200a Portable Lifepo + BMS + Balancing

[rgleason]

Portable Lifepo + BMS

ECPC-LBP-12V-100Ah
12V 100Ah Black Briefcase Style
LiFePO4 Lithium
EV-UPS-Bank Battery Pack
14.25 * 11.5 * 6.5 in. (362 * 292 * 165 mm)
33 Lbs. (14.9 KG)
$1,164

Features of your 12V 100Ah EV Li-NCM Lithium Battery Pack:

Waterproof plastic case with handle S-Type (D-Type wiring for DC charger input by one set and DC output by another set is available on request - Output is positive and negative poles and 3 meters in length-Longer or built in connector available on request)Black waterproof 50A connector pictured but can be changed as needed. Can be used in parallel configuration

Inside BMS supports up to 200A discharge and charge current

Optional LED capacity indicator to show battery SOC
======

Two of these (14.25 x 11.5 x 6.5) turned down with the 6.5" as vertical might fit under the cabin seat in one drawer area. Must lifepo be kept upright?

How about getting two set up to be paralleled and wired to accept a 200a alternator charge?

2 x $1,164= $2,328

Then I can take them home in the winter. Not bad.

What problems would I have?
Monitoring?
Protecting Alternator Diodes?

[john61ct]

Pouch cells, who knows? Unknown brand from a one-guy source. . .

Not even cheaper!

Just buy known good prismatics and adapt a Pelican style case, they come in hundreds of sizes.

[john61ct]

But if you do test them, please benchmark and report back, maybe they're great, we'll know for sure after a few dozen reports over say 7-10 years.

The sideways thing is an open question, at this point upright seems best.

[Singularity]

The portability is a great idea, particularly if you have a small lightweight charger/inverter (could use camping, etc).

I'd encourage considering DIY. A 3.2v 100ah Calb as of today are available in the US for $129 a piece.

https://www.electriccarpartscompany....fied-Batteries

Assuming a quality charger/inverter is present, at this point in history I wouldn't be too concerned about a BMS unless you top balance.

[CharlieJ]

Prismatics must be kept vertical and terminal side up. Don't ask :-(

[tanglewood]

Originally Posted by Singularity

Assuming a quality charger/inverter is present, at this point in history I wouldn't be too concerned about a BMS unless you top balance.

I think you need to consider the different rolls of a BMS. I agree that automatic balancing isn’t real important if you stay away from the ends of the SOC range. But I think there is still a lot of value in per cell voltage and temp monitoring, warning alarms, control signals to chargers, and last-ditch emergency disconnects.

[john61ct]

There is no "a BMS" that meets all needs, but looking at the desired functionalities is useful

Per-pack or bank level is more important, as is user adjustability of setpoints

Originally Posted by tanglewood

different roles of a BMS

> warning alarms, followed by last-ditch emergency disconnects

Yes based on voltage top and bottom

> temp monitoring
depends on the location, and usually on charging buss only

I don't consider
> control signals to chargers

to really be a BMS function necessarily, but user-level controls

At the very expensive high end e.g. Victron gear maybe the BM signalling all sources will come, one day

just opening a relay upstream, or shutting down a genset etc

works today with real-world existing sources

[tanglewood]

Originally Posted by john61ct

just opening a relay upstream, or shutting down a genset etc

works today with real-world existing sources

Is that not a "control signal"?

[tanglewood]

Originally Posted by john61ct

> temp monitoring
depends on the location, and usually on charging buss only

Wouldn't you want to measure the temp of the batteries, not the charging buss? I'm not sure why you want to measure the temp of the charging buss.

[Maine Sail]

They claim LiFePO4 and then state the cells are NMC (LiNiMnCo also called NCM). Which is it?

"Inside BMS supports up to 200A discharge and charge current"

What about that 10GA wiring at 200A....??

[rgleason]

The 3.2v 100ah Calb 5.6L * 2.6W * 8.6H in $129 may be a little high (physically).
Using two 100ah strings in parallel 2p4s (Correct order?) to get at least 200h, but would an appropriate BMS be

Orion Jr BMS EV
1-16 Cells-Batteries
0.5-5v LiFePO4, LiNCM, LiMn2O2, LiFeMnPO4, Li-Ion, LiPo, LiFeYPO4, LiCoO2, LiMn2O4
Has balancing and 3 temp sensors.



Top Balencing
https://www.electriccarpartscompany....Equalizers-12V

[newhaul]

Originally Posted by rgleason

The 3.2v 100ah Calb 5.6L * 2.6W * 8.6H in $129 may be a little high.
Using two 100ah strings in parallel 2p4s (Correct order?) to get at least 200h, but would an appropriate BMS be

clarification please what are you referring to with the a little high comment .
The price is actually well within expected per ah price of 5.16 per ah at 12v
Or the 8.5 inch height? To me both are well within desired specs.

And to clarify it would be 2s4p

[Maine Sail]

Originally Posted by newhaul

And to clarify it would be 2s4p

2S4P would give you a 6V bank... You need 4 series wired 3.2V cells for a 12V nominal bank.


Individual cells are normally paralleled first, to build cell capacity, then put in series to attain desired system voltage.



If you're using 100Ah cells and want a 12V nominal 200Ah bank it is 2P4S..

[newhaul]

Originally Posted by Maine Sail

2S4P would give you a 6V bank... You need 4 series wired 3.2V cells for a 12V nominal bank.


Individual cells are normally paralleled first, to build cell capacity, then put in series to attain desired system voltage.



If you're using 100Ah cells and want a 12V nominal 200Ah bank it is 2P4S..

your correct I mis typed for his the correct would be 4s2p correct?
(I thought you list series then parallel)


I am currently building a 4s4p 12v 100ah bank from 25ah cells

[tanglewood]

Originally Posted by newhaul

your correct I mis typed for his the correct would be 4s2p correct?
(I thought you list series then parallel)

You could, but it's different from 2P4S.


With 2P4S, you first wire pairs of batteries in parallel. Those become 2P building blocks. You then wire those 2P building blocks in series to get to 12V. That's the 4S part. Another way to say would be that it's 2 in parallel (2P), and four of those wired in series (4S)



With 4S2P, you create strings of 4 batteries wired in series. Those are 4S strings. Then you take two of them and wire them in parallel. That's the 2P part. And stated otherwise, it's 4 cells wired in series (4S) and then 2 of those wired in parallel (2P).


The advantage of 2P4S is that the 2P pairs are necessarily at the same voltage, so become a self-balancing pair. Then you only need to monitor the pairs for 4 monitoring points. With 4S2P, each cell has the opportunity to get out of balance with the others, so you need to monitor each for 8 monitoring points.