Bench Testing BigBattery 170Ah 24V Battery Pack

myrkr

New Member
I recently purchased (2) BigBattery 170Ah 24V battery packs for my camper conversion project. They'll be delivered in the next couple of days so I'm looking for any advice/input on recommendations for testing them out and making sure everything works as it should. Here is my basic list of tests to run-

1) Low Temp Cutoff Charging - I know this was a hot topic following Will's review and then BigBattery admitting to mistakes and making changes. I just want to confirm that my batteries have proper low temp cutoff. It seems like the best way to do this is to open up the pack, pull the temp sensor, submerge it in ice water (measured for temp) and make sure that current stops flowing. It appears that 0°C is the cutoff temp. Is my thinking sound here? I could also just leave the pack outside and test in the garage since it's below 0°C here (just not sure if this is accurate enough).

2) Capacity Test - Is the best way to do this to charge to a certain setpoint (voltage) and then discharge at a given wattage and record the amount of time it takes and then do the math to see if the total amount of watt hours were all there before voltage falls below a certain level?

Beyond that I'm not sure what others might recommend to make sure that the batteries are good. I could also test high voltage charge cutoff and low voltage charge cutoff? I also plan to open the batteries up and check the wiring, connections, fuses, etc. Just wondering if there are any other things I should be looking for as well.

And one final thing, I don't have the rest of my electrical system done yet, so I don't have a charger of any type capable of charging the battery packs and logging. I've been trying to read through other threads on here to look for recommended bench test equipment. One nice looking DC charger I saw was the RIDEN DC6018 since it appears I could use the software and a computer to track voltage and it's a decent price. But if my numbers are correct, it looks like it would max out around 460 watts of charging (26v @18amps max of the unit). That seems a bit low given the pack capacity is much higher. Are there other better benchtop DC charger options that will offer more charging current with some type of logging to track things? Thanks
 

snoobler

Solar Honey Badger
Moderator
1) confirm with BigB that your model has it. Test in garage. It should only impact your ability to charge.

2) charge it all the way to the maximum published voltage and discharge it to the minimum published voltage. Otherwise, you're comparing apples to oranges.
 

myrkr

New Member
1) confirm with BigB that your model has it. Test in garage. It should only impact your ability to charge.

2) charge it all the way to the maximum published voltage and discharge it to the minimum published voltage. Otherwise, you're comparing apples to oranges.

Thanks! That all makes sense. Any thoughts or suggestions on a bench top DC power supply capable of charging the pack with some type of monitoring/software?
 

snoobler

Solar Honey Badger
Moderator
The 30V/10A benchtop supply that Will recommends will work fine. Monitoring/logging is another matter.

This is a lower current PS that requires a DC source:


 

CMac

New Member
1) confirm with BigB that your model has it. Test in garage. It should only impact your ability to charge.

2) charge it all the way to the maximum published voltage and discharge it to the minimum published voltage. Otherwise, you're comparing apples to oranges.
What is the Min and Max voltage? I am assuming this is Min and Max of the BMS, such as min voltage cutoff.
I am having a hard time finding those published by BigBattery.
 

CMac

New Member
I recently purchased (2) BigBattery 170Ah 24V battery packs for my camper conversion project. They'll be delivered in the next couple of days so I'm looking for any advice/input on recommendations for testing them out and making sure everything works as it should. Here is my basic list of tests to run-

1) Low Temp Cutoff Charging - I know this was a hot topic following Will's review and then BigBattery admitting to mistakes and making changes. I just want to confirm that my batteries have proper low temp cutoff. It seems like the best way to do this is to open up the pack, pull the temp sensor, submerge it in ice water (measured for temp) and make sure that current stops flowing. It appears that 0°C is the cutoff temp. Is my thinking sound here? I could also just leave the pack outside and test in the garage since it's below 0°C here (just not sure if this is accurate enough).

2) Capacity Test - Is the best way to do this to charge to a certain setpoint (voltage) and then discharge at a given wattage and record the amount of time it takes and then do the math to see if the total amount of watt hours were all there before voltage falls below a certain level?

Beyond that I'm not sure what others might recommend to make sure that the batteries are good. I could also test high voltage charge cutoff and low voltage charge cutoff? I also plan to open the batteries up and check the wiring, connections, fuses, etc. Just wondering if there are any other things I should be looking for as well.

And one final thing, I don't have the rest of my electrical system done yet, so I don't have a charger of any type capable of charging the battery packs and logging. I've been trying to read through other threads on here to look for recommended bench test equipment. One nice looking DC charger I saw was the RIDEN DC6018 since it appears I could use the software and a computer to track voltage and it's a decent price. But if my numbers are correct, it looks like it would max out around 460 watts of charging (26v @18amps max of the unit). That seems a bit low given the pack capacity is much higher. Are there other better benchtop DC charger options that will offer more charging current with some type of logging to track things? Thanks
Did you get your 2 BigBattery packs?
How did/is your testing going? What were your results?
 
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