Battery Replacement for 36v system in series

[daggettb]

When you replace batteries for trolling motors that are in series do you have to replace all 3 or can you just replace one?

I just upgraded to a 36v system and my two batteries are about 2-3 years old can i just buy one new one or do i have to get all three?

I am a college student and have a tight budget but i also dont want to waste money on a new one if its going to be ruined by not buying 3

Thanks for the help in advance

 

[glenn property of pam]

Re: Battery Replacement for 36v system in series

you can just add one battery

 

[Silvertip]

Re: Battery Replacement for 36v system in series

The third battery should be the same capacity as the others.

 

[daggettb]

Re: Battery Replacement for 36v system in series

Glenn- I know I can but do you know if it makes it tougher on or reduces the life of the new battery

 

[glenn property of pam]

Re: Battery Replacement for 36v system in series

lol dam I didn't want to have to write a story.

a battery is a bucket of power. the trolling motor will remove the same amount or power from each bucket of power that is connected in series so the weakest smallest battery will go flat first. Once any battery in the chain go's flat then you need to stop trolling or you could damage the battery. Notice that you will damage the flat battery which can be any one of the three. This is why silvertips added the important point that all 3 should be the same size (capacity). Now you can argue all day about how a lead acid battery ages and reduces the amount of power it can hold ....blar blar blar but with out testing the battery there's no real way to say that the battery is now holding 90% of what it would have when new so your trolling time may be limited to the weakest battery. Charge all 3 then run them hard and long then take a voltage reading of each battery and you should be able to tell the health of each battery by how close the voltage readings are (if one measures 12.1 and another measures 11.5 then the lower reading will indicate that the battery is weak). Most of us use cheapo wally world deep cycle or off brand batteries because they are abused on a boat and double abused during the off season (yep ive been known to carry on trolling even when the volt meter says its time to stop) so at the end of the day if you are using $150-$200 batteries you may want to get better advise but as your a broke student I wouldn't suggest replacing 2 batteries to get a extra few months of life out of a 3rd battery when you will probably abuse them just like the rest of us and kill them anyway.

P.s make sure you charge all 3 batteries as soon as possible after they have been used.

 

[daggettb]

Re: Battery Replacement for 36v system in series

Thank you Glenn makes perfect sense you saved me $120