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.
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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)
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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
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Thank you!
All of LiTime’s documentation that I can find says you should regularly charge your batteries fully; I’m curious what document you found that suggested only charging to 80%?
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A representative suggested that some people only charge to 80% but said that 100% is ok. Based on further research and the excellent advice from this forum, I’m going with the 100%
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A common and often argued point andit comes from several misconceptions and misunderstandings.
My usual answer is that the manufacturer is already limiting the use of the cell voltage range to its 20% -80% range.
Yes, they tell you 0% and 100% SOC but that is of the useable range that they have decided to let the end user have.
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I did notice something somewhere about 80% from LiTime but can’t remember where.
It is true that when it comes to the lithium cells themselves you get more life long term with shallower discharges. It is very minor and not anything at all as extreme as with lead acid. And the other side of the argument is the cells are deteriorating over time anyway. So why not just use them to their full capabilities while you can? Seems like the best practice is to use the batteries for what they are intended.
And for sure you don’t want your battery fully charged if it is in storage for extended periods.
A reputable battery manufacturer should be setting up the BMS for the longest life and best performance of the battery.
I doubt that. Litime is a price fighter. They try to achieve as lot as energy from their batteries as possible. If they allow to charge to 3.45/cell - 13.8V in total with the right amount of absorption, the cell and battery is 100% full.
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Correct where the cell range for lifpo4 to the edge is 3.65v per cell so litime has already limited to what they have considered the best use for longevity range.
In any case time, cycling and temperature is what kills a battery so use it or lose it anyway.
I saw the blog /article everyone is talking about.
[edited see [quote=“mystudio, post:17, topic:51438”]
don’t think they use EVE cells
[/quote]
And then compare the use to ev use… Which is also different a toally different chemistry and use case.
In any case soc can drift so their guidline for 20/80 is not exactly helpflul for charging since most charger will use voltage and they haven’t made a way for the battery to communicate. So now everyone is just going to guess. If it was that important there should be better guidance from them.
It is almost as if they have installed a BMS to do a job (which is prevent overcharge etc) then told everyone who owns one they should do the job of a bms.
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I might not exactly get you here. I read there blog. I don’t think they use EVE cells. Too expensive for their battery. They state that they use EV grade cells. Furthermore, they recommend as a best practice for charging 3.6V/cell. So, with that voltage, their batteries will be fully charged, to 100% SOC. I guess you are right that if a user wants to handle the 20-80 range, he has to manage that on his own. The battery cannot communicate with the chargers, so, if you want to charge to 80%, then visually use the SOC of a Victron shunt or use a lower bulk voltage. Last might work too. And once in a while do a full charge for syncing SOC.
I would charge them to 3.45V per cell maximum, so 13.8V absorption, 13.4V Float.
#metoo, but that was not the discussion here 
Like I said, this 80% recommendation is problematic. Especially for a straight to consumer based company like LiTime. What RV owner has any idea how to do this or even wants to babysit his batteries to make sure their batteries stay between 80 - 20% as well as give them an occasional absorption charge to keep cells balanced?
This quote below is a joke. Even with all the programmability of Victron products this is not something a DIYer can easily achieve. Yet here it is to the consumer. Do they expect everyone to have a SmartShunt or to add a external BMS to their LiTime batteries?
1. Set your charger or BMS limits
Adjust your system so that charging stops around 80–90% SOC and discharging doesn’t go below 15–20% SOC. Many smart chargers and BMS (Battery Management Systems) allow this customization.
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