I was not aware that you can have a marine battery "tested". We have the latest and greatest battery testing equipment and every time I "test" marine batteries that I know are bad they show good on the test equipment?

If the plates have been exposed to air the battery capacity is probably significantly reduced.

Will they work, yeah, probably some. Whether or not they work good enough for you will depend on how much you expect from the batteries.

If you had a charger that has what's called an "equalization" mode or "desulfation" mode (different same for same thing, afaik), it might help bring them back to a higher degree than just a plain old recharge.

Quick update.

After charging last night and today - I unhooked the charger. I then checked the voltage on my depth finder and it read 12.6 volts. I then turned on the radio and the interior lights. I di that over 4 hours ago and just checked and they are running strong and the voltage now reads 12.3 on the depth finder.

I dont think I would ever run my interior lights for more than 4 hours - or even the radio. i might run my depth finder for all day - but i didnt want to have the depth finder on for long for this "test". I wonder if the depth finder takes more "juice" than say the radio or the lights? In any case I was pleasantly surprised that the battery charge lasted as long as it has so far - and only went from 12.6 to 12.3 volts in over 4 hours of use...is this a positive sign

Well, it is a good sign. But, neither of those are particularly demanding loads like a trolling motor would be.

Thats a good point!
I think tonight I will hook up the troller and let it run on medium speed for an hour - and see what happens. Do you thinbk that would hurt the troller at alI? havent tested out that battery yet - just the accessory one. I did leave the radio and lights on all night long - and they were still going strong this morning...checked the voltage and it was down - but only to about 11.4. and that was after being on for over 15 hours. I guess the real way to tell if these things are holding a good charge is to get out and use them - but I may leave for about 5 days to canada and probably wont be able to test them out much before that. I think the safe thing to do is just bite the bullet and buy 1 new starter and 1 new troller, have the others along for back up. We do havea generator to charge up the batteries but if I have a back up then I just have to switch the battery over real quick - and away you go.

You might want to place the motor head in a bucket to protect it from over-heating.

Bob

Are you going to have power to recharge while on your trip? I've been at a remote camp without 110 but have been able to rig up a line to batteries with some heavy cord and alligator clips to the photo cells the camp used to charge their system.

Sort of hard to rationalize buying a battery this late in the season and let it sit in the garage. How about one of those power packs that give you a quick jump $35-40?? It would be enough to get the motor started if things go south on you.

Tom 7227

You hit the nail on the head. That is why I am posting so much on this - just trying to save some bucks on one last trip this Fall. If it were this Spring - i would just buy a couple new batteries and not even worry about it

I think I am going to just buy one new good starting battery. I will move my older starting battery to the front as a spare for the troller - even though its a starter it should still run the troller for awhile. Then just hope the troller one up front lasts awhile and the accessory battery lasts. I really only need the accessory battery to last to run the depth finder...I dont need to run my lights much or use the radio etc...so hopefully it will last for awhile. We do have a generator up there (it is a private island...not a resort) but the generator always seems kind of iffy...for when it runs etc..and I dont want to take a chance with my starter battery - would rather just get a new one and be safe than sorry - but I think I will hold off on any deep cycle batteries until next spring. Thanks!!

As sure as the sun will rise and set. You will ruin whats left of the starting battery by using it to power your trolling motor.

Mr. DeLuca is dead on with this one. I have spent a bunch of time trying to understand batteries and have found that articles by Bill Darden have been helpful. Google him and spent some time reading his explanation of what the different types are, what helps and what hurts the batteries, and how to buy and care for them.

FYI I bought a 15 amp photo cell from Northern and rigged it up on the top of my boat lift. It works like a charm, pumps up the trolling battery in a day and has saved me from lugging the batteries home every two weeks. Might be a good investment for that cabin. Around $145 for the entire works.

Tom 7227 had a good idea just pick up a portable jump unit, If you have charging capability where your going you shouldnt worry to much since the trolling battery has been doing fine even though it was low. I'd just get everything
filled/ charged and ready to go and bring a small container of distilled water for a top off if needed. Then just hook up your charger each time your done fishing for the day/nite, and enjoy the trip.

FYI harbor freight tools in Columbia heights has a basic 100 amp battery load tester for about $18, might me worth it versus taking the batterys out transporting them then putting back in. Just a thought anyway, hope it helps.

Probably 15 watts. A solar bank capable of 15A (180-200W) would be pretty large and expensive. In contrast, a 10A battery charger is roughly 120-140 watts.

15W is fine for maintaining and trickle charging, but it won't fully charge a well-drained trolling motor battery in a day. Of course, charge time depends on how much the battery is drawn down.