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Discussion Starter · #1 ·
What is the maximum safe charge rate for LG chem modules?

Question 2:
I have 12 of these modules.

Long story short, I have two choices for installation:
4S3P 240V (uses all modules, acceptable voltage)
5S2P 300V (higher voltage, lower amperage, smaller wiring)

6S is not an option, voltage is too high for my controller.

I can only run my Warp 9 at 170V anyway.

What would you do?

Also, what size wiring should I use in each series?
Those m6 terminals seem awfully small to me.
 

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240V, more efficient closer to controller target, longer range.

Can't find the documentation for C-rates?

How about for the cells themselves?

High voltages like that, lower gauge wiring is OK, but going fatter never hurts.

It's the connections that get you, use a temp sensor testing at high amps once you think you're done.
 

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What is the maximum safe charge rate for LG chem modules?
It can be a little annoying when people say "LG chem modules" as if there is only one type of LG chem module. In fact there are multiple modules built by LG Chem, with different cell sizes, different cooling systems, and different wiring configurations... so of course they will have different limitations. For instance, the Chevrolet Volt has LG Chem modules, of two different cell sizes and configurations depending on vehicle generation; the Chevrolet Bolt uses LG Chem modules, with every detail (cell dimensions, cell capacity, cooling system, parallel/series configuration) different from either style of the Volt modules.

My guess is that you are referring to the modules intended for the Chrysler Pacifica Hybrid and sold (salvage? new from LG? fell of the back of a truck?) by various EV conversion suppliers. These are 16S1P modules designed to be mounted on a chill plate.

In the Chrysler Pacifica Hybrid, the onboard charger is only rated at 6.6 kW, which corresponds to 18 amps at battery voltage. Presumably they can handle a lot more than that, particularly with active cooling.

What are you using as a source for specifications of these modules?
 

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Once the modules are "freed" from the vehicles' TMS there is no more cooling

so probably best to tap into the existing temp sensors, or install your own

and limit if not dynamically regulate your c-rate based on any detected rise in cell temp.
 

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Discussion Starter · #5 ·
My guess is that you are referring to the modules intended for the Chrysler Pacifica Hybrid...
What are you using as a source for specifications of these modules?
Yes, that’s correct. The Pacifica modules.

I am using the charge/discharge specs on EV West’s website: 3.3/4.2 V per cell. Part of their description includes: “ A preferred configuration for a typical Model S drive unit is 2p6s for a total of 32kWh, However you can add modules in a 1p6s configuration for an additional 16kW per group.”

I have had some trusted people tell me outright: “The fewer P’s the better.” That’s why I question the 4S3P configuration, vs the 5S2P.

Also, I found a page that I think applies to this battery chemistry... Pages 5 & 6 of this webpage:
https://res.mdpi.com/d_attachment/batteries/batteries-04-00011/article_deploy/batteries-04-00011.pdf

I’ve been poking around the web and looking for information on these modules… There doesn’t seem to be much out there. I can’t find much “real life” info at all, from people who have actually installed them and run them...wire sizes and pack configurations and such.

On LG Chem’s own website, I saw information suggesting that this chemistry could be charged at 2 or 3C. But I don’t trust it… That sounds too high to me. Last Tuesday I charged one module at 30 A, and it barely heated up... just a little bit. I cut it down to 10 A for the last 5Ah or so.

Where might I find better specs and info?
 

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Once the modules are "freed" from the vehicles' TMS there is no more cooling

so probably best to tap into the existing temp sensors, or install your own

and limit if not dynamically regulate your c-rate based on any detected rise in cell temp.
Or build a cooling system... and still control charging based on temperature.
 

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Yes, that’s correct. The Pacifica modules.

I am using the charge/discharge specs on EV West’s website...
For reference: LG CHEM Lithium Ion Battery - 60.8V, 2.6kWh

Part of their description includes: “ A preferred configuration for a typical Model S drive unit is 2p6s for a total of 32kWh, However you can add modules in a 1p6s configuration for an additional 16kW per group.”

I have had some trusted people tell me outright: “The fewer P’s the better.” That’s why I question the 4S3P configuration, vs the 5S2P.
Tesla uses dozens of tiny cells in parallel, but they put a fuse on each one to minimize the destruction when one fails. Normal EV manufacturers routinely use up to 3 cells in parallel with no per-cell protection devices; this includes LG Chem modules in - for instance - the first-generation Volt and the Bolt.

The issue in paralleling with these modules is that unless you break welded tab connections within the module, you are connecting in parallel only at the module level or higher, not at every individual cell. Connecting in parallel at the module level is not good - for reasons that have been endlessly debated in other threads - so EV West is suggesting building complete strings to the desired voltage, and connecting only complete strings in parallel. Since every string requires its own BMS and disconnects to be managed properly, fewer is better... but any number can work.

My thinking is to connect in series to the highest voltage that the controller can safely handle, but that's just an opinion with no practical experience.

Where might I find better specs and info?
I don't know, but keep in mind whatever specs you're using that appropriate charge rates will depend on thermal management. In the OEM application, these modules are clamped to plates with fluid circulating in them, to cool or heat as appropriate, and to even out temperatures between cells.
 

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The Gen 1 Chevy Volt pack can in OEM configuration take a peak of 30kw dc charging When using the Spark EV DC electronics which is around 2C
It does have active liquid cooling
 
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