I have a 2000W Renogy Inverter/Charger in my RV coupled with 2 AOLithium 100AH batteries in parallel. The Renogy charger's default lithium charging profile drains the battery down to 12.4 before charging which is basically fully drained I think (brand new setup, not ever cycled once yet). So i created a custom battery profile and set the charge voltage to 14.6V (is this right?) and for charging to come on at 13.2V. After I changed the setup, the charger came on but I wasn't able to get a charge to 100%. It only got to ~14.1V and then stopped charging. Any ideas what's going on (look at the switch states - which I'm not clear how you interpret open and close)?
AOLithium 12v100AH / Renogy Inverter Charger - What's Going on here?
- Thread starter Bigbeam
- Start date
MisterSandals
Participation Medalist
I'd guess that one cell (in each battery?) reaches the BMS high voltage cut off and closes the charging port.
Are there any over volt messages or counts?
Have you watched the cell voltages when it gets to 14.1V?
How are your batteries wired in parallel? Any pics?
The AOLithium app doesn't give the cell voltages or error messages but they use a standard Jaibada BMS so I used another app. Didn't catch the voltages when it turned off. Where do I go from here? I can open the batteries up and reset (power on/off) the BMS and try again. Should I disconnect them and treat each battery on its own until I sort out the issue?
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MisterSandals
Participation Medalist
I'd try to catch those voltages to understand what is happening. The displayed high and low voltages are decent enough info to know if there are runaway cell(s).
Notice the temps are 3 and 4 deg C. The battery(s?) might have charging disabled because of low temp. Do you know the low temp cutoff for those batteries?
Solar Moose
New Member
Try the Overkill Solar app! It has a settings page and allows you to see all the settings.
I use it on a GenhoaIM 300AH battery.
I use it on a GenhoaIM 300AH battery.
Cutoff is 0 Celsius.
So right now I have disconnected the two batteries and testing to see if I can get each battery to 100%. I have charger tuned down to 45 amp and max charge rate for one battery is 50 amps. Right now the first battery is at about 89% but it looks like the BMS is cycling the charging I would say every 20 or 30 seconds. It gets up for 45 amps and then the charger goes off and restarts again. Is this normal? Not sure if its my charger or the BMS doing this (charger charge LED never stops blinking) Battery temps of fine, prolly 8 or 9 degrees C and all the cell voltages are within ~0.004V.
Yes, was just looking at that app which I had installed - way more data to look at!
So right now I have disconnected the two batteries and testing to see if I can get each battery to 100%. I have charger tuned down to 45 amp and max charge rate for one battery is 50 amps. Right now the first battery is at about 89% but it looks like the BMS is cycling the charging I would say every 20 or 30 seconds. It gets up for 45 amps and then the charger goes off and restarts again. Is this normal? Not sure if its my charger or the BMS doing this (charger charge LED never stops blinking) Battery temps of fine, prolly 8 or 9 degrees C and all the cell voltages are within ~0.004V.
Solar Moose
New Member
Cell voltages over 3.45V get into the ramp of the charge curve, so if the cells have been at 3.45 for an hour, you’re essentially at 100%.
The Overkill Solar app parameters page may have a setting for where the voltage needs to be to reset the SOC to 100%.
My battery at 13.8V for 1 hour is fully charged.
The Overkill Solar app parameters page may have a setting for where the voltage needs to be to reset the SOC to 100%.
My battery at 13.8V for 1 hour is fully charged.
Look at the app while the charging is cycling. If the current drops off and the BMS still has the charge switch ON, then it's your charger that is doing the cycling. If the BMS is hitting a limit it will turn OFF the charging switches.
mikefitz
Solar Wizard
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- May 28, 2020
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It's possible you are seeing cell overvolts disabling the charge path. You have some cell inbalance. To give more time for the balance process to take place, lower the charge voltage and current. Try a 14.0 volt charge voltage.
You most likely charged to practically full, perhaps over 98%. The BMS needs to 'see' a certain voltage to set the full indicator.
Once the battery has been cycled several times the BMS reading of SOC should improve, as will cell balance.
If you use the Overkill app you can see the individual cell volts, under charge. once each cell exceeds 3.5 volts, its full.
The graph indicates cell volts against SOC, there is nothing to be grained in terms of capacity by charging much over 14.0 volts.
Consider a quality battery monitor like the Victron smart shunt to establish battery state.
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