Best way to tap 24v trolling batteries?

[teecro]

I'm not looking to be rude here but just because y'all drew a picture on a napkin does not make it so.... I explained this in my first post to this thread; you can't hook a single pair of batteries up in both series as well as parallel..... The ONLY way to get 24 volts out of two 12 volt batteries is to hook them up in SERIES and ONCE hooked up in series the ONLY way to get 12 volts is to tap the (-) & (+) on one battery OR the other....

-24-----(-)--B1--(+)-----(-)--B2--(+)----- 24+

[HandymanHerb]

I have 36 volt TM, and used it as both 36 and 12 volt at the same time, and then my 3 bank battery charger would charge each battery as to what it needed, then during the week I would take the batteries and use them in my work trailer to run to run saws and sanders, and could do four houses when I was doing window trims, so I could do houses they haven't even had electric run to the neighborhood yet.

[teecro]

I have 36 volt TM, and used it as both 36 and 12 volt at the same time, and then my 3 bank battery charger would charge each battery as to what it needed, then during the week I would take the batteries and use them in my work trailer to run to run saws and sanders, and could do four houses when I was doing window trims, so I could do houses they haven't even had electric run to the neighborhood yet.

You are spot on Herb in that a multi bank charger can indeed charge batteries that are discharged differently.... I need to remember that...

[photonfanatic]

I'm not looking to be rude here but just because y'all drew a picture on a napkin does not make it so.... I explained this in my first post to this thread; you can't hook a single pair of batteries up in both series as well as parallel..... The ONLY way to get 24 volts out of two 12 volt batteries is to hook them up in SERIES and ONCE hooked up in series the ONLY way to get 12 volts is to tap the (-) & (+) on one battery OR the other....

-24-----(-)--B1--(+)-----(-)--B2--(+)----- 24+

Yeah we decided to run a little experiment on his idea just to find out. Using D batteries. It created a short. I kind of thought it would, but hey I'm an electricity noob so I was open to ideas. I was mainly just messing around when it comes to this idea, and trying to learn a bit through experience. But thanks for the reply.

But to be clear, you'd actually recommend buying the golf cart reducer, as opposed to just tapping a single battery? As we discussed earlier, tapping one battery would create an imbalance in the system. But at the same time, you guys are now talking about the battery charger correcting the imbalance once the boat gets plugged in, back at the house. So is it really ok to just tap 1 of the 12v batteries, or not? If it is, and its not going to cause any harm to the system, I think I'll save myself $100 on the golf cart reducer lol

Next question. 4.4amp charger, or 15amp charger? Which one should I buy?

With a smart two bank charger won't it charge the batteries at different rates as needed by each battery? Therefore eliminating the problem of over-charging one while charging the other?

That should work out very well I would think..... What is cost of a dual bank charger verse the voltage reducer and 24 volt charger would be the question.

Been awhile but I'm just now getting back to this project. Been really busy at work and haven't had time to mess with the boat much.

Anyway I wanted to ask you if I have to have a 24v charger for my 24v trolling motor battery system. Or can I just the 2 12v batteries individually? Would this be a good deep cycle charger? Its only a 4.4 amp charger though... so does that mean its a bit too weak?

http://www.amazon.com/NOCO-G4-UltraSafe ... le+charger

And then there's this one, which is 15 amps. What's the difference? Does one just take longer to charge?

http://www.amazon.com/Guest-2613A-Batte ... ry+charger

[JBO]

So is it really ok to just tap 1 of the 12v batteries, or not? If it is, and its not going to cause any harm to the system, I think I'll save myself $100 on the golf cart reducer lol

Next question. 4.4amp charger, or 15amp charger? Which one should I buy?

Tapping into one battery for 12V probably won't hurt much, but the batteries will equalize and the one you are draining off of will drain the other down a bit. If used sparingly, it won't matter. If used all the time it wouldn't be the best solution.

How many amp hours do you intend to use the batteries in a given outing and how long do you have to charge it?

Example: If you have an 80amp hour battery and use 30 every outing then it would take approx 2-3 hours to charge at 15amp or 6-8hrs with a 4.4amp. The time difference may not matter to you. Either way, its best to get them on the charger ASAP once they've been drained a significant amount to keep the batteries in better shape.

[photonfanatic]

I'd say I'll probably use up most of the power, but not all of it. Probably 80-90% of it. I don't really know though, I'll have to do some tests. Running the trolling motor a lot, and then all those lights at night. Trolling motor may not be used much at night, as that will be catfishing.

I'll have about 10 hours to charge it, maybe 14. I'll just buy the 4.4 amp charger and see what happens.

[JBO]

I'd say I'll probably use up most of the power, but not all of it. Probably 80-90% of it. I don't really know though, I'll have to do some tests. Running the trolling motor a lot, and then all those lights at night. Trolling motor may not be used much at night, as that will be catfishing.

I'll have about 10 hours to charge it, maybe 14. I'll just buy the 4.4 amp charger and see what happens.

If you plan to use 80-90% of the power everytime you use the batteries you should probably plan to add more /larger batteries. You'll kill your batteries really quick with that type of use.

With my above example, if you used up 60amp hours then it would take 12-16hrs to recharge at 4.4amp. Perhaps I'm not getting it, but it seems like you're trying to be too cheap with a charger. Why not just get the 15amp? What's the cost difference between the two?