Main and kicker connected to one battery

Hi, I posted this on another forum and not sure if I am getting accurate info. Can I connect both main BF135 and BF8 kicker motor to one battery without causing any damage, even if both engines are running? My kicker does not have electric start but does have the 12v, 6amp charging cord. I want to have it charging during trolling for electronics and keep the battery up. I have been known to keep main engine running while starting the kicker but don't have to do this.

It probably will not hurt anything, but is not the right way.

The recommended way is in a two motor installation, each motor should have its own battery.

Here is a potential solution to your dilemma....

If you do not want to add a second battery, you could install a battery switch but install it a little differently than a normal battery switch wiring.
1. Connect the battery positive lead to the common terminal on the switch.
2. Connect the positive lead of the big motor to terminal #1. Connect the positive lead of the small motor to terminal #2.
3. Connect the negatives of both engines to the negative terminal on the battery.

When you want to run the big motor, the switch should be on #1. It will charge the battery.l When you want to run the small motor, the switch should be on #2. Then the small motor will charge the battery.

If you want to run both motors at the same time, you will need to have the battery switch on #1 to start the big motor....leave it there. The big motor will then charge the battery. If you turn off the big motor, turn the switch to #2.

Never switch it to "all".....you will then have the same connection you have now.

Hope that was not too confusing or too much of a contradiction to what you have already been told.

Mike

Since you have no high current requirement for the kicker (no starter) a simple on/off switch wired to battery + from the kicker charging system will suffice. Off when running the main and ON when trolling. I DO NOT recommend operating the two systems simultaneously while both are connected to the battery. It could cost you a voltage regulator or charge coil.

I think I would want a two-battery solution for redundancy and safety and both batteries would be capable of starting the 135 - marine batteries will often fail without warning. Here locally on the Chesapeake, the various tow and rescue services get the most calls for dead batteries.

Yep! Agree with the chawk 100%. Marine batteries take a beating...literally...and fail much more often than those in the automotive world. The constant pounding of the hull banging about on the water's surface can cause them to come apart internally or, at the very least, cause pieces of sulphate to "sluff" off of the plates and that can cause an internal short. Gel Cell batteries alleviate this to some degree but can still be susceptible to internal damage.

Two batteries and the switch hondadude spoke of is the Cadillac way to go on the water.

Hey guys! Vtec1 just asked a simple question and just wants to trickle charge his battery with the kicker and we just redesigned his boat.

With the dual battery setup, he still could trickle charge one of the batteries with his small engine, but would have to disconnect the charge plug to his kicker if he ran his big engine with the battery switch on "all". So he is kind of back where he started. Although, his battery system would be much better.

Mike

Well, to complicate things even further, which is what I seem to do best, a diode in the charge line for the kicker should effectively isolate that system from the main engine's system and would allow him to run the main with the batt switch on ALL without a problem. Or wouldn't it?

A diode would protect the charging system on the kicker.

It would not protect the main engine if the switch was left on all. In reality, it probably would not hurt the big engine anyway.

It would be no different than the big engine connected directly to the battery with a battery charger connected to the battery.

Maybe all our discussion is a non issue other than accepted practice is to have one battery one motor.

Mike