Lithium-ion battery problem - or something else?

[popotla]

We bought our motorhome new on 31st August 2019. So far have driven about 23,300 km (14, 560 miles). The as-new electrical arrangement included two Relion Lithium-Ion 12-volt / 100-amp batteries, two x 110-watt solar panels and a VBCS 60/40/430 Triple Votronic charger.

We've normally been able to spend two or three weeks off-grid, though have tended to mains charge about once a week. Have recently been having days on end of uninterrupted sunshine, including today. Have not moved for the past thirteen days, nor started the engine. Today, no extra or unusual power requirements - in fact almost nothing. Then, suddenly, about 8 p.m., a reading of either 10.1 or 10.5 volts on the panel (can't remember which) and a flashing red light, "CHARGE NOW". We plugged in to the mains, are still plugged in - and will be, overnight. The reading is now 13.1. (I might add that normally, if the reading is 12.9, we take that as a signal to plug in to the mains.)

My immediate reaction was that the batteries have suddenly given up, have worn out, but aren't they relatively new? (Or have they given all the service they're going to give?) Please, what is your opinion? Why this situation?

 

[donkey]

Hi
No point in trying to guess what may be faulty, you need to carry out electrical checks to diagnose the problem.
Geoff

 

[Abacist]

Certainly far too new and expensive to have died or I would be claiming not merchantable quality!

 

[Millcourt]

Very unlikely that your batteries are “worn out” after 2 years. You should reasonably expect a service life of around 7 years, perhaps 10, from this type of battery. Doubt you have an internal fault in one or both of your batteries, but if this proves to be the case you should be able to make a warranty claim. (Not sure about Relion, but most Lithium-ion batteries come with a 5-year warranty.)

Most likely you have simply run then down to around 5-10% state of charge. The voltage profile for this type of battery does not fall away greatly until you reach a low level of charge remaining. (This is unlike the typical voltage profile for lead-acid batteries.) When you put on charge and read 13.1 volts, you are reading the output from the charger rather than the battery voltage. If you have a mains charger with a “Lithium“ setting, I would be surprised if your batteries do not fully recover. If your charger is not Lithium specific and the battery state of charge is very low (under perhaps 5% or so), your charger may not be able to “kick” them back into a state to accept charge and you will need to use a lithium battery charger (which only needs a small current output) to put an initial charge back in, before going back to your usual charger. I presume you have a B2B charger with a Lithium setting installed to supply charge from your engine alternator…… if so this may “kick” life back in, if your mains charger initially fails to do so.

I do not think that battery voltage readings are an accurate way of giving meaningful indications of the state of charge of lithium batteries. Do your Relion batteries not have an inbuilt BMS (Battery Management System), or do you have an external BMS controlling the charge state? If so, you may well have a Bluetooth connection to an App on your smartphone to monitor more accurately the charge, discharge and state of charge.

Hope that you resolve your problem without too much difficulty.

 

[Raul]

Do you have a battery monitor to keep track what you take out and what you got left? It could be one or more charging sources have failed and you run on deficit charging.

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[Ranger]

Our KS Energy batteries go to sleep and show low readings if no power drawn for a certain length of time. Even turning on a led light does not wake them up and just glow dimly so a quick prod of something like the step switch or pump wakes them up again.

 

[Millcourt]

popotla
Wondered if you had resolved your problem and had any feedback which might be helpful to others?