1111Aa RV3012M inverter installation photos

[Pete Masterson]

The (2008) LXIs I saw at CCW while I was on my extended service in Riverside have 10 (type 4D) house batteries located in (approximately) the same place as the house battery compartment in the '95 model. Since there are so many batteries, there's no room for the inverters in the same compartment as is the case for the '95. This compartment is just behind the tag axle. 

The inverters are next to the tool box (as in the 2000 LXI) -- but the cable run is quite probably no more than 12', taking the most direct route.

As for cable size, in the June 2008 Bus Conversions magazine, there is a discussion of suitable conductor sizes for 12v systems. With 120 v systems, cable size is generally based on the amp load expected, as the voltage loss due to resistance is usually not a significant factor with 120 v circuits. With 12 v systems, the voltage loss due to resistance is the primary concern as that usually becomes the more important factor before amp load becomes an issue:

Here's an excerpt from the chart in the magazine -- note that current and resistance are calculated from a combination of different sources ... they're about 24% lower than the National Electric Code but "slightly" higher than figures from the Radio Amateur's Handbook).

AWG       Size (in)        Max Amps      Ohms-per-foot resistance

0000      .53                195               .000051

000        .47                 165              .000064

00          .42                 145              .000089

0            .37                 125              .000102

The size (diameter) is approximate. These are stranded cables, so the size will vary.

To figure the loss in voltage, multiply the resistance (ohms per foot) times  the length (in feet) times the current (in amps). 

Since the maximum amps a 2500 watt inverter uses is about 20 amps at 120 v, the 12 v draw (well, actually 14v for a fully charged battery) would be about 180 amps. That suggests 0000 AWG wire as being the minimum size to use. (is there 5/0 wire available?)

Over a distance of 12 ft, the voltage drop would be .000051* 12 (ft) * 180 = .11016 or about 11% of the voltage. That's about 1.5 volts. As the voltage drops, the inverter will require more amps to output the required 120 vac amps and the wires will soon overheat and exceed the safe margin for the cable.

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Jun 11, 2008, at 9:45 PM, David Brady wrote:

Kurt,

Sorry I can't help with the cable size, I'm away from the bus,
but I don't think the inverters are more than 10 to 12ft from
the house batteries. I'll measure it when I have a chance. The
house batteries are behind the tag axle on the curb side. The
inverters are in the second to the last bay next to the toolbox.
I think the cable run is around 10 to 12ft.

David Brady
'02 LXi, NC

bumpersbird wrote:

I have posted two photos from e-bay of a 2000 Blue Bird LXI 43
Wanderlodge, the address is pasted below and I have these photos in a
new album in the photo section, named 1111AaRv3012M

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?
ViewItem&category=50056&viewitem=&item=110260798370&_trksid=p3907.m29

If the inverters cannot be more than 12' from the batteries, how does
this system work on a 2000 LXI ?????????????????????????