Ampere/ Li-time batteries in series

[Cheap 4-life]

Had purchased an ampere time battery for my trolling motor. I have since added a 24v trolling motor to the boat.
Can I buy another Li-Time battery to series with my Ampere time battery?
Would the bms of each battery be able to handle the 24v?

 

[sunshine_eggo]

Had purchased an ampere time battery for my trolling motor. I have since added a 24v trolling motor to the boat.
Can I buy another Li-Time battery to series with my Ampere time battery?
Would the bms of each battery be able to handle the 24v?

Battery specs will tell you the series limit. If they say up to 2 or more in series, should be no issue.

 

[Cheap 4-life]

The batteries specs do say up to 4 in series. What about the combination of the Ampere time and Li-time. Like if they have different bms in them and if they are compatible. I think (from Wills video) that the Li-time has low temp charging protection. I know the Ampere time I have does not

 

[sunshine_eggo]

The batteries specs do say up to 4 in series. What about the combination of the Ampere time and Li-time. Like if they have different bms in them and if they are compatible. I think (from Wills video) that the Li-time has low temp charging protection. I know the Ampere time I have does not

If both are able to be at least 2 in series, then you can do 24V.

The differences are simply that... differences. Putting a Li-time in series with your ampere time means the ampere time now has something resembling low temp charge protection. If the Li-time stops charging, it won't pass through the Ampere time either.

The official line is: same brand, same age, same capacity, same chemistry, same age.

MANY folks on this site parallel all kinds of combinations. Series is a little different. The most important thing is that BOTH batteries have the same capacity. If one is lower, the total 24V battery has the capacity of the lower capacity 12V, i.e., 90Ah 12V + 100Ah 12V in series = 90Ah 24V.

VERY important to individually charge each to 14.4V and then parallel charge them for a couple hours before putting them in series.

 

[Cheap 4-life]

Well they wouldn’t be the exact same age/capacit’s, although the ampere time was only used for roughly 10 fishing days since new. They aren’t the same exact brand but Li-time was Ampere time. I’m gonna go with it. Thanks for the discussion/help. If I have any issues I’ll put it on here.

 

[sunshine_eggo]

Well they wouldn’t be the exact same age/capacit’s, although the ampere time was only used for roughly 10 fishing days since new. They aren’t the same exact brand but Li-time was Ampere time. I’m gonna go with it. Thanks for the discussion/help. If I have any issues I’ll put it on here.

Agreed. Just be aware that there is a difference, and the 24V will only be as strong as the weakest 12V. Ensuring that you do the full individual and in parallel charges as 12V prior to placing in series for 24V will save some headaches.

Make sure the system is regularly charged into the 27.6-28.8V range. Preferably for several hours a month.

Additionally, one of these:

https://www.amazon.com/Battery-Equalizer-Voltage-Balancer-Support/dp/B09CYMXJRR

Can help keep the two 12V in balance at the top end of the range.

If you start seeing voltage spikes in any of your monitoring equipment, that's a sign that one or both of the batteries has entered over voltage protection and typically means one or both batteries are internally imbalanced.