inverter selection

[JohnEd]

If I'm starting from the beginning...what should I choose for the bat voltage to drive my inverter?  12, 24 or 48 seem to be the options and in the shore systems they seem to go with the higher voltage if they can.  I figure I can get 12 volts out of a 24 volt config to power my DC stuff.  It would also allow me to select lights, etc for 24 or 12.  Is this worth considering?  Ebay seems to have more 24 volt inverters available but that might be just today.

Thanks,

John

[H3Jim]

Its nice to have the house voltage the same as the bus chassis.   24  volts is a good choice,  depending on the voltage of the bus.  If the bus chassis is also 24 volts, then that allows you to charge the house bats from the bus alt with no further changes required.  It also allows you to jump the bus from the house bats if neccessary.

24 volts allow you to use smaller wire to those applicances that can use 24 volts.  DC wiring needs to be heavier than just what is normally requjired for safety for similar amps with AC,  This is due to voltage drop that can start to add up over some  fairly short distances.  Voltage drop is the driver for sizing your wire, so running 24 volts give you a little more leeway.  YOu can find 24 items if you look.  My refer is 24 volt, my water pump runs on either 12 or 24.  There are 24 volt halogen bulbs available for most household fixtures - a real plus so you don't have to have the inverter on to get light.

I have 0000 cable from my batteries to my 4000 watt 24 volt inverter.  You would be hard pressed to get that wattage from a 12 volt inverter. 

You need to have an idea of what your whole system will look like before you make the choice of inverter voltage.  There are consequences in applicances and wiring choices later on, so you don't want to be surprised when you get to those.

[JohnEd]

Jim,

I PM you a reply cause I thought I was getting a PM from you.  Tricky email system.

As I said I am really interested in those consequences...advantages....disadvantages.

I like the idea of the engine bat alternator doing double duty as that is a stout alternator.  The one I have been eyeballing is a couple hundred and puts out 185 amps at 12 volts plus the mounting adventure.

I hope others have info.

Thanks again,

John

[belfert]

185 amps at 12 volts will only get you 15 or 16 ampls of 120 volt AC by the time you factor in conversion losses and everything.  You'll pay more, but the 50DN will put out 270 amps at 24 volts.  You'll be able to do well over 40 amps of 120 volt if you can find an inverter large enough.

There are probably other 24 volt alternators that are less money than a 50DN, but I haven't been looking.

My bus has a Prosine 3000 24 volt so I can eventually charge off the alternator.  I wish I had an inverter with a transfer switch that could handle two 120 volt legs at 50 amp, but the Prosine was downright cheap as Xantrex had to factor refurbish a ton of them a while back due to a bad component.

[JohnEd]

Brian,

I miss-spoke.  My Bud has a 185 amp he will let me have for $135....not $200.  Thank you for your offer..sincerely.

Jim,

Who manufactures your 24 volt refer?

Thanks,

John

[TomCat]

John Ed,

I know of a fellow who offers rebuilt 12 volt, 200 amp Leece-Neville alternators, with three stage regulators, for just over $100, and not much shipping.
PM me if you'd like his info.

Good luck regardless of your action.

Jay
87 SaftLiner

[H3Jim]

Sunfrost.  Kind of pricy though.  It uses the danfoss compressor, there are others that use that compressor. 

I have a buddy that took a regular house refrigerator and change the compressor to the danfoss.  NOt sure how much it cost to do that, but a way to go.  The other thing that makes the sunfrost so efficient is the 4" of insulation around it.  The brains of the comporessor actually sense if its 12v or 24 volt and uses it accordingly.  The only difference between the 12 v and the 24 v fridge is the voltage of the light bulb inside.

[belfert]

I miss-spoke.  My Bud has a 185 amp he will let me have for $135....not $200.  Thank you for your offer..sincerely.

Hmm...  I wasn't offering anything.  Just giving an opinion on alternators and letting you know what I am using for an inverter.