Teardown & Rebuild of a MuscleGrid LiFePO4 Server Rack Battery

So 48v 160ah lifepo4 will have 15 cells right and we can re-arrange it to 24v and higher AH, will that give longer run time if running 1kw plus load.
 
rsaeon said:
  1. SoH, state of health, does this mean how much of the original capacity is left? Like, are my calculations correct? If a 105Ah cell tested at 104.689Ah, then is it correct to say it is at (104.689/105) x 100 = 99.7% State of Health?
  2. SoC, state of charge, would this be calculated at rated capacity of 105Ah or tested capacity of 104.689Ah?
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1. Yes, SoH is the measure of the capacity left in the battery.
2. SoC will be calculated for the available capacity (in your case-104.68 ah)
 
nithishsabapathi said:
1. Yes, SoH is the measure of the capacity left in the battery.
2. SoC will be calculated for the available capacity (in your case-104.68 ah)
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Thanks! I needed to know for when I make my own BMS and do some kind of coloumb counting to get SoC numbers for the whole pack.

I'm guessing the SoH for the entire pack would be updated only when it is discharged enough to have one of the cells reach 2.5V.

rockyo27 said:
So 48v 160ah lifepo4 will have 15 cells right and we can re-arrange it to 24v and higher AH, will that give longer run time if running 1kw plus load.
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Actually, that pack may be 16S, there's a repair video of a smaller 86Ah pack on YouTube and I think I counted 16 cells. Also the specifications on the side say it's a 51.2V pack, which implies 16S (3.2 x 16 is 51.2)

So you could rewire it as a 8S2P pack for 24V at 320Ah for a 24V inverter, using a quality BMS.
 
OT- Are there any cheap battery capacity testers for 60v battery packs?
I want to check the capacity of my e-scooter battery, getting really bad range these days.
 
nithishsabapathi said:
OT- Are there any cheap battery capacity testers for 60v battery packs?
I want to check the capacity of my e-scooter battery, getting really bad range these days.
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Cheapest way is to connect 5 identical new headlight bulbs together for a 60v load and connect that to your battery pack after a full charge.

Then time it to see how long it takes until the BMS cuts power.

If you're using 90w bulbs, then that's 90 / 12 = 7.5 amps, and if the pack lasts for 5 hours, then that's a 7.5 x 5 = 37.5Ah.

Have a voltmeter or a multimeter to check voltages every half hour or so to make sure it's not discharging lower than the safe limit. For a 60v/20S LifePO4, that's 50V. I don't know what it is for Lithium Ion.
 
rsaeon said:
Have a voltmeter or a multimeter to check voltages every half hour or so to make sure it's not discharging lower than the safe limit. For a 60v/20S LifePO4, that's 50V. I don't know what it is for Lithium Ion.
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Thanks for the suggestion, for the lower voltage protection, the BMS will cut off the pack at the set low voltage right?

Won't the battery tester work for this purpose since i saw it rated for 120v??
 
nithishsabapathi said:
Thanks for the suggestion, for the lower voltage protection, the BMS will cut off the pack at the set low voltage right?

Won't the battery tester work for this purpose since i saw it rated for 120v??
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Yes, the BMS should have a low voltage cutoff. I'm not familiar with EV packs but any Lithium chemistry should not degrade noticeably within three years of daily charging and discharging, so in your case it could be a wonky BMS.

Also yes, the battery tester linked above would work fine for this and it'll be quicker with a 20A discharge but it's 3500. If you go this route and don't want to keep it after you're done, I'd be interested in buying it — I need another one of these.
 
Would you happen to know if this Muscle grid battery has a PC software which can be connected using the RS485 communication and if there is a RS485 cable that works with it? since I see these ports are available on it. I have this exact same battery purchased a month ago and it came dented exactly as your picture showed with a 15s config. I use a Victron 48v Mppt charge controller to charge it via solar panels on a daily basis and run it at night till morning running an AC through the night. I also use a Victron Smart shunt to coulomb count the AH and get around 100Ah and the state of charge. Both the charge controller and the smart shunt are hooked up to home assistant to automate turning on/off my inverter which is a Delta2 - I use this extra battery to give me more hours of backup during the night. Though I would like to know if I can use PC software to give me the readings of the individual 15 cells and the State of charge and tweak the parameter cell values if need be. The pic below helps me monitor the battery and my inverter when away from home. I would like to also see the individual cell voltages if i can get the PC software to connect with this battery.

IMG_6631.PNG
 
rockyo27 said:
These 2kv online ups are very hard to find, new ones are quite costly.
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Yeah, I'm going to try with a UTL Inverter instead.

keithcardozo said:
I also use a Victron Smart shunt to coulomb count the AH and get around 100Ah and the state of charge.
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Thanks for the data point, it's very helpful to know.

keithcardozo said:
Would you happen to know if this Muscle grid battery has a PC software which can be connected using the RS485 communication and if there is a RS485 cable that works with it?
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I haven't personally tried it but someone has posted details on how to do this on another forum:


That is for the Shinwa LM-M01A BMS with Narada cells, which is what I found in this battery.

You might need an account on that forum to download attachments. There's another windows app linked that thread called "BMS ND Gyro" that may or may not work:


That thread also has a discussion on how to wire it up to a USB to RS 485 adapter.
 
rsaeon said:
Yeah, I'm going to try with a UTL Inverter instead.
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Have got in touch with reseller for ups. Will be discussing with him. Got a quote of 3500 for 2kva Emerson MT/Numeric/BP UPS and 4k for APC src model 96v one. Don't know if price is good or what but seems fine to me considering can't find other models
 
rockyo27 said:
Have got in touch with reseller for ups. Will be discussing with him. Got a quote of 3500 for 2kva Emerson MT/Numeric/BP UPS and 4k for APC src model 96v one. Don't know if price is good or what but seems fine to me considering can't find other models
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3500 inr for 2kva Emerson MT ups? Used? Even if used, 3.5k is very, very cheap.
 
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