6 v GC batteries versus 12 v lithium deep cycle batteries

[str8shooter_mn]

Disregarding price, is there a distinct advantage having 12 volt deep cycle batteries over the standard 6 volt golf cart batteries. These are for house batteries, have four, wired to provide 12 volts. On a Thor Tuscany pusher.

[time2roll]

The internal BMS should be cutting off the discharge at low voltage before damage is done. Same as the top end. If you are consistently going into the lowest 20% I will recommend more battery or at least charge closer to the top. Then you end up top balancing. It all works out fine without worry.

Yes bottom balancing has been replaced with top balancing. Bottom balance was from the days before BMSs were put on the battery. Top balance is a more practical method as it happens when power is available vs near shut down.

[BFL13]

The Trojan guide mentioned that not balancing could lead to a "low" cell going "too low" when you got to a low SOC (as measured by the average voltage?) where the batt is "top balanced" as a reason to balance.

ISTR ( needs to be confirmed) "too low" for a cell ruins it for good.

AFAIK these RV type LFPs are not "bottom balanced".

[time2roll]

BFL13 wrote:
Why is it being "obsessed" when you try to follow the (eg) Trojan users' guide?

On a more "casual" approach, how do you know how much you can get away with when not doing what they say? You will only know that by not doing what they say, and seeing how long you got away with it.

Many of us learned battery care from our first ("learner set") set of RV batteries. If you have the money, then you could just count your first set of LFPs as your "learner set" I suppose. 🙂

Unlike lead-acid you do not lose capacity for not doing the full charge and balance. LFP actually extends the life by doing partial charges. So the longer you get away with it the more you get away with.

[MEXICOWANDERER]

I think outside influences have grated on people's nerves. Families jammed indoors has got to rub things tender. It's easier down here where things are a different reality.

[BFL13]

time2roll wrote:
There is no particular reason to be obsessed with balancing or fully charging the LFP.
This drive for some perfect charge and balance is a hangover from the days of servicing lead-acid.

Why is it being "obsessed" when you try to follow the (eg) Trojan users' guide?

On a more "casual" approach, how do you know how much you can get away with when not doing what they say? You will only know that by not doing what they say, and seeing how long you got away with it.

Many of us learned battery care from our first ("learner set") set of RV batteries. If you have the money, then you could just count your first set of LFPs as your "learner set" I suppose. 🙂

[3_tons]

Well, I kinda doubt that any Mod would favor the presence of an unchecked disinformation campaign...JMHO

I would suspect that most who visit here (the “Snooty”??) are seeking ‘solid information’, so grow tired of this undermining disinformation crusade - and, I would only ask that when reproducing a previous comment I’ve made, rather than ‘cherry-picking’ a select few words to make a point (valid context matters, why then omit??), in all sincerity, words should be considered within their proper context (to be fair, context matters, so as I have done, provide the link!!).

3 tons

[time2roll]

There is no particular reason to be obsessed with balancing or fully charging the LFP.
This drive for some perfect charge and balance is a hangover from the days of servicing lead-acid.

[BFL13]

I agree. I saw where he went after another guy (Freep was it?) drove him crazy. Poor old Freep never found the block button I guess.

Freep

Wisconsin

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Posted: 04/19/21 01:40pm Link | Quote | Print | Notify Moderator
3 tons wrote:

“ The snark and derision is unnecessary.”??...Snark, How so ?? (apparently only when I use your same words??)..I really don’t get it - I guess I forgot to check the box for a ‘sensitivities waiver’..

3 tons, in the High NV Desert, where sensitivities are not a currency


Please stop.

[Boon_Docker]

Surprising why a Mod has not shut down this playground squabble yet. Most of the time it does not go on for this long. :B

[3_tons]

BFL13 wrote:
I do not belong to the snooty LFP community, and don't even have the T-shirt, but I can read.

BB says to wait 20 minutes per battery to be sure the battery is balanced, and Trojan says 10 minutes (for one battery?), but whatever---it takes time to get that done, so how can it be a good idea to stop the charge as soon as you get to Vabs (which needs to be over 14v--ISTR BB saying it needs to be 14.2v but they also say over 14, so whatever)

2.For your Bulk/Absorption stage, the ideal voltage is between 14.2v-14.6v. For full charge and BALANCE, the absorption mode should be set to last for at least 20 minutes per battery (for multiple batteries in parallel).

I don't think a "good old boy" approach (if all else fails, read the instructions) to LFP charging is appropriate considering what LFPs cost, but YMMV.

Though I found this of no relevance, maybe you can find the answer to your question in what you’ve previously offered :


https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30210186/srt/pa/pging/1/page/6.cfm

3 tons

[BFL13]

I do not belong to the snooty LFP community, and don't even have the T-shirt, but I can read.

BB says to wait 20 minutes per battery to be sure the battery is balanced, and Trojan says 10 minutes (for one battery?), but whatever---it takes time to get that done, so how can it be a good idea to stop the charge as soon as you get to Vabs (which needs to be over 14v--ISTR BB saying it needs to be 14.2v but they also say over 14, so whatever)

2.For your Bulk/Absorption stage, the ideal voltage is between 14.2v-14.6v. For full charge and BALANCE, the absorption mode should be set to last for at least 20 minutes per battery (for multiple batteries in parallel).

I don't think a "good old boy" approach (if all else fails, read the instructions) to LFP charging is appropriate considering what LFPs cost, but YMMV.

[Almot]

3 tons wrote:

Once the LFP is charged (to whatever desired user acceptable level - a LFP thingy...) with an existing multi-stage converter-charger, all you need to do is shut off the converter-charger at the breaker panel (or solar charge controller)...Another option (if so inclined...) would be to install a disconnect switch at the battery terminal, and keep the onboard converter-charger active, Presto, problems solved...

3 tons

I was only making a point that most converters (or all of them?) don't automatically do what is the best for LFP. And neither do many solar controllers - though in a decent controller you are normally able to set a custom profile for LFP.

Yes, you could shut off the charger when voltage hits 14.x. By the same token I could eliminate solar controller altogether and charge the battery directly from solar panel, keeping an eye on it and disconnecting when it hits Absorb. (In fact, did this for a month when my controller died - even though it was 24V panel with 12V battery). You just have to watch it. Having an equipment doing watching and disconnecting would've been much better 🙂

[Itinerant1]

BFL13 wrote:
Itinerant1, in your opinion, is jaycocreek seeing balancing on his smart shunt from what he describes or not?

Is that the same as what 3 tons sees? (I can't see his posts) If so, why wouldn't that show on any monitor such as the Trimetric?

It was probably balancing during the 14.4/ 13.6 cycles but it would of happened at the higher voltage period but that is not the bms balancing, that's the charger doing what it was programmed to do?

"If" the bms was causing the shutdown and restarting I would guess the cells certainly have runners that the passive balancing can't keep up with. Without the ability to see individual cell voltages it's just my guess what someone else's batteries are doing.

You do understand what passive balancing or active balancing is or does, most dropins will use passive just because it's cheaper. My cells use passive with the sense boards (bms component) that start balancing when a cell reaches 3.55v, the sense boards will draw 0.5A until the voltage has dropped below 3.55V. During this process it's normal for some cells to balance more than others and some cells to rarely balance.

[3_tons]

For ‘the yet to be initiated’, here is ‘just one’ in a continuing stream of BFL’s faked data based constructs -

https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30210186/srt/pa/pging/1/page/6.cfm

3 tons

[BFL13]

Itinerant1, in your opinion, is jaycocreek seeing balancing on his smart shunt from what he describes or not?

Is that the same as what 3 tons sees? (I can't see his posts) If so, why wouldn't that show on any monitor such as the Trimetric?