Battery connection question???

Gundog · 03-28-2010, 03:01 PM

My new boat that is still being built will have 3 batteries, one for starting and two paralleled together for the house. I run an electric pot puller when shrimping and use dual house batteries connected in parallel like one big battery. The system has a battery switch and an ACR.

My plan is to keep an inflatable dingy on the roof of the new boat and I have an electric trolling motor to power the dingy. I was thinking of connecting the 2 house batteries in parallel with an Anderson connector so I can unplug one battery for use with the dingy avoiding hauling an extra battery. The dingy will not see much use it will be for safety or going ashore on islands in AK. The raft won't be on the boat all the time. I will also use an Anderson connector on the leads of the trolling motor so the battery can be unplugged moved to the dingy and plugged into the trolling motor.

Now back to the battery being used for the boat through the battery switch the 2 house batteries provide emergency backup power for engine starting through the battery switch. The Anderson connectors are made in different wire size and amp ratings. I am not sure how big I should get to tie these 2 house batteries together. I can get them in most any wire size and in several amp ratings 50amp #6 or #8 wire size. 120 Amp, 175 amps & 350 amps. If you don't know Anderson connectors are what they use on Electric forklifts or jumper cables on tow / service trucks they are very high quality. I will solder and heat shrink the marine grade wire.

For the amp draw in my house use 50 amp would be plenty but I am wondering when the battery is used for emergency starting I might need to up the amp ratting to 120 or 175 but if I do finding a connector to fit the leads on the trolling motor will be hard but I guess I can solder it.

What do you marine wiring experts think? Another thing I am wondering is what will happen when I use the trolling motor and run down one of the house batteries and then connect them back together I would think it would drain the other one until they equalized but then they would both get charged again. This system will not see much use this way but on occasion it will be used.

Mike

Boat Doc' · 03-29-2010, 10:37 AM

Quote:

Originally Posted by Gundog

My new boat that is still being built will have 3 batteries, one for starting and two paralleled together for the house. I run an electric pot puller when shrimping and use dual house batteries connected in parallel like one big battery. The system has a battery switch and an ACR.

My plan is to keep an inflatable dingy on the roof of the new boat and I have an electric trolling motor to power the dingy. I was thinking of connecting the 2 house batteries in parallel with an Anderson connector so I can unplug one battery for use with the dingy avoiding hauling an extra battery. The dingy will not see much use it will be for safety or going ashore on islands in AK. The raft won't be on the boat all the time. I will also use an Anderson connector on the leads of the trolling motor so the battery can be unplugged moved to the dingy and plugged into the trolling motor.

Now back to the battery being used for the boat through the battery switch the 2 house batteries provide emergency backup power for engine starting through the battery switch. The Anderson connectors are made in different wire size and amp ratings. I am not sure how big I should get to tie these 2 house batteries together. I can get them in most any wire size and in several amp ratings 50amp #6 or #8 wire size. 120 Amp, 175 amps & 350 amps. If you don't know Anderson connectors are what they use on Electric forklifts or jumper cables on tow / service trucks they are very high quality. I will solder and heat shrink the marine grade wire.

For the amp draw in my house use 50 amp would be plenty but I am wondering when the battery is used for emergency starting I might need to up the amp ratting to 120 or 175 but if I do finding a connector to fit the leads on the trolling motor will be hard but I guess I can solder it.

What do you marine wiring experts think? Another thing I am wondering is what will happen when I use the trolling motor and run down one of the house batteries and then connect them back together I would think it would drain the other one until they equalized but then they would both get charged again. This system will not see much use this way but on occasion it will be used.

Mike

My opinion would be a 4th battery with connecters for the dinghy. I would avoid any quick disconnects except on the battery that will be removed from the circuit. you don't say how big your main engine is but 350 amp is probably on the low side of what would be required. The low battery will bring anything else hooked up to it to a level that would be even among them.
Something else to think about anyway.

Gundog · 03-29-2010, 12:24 PM

Quote:

Originally Posted by Boat Doc'

My opinion would be a 4th battery with connecters for the dinghy. I would avoid any quick disconnects except on the battery that will be removed from the circuit. you don't say how big your main engine is but 350 amp is probably on the low side of what would be required. The low battery will bring anything else hooked up to it to a level that would be even among them.
Something else to think about anyway.

Thanks for the input the main engine is a 250 Yamaha.