name> wrote:
> 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 4
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| Subject: | Re: Revmaster engine with EarthX battery |
I'm using a Scorpion LiFePO battery, and due to some carb tuning issues, h
ave had the chance to drain it a few times.=C2- It never seem to have a l
arge reserve capacity.=C2- The regulator for my 20A John Deere regulator
was set to 13.2V, so this makes sense.
I'm switching to Bill Clapps generator design, that uses a Harley-Davidson
32A generator, and the regulator is advertised at 14.7V.=C2- This email c
hain has me wondering if I should look for a regulator that goes to 16V, bu
t Scorpion advertises that the max should be 15.0V on their website.=C2-
Maybe Scorpion is just being overly conservative due to the LiFePO's sensit
ivity to overcharge?
SSTZ14S-FP Scorpion Stinger 12v 387 CCA LiFePo4 Extreme High Output Battery
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SSTZ14S-FP Scorpion Stinger 12v 387 CCA LiFePo4 Extreme High Output Battery
Lithium Batteries are discharged to 30% of capacity for shipping requiremen
ts. When you receive the battery it w...
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On Sunday, August 9, 2020, 11:44:03 PM EDT, Robert L. Nuckolls, III <nu
ckolls.bob@aeroelectric.com> wrote:
What about active current management? More complicated from a totalparts co
unt, but might be dirt simple to implement, for less than $20.Something lik
e:
current limited supply
=C2- Man, if you don't scan the offerings every
=C2- week in that venue, you'll miss some new
=C2- gizmo! Thanks for the heads-up.
=C2- Your find reminds me of a bench study I
=C2- did on similarly 'upgraded' rectifier/
=C2- regulator philosophy for pm alternators
=C2- a couple years ago. Didn't find any
=C2- really attractive options . . . then.
=C2- But the item you've cited suggests a
=C2- further look is called for. It's getting
=C2- late . . . I'll sleep on it and do some
=C2- 'asphalt engineering' on it tomorrow.
=C2- Need to drive into Wichita for remodeling
=C2- materials.
=C2- Re: my post of a few minutes ago.
=C2- I've got a stable of flashlights and tools
=C2- that use LiFePO4, 18650 cells. The chargers
=C2- for ALL of these cells tops off at 4.2 volts.
=C2- This doesn't seem to put the cell in any
=C2- manner of overcharge stress. The charging
=C2- currents fall to 1 milliamp or below at 4.2
=C2- volts.
=C2- I've got EarthX and AeroVoltz batteries on
=C2- the bench now that have been getting characterized.
=C2- Based on what's been gathered so far, both products
=C2- do indeed get your engine started . . . but when
=C2- charged at 14.2-14.4 volts, their discharge curves
=C2- look very similar to the plots I've been
=C2- getting on energy-starved, individual cells.
=C2- I'm thinking that BOTH products have untapped
=C2- chemical potential that is not available for
=C2- operating an airplane during alternator out
=C2- conditions. I think this shines a spot-light
=C2- on early lithium marketing claims for "lead
=C2- acid equivalency" and "engine startingbattery".
=C2- Both terms sort of hat-dance around the capacity
=C2- issues forsaken in a quest for the holy-grail
=C2- of lighter weights.
=C2- To acquire the SAME capacity as a PC680 by
=C2- replacing it with THREE or FOUR AeroVoltz
=C2- AVAI-270 or TWO EarthX ETX36D.
=C2- Not a problem if your design goals for alternator
=C2- out endurance are approaching zero.
=C2-
=C2- Bob . . .
Message 5
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| Subject: | Re: Revmaster engine with EarthX battery |
At 08:53 AM 8/10/2020, you wrote:
>I'm using a Scorpion LiFePO battery, and due to some carb tuning
>issues, have had the chance to drain it a few times. It never seem
>to have a large reserve capacity. The regulator for my 20A John
>Deere regulator was set to 13.2V, so this makes sense.
>
>I'm switching to Bill Clapps generator design, that uses a
>Harley-Davidson 32A generator, and the regulator is advertised at
>14.7V. This email chain has me wondering if I should look for a
>regulator that goes to 16V, but Scorpion advertises that the max
>should be 15.0V on their website.
Nope. Most suppliers cite the same number knowing
full well that contemporary systems would never
be purposefully adjusted so high. In fact, charging
plots I'm gathering suggest that charging voltages
at the upper end of recommended range DO NOT increase
stored energy.
Your legacy regulator adjusted 14.2 to 14.4 will
be just fine.
> Maybe Scorpion is just being overly conservative due to the
> LiFePO's sensitivity to overcharge?
>
><https://www.batterystuff.com/batteries/lithium-iron-batteries/sstz14s-fp.html>
>
>SSTZ14S-FP Scorpion Stinger 12v 387 CCA LiFePo4 Extreme High Output Battery
>
><https://www.batterystuff.com/batteries/lithium-iron-batteries/sstz14s-fp.html>
I presume that this battery is fitted with some form
of battery management system. Unfortunately, there is
no obvious consensus as to what constitutes the
optimum BMS nor are there published numbers as to
how they are set up.
In general, a BMS will manage one or more
of the following aspects of battery
operations:
Disconnect when overloaded
Disconnect when over charged (I guessing that
the 'unhook' happens at around 14 volts)
Disconnect when over dis-charged
Disconnect on over temperature
Cell balancing for recharge of a
deeply discharged battery -OR-
overcharge prevention for a
degraded cell.
Note that the BMS can only UNHOOK
a battery from the rest of the ship's
electrical system. It cannot boost
the effective charging potential for
enhancing energy stored.
So when the battery manufacturer speaks
to recommended bus voltage, the voltage
impressed on each layer of cells is
1/4th that value.
Going back to the plots I've gathered
in weeks past, the legacy bus voltages
for lead-acid based DC power systems
will be incapable of charging a LiFePO4
cell to its chemically limited energy
potential.
Unlike popular products in the OBAM aviation
market, lithium batteries for TC aircraft
are designed, tested, qualified and
maintained to exceedingly detailed
requirements. See:
https://tinyurl.com/y49tvwlz
Unlike our friends in the OBAM aviation
lithium market, the TC suppliers prominently
cite Ampere Hour ratings of their products.
This is because their target market is
FORM, FIT AND FUNCTION replacement for
legacy lead or nicad products. Therefore,
even tho they can start an engine with
a lighter/smaller battery, they are
required to keep stuffing cells into the
package until capacity requirements are met.
This makes for a SUPER cranking battery!
I'll have some more data plots to share
later today. I had to postpone my expedition
to Wichita.
Bob . . .
Message 6
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| Subject: | Re: Revmaster engine with EarthX battery |
OK.=C2- I'm missing something major here.=C2- Earlier you stated:
=C2- Take a peek at the capacity vs. charge voltage=C2-=C2- plots. A
3.6 volt charge (14.4v bus) would
=C2-=C2- charge an LiFePO4 to about 25% of its
=C2-=C2- potential chemical potential capacity.
The chart you shared showed it clearly.=C2- To get to the 100% capacity o
n the charging plots you shared, I'd need to run a bus voltage of 16.8V (4.
2V/cell).
Below, you're saying that 14.4V will be fine.=C2- I'm thinking, "How coul
d 25% of capacity be 'fine'?"=C2- I've obviously lost the plot somewhere
in here.
BTW, I killed one of these by putting it right above the exhaust with no pr
otection.=C2- Don't do that.=C2- It's expensive.=C2-
However, due to that slight misfortune, I am able to confirm that it is mad
e of 12 "bags", wired so that current flows through 4 groups, with each gro
up having three bags.=C2- The external connectors are attached directly t
o each end of the string, with what I'm eyeballing to be 10 or 12AWG wire.
=C2- The only electronics in the case is a small circuit board that allow
s for a rudimentary check of the batteries charge.
On Monday, August 10, 2020, 1:38:06 PM EDT, Robert L. Nuckolls, III <nu
ckolls.bob@aeroelectric.com> wrote:
At 08:53 AM 8/10/2020, you wrote:
I'm using a Scorpion LiFePObattery, and due to some carb tuning issues, hav
e had the chance to drainit a few times.=C2- It never seem to have a larg
e reservecapacity.=C2- The regulator for my 20A John Deere regulator was
set to13.2V, so this makes sense.
I'm switching to Bill Clapps generator design, that uses aHarley-Davidson 3
2A generator, and the regulator is advertised at14.7V.=C2- This email cha
in has me wondering if I should look for aregulator that goes to 16V, but S
corpion advertises that the max shouldbe 15.0V on their website.
=C2- Nope. Most suppliers cite the same number knowing
=C2- full well that contemporary systems would never
=C2- be purposefully adjusted so high. In fact, charging
=C2- plots I'm gathering suggest that charging voltages
=C2- at the upper end of recommended range DO NOT increase
=C2- stored energy.
=C2- Your legacy regulator adjusted 14.2 to 14.4 will
=C2- be just fine.
Message 7
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| Subject: | Re: Revmaster engine with EarthX battery |
Ditto what Ernest says. I too am lost. Seems like on the one hand 14.x
volts is just fine and on the other hand 14.x volts is terrible and will
never charge the battery. Clearly I am missing something important.
On Mon, Aug 10, 2020 at 1:07 PM Ernest Christley <echristley@att.net> wrote:
> OK. I'm missing something major here. Earlier you stated:
>
> 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.
>
>
> The chart you shared showed it clearly. To get to the 100% capacity on
> the charging plots you shared, I'd need to run a bus voltage of 16.8V
> (4.2V/cell).
>
> Below, you're saying that 14.4V will be fine. I'm thinking, "How could
> 25% of capacity be 'fine'?" I've obviously lost the plot somewhere in here.
>
> BTW, I killed one of these by putting it right above the exhaust with no
> protection. Don't do that. It's expensive.
> However, due to that slight misfortune, I am able to confirm that it is
> made of 12 "bags", wired so that current flows through 4 groups, with each
> group having three bags. The external connectors are attached directly to
> each end of the string, with what I'm eyeballing to be 10 or 12AWG wire.
> The only electronics in the case is a small circuit board that allows for a
> rudimentary check of the batteries charge.
>
>
> On Monday, August 10, 2020, 1:38:06 PM EDT, Robert L. Nuckolls, III <
> nuckolls.bob@aeroelectric.com> wrote:
>
>
> At 08:53 AM 8/10/2020, you wrote:
>
> I'm using a Scorpion LiFePO battery, and due to some carb tuning issues,
> have had the chance to drain it a few times. It never seem to have a large
> reserve capacity. The regulator for my 20A John Deere regulator was set to
> 13.2V, so this makes sense.
>
> I'm switching to Bill Clapps generator design, that uses a Harley-Davidson
> 32A generator, and the regulator is advertised at 14.7V. This email chain
> has me wondering if I should look for a regulator that goes to 16V, but
> Scorpion advertises that the max should be 15.0V on their website.
>
>
> Nope. Most suppliers cite the same number knowing
> full well that contemporary systems would never
> be purposefully adjusted so high. In fact, charging
> plots I'm gathering suggest that charging voltages
> at the upper end of recommended range DO NOT increase
> stored energy.
>
> Your legacy regulator adjusted 14.2 to 14.4 will
> be just fine.
>
>
Message 8
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| Subject: | Re: Revmaster engine with EarthX battery |
At 03:57 PM 8/10/2020, you wrote:
>OK. I'm missing something major here. Earlier you stated:
>
> 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.
>
>
>The chart you shared showed it clearly. To get to the 100% capacity
>on the charging plots you shared, I'd need to run a bus voltage of
>16.8V (4.2V/cell).
>
>Below, you're saying that 14.4V will be fine. I'm thinking, "How
>could 25% of capacity be 'fine'?" I've obviously lost the plot
>somewhere in here.
Yes, you missed the irony of my observations.
The plots I published so far show the voltage vs.
capacity characteristics of a single, 'barefoot'
cell. These are generally marketed as flashlight/
tool/electronics batteries. Almost without exception,
you cannot achieve the advertised capacity unless
the cell is charged to the maximum, 4.2 volts
rating . . . which translates to a bus equivalent
of 16.8 volts.
Now, vendors like AeroVoltz, EarthX, True Blue,
Shiorai, et. als. will take combinations of
individual cells and package them together
with a battery management system (BMS). The
BMS will implement certain protections as mentioned
in my previous post. One such protection is for
too high a charge voltage such that the device is
compatible with legacy vehicular DC power
systems. i.e. 14.2 volts or thereabouts.
The BMS is a significant piece of electronics.
1/4 to 1/3 the battery's internal volume can
be occupied by transistors and such.
Check out the attached plots on an EarthX
ETX36D battery I've had on hand for a few years.
There are three plots where the battery was charged
at 14.2, 14.4 and 15.0 volts. Note that unlike
the plots on individual cells, these all lay
practically right on top of each other . . . all
three show a battery capacity of 10.2 to 10.6 A.H.
This tells us that the BMS is in control of how
cells in this battery are charged INDEPENDENTLY
of the charging voltage. Stepping up your alternator
output voltage with some hope of exploiting latent
battery capacity would not be fruitful . . . and
possibly harmful to other electro-whizzies in the system.
The data I've gathered so far seems to say that
cells incorporated into batteries for lead-acid
replacement are DE-rated by design of the BMS.
This doesn't mean that the lithium batteries
offered do not deliver to their nameplate ratings . . .
it simply says these batteries contain chemical
capability that cannot be exploited in
a 14 VDC system.
Bob . . .
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