I work at best buy and we recently put in a full system into a new ford golf cart. Think Neighbor is what it was called. The golf cart has a 72 volt system. We put in a red top battery and as we were a arguement came up. Some installers said that we shouldn't ground the battery. Some of the installers said we should ground the battery. Would some one help us end this arguement. If any further questions just ask.
A 72 volt system, huh? Does this mean it's got a battery bank with 6 twelve volt batteries? If so, why do you even need another battery? Just wire your equipment directly to one of the batteries for power: Connect yellow and red (on a switch) to positive, black to negative of the same battery.
If you do need to add a battery, you can ground it, or not ground it. The choice is yours, and since the Optima will not be paralleled with the other batteries, it's still on an isolated system, so it won't induce noise.
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My ex once told me I have a perfect face for radio.
The reason we used another battery was because none of us have ever touched a 72 volt. We weren't sure what it would do to the customers $14,000 golf cart, so to play it safe we threw another battery. That he would just put on a charger. So we could do it either way. If so, which way would be better.
As geepherder said, it wont really matter. Even if you DON'T ground it, the system will likely be grounded to the chassis through the components. This being mentioned, personally, I'd ground the two negative ENDS of the battery banks (just pretend the Optima is a battery bank - cause really, it is) to the chassis, and run all of your positive wires off the positive terminal of the Optima. DO THIS ONLY IF THE VEHICLE IS NEGATIVELY GROUNDED!!! It's going to be pretty important that you are certain your system grounds are all VERY solid, as at 72 volts, ANY kind of resistance introduced could provide a pretty good voltage difference... POP! go your components...
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
The Th!nk neighbor uses 12v lighting.. there is also an optional 12v 15a power point. Where is the manufacturer getting the 12v from? I'd consider using the same place.
Jim