I have new cells to test/charge The EBC A40L tester works great but Id like to speed things up on the charge side to free up the tester. I also have a switching power supply that is 0-8v and can do 30-40 amps but has to be in the upper volt range to get the amps. Can I use this to charge the cells as long as there monitored to not go above a certain voltage say 3.45v or would this not be a good thing and just wait till all tresting is done then charge them up as one big 3v battery at 40 amps using the EBC or a 60v 5 amp bench power supply
looking to speed things up
- Thread starter Hendo
- Start date
BentleyJ
Solar Wizard
If the Voltage is truly adjustable from 0 to 8V you should be able to use the switching power supply to charge the cells. If it also has a constant Current setting all the better and it should be set at 0.2C based on the Ah capacity of the cell.
If voltage is the only adjustment available then you test the cell resting voltage and use this as you initial power supply setting then with the battery connected slowly turn up the voltage until you hit 0.2C Amps and leave it alone. When the amps start to fall turn up the voltage again to the 0.2C Amp value. Once you reach 3.45V let it ride until the amps fall to near 0 indicating a fully charged cell.
I use a cheap ebay DCDC boost converter with both CV and CC settings to charge 18650 cells on the bench all the time.
If voltage is the only adjustment available then you test the cell resting voltage and use this as you initial power supply setting then with the battery connected slowly turn up the voltage until you hit 0.2C Amps and leave it alone. When the amps start to fall turn up the voltage again to the 0.2C Amp value. Once you reach 3.45V let it ride until the amps fall to near 0 indicating a fully charged cell.
I use a cheap ebay DCDC boost converter with both CV and CC settings to charge 18650 cells on the bench all the time.
I would not set the voltage higher than 3.45-3.65 if you are relying on manual monitoring of voltage. May as well assemble as a battery with BMS and place it in service. Observe how well balanced it is and go from there. Post the results. As long as the BMS is protecting the cells all will be fine.
I charged it as a pack to 3.4/5 with a bench power supply then added the bms to finish and balance to 3.625 then let it sit for 15 hrs then started capacity checking down to 2.8v now I'm looking to get them started charging with the a supply till I finish checking all the cells to reassemble and put in service
chrisski
Solar Boondocker
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- Aug 14, 2020
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I sped things up by putting my cells in 8S with a BMS and charging to 3.45 per cell, and then breaking down and rewiring for 8P and charged to 3.65 VDC. This changed this from over a week in 8P on a 30 amp power supply to two days with a 15 amp charger for a 24 VDC battery pack and then aboit 6 more hours on 8P to top balance.
Thanks thats what I plan to do once I hope to get some recharge on them after being tested (not letting them sit empty for long) But think I'm waiting to long to test them??? I did initial charge let sit and slowly working thru them (16) pretty sure my numbers will go down the longer they sit ( I expect some small loss but not sure at what point its to much self drain?
