Lifepo4 battery upgrade

[rboat]

Hey guys just bought a Lifepo4 battery for my 12v bow mount trolling motor. I also bought a new onboard 2 bank charger, 6amps per bank, that works for the lithium and the flooded start battery. With my old batteries, I always left my onboard charger plugged in at home to keep the batteries charged and ready to go. The new charger says it has a float mode for when the batteries reach full charge. Can I still keep them plugged in at home or would it ruin the new lithium battery? If so, could I unhook the lithium and leave the one bank charging the start battery? Just need some help from someone who has used a similar setup. Thanks for your help.

 

[Tennessee Boy]

It’s hard to say with any certainty without knowing what battery you have and what charger you have.   Generally,  if your charger is made for lithium batteries you should be fine and even if it’s not the BMS should protect the battery from overcharging.   Personally,  I don’t leave my chargers on indefinitely because it shortens the life of the charger.

[casts_by_fly]

I leave my lifepo plugged in for extended periods often.  I plug it in when I get home from a trip and then unplug it next time I am nearby and think about it.  Sometimes that is multiple weeks.  If the charger has a maintainer mode or similar then it will be fine.

[Bankc]

It can depend.  But most modern chargers are designed so that they can be left on, and they have circuitry to stop charging once the battery is full.  Same with most lithium batteries.  They have circuitry built into them to cut off the battery off to prevent overcharging or overuse. 

 

That being said, it's still a risk.  I definitely wouldn't leave it plugged in outside in the extreme weather.  You can ruin a lithium battery if you try to charge it below freezing.  And charging it in high heat will shorten it's lifespan.  Plus, there's always a risk the circuitry fails and could start a fire.  But, having said that, I do leave mine plugged in sometimes for several days, sometimes even weeks, at a time, if I forget to unplug it.  And it hasn't done anything bad yet. 

[GaryH]

I always used to leave mine plugged in, until last year we were hit with lightning .major damage to the house and luckily only 1 of the 4 lithium batteries was hit. Even more lucky was Ionic fixed the 125 ah battery for no charge. Now when charged I unplugged the MinnKota charger when charge is complete. Also with a Lithium battery there’s no reason to keep them on a tender after charging because they won’t loose a significant charge for quite a while.

[Craig P]

Not saying it is what to do but my best practices have been plugging the boat in to charge and unplugging when indicated fully charged.  I fish often but it could be a couple of weeks between trips, depending on life.  Rinse and repeat.  I do not charge my starting battery, my charger charges my 3 lithiums.  The starting battery operates just the starting, lights and livewell. I do make sure that one is up to snuff though after winter break.  

[LonnieP]

I leave my Noco charger plugged in on my Ionic batteries but I usually fish at least twice a week. If not I’ll unplug it.

[FishTank]

I charge mine as needed but also charge it at least once a month in winter in my heated garage. I haven't had an issue yet. I can say from my experience and two fishing buddies, don't charge them when they are cold. I don't know why but it ruined two of ours. Dakota sent my buddy a new one which took months.  Also dont store them in outside in the cold or on a cold garage floor. 

 

Also, I'm not sure what the OP charger does exactly but mine says to charge lead and lithium separately.  

[casts_by_fly]

1 hour ago, FishTank said:

I charge mine as needed but also charge it at least once a month in winter in my heated garage. I haven't had an issue yet. I can say from my experience and two fishing buddies, don't charge them when they are cold. I don't know why but it ruined two of ours. Dakota sent my buddy a new one which took months.  Also dont store them in outside in the cold or on a cold garage floor. 

 

Also, I'm not sure what the OP charger does exactly but mine says to charge lead and lithium separately.  

 

If its a noco genius multi bank, you can select the type of battery by bank and charge 3 or 4 different types at a time.  

 

Cold hinders the polymer matrix I believe and that's the issue with low temp charging.  Some batteries have a 'warmer' built in and will detect the charging temps.  And in a different application Tesla's will warm the battery to optimal charging temps if you're navigating to a charging station in the cold.  Keep in mind that 'cold' is relative.  Below freezing is a bad thing for charging lifepo, but a 40-50 degree garage isn't so bad.

[BayouSlide]

On 7/22/2024 at 1:40 PM, Bankc said:

Plus, there's always a risk the circuitry fails and could start a fire.

 

This happened to me (with a conventional battery and charger) and I was lucky to come out to the driveway and see the fire before it totally melded the gas tank. By the time repairs were complete my $4000 G3 had become a $8,000 G3.

 

Personally, now, even with a 5 amp per bank charger, I will never leave it connected to power overnight.