Thread: Power Inverters
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Larry Larry is offline
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First recorded activity by BoatBanter: Jul 2006
Posts: 5,275
Default Power Inverters

"Robert Burkard" wrote in
news:flJwg.2161$fL3.1489@trnddc07:

Wow! Thanks, Larry. That was more information than I could ever have
hoped for.


Aw, p'shaw. T'wern't nuthin'...(c;

After reading your post, I checked the battery I'd be using to run the
inverter. It is a Seavolt 550 Marine **STARTING** battery. Got it from
WestMarine for $65.00. I don't know much about batteries (although I
now know more than I could ever thought possible - thanks again) but
the folks from WestMarine said this was a gel cell battery. Based on
your post, I'm not so sure that it is in fact a gel. Doesn't say so
anywhere on it. Also, based on your post, this battery will die a
quick death from my use with an inverter and recharging each time.


I looked at it. It's not a gelcell. "Maintanence Free" just means
"we've done all we can to keep you from dropping a hydrometer and
distilled water into it to save it". Those long plastic thingys along
the middle pry out then you can water and test it. They had to fill it
SOMEHOW. It's a wetcell and unsuitable for your power supply....


Against advice from those responding to this post, I did buy a Seavolt
400W power inverter from WestMarine yesterday. The cost was $40. I
looked for power inverters at Wal-Mart and Kmart but you ask the clerk
in either one of these stores for help in locating one of these in
their own store and you get a blank stare followed by the question
"You want to do WHAT with your battery?" So I chucked the frustration,
went to WestMarine and got the inverter.


That price is OK for a 400W inverter. I'm surprised it was so cheap at
Waste Marine. Next to the battery rack at WalMart they sell Black &
Decker branded Vector inverters. For $40, you probably could have gotten
the 750W model, but you're fine. It'll pull about 450 watts at full
power loaded to 400W so 450 divided by 12 = 37.5A. Use a 50A fuse and #8
wires if it has terminals. #10 is fine if you mount the inverter close
to the battery it's running from. Radio Shack has #8 flexible wires used
for big car stereos at reasonable prices. Unlike the Waste Marine #8,
you can BEND the Radio Shack cabling and it will survive a lot of flexing
the stiffer cheap wire won't before the strands start breaking. The
inverter is fused and that's all you need if you mount it next to the
battery with heavy wire. But, if you mount it where you have wires going
through bulkheads to power it, you need a primary fuse between those
wires and the battery to protect the wires from fire if they short.


The 550 is a spare battery so I guess I don't have a problem with the
recharging of it. When you get down to it, this might be
acceptable.I'm not going to power a microwave or anything like that. A
portable boombox, cell phone charger or the like.


Your 400W inverter is overkill for these items and will use nearly as
much power, itself, as you'll get out of it. The larger the inverter, the
more idle, no-load current it uses. Use the 550 until it fails, then get
deep cycle batteries later on.

There's a special rule for inverters:

"Loads increase to inverter capacity in one year."

If you had bought a 150 watt inverter, that would be your load on it a
year from now. But, alas, next year you will have found 400 watts of
"things" to plug into it....(c;

Nothing is funnier than watching the guy with the new 4KW inverter
carrying his electric heater down the dock with that special smile on his
face.....(c;