24v Battery issues – HELP!

A couple of weeks ago I had to make a quick replacement of my old 12v 42# thrust AutoPilot before a trip to Canada. I installed a 24v IPilot PD2 with70# thrust. In doing so I had to add a new battery Now I have 1-12v for starting and accessories, and (2) identical batteries for the trolling motor, one new, one 10months old. During the trip I found the new trolling motor wouldn’t last more than 6-8 hours. I found this disappointing as the old 12v would run much longer than that. What I discovered is when the trolling motor would no longer run the new battery had 10.7v and the older battery had 0.3v. I separated and charged the batteries independently and had the same problem the next day. The old battery performed very well prior to adding it to a 24v system. Any ideas what might be causing one battery to drain so much quicker than the other?

The 24v system will only be as good as your weakest battery, which sounds like it is your original battery. Sounds like you need to replace it with a new one exactly like the second one you added.

As for charging you should always charge each battery on its own. A 2 bank smart charger like the min jigs 210 would only help the batteries last longer.

That was the answer I was hoping not to here (but expecting it). I hate to run out and buy another battery to find I have the same problem. Under normal circumstances I use a Guest 3 bank charger. When I found one battery so much lower than the rest I pulled it from the boat and placed it on a different charger to make sure it was getting an adequate opportunity to charge.

If no one else has any tips on things that could be wired wrong, I’ll be purchasing a new battery.

Thanks for the response.

put a load tester on -meters do not cut it – that is only way 2 B sure

Charge them again, and take the 0.3V one to a shop that has free battery testing.. Autozone is the closest to me, they will put it on the load tester and tell you within 2 minutes if its good. They will show you the meeter so you can be sure. if it needs replacing make sure you get the same as the other one you bought. Then the two batteries will be the same and you can replace them both at the same time when one fails in the future.

I am having the exact same thing done to mine right now. Good thing to watch out for

Earlier this season I was experiencing shorter than usual run time on my terrova.

It turns out that my water was extremely low in my batteries. Something to check.
-mark

I am sorry to tell you this but 85Lund is exactly correct. I have struggled with the same thing for just over 3 years. I had a 12volt system that I apparently should of kept in my boat but decided that I needed “More Power!”. I had what I thought were two new or near new 27 series Interstate batteries so I never looked back. I found out quickly that one of them was a bit older that the other and sure as $hit It was only good for about 2 hours of trolling. I have pleaded with the place I purchased them from with no help even though they were in warranty. After many visits they finally gave me a new used battery that was equal to the charge time of the other. They both worked for 2 seasons and this last week I finally had to replace them. 24 months on the batteries with a 30 month warranty. The only way I would bring them back is if I was going to shove them were the sun doesn’t shine. As I explained to the store owner the first time, I went to Wal-Mart purchased (2) 29 series marine batteries because I will never have to fight them if there bad, they just take them back. They are also $82 which is a fraction of what I paid when I needed the last ones. The key is to also get into a 29 series vs the 27 series. It will be labeled in the model number. If you don’t get a new battery you will fight that problem forever and be as unhappy as I was….

Sad to say but Interstate Batteries have gone down hill as far as quality goes. They were the best for a long time but something has changed in the manufacturing process and at the price they get I just don’t see the reasoning for buying or recommending them in the future.

Youve always been my favorite Pier! Well stated.

Thanks everyone.