Paralleling batteries for my 12V trolling motor

[410001661]

Hi Guys,
I purchased a Minnkota Powerdrive V2 (12V) with iPilot for my StarCraft Renegade 168DC boat.  I would like to wire up (in parallel) two new, identical 12V marine batteries (27DC-180   MCA=1,000  RES 180 min  A.H. 120).  These two batteries will be feeding my MinnKota PowerDrive V2 trolling motor with iPilot.  Can I hardwire these batteries in parallel using and #2AWG flex cables and then connect the leads to the trolling motor.  

Is this a best practice or should I wire both batteries to a transfer switch and then toggle between them as needed.  The only issue I see with this is charging the batteries - I would have to charge battery #1 then move the switch to the second position to charge battery #2.  Presently I am using a ProSport 12 two bank battery charger.

Thanks - John

 

 

[Terry]

 

you can only use one bank of the charger to charge the batteries 

Edited December 3, 2021 by Terry

[Fisherman]

Yes you can use 2AWG, that way both batteries get identical use.  You can charge them in parallel this way with one charger.

[BillM]

You definitely don't want to switch between batteries.  Wire them in parallel and enjoy the extra capacity. 

[Garnet]

24 volt troller is the way to go. You have the battery's .

If you buy quick connects to change battery's and the cables for parallel would be cost of the 24 volt troller plus your 12 volt.

[410001661]

I already have a 12V trolling motor with iPilot.  To replace that motor for a 24V unit it would be around $2,400 even if I could find one.  

Paralleling the two identical 12V batteries doubles my capacity (120A.H. x2 batteries - 240A.H.) while keeping my voltage the same.  If I wired the two identical batteries in series my system voltage would double to 24V but my capacity would remain the same (120 A.H.).  I would much rather have the increased capacity IMHO.   

[410001661]

15 hours ago, Fisherman said:

Yes you can use 2AWG, that way both batteries get identical use.  You can charge them in parallel this way with one charger.

I received an email from ProSport and they are advising me to connect one bank of charging leads to one battery and the other bank of charging leads to the other battery even if they are wired in parallel.  

[Fisherman]

Yes that can be done, just undo one of the 2AWG wires between the batteries when doing that.

[Terry]

Exactly, when in parallel they act as one battery 

you can’t charge one battery with 2 chargers they shut each other off when they detect the voltage from each other 

Disconnect  one connector will let you charge them with 2 banks

[Sinker]

I have this set up, and do it as you described. I just have the two batteries wired together with the 2 AWG jumpers, then the TM connected to one battery.  My charger is connected to one battery, and they both charge. It takes a little longer to charge them if they are low, but still faster than charging 2 separately, and its very rare that I drain them. I charge them on 10A. 

I can troll steady at 1.5mph for hours and hours with no worries about draining the batteries. 

S. 

Edited December 3, 2021 by Sinker

[AKRISONER]

Honest question about your application and usage...is there any specific reason for wanting two batteries for that much capacity? Are you a heavy troller using specifically the trolling motor? The boys and I have put some extremely long hours on the boats and never once has anyone ever ran out of juice for their TM. To the point that our main batteries were low from running the graphs all day.

Do you specifically fish places for multiple days without access to a charger in open water?

The idea of using two batteries simply for capacity seems like a lot of weight for not much benefit, especially if you only have a 2 bank charger.

personally? save yourself a hell of a lot of money, weight and hassle, buy yourself 1 really high quality large AGM battery and call it a day.

Edited December 3, 2021 by AKRISONER

[Garnet]

Hooking 2 battery's in parallel doesn't make 24 volts. It's still 12 volt system and runs out of stuffing quick. A 24 volt system you will run your troller on a lower setting and still have  plenty of up power when wind gets mean.

24 volt system is worth every dime.

[Fisherman]

2 minutes ago, Garnet said:

Hooking 2 battery's in parallel doesn't make 24 volts. It's still 12 volt system and runs out of stuffing quick. A 24 volt system you will run your troller on a lower setting and still have  plenty of up power when wind gets mean.

24 volt system is worth every dime.

I think you need another look at basic electronics.  12 volts with 240 AMP/hrs will get you just as far as 24 volts with 120 Amp/hrs.  Either way you get 2880 watts of power.

[Terry]

A 24 volt system pulling a boat  at the same mph as a 12 volt system will last much longer mostly because of the amps needed to obtain the same speed the more amp the more heat is produced and heat wastes extra power

[410001661]

1 hour ago, Garnet said:

Hooking 2 battery's in parallel doesn't make 24 volts. It's still 12 volt system and runs out of stuffing quick. A 24 volt system you will run your troller on a lower setting and still have  plenty of up power when wind gets mean.

24 volt system is worth every dime.

batteries in parallel double your capacity.......and will last longer

Batteries in series double your voltage

[AKRISONER]

1 hour ago, 410001661 said:

batteries in parallel double your capacity.......and will last longer

Batteries in series double your voltage

 

this

[Garnet]

24 volt trolling motor will 100% less amps.

So your 12 volt  on 6 a little over half your 24 will be on 3. If the wind blows your 12 volt will quickly be on 10.

The 24 comes with larger prop so will handle the wind much better.

So 100% more efficient use of battery power and larger prop to handle conditions.

[DanD]

Sorry to some of the guys here; but the OP didn't ask for opinions of 12 volt verses 24 volts. OP asked, if the way he's wired his 12 volt batteries was a good way to do it. Yes (IMHO) it is probably the best way of getting the most out a 12 volt system. As for charging the batteries, just use the one bank of the charger for the two that are connected in parallel and the other bank to charge the starting battery; assuming you have one? As Shane (Sinker) said it will take longer to recharge the TM batteries; but 6-10 hours at 10amps should bring them back to full. Every fisher needs to sleep sometime. LOL So plug in the charger; let your Toddy of water, honey, cinnamon and your favorite whiskey warm and enjoy. Knowing the batteries will be happy and ready to go in the morning. 

Dan.

Edited December 6, 2021 by DanD

[410001661]

4 hours ago, DanD said:

Sorry to some of the guys here; but the OP didn't ask for opinions of 12 volt verses 24 volts. OP asked, if the way he's wired his 12 volt batteries was a good way to do it. Yes (IMHO) it is probably the best way of getting the most out a 12 volt system. As for charging the batteries, just use the one bank of the charger for the two that are connected in parallel and the other bank to charge the starting battery; assuming you have one? As Shane (Sinker) said it will take longer to recharge the TM batteries; but 6-10 hours at 10amps should bring them back to full. Every fisher needs to sleep sometime. LOL So plug in the charger; let your Toddy of water, honey, cinnamon and your favorite whiskey warm and enjoy. Knowing the batteries will be happy and ready to go in the morning. 

Dan.

Thanks Dan.  I already have a 12V TM with iPilot and forking out $2,400 - $3,000 for a 24V TM is not gonna happen.

[Sinker]

On 12/6/2021 at 7:42 PM, 410001661 said:

Thanks Dan.  I already have a 12V TM with iPilot and forking out $2,400 - $3,000 for a 24V TM is not gonna happen.

Forgot to mention, it is a lot easier on your batteries. I can kill one 31DC battery in a day trolling for walleye, but with the 2 in parallel, they only get drained down maybe 60%, so they aren't getting as much abuse. Before I added the second battery, i was lucky to get 2 full seasons out on one battery. With the two batteries, I am going into my 4th or 5th season and they are still as new. 

 

I also have the option of removing a battery if I wan't to lose 80lbs of weight out of the boat (ie duck hunting) and it helps a lot. 

 

S. 

[Salmon Catcher]

On 12/4/2021 at 10:39 AM, Garnet said:

Hooking 2 battery's in parallel doesn't make 24 volts. It's still 12 volt system and runs out of stuffing quick. A 24 volt system you will run your troller on a lower setting and still have  plenty of up power when wind gets mean.

24 volt system is worth every dime.

Wiring batteries in parallel or in series will not change your total battery capacity (total power). Im salmon troller on Great Lakes. Before that while fishing in small boats used to have electric charger built in to 7.5 Johson outboard to run graphs. 

[410001661]

59 minutes ago, Salmon Catcher said:

Wiring batteries in parallel or in series will not change your total battery capacity (total power). Im salmon troller on Great Lakes. Before that while fishing in small boats used to have electric charger built in to 7.5 Johson outboard to run graphs. 

Sorry but connecting batteries different ways you get different results:

- Series:  Capacity remains the same but your voltage is additive (12V+12V=24V)

- Parallel:  Voltage remains the same and your Ah is additive

Trust me on this.......I'm a master electrician

[Salmon Catcher]

3 minutes ago, 410001661 said:

Sorry but connecting batteries different ways you get different results:

- Series:  Capacity remains the same but your voltage is additive (12V+12V=24V)

- Parallel:  Voltage remains the same and your Ah is additive

Trust me on this.......I'm a master electrician

 

[Salmon Catcher]

My message above does not dispute your statement. It says ampere hours do not change. P=U * I

You must be familiar with this formula. Folks on this site attempting to play with two batteries to get more power.  

Industrial electrician, retired.

[410001661]

On 1/12/2022 at 12:59 PM, Salmon Catcher said:

My message above does not dispute your statement. It says ampere hours do not change. P=U * I

You must be familiar with this formula. Folks on this site attempting to play with two batteries to get more power.  

Industrial electrician, retired.

I think you might want to look at that again.  If you parallel two identical batteries your Ah rating of your batteries double (you add them together).  Remember doing series and parallel circuits in trade school? 

If your battery capacity did not change what would be the benefit of paralleling two batteries?