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1980 LWB 280GE
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Discussion Starter · #1 ·
In another thread a question came up that was basically, "Why not use an inverter?"

It got me wondering what sorts of things people that DO have inverters in their G's are using them for. I have a little one (650w) that I'ce used to power a little charger for my camera batteries, or things like that. But I know some of you folks do lots bigger and better things with AC power in the outback.

So how about it? What kind of inverter capacity are you carrying and what are you doing with it? If it required any additional upgrades like larger batteries or alternator, that would be helpful to know too.

-Dave G.
 

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2016 G550 & 2016 350 GLE
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698 Posts
Hipine,
You probably already know this, but I go over it anyway. Power is figured in watts that equals amperage times the voltage. P=ExI Then, I=P/E. If the power is 100 watts divided by 12 volts then the current is 8.3 amps. If a 700 watt inverter is installed in a Gwagen then the cable needs to be a #6 fine stranded. This is a drain of 58.3 amps on the alternator. The Drain on a battery would be fast and deadly if the engine was not running at a reasonable speed. I thought about putting one on mine as I had bought one a few years back. Luckily the inverter had died and I dropped the idea. Didn't need 700 watts anyway![;)]
 

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I've used them for more than 25 years. I actually had an old "vibrator" inverter in my SIII Land Rover back in the late 70's. Since I'm just now starting my equipment install in the G, I have none permanently mounted there. However, I've had a 600 watt inverter in my Rangie for about 10 years, and used it a LOT! I pretty much find it's hard to go without it now.

In actual use, it's rare that I draw more than a hundred watts. Usually for laptops, radio and tool chargers or other instruments that are temporarily installed in the passenger seats. Although I have on several occasions plugged in work lights and fans.

As for the installation itself, I personally always install a disconnect solenoid which is controlled by the accessories switch via a battery level sense controller. This also provides power to the radio transceivers too. This automatically disconnects all of the electronics during vehicle starting, which does double duty 1) allows max power for starting and 2) prevents voltage spikes from the starter damaging the electronics. This last is pretty important in the long run, considering that the vast arrays of power transistors in the Inverter and in the radio transmitters are permentently connected to the 12v input line. Also, using the disconnect solenoid prevents any chance of small power drains from the equipment running down the battery.

For wiring, last time I ran #2 welding cable via 3/4" liguid-tite flex conduit under the truck to the inverter/radio in back. Other essential upgrades were a 150 amp Delco 21SI alternator. I absolutely always put a main fuse right at the power feed from the battery circuit, and usually a power distribution box at the equipment in back, after the solenoid. I've found that marine power distribution boxes work pretty well for this.

As for the inverter itself, I've been using modified-sine wave inverters. These are dirt-cheap and reliable, however they have the very bad side-effect of producing considerable low-frequency emissions which can wreak havoc on HF radio reception. I suspect I will install a 1kw pure sine wave inverter in the G.

Something else worth thinking about is safety. Most all power inverters have a completely isolated ground output. This is good and bad. Good in that it's safer for a mobile environment, kind of like a permanent GFI, but bad in that sometimes strange ground-loops occur when they shouldn't. Probably due to the capacitive coupling in the output circuit filters. More than once I've had my face stung by metal-faced cell phones plugged into chargers running on the inverters.

As for my impending G installation, I'll be posting on here how it finally ends up. It will be completely different, as the G is representing a significant challenge. It is so much tighter-built in every respect than most any other truck-type vehicle I've worked with. Finding room for things is difficult, especially in the engine-bay. Getting a big alternator in there will be a challenge, and I guess I'll have to forget about dual batteries. But I will make it work.


Garret
 

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1982 300GD Turbo
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134 Posts
Dave, Great query.

Scottgs,
If you have time during your installation, it would be really great to see pics and narrative along the way. Maybe even for a clubgwagen.com tech post! Sounds like youv'e done your homework..........very interesting. Thanks for what you've posted thus far.
 

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1980 LWB 280GE
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3,505 Posts
Discussion Starter · #5 ·
Thanks Garret!

1kw pure sine sounds sexy. What kind of uses would necesestate such a piece of kit? I guess a better way to say it would be, "If I were just plugging in XXX, YYY, or ZZZ, the mod-sine inverter would be fine, but the JJJ really needs the pure sine power." What would fill the blanks above?

I've heard of some things that really didn't like to run on cheap inverters, but I don't remember what kinds of things they are, or what kind of damage/poor performance could be realized from such practice.

I also like the sound of your isolation relay setup. Would you mind drawing a little schematic and scanning it in here some time?

Thanks for your input!

-Dave G.
 

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73 Pinzgauer 710, '63 Unimog 404, '09 Jeep JK Rubicon
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53 Posts
I have a 1000watt inverter in my G. I use it for all sorts, its rather like a swiss army knife for anything that needs AC power. I work in film so more often than not it is recharging batteries, powering printers & laptops, running AC tools for running repairs and so on. It's most important function is running a small coffee machine that lives in the G for those sunrise "magic hour" shots.

It is connected to my backup battery and is mounted under the rear bench seat.

Its part of the Gs standard equipment as far as I am concerned.
 

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230 G BGS 300G TDI
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I am lucky in as much as when I bought my Military G it came equiped with a 1000watt inverter dual batteries dual cicuits and uprated alternator care of MBs original build spec for this NATO vehicle,I recharge my tooth brush and camera on it when on treks and use a lap top and dvd player, it came in very usefull recently during a power outage when my wife was half way through doing her hair.
 

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04 Adventurewagen
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As for my impending G installation, I'll be posting on here how it finally ends up. It will be completely different, as the G is representing a significant challenge. It is so much tighter-built in every respect than most any other truck-type vehicle I've worked with. Finding room for things is difficult, especially in the engine-bay. Getting a big alternator in there will be a challenge, and I guess I'll have to forget about dual batteries. But I will make it work.


Garret

Hi Garret, I do have similar plans - maybe not such a large inverter but for sure a dual battery set-up. I have looked under my truck (300GE) and there is quite a bit space between the frame rail and the drive shaft. It seems to be large enough for an compressed air tank and a second battery. I like to have the battery outside of the cab, the right engine compartment has some space, but it's over the exhaust manifold and going nuclear (the heat). Any thoughts?

Karl
 

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96 G300DT
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2,303 Posts
fernweh - 3/20/2006 9:36 PM

<snip>I have looked under my truck (300GE) and there is quite a bit space between the frame rail and the drive shaft. It seems to be large enough for an compressed air tank and a second battery. <snip>

Karl
The transverse frame tubes hold about 7L each. With adequate protection (wax, drains, etc) one could weld one or two up and have a good tank.
 

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04 Adventurewagen
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AlanMcR - 3/20/2006 9:52 PM

fernweh - 3/20/2006 9:36 PM

<snip>I have looked under my truck (300GE) and there is quite a bit space between the frame rail and the drive shaft. It seems to be large enough for an compressed air tank and a second battery. <snip>

Karl
The transverse frame tubes hold about 7L each. With adequate protection (wax, drains, etc) one could weld one or two up and have a good tank.
Alan, very good idea - like the vacuum tank in the front! Have to make a note of it, add it to my wish-list.
Karl
 
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