oteymc Posted September 6, 2011 Posted September 6, 2011 I need you to check my thinking here. I am replacing my 12v trolling motor with a 24v. I know how to wire the batteries in a series. What I need help with is charging. I currently am using a 2 bank on board charger, one bank for the starting battery, one for the trolling battery. What I am thinking I will do is use the same charger and put one bank on each trolling motor, then use a separate charger (one I currently use to charge a battery for my pond boat, it just hooks up with alligator clips) for my starting battery. My question is, since the trolling batteries will be joined in a series, do I need to disconnect them or have an isolator switch when charging. Will it mess things up if I don't? Thanks, Otey Quote
Sfritr Posted September 6, 2011 Posted September 6, 2011 I just switched to a 3 bank charger to cover all of my batteries. However, just running your motor should keep your cranking battery charged. I was previously using a 2 bank and they were both on my 2 trolling motor batteries. I never had any issues with my cranking battery not being charged. Cranking battery lasted 3.5 years with moderate use and never didnt crank when asked. I think you will be fine just using the 2 banks for each trolling motor battery. Quote
acar555 Posted September 6, 2011 Posted September 6, 2011 On 9/6/2011 at 2:52 PM, oteymc said: I need you to check my thinking here. I am replacing my 12v trolling motor with a 24v. I know how to wire the batteries in a series. What I need help with is charging. I currently am using a 2 bank on board charger, one bank for the starting battery, one for the trolling battery. What I am thinking I will do is use the same charger and put one bank on each trolling motor, then use a separate charger (one I currently use to charge a battery for my pond boat, it just hooks up with alligator clips) for my starting battery. My question is, since the trolling batteries will be joined in a series, do I need to disconnect them or have an isolator switch when charging. Will it mess things up if I don't? Thanks, Otey To answer your questions. You will not need to remove the jumper wire when charging. It just connects the + of one battery to the - of the other so each battery is not affected when charging. Quote
Super User Way2slow Posted September 6, 2011 Super User Posted September 6, 2011 Batteries in series are still individual 12 volt batteries, doesn't matter how many you have connected series. If you had five, 12 volt batteries in series, you could hook five 12 volt chargers, one to each battery, to charge them. Doesn't matter they would have 60 volts total, each charger is only going to see 12 volts. Now, if you are wanting to make do with what you have, I would go about it a little different. I would leave the charger just as you have it now. When I added the second TM battery, I would use the extra charger to charge it. Then I would make me a couple of jumpers with some #10 wire. When the boat was not going to be used for a couple of months or more, I would disconnect my series cable and use the jumpers I made and connect the TM batteries in parallel. That way all three batteries have the benifit of being maintained by the onboard charger. As for the motor's charging system keeping the cranking battery charged, don't plan on that unless you make very long runs at the end of the day. Several years back, there were a number of studies done on tournament anglers batteries and the vast majority of them were only at 80% charge when they quit for the day. Batteries start to sulfate rather quickly when a battery gets below 80% charge, so there's a good chance you will help you battery die a slow death. Quote
NBR Posted September 7, 2011 Posted September 7, 2011 I second Way2Slow's comment re don't count on the big motor charger keeping the cranking battery charge up. The set of jumpers in my boat are the result of that faulty thinking. Quote
Ann-Marie Posted September 12, 2011 Posted September 12, 2011 Consider the Trollbridge24. It automatically puts the 24 volt batteries in parallel for charging so you can use your existing charger. It switches to series when you start your trolling motor. A big advantage is you can also charge the 24 volt trolling battery from your 12 volt alternator when the main engine is running. This will extend trolling time and extend battery life. Quote
oteymc Posted September 17, 2011 Author Posted September 17, 2011 Thanks, I will check that out. Quote
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