Trolling motor battery(s)?

[ll150stang]

I have a 92 Bass Tracker w/ a 36 thrust trolling motor. On windy days when using the trolling motor more frequent, the battery dies after 5 hours, shortening the fishing trip.  My question is, can i use 2 batteries twined together or will that harm the trolling motor? Also, how do you connect the two batteries together (just connecting the positive sides)?  Does anyone recomend a certain 2 bank/4 amp chargers? my stock charger is done. Thanks for any advice

[surfer]

If the battery is old it might just need replacing.

Yes, two batteries paralleled will act as one big one. + to + and - to -

[Nick B]

With at 36lb thrust you are using 12V, so if you wanted to tie 2 batts together, you would do it in series (Red wire on pos term of one batt, black on neg term of other batt, then connect the pos to the neg of whats left unconnected). If you go pos to pos, it would be wired in parrell and you would be using essentially a 24V batt. which would be very bad for a 12V system. (Oops my electrical knowledge has gone dislexic on me, I got it turned around )

Personally I would just carry another batt, you will actually get more life out 2 seperate batts then 2 tie together.

[Jig Man]

With at 36lb thrust you are using 12V, so if you wanted to tie 2 batts together, you would do it in series (Red wire on pos term of one batt, black on neg term of other batt, then connect the pos to the neg of whats left unconnected). If you go pos to pos, it would be wired in parrell and you would be using essentially a 24V batt. which would be very bad for a 12V system.

Personally I would just carry another batt, you will actually get more life out 2 seperate batts then 2 tie together.

You better rethink this advice.

[NBR]

Jig Man is right on. Parrallel extends hours at the same voltage, series of 12v to 12 v makes the voltage additive. 12v to 12v = 24v baaad for a 12v motor.

You don't say how old the battery is. Most autoshops, including Wal-Mart, can run a load test on the battery right in the boat. Don't hook a new battery in parrallel or series with an old one. Assuming the load test showed a good battery, I'd buy a new battery and if it gave out in 5 hours then I'd immediately get a second one of exactly the same brand and size.

It might be that

[nick76]

It may not be just the battery.  I had a brand new trolling motor and battery, could not keep a charge for more than 5 or 6 hours out on the lake.  I ended up rewiring the thing with new heavier gauge wire and installed an in-line ciruit breaker.  Mine came with 12 gauge wire and an in-line fuse of 35 amps.  My TM would over heat and blow the fuse, changed it out with 10 gauge wire (figured it out using a chart by the mfg with the distance of the run) and installed the circuit breaker, now it lasts 4-5 trips out on one charge and charges must faster as well.

P.S.   like a few others have said, if your TM is not capable of running in 24V mode then do not hook the batteried together, it will damage it.

[Garnet]

You can hook your batterys in parralell but you only get 25-30% more running time on batterys.

I carried the exacter battery and switch them when the first got weak.

This is very hard on batterys but keeps you fishing longer.

Garnet

[jim payne]

Don't know were thst 25% came from but if the batteries are good then you would get twice as much trolling time with two batteries.

[Garnet]

If you have 2 800 crank batterys in parralell you will get 1200 not the 1600 you are hoping for and then if they were not charged to the same level you will lose again and if 1 connection is just a little fuzzy you lose again, if your battery are not match set you lose again.

Most setups you will be really lucky to get 30% so use 1 then use the other. Theres is nothing harder on batterys than complete discharge and charge but to get the most time on the water use 1 at a time.

Garnet

[Wayne P.]

Garnet, what principal is involved that will not allow for doubling the amperage when connecting like batteries in parallel? I've never heard of that not being the case.

Does the same principal apply when doubling the voltage when connecting like batteries in series?

[Garnet]

30 years ago I hook my batterys together and was very dissappointed and had heard these #'s.

A couple years ago Anne Marie ran the #'s and spanked me for trashing batterys. I of course don't care if trash batterys are the result as long as fishing fishing time is increased.

Garnet

[bilgerat]

1) Is the battery a deep cycle marine battery or just a regular automotive battery ? A regular battery will not stand up to trolling motor use.

2) It's impossible to tell if wires and cables are good by just looking at them. They have to be checked with a meter to measure resistance. High resistance = batteries and motor working harder. Even if the terminals look good.

3) Are the trolling motor wire to battery connections alligator clips or eye terminals. Get rid of the alligator clips.

Lastly, how are you charging the battery ? A slow trickle charge is best as opposed to quick charging.

[wasabi_VA]

A slow trickle charge is best as opposed to quick charging.

Not true. Most modern deep cycle batteries want a high rate of recharge for most of the charging cycle. Then they want a lower rate for the finishing/topping off charge. Newer chargers provide this charge profile.

[Way2slow]

Wow, don't know were some of these fancy figures and "facts" came from.

FACT: Two batteries in parallel, will give you more than twice the run time of one battery. Most batteries you find advertising say an 105 Ah rating is based on a 20 hour draw. In other words you can only have approx a 5 amp draw on the battery for it to be a 105 Ah battery. Incease that draw to 25 amps and your battery just became about an 80 Ah battery. The more you load a battery the lower the capacity of that battery becomes. Now, if you connect another 105 Ah battery in parallel you just cut the draw in half, thereby increasing the effective capacity. If you run one battery for five hours and it dies, connect to a second battery battery and run it five hours and it dies, if you had connected the two in parallel, you pobably would have been able to run for 12- 14 hours instead of 10.

While it is"best" to have like batteries "and this is a must in series" it's not required in parallel. It's just going to pull the most load off the strongest battery and the other is just going to help out some. If you have a 105 Ah battery and a 80 Ah battery, you're still going to get 185 Ah, but the 105 is going to be doing more of the work. Unlike series batterys where the current draw is equal through all batteries and can damage unlike batteries.

Forget this 2 amp charge stuff also.  To properly charge a deep cycle battery it should be charged at approximately 10C (10% of it's rated capacity).  In other words a 120 Ah battery will charge at 12 amps.  

As also mentioned, the newer Smart chargers are much better and quicker at charging batteries because the the can charge heavy for the first part and when reaching 80% or so, they slow the rate to finish it off at a safer level.  Goods ones even have a float mode so you can leave them connected 24/7.

[Garnet]

You hook 2 batterys in parallel and excpect 12-14 run time you are in for a world of dissappiontment. Thats not smoke it's experience.

Garnet

[Way2slow]

I was probably a little high on the 14 hours, it would be more like 11 - 12 hours, but trust me, I don't claim to be an expert since I've only been dealing with them almost daily for the last 15 years.  Thats why I usually stay away from these battery topics.

[ll150stang]

Thank you all for the help. The battery is only a year old, and im running a little 25hp johnson tracker. Do they sell on-board chargers that shut themselfs off? Where i fish in connecticut, there not too many big bodies of water, so i only use the outboard for about ten minutes each trip, so the cranking battery doesnt lose charge. I think i'll get a new 2 bank charger and hook the trolling motor batteries up only SEPERATELY! thank again

[Dogface]

Cabela's just put the onboard 8 amp charger on sale for $80.00, normally $100.