Battery experts - need help

[Doug Stanek]

Hi



I have a 55lb thrust 12V trolling motor. I currently have two batteries in my boat - one a large deep cycle trolling battery and the other a marine starting battery. They are not connected. I would like to add another deep cycle battery to the system. I understand it I will have to place them in parallel (the two deep cycles). How do I do this and what gauge wire do I need?? Also, how will this affect charging the batteries. I have an XPS two bank 10V onboard charger, that works great now. Will the one bank still charge the two deep cycle batteries normailly with them in parallel mode? thanks

 

[Brian Bell2]

You will need to get a 3 bank charger if you want to charge all 3 batteries at same time.

 

[Doug Stanek]

so the charger wont be able to charge across the parallel connection of the two deep cycle batteris??

 

[Staci Matheis]

Yes, the charger will charge across the parrellel connection.



The easiest way to connect them is to just go to an auto parts store and pick up some premade battery cables the length you need. If the batteries are going to be next to each other, short ones will do fine!



Cut one end off each of the new cables and the end off the cables already attached to the batteries. The new cables will likely have one end that just fits over a bolt; that's the end you want to cut off. Leave the terminal end on because you are going to attach that to the new battery.



Take two loose ends from one each of the new jumpers and old cables and fit them into replacement cable ends that you can also pick up while you're at the parts store.



Run the jumpers from POSITIVE TO POSITIVE and NEGATIVE TO NEGATIVE between the two batteries.



Leave your charger hooked up just the way it was originally.



I keep trying to reword this..... I hope I'm making it understandable.....



me!

 

[Jim B]

Yep it will absolutly work, it will just take longer to charge is all.



Me! is right on. Yuo may even find an autpoarts store that carries premade cables with two ring terminals already one them. i got mine premade for about 6 bucks at autozone.



here is a picture to go with Me!'s explanation.

 

[Staci Matheis]

Good diagram, Mr. B!

 

[Staci Matheis]

Since it is for the trolling motor..... Attaching the ring terminal ends to the tightening bolt on the existing cable would probably work fine!

 

[Staci Matheis]

Additional thought.....



Be sure that you have a good flat surface to flat surface contact if you do that. Then, after running your trolling motor on high (under a load, in the water) for a short period, check back to see if the connection point heats up at all.....

 

[Brian Bell2]

Yep, that will work ,, I was suggesting 3 bank, cause I was just down this road, and ended up just getting Dual Pro SE 30 amp / 3 bank. The problem is the time it is going to take to charge the batteries, if your fishing both sat/sun all day, your batteries may not get fully charged in time for sunday

 

[Doug Stanek]

ok, here's what I did. went to walmart and bought the new deep cycle battery. they had cables for lawn and garden tractor batteries. 19 inch cables with ring terminal ends (flat). gonna use these to link the two batteries. should work fine. thanks for all of your help. tight lines to you all.

 

[Bill Gintzel]

I set my old twelve volt system up just like you are doing with the two ring terminal ended short jumpers. When hooking up the charger, put the positive (red) wire on one battery and the negative (black) wire on the other of the two. I used a 10amp charger, trolled for 6-8 hours and it always charged up overnight. Remember, this setup basically doubles your reserve capacity if were using only one battery before. The batteries I had were 55 Amp Hours Reserve each so together I had 110 Amp Hours. That only works on batteries hooked up parallel.

 

[Scott Hammer TOXIC]

Remember to swap the batteries around once in a while also so the drain cycle isn't always on the same battery.



TOXIC

 

[Bruce Freeman]

Not needed to work but if you do the same with the TM wires as suggested with the charging wires, 1 each on each battery it will think it is one huge battery and no need to swap them around as Toxic suggested.

BF

 

[Scott Hammer TOXIC]

You sure Bruce? I thought the first battery in the series drained faster than the second battery could replentish....not a lot faster but it will take the easiest current first.



TOXIC

 

[Staci Matheis]

Bruce and TOX, the electricity just doesn't care.

It is NOT necessary to switch them around.

 

[Staci Matheis]

I'm sorry, Tony, but I just don't see what the logic is in all that.....

Am I missing something?



If you have a bad cell in one battery.....

Replace the battery!

 

[Tony Hughes]

Me,

If the batteries are hooked up parallel, and one battery goes bad 1. You won't be able to fully charge both batteries because the bad battery will be continously draining the good battery. You may not realize you have a bad battery untill you are out on the lake and the trolling motor just doesn't last all day. By that time battery #2 is weak from continuosly being discharged. 2. A battery switch isolates both batteries individually or allows you to use and charge both of them together. If you are fishing a two day tourney and you don't have access to power at the hotel, use battery #1 saturday and then sunday you have a fully charged battery for that days tourney. If you didn't have the battery switch, you would be using both batteries saturday and they may not be strong enough for sunday especially if you were fighting the wind all day. 3. How do you know which battery is bad to replace? Both may read 12.5v untill you put a load on them. You would have to disconnect them, charge each one individually, and then load test both of them. But if you had a switch, just turn the switch to isolate the two and test them.

 

[Staci Matheis]

1. That's bunk.



2. Well... That is true... BUT... If you're a serious tournament angler, you should have your batteries checked on a regular basis. No juice is still no juice no matter which day it comes on.



3. Even if one battery is VERY weak, tested for voltage only it can still read good. This arguement doesn't hold water - or acid.

 

[Tony Hughes]

Me,

The guy was asking for help with his battery setup. I gave him my personal opinion. What do you do for a living? Do you have a technical background to back up your statement. I can assure you I know what I'm talking about and I am a serious tournament angler, and I do have a battery switch mounted in my boat. Staci since you are boatless, I'm sure you have a lot of time on your hands to nit-pick my posts, but I can assure you I have the background to help this fellow fisherman. If you don't like my posts,please keep you're comments to yourself.