Where to ground a 12-volt power supply?

[In2ice]

I am trying to install a 12-volt power supply/cigarette lighter to my Yamaha G22. From everything I read it says not to ground anything to the frame but ground it back to the battery. The power supply will be wired to an existing switch that is not being used for anything. The switch is wired to the positive terminal of the battery with a fuse block as well. Do I just wire the positive to the switch and run the ground to the negative terminal on the battery? I don't want to wire anything wrong and cause any problems. Thanks in advance for your responses.

[scottyb]

You will need to check with a voltmeter which battery negative terminal gives you 12v before connecting.

Batteries wired in series like in a golf cart, add the voltage as they are strung together in series. Put your test leads on the first battery and you will get 6v. Move one test (-) lead to the next (-) and you should read 12v and then next (-) 18v.... etc. in this way you will see that depending upon where you start you can find 12v from any 2 6v batteries connected in series.

Having said that, remember that this type of 12v connection is only good for occasional use. If you use this 12v supply a lot you will draw those 2 batteries down more than the rest of the pack which will create an imbalance in the pack with 2 batteries needing more charge than the other 4....... the good 4 will get over charged waiting for the 2 low ones to come up. The 2 low ones will not come up as high as the 4 overcharged ones and this scenario will play out each time you recharge the imbalanced pack. Eventually this will shorten the life of the whole pack.

If you are going to use 12v power a lot, use a good quality voltage reducer.

[In2ice]

Thanks Scotty but I should have mentioned it is a gas G22 with only a single battery. Can I ground it back to the negative terminal?

[BeatYourTruck]

Originally Posted by In2ice

Thanks Scotty but I should have mentioned it is a gas G22 with only a single battery. Can I ground it back to the negative terminal?

Yep - I just installed one in my G14 and ran both the pos and neg back to the battery. Works like a charm and is very handy! I might add another to the passenger side