You have not given quite enough information about your system to fully
understand your issue.
However, to fully charge your 25 LFP cells to 100% SOC, your charger
should shut off at a voltage of a minimum of ~3.45 volts on all cells.
The full-charged pack voltage should be 87.5 volts, or a bit more.
3.6 to 3.8 volts on the highest cells is where your BMS should be set to
reduce the output of your charger. You should not be going over ~3.8
volts on any cell.
Your charger should be controlled by your BMS somehow, hopefully.
Like I said, we need a bit more information on your system to understand
exactly what your problem really is.
Bill D.
On 8/7/2017 12:53 AM, Matthew Quitter wrote:
Thanks guys... but if the charger is turning off at a fixed voltage how do I
get more power into the pack?
On 7 Aug 2017, at 05:02, Bill Dube via EV <[email protected]> wrote:
I agree. Voltage on LFP cells is useless for determining the SOC.
The voltage is very constant except at near 100% SOC and at 0% SOC.
You really need information about the middle, and voltage doesn't give any clue
about that.
You need to count the amp-hours, like with an E-meter or a Cycle-Analyst.
Bill D.
On 8/6/2017 7:00 PM, Willie via EV wrote:
On 08/06/2017 07:38 PM, Matthew Quitter via EV wrote:
Hi Guys,
My 1238-6501 Curtis controller gives very different SOC % for similar
voltages.
For example I've recorded a pack voltage of 82.2 and had the Curtis show
22%, 31%, 43%.
The pack is made up of 25 Thundersky 160Ah batteries.
With LFP cells, you can't accurately infer SOC from voltages in the middle of
the range. The voltage/SOC curve is too flat.
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