Trickle Charging a group of Batteries: Is there a correct way?

[Old_Skewler]

I have (4) Lead-Acid batteries that run (2) bikes, (1) RV and (1) Generator. Every winter I bring them inside and rotate them on a trickle charger, so that next spring I have them ready to roll.

I suspect I could connect these batteries either in parallel or in series and leave the trickle charger over the winter and not having to keep track of them and which one is next for the charger.

Anyone with practical experience could tell me how to wire these (4) batteries so that I could safely connect to one charger and have them ready for next season?

Thanks in advance!

 

[MurphyGuy]

As long as they are all the same type of battery, you should be fine..

But I don't think you want to mix flooded lead acid with AGM cells and do that.

 

[Old_Skewler]

As long as they are all the same type of battery, you should be fine..

But I don't think you want to mix flooded lead acid with AGM cells and do that.

I tried finding more info on this online and it seems like you are correct: I should be able to connect the two larger batteries in parallel to the charger and also the two smaller batteries in parallel to the charger but should not mix them up.

Do you know what cable/wire size I should use to connect two of these batteries in parallel?

 

[RCinFLA]

Many trickle chargers, like Battery Tender, will take the battery to 14.2v before dropping back to 13.4 vdc.

Just make sure the paralleled batteries do not draw so much charge current the trickle charger cannot make it to absorb voltage with its available current so batteries just sit at near absorb voltage indefinitely.

 

[Old_Skewler]

Just make sure the paralleled batteries do not draw so much charge current the trickle charger cannot make it to absorb voltage with its available current so batteries just sit at near absorb voltage indefinitely.

I suspect what what you predicted is actually happening: the trickle charger stays in "blinking mode" indefinitely.

But I do not understand what I should/could do about that or even what are the implications.

Could you please explain what is happening and what actions I could take - I guess the only thing to do is charge them individually?

After they are all full, would it be a problem to leave them connected in parallel and under "blinking charger mode" ?

 

[RCinFLA]

For calcium alloy lead acid batteries, they have about 10% capacity self discharge per month. As they get older this could be higher.

Most small battery tenders put out about 1 amp maximum. They are intended for a car battery sized batteries.

You can put a regular charger in parallel to get to the absorb voltage then disconnect regular charger and the tender should maintain at 13.5v.

Better if you get a larger maintainer that puts out more current capable of bringing battery up to absorb level.