Lipo vs lifepo4

[newhaul]

Originally Posted by Delfin

I DO NOT understand the 10amp charge current for an LiFePO4 battery. 100 amp, maybe.

that is just the charger that they provided to charge with .they spec to me a charge rate of .5
Or 50 amps
They are just not going to send a 50 amp charger with it from the factory

[newhaul]

Originally Posted by StuM

I doubt that it's LiFePO4

the specs are right and if it has the ah it should I may crack the case but more likely I will just use it and set my solar controller appropriately.
And order another one

[john61ct]

Originally Posted by newhaul

actually the minimum by specs is 9.8 when the bus system auto disconnects to protect the bank. And a max charging of 14.5.

Exactly.

Unlike lead batts, treating the vendor spec'd min & max voltages for lithium as if they were appropriate to actually get anywhere near in practice is silly.

Doing so regularly is a sure formula for only getting 10-20% of their potential lifespan.

But if the cost is chump change for you, definitely worth experimenting "for science".

Do you have any definitive documentation or statement from the seller or maker as to exactly what chemistry it is?

Once "fully charged" - however you want to define that - please let it rest isolated for 24 hours and post a precise voltage reading.

[john61ct]

Originally Posted by Delfin

I DO NOT understand the 10amp charge current for an LiFePO4 battery. 100 amp, maybe.

If it is a chemistry subject to a high risk of "thermal runaway" aka exploding in flames, then keeping charging C-rates low is one way to help reduce liability.

[StuM]

The DMD on the second photo was the clue.


Here's a guy who actually pulled his apart and provides quite a bit of info:
DeMuDa / DMD Chinese Lithium 12v 100aH Battery | FastMHz.com


Apparently it's Li(NiCoMn)O2 and the 10A is the output from the supplied mains charger.

[john61ct]

Yes, also found this listing on eBay, 200AH version supposedly.

https://m.ebay.com/itm/12V-Lithium-L...H/273392828418

NMC chemistry.

I believe nominal 3.6V per cell rather than LFP's 3.2

Makes things awkward to get to nominal 12V, LFP is fine as 4S (12.8 nominal 13.2 actual) but for NMC 4S is too high and 3S is too low.

Powerpak manufacturers will sometimes build DCDC conversion circuitry into the case to allow "drop-in" marketing claims, charge and discharge with standard 12V gear.

And that's where the silly-low current limitations often come from.

As long as you know what's going on with a given product and are happy keeping within its limits, no problem,

but what really gets me about the whole market segment is the lack of transparency when a more knowledgeable customer wants to get specific answers to detailed questions, it's like pulling teeth.

[newhaul]

Originally Posted by john61ct

Yes, also found this listing on eBay, 200AH version supposedly.

https://m.ebay.com/itm/12V-Lithium-L...H/273392828418

NMC chemistry.

I believe nominal 3.6V per cell rather than LFP's 3.2

Makes things awkward to get to nominal 12V, LFP is fine as 4S (12.8 nominal 13.2 actual) but for NMC 4S is too high and 3S is too low.

Powerpak manufacturers will sometimes build DCDC conversion circuitry into the case to allow "drop-in" marketing claims, charge and discharge with standard 12V gear.

And that's where the silly-low current limitations often come from.

As long as you know what's going on with a given product and are happy keeping within its limits, no problem,

but what really gets me about the whole market segment is the lack of transparency when a more knowledgeable customer wants to get specific answers to detailed questions, it's like pulling teeth.

john that unit is in fact Lipo not Lfp and I can get it direct for under 200 USD if I wanted that pos. The Lfp are a bit more just about 300 USD but the problem is you need to be specific when ordering as to specific chemistry. They both come in the same case. Notice in the eBay listing they don't show clear pictures of the labels that give battery parameters.

[john61ct]

Ryobi One+ platform "lithium" batteries apparently uses NMC, ​made up of 18650 sized cells, some call it nominal @3.7V

5S makes 18.5V, which translates to 4S = 14.8

I believe they charge at 21V, which would mean 4S would be looking for 16.8V internally.

Would be interesting to find out the measured output voltage of the charger included with the batt.

[john61ct]

Apparently just like the broad "lithium" umbrella,

LiPo is also a non-useful, too general label

Can include

Li-cobalt
NMC
Li-phosphate or
Li-manganese

Li-cobalt has traditionally been the most common in RC applications, energy-dense but very high risk of thermal runaway.

So I take it you believe what you bought is actually LFP ?

Could you please run through your evidence of that for us skeptics?

[john61ct]

Originally Posted by Maine Sail

Here's what one guy got when buying direct from China.... As far as I know he is still in dispute resolution but the company is still fighting it. Cells were not even the Ah capacity claimed.



https://youtu.be/SDJIMi_xkNk


"After two weeks of fighting, AliExpress buyer protection has been completely unhelpful."

I don't think there is any connection between this specific unit and what the OP purchased.

But if the point is simply "beware buying through Ali / AliExpress" then of course that's true and important.

[newhaul]

Originally Posted by john61ct

Apparently just like the broad "lithium" umbrella,

LiPo is also a non-useful, too general label

Can include

Li-cobalt
NMC
Li-phosphate or
Li-manganese

Li-cobalt has traditionally been the most common in RC applications, energy-dense but very high risk of thermal runaway.

So I take it you believe what you bought is actually LFP ?

Could you please run through your evidence of that for us skeptics?

numerous conversations with company as well as charge and discharge parameters .
( the math lines up )
I will do a complete test and analysis in the next few days , as of now I am on vacation for a few days.

[newhaul]

Originally Posted by john61ct

Apparently just like the broad "lithium" umbrella,

LiPo is also a non-useful, too general label

Can include

Li-cobalt
NMC
Li-phosphate or
Li-manganese

Li-cobalt has traditionally been the most common in RC applications, energy-dense but very high risk of thermal runaway.

So I take it you believe what you bought is actually LFP ?

Could you please run through your evidence of that for us skeptics?

here is a question how does anyone know what type of Lithium based chemistry is in their battery? Real world question.

[john61ct]

Buying units made by one of the half-dozen manufacturers in the world recommended by people you trust.

Buying them from a known trustworthy vendor.

Paying the going market rate, maybe 5-10% variation can be explained, but beyond that if it is too good to be true. . .

Especially since below container quantities (or at least less than a pallet), shipping costs are such a high proportion of the total.

I had a few dozen small CALBs (under 100AH) shipped 1/2 way across the US and best rate was $240.

So coming from Asia, the seller is subsidising your freight, has to come from somewhere.

[john61ct]

Also my question earlier.

Go to Full (not too full), then let them rest 24+ hours, measure voltage.

NMC will be much higher than LFP, each chemistry is likely different, but not sure since I'm only interested in LFP for House use in a mobile context.

[newhaul]

Originally Posted by john61ct

Also my question earlier.

Go to Full (not too full), then let them rest 24+ hours, measure voltage.

NMC will be much higher than LFP, each chemistry is likely different, but not sure since I'm only interested in LFP for House use in a mobile context.

actually draining it as we type through my counter just started a couple hours ago . Will let you know