adding a 2nd starting battery

[HaleDamage]

I’m thinking about adding a 2nd starting battery.
With all the electronic and pumps, I just want to be able to start the motor.
I have read some guys using “isolators” –“combiners” –“switches”.
Are these needed?
I just want to keep it simple.
I get 2 new starting batteries - connect them in parallel - then add a 2 bank charge.
Will this work?
Thanks
Rick

[rh1129]

I just did that in my boat you can certainly hook them together but if you get some kind of drain they both will be dead.I bought a simple on off switch fron napa I can send you a pic.it works really nice and you can charge them together but seperate them when on the water to always have that second full battery when you need it.

[ffishman]

That is a good idea. But, make it even better by adding a "battery switch". With the switch, you can use battery 1, or battery 2, or if need be both together. In the past, I've gone that route and it worked out great.

[1860Angler]

Originally Posted by ffishman

That is a good idea. But, make it even better by adding a "battery switch". With the switch, you can use battery 1, or battery 2, or if need be both together. In the past, I've gone that route and it worked out great.

If I were to add a 2nd starting battery I would also add the switch, then you could go from 1 to 2 or both, and when you are charging with a 2 bank charger they can be charged separately. If it was me, I'd go with a single Group 31 AGM battery and be done with it.

[REW]

X10 on the group 31 battery.
I don't think that it is necessary to go to the AGM battery, but going to a standard lead acid group 31 battery makes a lot of sense.

Since I have gone to the group 31, never an issue with the battery.

It is also a good idea to carry a pair of jumper wires to be able to jump from your starting battery to one of the trolling motor batteries.

In my case, I made a custom set of jumper wires that just reach nicely from the starting battery to one of the trolling motor batteries.

I have a permanent connection on the ground wire between the batteries. I then have a + jumper cable that will reach from one battery to the other. In order not to discharge, or have charging problems, I leave the jumper wire coiled up on the + terminal of the trolling motor battery. That way, I don't have to worry about shorting anything at all. If I do have the misadventure of needing a jump, I just take the nut off of the + terminal of the trolling motor battery and the nut on the + terminal of the starting battery. Connect the jumper wire between the batteries, and replace the nuts and tighten down.

When returning home, remove the jumper and charge the batteries normally.

The only time that this won't work, is that if you have had a very long day of using your trolling motor and have run both of your trolling batteries dead.

Be safe
REW

[4JawChuck]

What you want is a voltage sensitive relay and battery switch, this will allow battery selection combining and also permit secondary battery charging from the engine alternator once the main battery is above the cutoff voltage.

I have a BEP model, there are other models/mfgs in the marketplace to choose from but I've found this one to be reliable and compact...a quality component when compared to some of the flimsy ones I've seen.

This is a 12vdc dual battery model.
http://www.bepmarine.com/home-mainme...-battery-banks

Cutoff voltage is 12.8vdc so as soon as the engine is stopped and you use the secondary trolling battery, the two are seperated. I've never had to charge my twin Agm's when camping as long as the main motor is run long enough after trolling all day to charge the secondary...about 15-30 minutes with a 40A alternator.

These units connect together and there are various modules that plug in to expand the system if you add a third battery for a 24volt or a third module to expand to a 36volt system in the future.

Not the cheapest, but the best never is...I've transferred this switch/relay from boat to boat each time I sell...it's that valuable to me. Although I carry booster cables in the boat in case of emergencies I don't recommend running with them as a charging circuit between two batteries...great way to start a fire while underway and pounding through the waves trying to get home...a dedicated cable assy's with eyelets that get screwed down would be the only way to do that safely...not a spring clamp designed for temporary boosting or static charging.

Also acts as a disconnect which is handy in storage or a theft deterrent if it's placed behind a locking door. Wiring one of these into your boat can be complicated especially if you want certain circuits connected to specific batteries or have your bilge switch hot constantly, you might not want to do this yourself if your not handy with high current low voltage supplies, a mistake in wiring can be dangerous.

The instruction sheets for the various models give detailed wiring schematics to illustrate various methods of connecting their products to achieve specific results, not to mention minimum wire gages for interconnection.

[HaleDamage]

We normally hit a spot ..may fish there for 3-4+ hours using the TM...crappie fishing working brush and dipping trees.
With 2 HDS7's - LSS-1 - sometimes 2 live wells going..My voltage will drop to 12..0 -12.1V.
When I start the motor, my voltage drops enough to give me a "low voltage Warning" or restart the HDS7.
This does not happen if I start the motor every hour or 2.
Also want to start night fish ..that would add running lights.
I have a size 27 starting battery now. 2 years old..Just don't want to worry about getting stuck on the water.
And yes I have jumpper cables in the boat.

Just maybe replacing my battery with good size 31 battery starting battery would work for me???
Any Ideas on a good 31 size starting battery that won't break the bank?

I don't have a high powered stereo / big screen TV or Sat. dish on the boat yet..LOL

Thanks
Rick

[PJM]

HaleDamage

What brand of engine are you running?

[itsagr8day4fishing]

http://bluesea.com/productline/overview/329

Had the same issues and fish long drifts running nearly identical gear. Bought a second battery with the blue sea systems kit and It works flawless.
Peace of mind everytime I go out now.

[HaleDamage]

Originally Posted by PJM

HaleDamage

What brand of engine are you running?

I have a 2003 Murc. 115 hp 4 stroke.

Thanks Rick