Lithium battery charging advice needed

[tacomatraveller]

Need advice on the best way to keep my 100AH Battleborn Lithium charged. Up until a few weeks ago I kept my camper outside and the solar panel kept my battery fully charged. I now have moved the camper indoors. I assumed that the battery would stay fully charged, but a look at my Victron 712 battery monitor shows that I am consuming approx. 3 to 4 % of my battery capacity every day. I assume that is because the battery monitor uses a little power daily.

1st question. Is it fact normal to have the battery discharge 3 to 4 % daily when the camper is sitting in the garage with nothing using power, except for maybe a little from the battery monitor?

2nd question. Since the battery is slowly draining, what is the best way to keep the battery healthy. Should I let the battery get down to let's say 60%, and then charge it with my Blue Smart IP65 charger, or should I have the battery permanently hooked up to the charger and keep it at 100%. Which way is better?

 

[Jon R]

Your battery monitor is not the culprit assuming it is working properly. I have a BMV 712 and my 200 AH battery stays at 100 percent for a week or so IF I pull the switch that disconnects all the loads at the fuse block. I suspect something in your camper is drawing current even though you believe everything is off. Do you have an inverter? Is the fridge light on because you have the door cracked. Propane detector? 3 or 4 amp hours used per day equates to a constant current of about 150 to 200 milliamps. Your battery monitor should show that current going out of the battery. Maybe pull fuses until you find the load?

 

[tacomatraveller]

Don’t have a fridge or inverter. All light are off. Could the smoke detector use that much power.

 

[Jon R]

I just turned off my solar charger and observed the current on the monitor. I see about 160 milliamps of discharge current when my camper master switch is on, and zero with it off. The Victron solar and dc to dc chargers remain connected to the battery when the camper master switch is off, so the current draw is not the chargers. I have everything possible turned off, so as far as i know the only thing being powered when the switch is on is the propane leak and carbon monoxide detector. Its labeling says it draws 108 mA. The smoke detector has its own 9v battery.

 

[tacomatraveller]

Any suggestions regarding how to charge my lithium battery. Keep it on the Blue Smart ip65 charger and keep it fully charged or let the battery slowly drain and occasionally recharge it fully (maybe every 2weeks or so)

 

[Jon R]

I’m not sure one is better than the other for short term storage. For long term storage the recommended practice seems to be to store it at maybe 60 to 80% charge and disconnect it so it won’t discharge. It should be fine for 6 months that way.

 

[Vic Harder]

Like Jon R says, let it go down to 60% and then leave it there for up to 6 months. At the same time, figure out where the power loss is coming from. Are you pushing/pulling the Kill switch to disable ALL power to the camper? If so, and you still have a draw, something is wrong... If you don't want to troubleshoot the drain, simply disconnect the battery ground at the battery.