Getting Started...need some help

rcota86

I was just wondering how to and if i have to ground my system i have a 12v deep cell battery running to a 400w 120v power inverter that i will be using in my ice shack. It is built directly to a metal frame trailer should i run a ground cable from my battery to the frame or do i need to ground the inverter itself or do i really need to ground anything at all? Thanks for any advice it would be appreciated

niel

Re: Getting Started...need some help

that depends. if it is off grid and no inspection then i'd say do without the ground. if grid ac is present you may want to tie to the same ground rod if it is one of the quality sine wave inverters that won't get messed up with a ground connection like many cheaper (usually modsine) inverters do.

westbranch

Re: Getting Started...need some help

If you are on a frozen lake where is the "GROUND"? ie the bottom of the lake. My view is don't bother as it wont do anything...

waynefromnscanada

Re: Getting Started...need some help

westbranch wrote: »

If you are on a frozen lake where is the "GROUND"? ie the bottom of the lake. My view is don't bother as it wont do anything...

Don't totally agree with the "it won't do anything" part. It it's as I /we expect, a MSW inverter, "grounding" one side of it's output and the battery negative to the frame of the metal trailer will cause very interesting things to occur. Things like smoke and maybe even sparks being emitted by the inverter. Perhaps properly defined as a short "circus".
But all joking aside, I wouldn't bother grounding anything. If you ground the battery negative to the metal trailer, then you stand the chance of getting a jolt from either of the 120 volt output lines from the MSW inverter if you were to accidentally contact either one, and the metal trailer at the same time. There is no neutral with most MSW inverters, and each output wire hangs around 50 or 60 volts above battery negative. Thus the smoke if you ground either one, and the jolt available if you touch either one while you yourself, and the inverter are grounded. And yes, I have been on the receiving end of such jolts after forgetting that the "neutral" wire was indeed not neutral!

rcota86

Re: Getting Started...need some help

Thanks for the info didnt really think i needed a ground but it was worth asking i guess. I plan to put a 5 watt panel on soon also which should be good enough for the amount of use the battery will get which will maybe about 3-4hours a weekend in the winter

waynefromnscanada

Re: Getting Started...need some help

rcota86 wrote: »

Thanks for the info didnt really think i needed a ground but it was worth asking i guess. I plan to put a 5 watt panel on soon also which should be good enough for the amount of use the battery will get which will maybe about 3-4hours a weekend in the winter

Don't be too sure the 5 watt panel will do the job. Batteries naturally self-discharge, and usually a 5 watt panel will only just keep up with that self-discharge, leaving nothing to actually recharge the battery. Also, even if it would over time, do any useful recharging, it would take a long time, during which your battery could well be damaged through sulfation of the plates that takes place over time when the battery is not fully charged. Many of us leave a 5 watt panel connected to small batteries like used in bikes, lawn mowers etc, just to keep the battery from going dead from self-discharge in the off season. The charge rate is so low that we just leave them connected with no fear of ever overcharging.