Hello lithium knights,
I bought Sanyo NCR18650BF protected cells. I want to do a capacity test on it using Liitokala. The smart charger will do a complete discharge/charge cycle. As we know the batteries have overdischarge cut-off, What if it cuts off earlier than the test? Will it give correct capacity reasults?
Thank you.
Depends on the LVP cutoff of the protection circuit, if it’s down to 2.5V or 2.7V the capacity shouldn’t be affected. Most modern protected batteries triggers LVP at 2.5V.
But really there isn’t much usable capacity left after you reach 3.0V, unless tested with a very low current draw.
As will34 said.
So you might want to watch the readout when nearing the end of the discharge cycle.
I was doing a discharge test of some old protected cells i have on the opus and some of the protection circuits cut out at about 3v - wiping the display as the charger thinks the cells removed. So annoying!
Thank you for reply, yes thats what I was thinking about. But I checked later on when cells arrived, it does not do that in the Lii500 :laughing:
Hello, thanks,
The Opus firmware is upgradable?
What about Liitokala Lii500?
You cannot Update Lii-500.
You will not be able to perform a real capacity test with li-ion charger only unless you know the exact current load value.
Even then you will have one test under one current load value.
I do not think that protection will cutoff because charger (if any good) should not go below 2.5V (probably 2.7V).
Rule Nr.1- never discharge li-ion battery below 2.5V (under load).
Charger manuf. should follow this rule, but I personally do not know about that particular charger (specs).
I have a Lii-500 as well and it is a very nice charger/discharger for the price, but not suitable to get absolute numbers when discharging as almost all chargers/dischargers. Comparing batteries will be ok, but to get precise measurements you need to have a lot of factors under control. Expanded effort is needed to get more precise results.
Meanwhile I spend hours to calibrate my Icharger with a Fluke DMM, prepare the 4-wire batterie holder with suitable leads, plugs and balancer connection (to get real cell voltage when charging/discharging) and doing a real lot of measurements while this setup is charging/discharging. I think that this setup does work really fine now, but I am sure the measurements are still not precise, but very acceptable for the budget.