Inverter installation help

M

mwilson

New member
Any electrical advice out there. I'm trying to install an inverter and it seems if I do not attach the inverter close to the battery it shuts down from too much load. I'm putting in a 1000 watt, is there a formula for the size wire to use as you add distance from the battery? Thanks Michael
 
This is your lucky day. West Marine has a table of Marine Wire which shows wire gauge vs length and current. It's on page 422.

For a 1000 watt inverter, you're drawing about 80 amps (1000 watts/12.5 volts=80 amps) and your total distance is twice the wire length. Remember the current has to get there from the battery and then return. When I installed a 1000 watt inverter in Journey On, it was a 25' run from the battery to the inverter, so make sure you measure the run accurately. I used 25' of 4 gauge to and 25' of black back. Works well.

I hope you have a true sine wave inverter, everything works so well, as opposed to the square wave.

For the wire, I did an internet search to buy it. At the moment West Marine wants $3/ft for the tinned stuff. Since you're using the inverter in a closed boat, you can consider non-tinned wire. I crimped the lugs with an Anchor heavy cable crimping tool, P/N 701010. They're expensive at West Marine, so another internet search would be good. I also sweat soldered the connections, but that's not necessary.

Remember, smaller wire will just spend your battery energy in heat, so get the right size. That's why your inverter is shutting down: low voltage.

Boris
 
If it were me, I would not solder the joint. Solder can wick up the wire and make it too rigid and crack if stressed.
Instead, I would use a heat shrink tubing on the lugs that has glue on the inside. On aircraft, there is a product called PD-70 that was such a type of heat shrink.
The joint can be considered water resistant when applied correctly.
 
I liked what I got, and the price, from the below site. You can order exactly the length and gauge you need. They have a table and a calculator to figure out the right gauge. I have absolutely no connection to the business.

http://shop.genuinedealz.com/

Steve in Olympia
 
At your local West marine you can use their big crimp tool for free. Just bring in what you need done.

As for soldering. I do it when I can and its the better way to go but you have to back it up with a anchor of some sort. Wither its a tie wrap to some thing or one of those stick one anchors with a tie wrap you need one about a inch from the solder. If you do that you will never have a crack and you will have a much better connection.

If you use in line or terminal crimps use the one with the built in shrink wrap. Most electrical supply shops, there's one on Broadway in Everett, should have them. Use a tube of dielectric grease. Just squeeze some into the crimp connector before you set the wire in. When you use a heat gun to shrink the heat shrink the grease will run thru the wire and out to the end of the heat shrink. hard for the water to get in that way.
 
Sorry Tom, but I'm with sawmildon on this one - use the heatshrink with the glue inside. Dialectric grease is designed not to conduct electrical current. It is used to prevent stray current leaks and can be used to prevent corrosion after the connection has been made.

Installation instructions for high current/low voltage devices like batteries and inverters usually include a warning Not to use dialectric grease on the connections before a metal to metal connection has been made tight. It can result in overheating the connection because of the increased resistance.

I made my own tool for crimping 2/00 battery cable lugs. Rather crude looking and involves the use of a hammer :shock: but it works great.

Regards, Rob
 
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