Advice on Charging Battery When Not In Use

I'm planning a 4 month trip and will be leaving one bike and its battery at home. I was told that a battery has to be charged every so often, otherwise it's management system automatically shuts it down. And was also told that it won't just automatically come back to life when you next charge it after a shutdown.

 

Is this the case?

 

And if it is, can someone please advise me on whether 4 months would be too long to leave it without charging?

My handbook suggests storing at circa 70% charged.

To wake it up, which I have needed to do if not using it for over a week, all I need to do is press the on battery "push to read" battery status button.

I would certainly follow their recommendation for a 4 month storage.

I recall similar 50>70% state of charge being recommended for phone and laptop batteries.

I personally wouldn't worry about it too much. Just fully charge before you leave, then charge it again when you get back. Obviously, it's dependent on the quality of the cells how much charge you will lose, but it should be minimal after only 4 months.

 

If it has any sort of switch on the battery which turns it on, be sure it is off when you leave. Otherwise the BMS will be active and can drain the battery.

Hibernation or not is down to what make of battery you have. Generally, storing at full votage is not a good idea. Charge it, then put about 10 miles on it. Store it indoors in an unheated room. Ideally repeat every 3 months, might be able to stretch that to 4 months. Don't try to partial charge as cell balancing only happens at the end of the cycle.

A battery regulary used and charged fully will remain in balance even with the odd part charge, it is only regular part charging < then circa 4.15v that eventually leads to unbalance.

IMHO I would charge to 3.85/3.9v or as near check with a meter and then leave it in in a cool/cold frost free place. The sleep mode will shut off supply so battery will be in safe mode, wake it up a usual next time with a push of the button.

[mention=5140]OldPedaller[/mention] Maybe you could let the forum know the brand and model number of the battery, so we can search for a more definitive answer for you.

Once in sleep mode then it will charge as normal once woken again.

Between 50-70% go on your trip and don’t worry about it