s - Alternators, 2 Batteries and Inverters...

OK, I am thinking of a new mod that involves mounting a larger (1600-2000 watt) power inverter in the rear area of my VX so I can run some more luxury items while camping :) . Now, I could simply install the inverter and run cables up to my battery from there. However, it is my understanding that you want your inverter to be as close to the battery as possible. In this case, I want my inverter all the way in the back, so I will be running cables the length of the VX to get to the battery in this case.

Now, that said, installing a second deep cycle battery seems like it would be a cool idea, and I think I have the space to do it where I want to do it. But, given that, would I need to upgrade my alternator to handle charging 2 batteries? If so, what does an alternator upgrade entail?

A second (backup) battery seems like the optimal way to do this. This way, I can run stuff off the second battery (coffee maker, Hella lights, etc) while not running any risk of draining my main (starter) battery.

So, can someone break all this down for me? What is the *best way* to accomplish this?

Thanks,
Bart

i upgraded my alternator with a 150a Alterstart alternator i got from biju

the install wasnt bad.. i had to raise the vx to articulate the suspension to get the old one out of the fender well.. other than that it was a pain to try to attach a 2/0 gauge wire to the alternator and had to get new battery terminals to support the wire size

ill effects... at idle the high output alternator only puts out 75 amps.. bumps to 150 at 1000 rpms.. made me nervous at first.. ive gotten used to seeing my idle voltage at 12.5 or so.. as soon as i touch the gas it jumps to 13.6-14.4

also my battery indicator lamp on the dash is always lit now because the circuit doesnt like the signal it gets from the alternators regulator (only supplies power when there is a draw, no extra to satisfy the stupid light that the alternator is working properly) so if i were to get my battery/alternator tested at autozone.. they would tell me its faulty.. even though ive driven like 3k miles on it

i believe that you will also need a system to divert power between the two batteries.. i think a PM to biju or spazz is in order

Thanks for the insight, E. Sounds like the 2nd battery/alternater upgrade might be something I should try to avoid.

So, that said, if I ditch the 2nd battery option and just run a bigger inverter up to my main battery, could I still do it from the back of the VX to the front? Or is that distance possibly too far? Or could I just get away with some heavier guage wire?

Basically, I want to avoid killing my main battery during a camping trip in the middle of the desert. That would be bad.

Bart

You could alwats bring along "ROM: Spaceknight", and plug stuff into him;)
How about relocating battery to the rear?
Best,

I personally think you're ok doing either of these.

A: Installing a second battery in the back, and no new alternator.
B: Installing the Power Inverter in the back with no alternator or battery.

I've ran multiple batteries, and 3,000 watts of amplifiers on a stock GM alternator, and it never went on me. I'd say start with Option B running a 0 gauge wire to the back of the VX to a fuse then to the Power inverter. Put it under the load you think will be typical while you're camping. If all seems well, roll with it for a while, keeping an eye on things. If you need to add a second battery, you'll already have the 0 gauge ran back there so installation will be a snap.

Thinks to keep in mind, Make sure you ground the battery with the same gauge wire as you ran the power. IMO Battery Isolators are unnecessary, but you may want to put one in if you're worried about the load on your alternator.

Worst case scenario, you start with just the inverter... then add the extra battery... then end up adding an alternator down the road. No need to get hit with everything at once.

Just my 2cents :D

U Will Need To Install A Auxillary Battery Solinoid Which Will Only Open When Engine Is Running Or U Can Install A Battery Isolator. The Solinoid Will Cost Far Less And Should Be Rather Easy To Install U Just Need To Wire The Excitor Lead To The Cold Side Of The Ignition And Route Your Battery To Battery Cables Thru The Solinoid. This Is How The House Batteries On A Motorhome Get A Charge From The Engine Same Concept. Hope This Helps You Can Get 3 Or 4 Post Solinoid From Almost Any Rv Dealer. If You Are Really Industrius You Could Also Wire In A Switch If You Get A 4 Post Solinoid And Then Could Use The Secondary Battery To Start The Engine If The Engine Battery Were To Die.

Yeah, it would be ideal to just leave out the 2nd battery alltogether. That would make it simple, and much less expensive.

So, if I went inverter only, I could run my + wire up to the battery and then the - wire to ground, so technically I could get away with 15-20' of wire.

Bart

Just buy one of those Honda generators. Super quiet and will power all your toys!:cool:

Bart,

I preach the KISS principle: Keep It Simple Stupid.

Your inverter should be OK without the second battery but grounding it at the back of the vehicle has the POTENTIAL of minor electrical gremlins. Try it that way first but if there are problems ... then run a ground to the battery.

A second battery will give you a lot of peace of mind. The set up erland mentioned is the most user friendly but more complicated for install. As an alternative, you can install an inline switch & a 5 ohm resister in line between the batteries. The switch will allow you to isolate the rear battery while camping and the resistor will allow the rear battery to charge without drawing down the altenator.

I don't think there is any need to upgrade your altenator unless you are installing some workhorse electrics like a winch or enough lights to outshine Vegas.

Have a look at West Marine Battery Combiner 150, PN 128293.
Every time I start thinking about a new electric system function, I goto the marine parts web sites for quality and useful items.
Roy

Quote:

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Originally Posted by newthings

Have a look at West Marine Battery Combiner 150, PN 128293.
Every time I start thinking about a new electric system function, I goto the marine parts web sites for quality and useful items.
Roy

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Hmmm, is that specifically to connect 2 batteries to an existing alternator with out overloading it?

Bart

Bart,

Did you ever do this mod?

I just worked the math & if you install a 2KW inverter and assume 90% efficiency (typical for Modified Sine Wave (MSW) units), you'll be drawing 185 Amps at max power. That's a lot of juice to run through a 12' cable.

I'm working on something similar on the Coachman & started a new thread on the topic.

http://www.vehicross.info/forums/sho...648#post167648

Tom

Quote:

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Originally Posted by tom4bren

Bart,

Did you ever do this mod?

I just worked the math & if you install a 2KW inverter and assume 90% efficiency (typical for Modified Sine Wave (MSW) units), you'll be drawing 185 Amps at max power. That's a lot of juice to run through a 12' cable.

I'm working on something similar on the Coachman & started a new thread on the topic.

http://www.vehicross.info/forums/sho...648#post167648

Tom

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Nope, I just kept the small inverter in my dash. I never found a suitable place for the bigger 1200 watt inverter. I actually FINALLY put the 1200 watt to use in my Trooper. Installed it and wired it up directly to the battery.

:) Bart

Bart, just wag'ing, and maybe someone already suggested it, but if your going to have the battery on the inside of your VX, think about venting gases to the outside.

But then since you always have your gas masks handy, guess it won't be an issue.

wag over:_thinking