Date: Thu, 24 Jul 2008 19:12:31 -0600
Reply-To: Paul Connelly <vanagonhummingbird@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Paul Connelly <vanagonhummingbird@GMAIL.COM>
Subject: Re: Inverter Questions
In-Reply-To: <20080724222913.FFEQ8977.eastrmmtao107.cox.net@eastrmimpo03.cox.net>
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Hmmmm,,
Thanks David.
I thought that 100 amps seemed excessive (it was for short circuit
protection not normal operation - it has 2 x 30 amp fuses on board for Short
circuit protection, as well as overload and over temperature shutdown
protection too) and the wiring instructions calls for 10 awg (for cable runs
of 10' or less, 8 awg for longer runs - I am using about 5' in the original
plan). 500 watts at 12 Volts running at max would draw a little over 40 amps
- don't really plan to be up there, but that's the potential draw! Actually
the clips and wire that they supply with the unit is less beefy than the
wiring that I ran - maybe closer to 12 awg. They also supply a cigarette
lighter socket for uses up to 150 watts with like 14 or 16 awg!
I can mount it on the front side of the cabinet behind the drivers seat (I
was was leaning that way with Roger's comments earlier anyway, and Velcro
seemed like a good solution too) and use those cables to run to the back as
the 110 volt feed to the breaker box and run some fresh cables to the
auxiliary battery. Maybe a 40 amp breaker might be a better idea than a 100
watt fuse (also solves the switch rating problem)?
On the feeding the external circuit with the inverter rather than plugging
directly to it, I don't see any major difference between doing that and say
plugging an extension strip to the inverter and running a couple of small
loads off of it. I'm talking like cell phone charger (.15 amps, laptop 1.5
amps, if not using the laptop maybe a small DVD player, nothing major).
Although, if the inverter is accessible then so are the sockets - just kinda
makes the stock sockets obsolete ( I never hook up to shore power unless I'm
drawing the Dometic down at home before a trip. Talking of the Dometic,
that's the only potential high draw from that circuit if I forget to switch
it from 110 volts to DC or Propane. (Sorry BTW, the 240 V thing is inured in
my brain!)
However, what the application of 110 VAC to the output of the inverter might
do if that switch was left on (on the inverter unit or breaker) I do not
know - might be worth a try first!!! Also, looking at the manual a little
more, there is the phrase "Do not connect to ... any AC circuit where the
neutral conductor is connected to ground or the -ve of the DC source"....
which would mean the Dometic - which is connected to the distribution
circuit for the 110 VAC. So maybe you're on the right track with the grounds
issue!
Some more thought needed methinks... Thanks for your thoughts - much
appreciated.
Cheers, Paul.
1986 Syncro Westy - Hummingbird
On Thu, Jul 24, 2008 at 4:29 PM, David Beierl <dbeierl@attglobal.net> wrote:
> At 12:46 PM 7/24/2008 -0600, Paul Connelly wrote:
>
>> "no-no". Does anyone see any problems with setting the inverter up this
>> way?
>>
>
> Yes!
>
> against the "wall" between it and the lower closet. I have run 10awg
>> cables
>> behind the cabinetry to the auxiliary battery (Optima D34/78 run with the
>> "stock relay" setup).
>>
>
> If they want 100 amps fusing then you'd better run wiring that can carry
> 100 amps. That would be 3 AWG if you can get it, otherwise 2 AWG. Or to
> use 10 AWG, fuse for 30 amps.
>
> Not great ventilation in that location, but reasonable
>> volume of air, and the inverter has an internal fan.
>>
>
> I'd expect it to overheat on continuous high-draw use without additional
> ventilation.
>
> Its only a 500 Watt
>> unit with a no load draw of 0.3 Amps.
>>
>
> Heh. "Small" to me is a 50 watt unit, not 500. 500 is well up in the
> serious class.
>
> The installation guide recommends a
>> 100 Amp Fuse or circuit breaker close to the +ve battery connection and I
>> was going to put in a switch to eliminate the no load draw when not in
>> use.
>>
>
> Have you got a switch that can carry 100 amps? Let alone switch it...
> Better to bring the panel switch out on leads to an accessible location.
>
> I was going to then take the output (2 x 240V standard outlet plugs) and
>> wire them into the little distribution box with the circuit breaker below
>> the power outlets. However the installation instructions say that's a
>> "no-no."
>>
>
> Believe them! I can't tell what you're planning without more info, but
> whatever it is the answer is "don't even think about it." Even if you mean
> completely removing the external power connection there could still be a
> serious, maybe even spectacular issue with grounds. Talk to the mfr for
> advice if necessary.
>
> (Or any better ideas - I don't plan a lot of 240V use but would be nice
>> for
>> the laptop or DVD player etc).
>>
>
> How about get a nice little 100-watt unit that will stick on the cabinet
> aft of the driver's seat with velcro? And runs without a fan, and draws 75
> ma on standby. Although if you're talking about running AC-powered hi-fi
> equipment, you probably need a sine-wave unit to eliminate hum, so that puts
> you back in 500 watt territory probably. Incidentally, I presume you're
> actually talking about 110 VAC, not 240.
>
>
> --
> David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
> '84 Westy "Dutiful Passage," '85 GL "Poor Relation"
>
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