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Battery Switch Install Question

T

TheBurbs

New member
I did some searching on the forum and couldn't find exactly what I'm looking for. I have a 1999 Crownline with a 4.3l Mercruiser in it. It currently has a single starting battery for everything. I want to install a second deep cycle battery with a 1 2 both switch so when stopped I can run accessories without worry. I've read the instructions, but I still have a question. My battery currently has a 1 AWG wire along with a few smaller gauge wires connected to the positive terminal. The switch instructions say that the common connection should go from the switch to the starter, but I'm wondering about all the wires that are currently connected to the battery. Should everything that is connected to my battery go to the common on the switch? Then I would wire each batter to the respective 1 and 2 spots on the switch?
 
Ayuh,..... You have to figure out where the smaller wires go, then decide which battery to hook 'em too,....

The switch's common post should only have 1 heavy gauge wire, which goes to the starter's main big lug,.....
 
bondo said:
Ayuh,..... You have to figure out where the smaller wires go, then decide which battery to hook 'em too,....

The switch's common post should only have 1 heavy gauge wire, which goes to the starter's main big lug,.....
Click to expand...

Ok, so I traced the wires. The biggest wire goes to the engine/starter. I've got a wire that goes directly to the power tilt trim pump. Then a small wire that looks like it goes to what I'm guessing is the bilge pump under the motor. Then I've got a medium size wire that powers all the accessories on the boat, the radio, amp, etc.

Would it be alright to have all of the other wires go to the 2nd deep cycle battery, leaving the starting battery with only one job?

Or should the bilge and trim pumps be attached to both batteries?
 
I would install a voltage sensing relay and forget about the battery switch. It won't do what you are hoping it will.
Only put the starter wire on the start battery. All other power comes from battery 2...trim, bilge, accessories, etc. The reason for this of course is that all those other things become parasites on the battery that you want to be dead sure is constantly fully charged and able to start the engine. Put all the secondary draw on the second battery. Depending on your draw, the second battery could be one, two or more connected in parallel making one big array.
The voltage sensing relay will always charge the start battery. Once it is full, the extra voltage is channelled over to the storage batteries to charge them up. With this setup, you needn't manually switch batteries or worry if the starting battery has enough juice.
There are good books on all this, along with some really informative articles and videos on the web.

I use a Yandina Combiner 200 (https://www.yandina.com/c200Info.htm) which can parallel both batteries in an emergency.
 
Last edited:
o2batsea said:
I would install a voltage sensing relay and forget about the battery switch. It won't do what you are hoping it will.
Only put the starter wire on the start battery. All other power comes from battery 2...trim, bilge, accessories, etc. The reason for this of course is that all those other things become parasites on the battery that you want to be dead sure is constantly fully charged and able to start the engine. Put all the secondary draw on the second battery. Depending on your draw, the second battery could be one, two or more connected in parallel making one big array.
The voltage sensing relay will always charge the start battery. Once it is full, the extra voltage is channelled over to the storage batteries to charge them up. With this setup, you needn't manually switch batteries or worry if the starting battery has enough juice.
There are good books on all this, along with some really informative articles and videos on the web.

I use a Yandina Combiner 200 (https://www.yandina.com/c200Info.htm) which can parallel both batteries in an emergency.
Click to expand...


Thank you. I think you are right. I essentially just want to be able to run the stereo when stopped without fear of not being able to start the boat. The switch seemed like the easiest option, but I did some reading on the VSR and it is really a much better solution.
 
I recommend two battery Blue Sea ACR and turning the trailer ski boat On/Off. No more 1, 2 off, all. Also have the boat switch in plain view (easy access). Note: this is a FW environment, if I was back on SW this switch would be placed back in its original location. See the trailer boat electrical diagram in the blue sea marine manual (Page 8?). Good luck

boat switch2.jpg
 

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