petr-k avatar image
petr-k asked

MPPT 100/30 suddenly allows battery to be charged to only around 50 %


i have approximately 6 months old solar system on a camper consisting of these components: Victron mppt 100/30, LIONTRON Lithium LiFePO4 LX Smart 12,8V 100Ah, three solar panels 12V/100W, Converter SINUS Victron Energy Phoenix VE.Direct 800VA 12V, Cyrix-ct 12-24V 120A connection to alternator.

Everything was working perfectly until recently. Suddenly im no longer able to fully charge my battery. I can usually get it to around 50 % and then mppt turns to float. I think it shows absorption point has been reached [14.20V], which should indicate battery is full [unless im mistaken], however that is definitely not the case. If a turn solar panels on/off, it goes back to bulk, but only for a couple of minutes. Adding screenshots of mppt history and battery overview. Im somewhat suspicious its connected to the firmware update a while ago, however im by no means certain as i dont check it that regularly and therefore only noticed the issue with a delay.

Thank you for any suggestions,

Petr K.








Screenshot_20220521-205312_LIONTRON Multi.jpg

MPPT Controllersbattery chargingLithium Battery
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2 Answers
klim8skeptic avatar image
klim8skeptic answered ·

It looks loke your BMS needs some attention. Your 100ah battery has a Kapacita of 114.25ah??

Your mppt history screenshots show that the battery has gone through an absorb phase (14.2v for xx mins) at least 21 times during the last 31 days. The BMS should have reset the battery capacity to 100% when this occurs.

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Thank you for a quick response. What do you mean by BMS needs some attention? Should i return the battery to the store? As for the slightly increased capacity, that was shown since day one when i had the system installed. Even when everything was working fine – didnt give it too much thought as i dont really understand any of it.
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A lot of times these BMS are configurable.

This gentleman shows a different part of the app (or a second app).

Perhaps you should contact you retailer and mention the incorrect SOC and Battery capacity?

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macca61 avatar image
macca61 answered ·

I dont know if this was the same but my solar wouldnt charge to more than 80% , the MPPTs were reading the batteries at 14.2 volts and going into float when in actual fact the batteries were about 13.2 volts.

i found the problem to be a loose connection on one side of a fuse and the cable and connector were quite hot to touch, it was where both controllers combine so both controllers were reading the same voltage which added to the problem , i have tightened all the connections and the Mppts now read the voltage correctly within .2 but i have ordered a smart battery sense anyway which will tell the networked controllers the true voltage

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