| Inverters [message #124158] |
Sun, 01 May 2011 22:35  |
waynefraser
Messages: 38
Registered: December 2010
Location: Delta, BC
Karma: 0
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Hi all - I need some help:
I need to find the right 12v to 120v inverter for the coach. I have two 6v Golf batteries for house power, 1 12v battery for the engine and a newish 80amp alternator.
I just hooked up a used Vanner IT12-2400 Sine Inverter to the house batteries and could not get any more that 750 watts from it before it either caused the running coach power to drop to below 10v or switched off (due to "overload" or "low DC") even if the engine was running at RPMs well above idle.
What inverters have been sucessfully used on the GMC?
Thanks and Cheers, Wayne
Wayne Fraser,
1973 Glacier 260,
Ladner, BC
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| Re: Inverters [message #124159 is a reply to message #124158] |
Sun, 01 May 2011 23:06  |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
Karma: 0
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Senior Member |
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Wayne,
It may be how you have the inverter hooked up. For a while, on a temporary basis, I had my 2,000 watt inverter hooked with jumper clips to the heavy 1/0 battery cable that runs past the electrical closet and feeds the old converter and house fuse panel. That is current limited to around 50 amps (600 watts) by a circuit breaker that is near the house batteries in the battery/onan compartment. The circuit breaker is only bypassed when the boost switch is pressed. The amount of alternator charge you can get to the house batteries is also limited by the isolator or combiner that you use. I'm not sure what the original isolator is rated at, but my combiner will also only do 50 amps. Also, the original boost cable has been problematical on old coaches from an insulation standpoint. When I permanently wired mine in, I used 1/0 battery cable directly between the inverter and the house batteries. For my length, the cable actually should have been a little larger than that, but I found too good of a deal on the 1/0 cable not to use it. At any rate, if you really want 2400 watts, you need around 240 amps of battery cable capacity, which is getting close to thumb-sized if it's very long. And, even with 2 golf cart batteries, you can't do that for very long.
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: Inverters [message #124164 is a reply to message #124158] |
Sun, 01 May 2011 23:57 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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Senior Member |
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| waynefraser wrote on Sun, 01 May 2011 20:35 |
Hi all - I need some help:
I need to find the right 12v to 120v inverter for the coach. I have two 6v Golf batteries for house power, 1 12v battery for the engine and a newish 80amp alternator.
I just hooked up a used Vanner IT12-2400 Sine Inverter to the house batteries and could not get any more that 750 watts from it before it either caused the running coach power to drop to below 10v or switched off (due to "overload" or "low DC") even if the engine was running at RPMs well above idle.
What inverters have been sucessfully used on the GMC?
Thanks and Cheers, Wayne
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I assume you connected it to the pair of 6 volt golf cart batteries. If the voltage is dropping that much, either they are not charged well, or they are weak batteries. When you put a heavy load on weak batteries (that is their capacity is not what it was when new) the voltage will drop fairly quickly and shut down the inverter. Remember, you need roughly a 10 to 1 ampere capacity via the inverter. That is if you have an 8 amp load at 120 volts, you will need about 80+ amps at 12 volts from the batteries and into the inverter. That will drain those batteries very quickly.
Rob Allen
former owner of '76 x-PB
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| Re: Inverters [message #124171 is a reply to message #124162] |
Mon, 02 May 2011 06:58 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| waynefraser wrote on Mon, 02 May 2011 00:46 |
Thanks Craig
Im guessing we were using 15' of MCM 300 (at least) to connect the inverter directly to the battey terminals.
In my coach I have three batteries up front, accessable through the left side external hatch. I beleive that two are house and one is for the motor.
We didnt go through any of the coaches existing circuits. Is this an acceptable way to test the inverter.
I noticed that rest of the wires running to the battery from the isolators (etc) were a way smaller size wire (maybe 2ga?)could this be the problem?
Cheers, Wayne
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Wayne,
You say you have 15' of 300MCM to the battery terminals.
If you have both sides wired directly to the battery, and are not using the vehicle frame as the return path, then it is the batteries (that are in the right side hatch).
Want to test the inverter at load?
Charge the house bank with the coach's converter.
Make sure that the battery terminals are CLEAN.
Get two hunk of serious - 300mcm will do if you have more - like 2/0 in very short lengths and leave the inverter hanging out the front of the coach.
Put some kind of reasonably accurate meter on the battery terminals. Record what you see.
Turn on the inverter and load it up.
Record time, load and battery voltage as you step up the load.
When/If it crashes, drop the load and watch the battery recovery rate (this tells a lot about how the batteries are doing.)
Put this information on the forum.
Wait for three or four EE types here to get you a good diagnosis of your situation.
I run a CCV 750/1500 inverter of my house bank all the time. While I seldom ask it for more than 500W, it will do 750~800W for 12~15 minutes without loosing much bank voltage.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Inverters [message #124177 is a reply to message #124158] |
Mon, 02 May 2011 07:49 |
robert caudle
Messages: 25
Registered: January 2004
Karma: 0
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Junior Member |
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my guess would be too small of wire from batteries to inverter, and too long
a run.....the inverter should be as close to the batteries as is possible
because DC doesn't travel well, and the voltage drop in 15 feet will reduce
your available power. Big wire and big terminals for the DC run from
batteries to inverter, also both wires need to be the same length and
twisted to reduce hum. Then you can run the AC from the inverter with a
whole lot more efficency than the DC. Lots of info out there about
batteries and inverters, just put that in google
----- Original Message -----
From: "Wayne" <waynefraser@telus.net>
To: <gmclist@temp.gmcnet.org>
Sent: Sunday, May 01, 2011 10:35 PM
Subject: [GMCnet] Inverters
>
>
> Hi all - I need some help:
>
> I need to find the right 12v to 120v inverter for the coach. I have two 6v
> Golf batteries for house power, 1 12v battery for the engine and a newish
> 80amp alternator.
>
> I just hooked up a used Vanner IT12-2400 Sine Inverter to the house
> batteries and could not get any more that 750 watts from it before it
> either caused the running coach power to drop to below 10v or switched off
> (due to "overload" or "low DC") even if the engine was running at RPMs
> well above idle.
>
> What inverters have been sucessfully used on the GMC?
>
> Thanks and Cheers, Wayne
> --
> Wayne Fraser
> 1973 Glacier 260
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
> -----
> No virus found in this message.
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