oldphart Posted October 30, 2013 Report Share Posted October 30, 2013 ~~~I need 3 12v deep cycle batteries for my trolling motor. My question is can I charge them up as 1 leaving them connected as 36 in series, or should I charge them up singly Link to comment Share on other sites More sharing options...
Roy Posted October 30, 2013 Report Share Posted October 30, 2013 Charge them independently. Link to comment Share on other sites More sharing options...
steelhedrmatt Posted October 30, 2013 Report Share Posted October 30, 2013 Do yourself a favor....buy a 3 bank on board charger. Saves a lot of hassle. Link to comment Share on other sites More sharing options...
BillM Posted October 30, 2013 Report Share Posted October 30, 2013 (edited) Do yourself a favor....buy a 3 bank on board charger. Saves a lot of hassle. Yup. Plug it in and forget it. I love my Guest onboard charger. Edited October 30, 2013 by BillM Link to comment Share on other sites More sharing options...
Garnet Posted October 30, 2013 Report Share Posted October 30, 2013 Buy the 4 bank and charge your starting battery to. Link to comment Share on other sites More sharing options...
BillM Posted October 30, 2013 Report Share Posted October 30, 2013 Buy the 4 bank and charge your starting battery to. I don't think I've ever charged my starting battery.. The F115 on the back takes care of that anytime I'm out, lol! Link to comment Share on other sites More sharing options...
lew Posted October 30, 2013 Report Share Posted October 30, 2013 I love my Guest onboard charger. Best charger I've ever owned. When the MK charger that came with my boat wears out it'll be replaced with a Guest. Link to comment Share on other sites More sharing options...
DanD Posted October 30, 2013 Report Share Posted October 30, 2013 If you already have one of those small portable battery chargers and want to use it, there is a way to connect it to all three batteries and charge them all at once. You don’t have to disconnect the batteries from the trolling motor or each other. Take the charger’s leads and connect it to one of the three. Then with jumper wires of the same gage size or larger of the charger’s cables; connect the other two batteries in parallel. In other words positive to positive negative to negative; like you would while boosting a car’s dead battery. Even though the batteries are connected in series to get the 36 volts; individually each battery is still only 12V. If you want to confirm this, connect a volt meter to one of the battery’s terminals and then another and you’ll see that they’re still 12 volts. You can charge fifty batteries this way as long as the charger has the capacity. The only thing about charging the batteries this way; is that if there is one battery that is partly sulphated (only takes a light surface charge with voltage climbing quickly) the charger (if it’s a voltage sensing charger) will shut down before the other batteries get a full charge. That’s where a 3 bank charger would be your best bet; it has the ability to sense each battery individually. Here a crude schematic of what I tried to explain. Dan. Link to comment Share on other sites More sharing options...
Garnet Posted October 30, 2013 Report Share Posted October 30, 2013 Trollers wouldn't need to charge there starting battery's. High end electronics a very sensitive to low batterys. Link to comment Share on other sites More sharing options...
Gerry Posted October 30, 2013 Report Share Posted October 30, 2013 Charging them independently is best. As for the cranking battery, I know that my Mercury Optimax's computer has a constant draw on the battery, as does the GPS antenna. So, if you park the boat for a long period, i.e. 6-8 weeks you may have a dead battery when you get to the launch. I don't know what make of motor that you have but if has an ECM (i.e computer) then it probably does the same thing. I have a 4 bank DualPro unit on my boat and it does what it's supposed to do.....plug it and forget it. I've had DualPros for 10-12 years, on 3 different boats and they've never failed. Link to comment Share on other sites More sharing options...
oldphart Posted October 31, 2013 Author Report Share Posted October 31, 2013 ~~~Thanks guies, triple charger seems the way to go, Link to comment Share on other sites More sharing options...
Cosmos Posted February 11, 2014 Report Share Posted February 11, 2014 Guys, If I have 2 - 12v batteries connected in parallel(12v trolling motor) do you still recommend to use 2 bank charger or 1 bank? Link to comment Share on other sites More sharing options...
BillM Posted February 11, 2014 Report Share Posted February 11, 2014 If you use a 2 bank you'll need to remove the link between the batteries before charging.. 1 bank is easier for that setup (I had the same in our boat before I switched over to a 24v system) Link to comment Share on other sites More sharing options...
Cosmos Posted February 11, 2014 Report Share Posted February 11, 2014 If you use a 2 bank you'll need to remove the link between the batteries before charging.. 1 bank is easier for that setup (I had the same in our boat before I switched over to a 24v system) Thank you Bill, I thought same way. So basically with 1 bank charger negative is going to 1st battery negative and positive is going to positive on 2nd battery, right? Link to comment Share on other sites More sharing options...
BillM Posted February 11, 2014 Report Share Posted February 11, 2014 You got it. Link to comment Share on other sites More sharing options...
Cosmos Posted February 11, 2014 Report Share Posted February 11, 2014 Thanks Bill Link to comment Share on other sites More sharing options...
Cosmos Posted February 21, 2014 Report Share Posted February 21, 2014 Guys, I understood how charger needs to be connected. Now please tell me how I should connect trolling motor to those 2 batteries. Is it exactly same way as charger or I can connect it to positive and negative post of first battery and it will do it. Link to comment Share on other sites More sharing options...
BillM Posted February 21, 2014 Report Share Posted February 21, 2014 You need to connect the + and - to a single battery. That's 12V... Link to comment Share on other sites More sharing options...
Cosmos Posted February 21, 2014 Report Share Posted February 21, 2014 You need to connect the + and - to a single battery. That's 12V... Thanks again Bill. I thought if for charger I need to connect it wires to both batteries same principal is also applicable for motor. Link to comment Share on other sites More sharing options...
BillM Posted February 21, 2014 Report Share Posted February 21, 2014 (edited) You could try and run that 12V @ 24V but I don't know how long it would last, lol! Edited February 21, 2014 by BillM Link to comment Share on other sites More sharing options...
Old Ironmaker Posted February 21, 2014 Report Share Posted February 21, 2014 If you already have one of those small portable battery chargers and want to use it, there is a way to connect it to all three batteries and charge them all at once. You don’t have to disconnect the batteries from the trolling motor or each other. Take the charger’s leads and connect it to one of the three. Then with jumper wires of the same gage size or larger of the charger’s cables; connect the other two batteries in parallel. In other words positive to positive negative to negative; like you would while boosting a car’s dead battery. Even though the batteries are connected in series to get the 36 volts; individually each battery is still only 12V. If you want to confirm this, connect a volt meter to one of the battery’s terminals and then another and you’ll see that they’re still 12 volts. You can charge fifty batteries this way as long as the charger has the capacity. The only thing about charging the batteries this way; is that if there is one battery that is partly sulphated (only takes a light surface charge with voltage climbing quickly) the charger (if it’s a voltage sensing charger) will shut down before the other batteries get a full charge. That’s where a 3 bank charger would be your best bet; it has the ability to sense each battery individually. Here a crude schematic of what I tried to explain. Dan. The drawing shows the blue "jumper" going from positive on battery 1 to negative on battery 2 and positive on 2 to negative on battery 3. Is this correct? Link to comment Share on other sites More sharing options...
BillM Posted February 21, 2014 Report Share Posted February 21, 2014 The drawing shows the blue "jumper" going from positive on battery 1 to negative on battery 2 and positive on 2 to negative on battery 3. Is this correct? For a 36V system? That's correct. Link to comment Share on other sites More sharing options...
Old Ironmaker Posted February 21, 2014 Report Share Posted February 21, 2014 Thank you. Link to comment Share on other sites More sharing options...
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