Can’t find on the app where to set maximum charge level for battery.
You cant set a percentage.
You set the voltage for absorption/bulk.
If the presets are not correct switch on expert mode.
Is that absorption voltage?
Absorption is the maximum voltage your battery can charge to. Give or take 0.2v. i have noticed a few litime users have had to use 0.2 or 0.3 under the max voltage stated on the battery to prevent the bms tripping.
Use the lithium preset profile then edit the voltages using expert.
Yes, it’s a little confusing but setting the absorption voltage in the settings for the MPPT IS setting the bulk AND absorption charge. It will essentially bulk charge at the set voltage at maximum amperage and then drop the amperage in the absorption stage.
Choosing a LiTime, especially if its a “smart” version may have put you in a tricky spot. They can be finicky with over voltage protection in the BMS. What can happen is that the BMS will disconnect from charging as it, more or less, thinks the charging voltage is too high. This is sometimes made even worse with mulitple batteries in parallel. As @lxonline mentioned you may need to drop the charging voltages a bit to compensate for this. You will want to watch what happens when the charger goes into absorption. If it shuts off really early or jumps back and forth between on and off(fluctuating voltage) you may have this problem. I would set the voltages to what LiTime recommends and see what happens first. If you can see the charging stages performing as the should you may be fine.
1 Like
LiTime recommends charging to 80%. Sorry but I’m totally new to lithium batteries. So, 12.8 x .8 would be 10.24v. Correct? Or should I fully charge with the slight adjustment suggested?
No state if charge does not work like that with lithium and voltage.
The 10.2v is likely the low voltage cut off for the battery.
The difference between bulk charge and absorbtion is this
Bulk charge is constant current (up to a target voltage) and absorption is constant votage (the target) for balancing.
Usually only charging to 80% the cells dont balance and that can lead to other issues.
Of anything use the bulk/absorption set a short duration and the float voltage will be what they consider the 80% mark (ish)
1 Like
The 80% recommendation is problematic in many ways and sounds like a CYA(cover your a**) thing and frankly a cop out by the manufacturer. “Did you consistently charge the battery to 100%? So sorry we cant cover your warranty claim.”
The closest you could get to this would be to change your charging parameters and set your charging voltages lower so the charger will stop charging earlier. Maybe around 13.8V. Still it won’t be reliably 80% SOC. It would require messing with the settings and having a reliable way to actually monitor the true SOC with a battery monitor(or the LiTime App if its a “smart” version) until you consistently get 80% SOC. I don’t see how LiTime thinks this is reasonable for your average consumer.
This doesn’t solve the bigger issue that @lxonline mentioned regarding the cells never balancing. Insufficient full charging and absoption time will, in the end, reduce the batteries life span. ANY LFP battery should be completely charged and balanced at least every week or two.
The BMS should be set up to use the battery to its full potential. It should cut off charging when it is proper for the battery. If they only want you to use 80% they should program the BMS to do this and then downgrade the stated AH of the battery by 20%.
A good video on what we are talking about. https://www.youtube.com/watch?v=1G8WxY_jcUM
1 Like
Thank you!