Large inverter wiring? Low voltage, yes; low energy, no.

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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Hey, guys, I want to install my 2500w inverter in the work van, most likely on the bulkead behind the driver's seat. I'll probably install a second battery, too, a deep-cycle marine/starting battery in a battery box.

While I know it's not recommended to merely parallel dissiimilar batteries, I did so in an older mini-van when I had a high-power, multi-amplifier audio system, with #8 between the batteries, and it worked fine.

I guess the length of wire between the main battery and the audio battery positive terminals was enough to limit charging current and back-feed starting current. The audio battery was in a box behind the driver's seat.

I know the battery isolator is the way to go, and probably what I'll do, which brings me to my question: What's the best type of wire to use in a vehicle? Welding or DLO cable, THHN/THWN, or auto battery cables?

I'll need wire for the alternator/isolator and the aux. battery, and between the battery and the inverter. At full power, the inverter could use 200a, so I'll want a 200a fuse between the battery and the inverter, too.

So, do I use 3/0 copper, or is that overkill for what should be a relatively low-duration current, and would simple, pre-assembled battery and starter cables from the auto-supply store be adequate for the purpose?

Also, do any of you guys have ideas for a better place in a van for an inverter? I have a remote for it on the way, so it can be hidded. The inverter is an AIMS PWRINV2500W (imaginative number :roll:), about 19" x 10" x 3.5".

As always, thanx!
 
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iwire

Moderator
Staff member
Location
Massachusetts
This is a case where bigger is better, I would not under size any of the cables running 12 VDC as voltage drop will really kill the inverters efficiency and you know any heating of the cables is power wasted.

You should PM "hurk" he is (or was) running a killer inverter / battery / charger / control in his work truck.

When the battery voltage dropped to low it would start the truck.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
This is a case where bigger is better, I would not under size any of the cables running 12 VDC as voltage drop will really kill the inverters efficiency and you know any heating of the cables is power wasted.
I grok.

What about insulation type? I'm concerned with durability.

What is used in the PV systems you work on?

You should PM "hurk" he is (or was) running a killer inverter / battery / charger / control in his work truck.
I shall do that.

When the battery voltage dropped to low it would start the truck.
My remote starter has that feature built in, if I'm not mistaken.
 

hurk27

Senior Member
Hey, guys, I want to install my 2500w inverter in the work van, most likely on the bulkead behind the driver's seat. I'll probably install a second battery, too, a deep-cycle marine/starting battery in a battery box.

While I know it's not recommended to merely parallel dissiimilar batteries, I did so in an older mini-van when I had a high-power, multi-amplifier audio system, with #8 between the batteries, and it worked fine.

I guess the length of wire between the main battery and the audio battery positive terminals was enough to limit charging current and back-feed starting current. The audio battery was in a box behind the driver's seat.

I know the battery isolator is the way to go, and probably what I'll do, which brings me to my question: What's the best type of wire to use in a vehicle? Welding or DLO cable, THHN/THWN, or auto battery cables?

I'll need wire for the alternator/isolator and the aux. battery, and between the battery and the inverter. At full power, the inverter could use 200a, so I'll want a 200a fuse between the battery and the inverter, too.

So, do I use 3/0 copper, or is that overkill for what should be a relatively low-duration current, and would simple, pre-assembled battery and starter cables from the auto-supply store be adequate for the purpose?

Also, do any of you guys have ideas for a better place in a van for an inverter? I have a remote for it on the way, so it can be hidded. The inverter is an AIMS PWRINV2500W (imaginative number :roll:), about 19" x 10" x 3.5".

As always, thanx!


Got the PM,:grin:

I was running a 36kw, triplett full sine wave, with an auto battery maintainer system for a travel trailer of the same rating, the neat thing about this set up was this travel trailer system had a male plug to plug in to 120 volts 30 or 20 amps, and a auto transfer switch, and would also recharge the battery's, the suggested amp hour ratting of battery's was 5 120 AH, I used 10 240 Delco deep cycle.

Remember the float charge of a deep cycle and a starting battery are different, deep cycle is 13.6 volts and a starting battery is 14.2, without a regulator you will be over charging a deep cycle, go to your nearest camper parts and sales and look for a regulator for about 30-60 amps output depending upon your alternator size.
I was using a 285 amp GM big truck alternator, installed by GM for my van when I ordered it, 246 amps will drain any battery even running the motor at a high idle, if your using a stock alt. which for most is only 104 amps if that.

I used 3/0 fine braid HD truck cable, available from most truck garages, or cheaper if ordered online, still a few bucks.

and last but least, my Bull Dog keyless auto start system, paid a big ol 49.95 at Sam's club LOL it was a down size that was supposed to only start the van, but when I got to digging into it, I found out they had put everything in this unit but didn't give the instructions how to wire or program the other functions, but all the electronics were in it, I think they just made one unit for all, just had to go to their web site and down load the PDF's for other units that offered these functions and which capped off wires to use, they had some neat functions, like having it start the van up when the inside temp got below 50?, set the van to start up every morning at 6:00am Monday-Friday to be all warmed up when I went to jump in it, and last but not least monitor the trucks main starting battery, and another wire would monitor optional batteries, both programmable to what voltage you wanted it to start the truck at, I set them both at 11 volts, plenty to start the truck without having the inverter going into alarm, and also not to cause too much cycling,

For 2500 va, (13.6/2500 is about 183 amps) I would not use less then 5 240 AH deep cycles, using a Milwaukee extension drill, it should last all day with maybe truck starting once. if you isolate your optional batteries from you main battery, and your auto start doesn't have the optional monitor, it will not start the van when your optional batteries are drained, Bull dog is the only one I know of that has the two monitoring circuits, but then I haven't looked in a long while.
the main monitor is tied into the the regular input battery hook ups, so it isn't separable.
If you don't isolate you will need a ballast resistor, to limit the charging and load on your alternator, it will have to be sized to about 30-60 amps or less depending upon how much your van uses for operation, but I would look into the travel trailer system, as it would make your batteries last the longest, just make sure the charger/regulator is a float charge type, not a constant charge. big difference in burning up battery's.

I had the triplett, mounted on the top of my speaker box right behind my seat the trailer system was on the other speaker box behind the passagener seat, the battery's were in a sunken floor space I made by cutting open the floor by the frame and making a well that fit down into it, made a nice removalble cover, the only problem was I had to put some heat reflecting insulation on one side because of the exuste pipe was within 6", used a small 12 volt duct fan and 4" hose to vent the box, from above positive flow into the box from the fan, but the fan was ducted to another round hole with lovers point to the rear to pervent water from getting in, built that under one of the bottom shelves in a useless area, had a rocker switch on my dash to turn on the inverter, 4 plex's at each door, and two in the back door.

Well that was the 2006 van I have photos of on here, but unfortuntly it was totaled in Dec of 2007 hit head on, I was able to recover everything but the Bull Dog and all the hookups up front, had to remove the seats to get the speakers, and inverters out, out of the 10 battery's only 4 made it, the rest came out from under the van and smashed when the end of the sunken box broke open, cables held 4 back, this system was first in my 1994 chevy van, and moved to the 06 after a few months of travaling., for now I'm driving a 2005 chevy express, and just have a 1800 watt modifide sine wave, with 10' of cable from before, and some monster clamps to connect to the battery in the van when needed, I have a 400 watt in the cab to charge my dewalts, and other things, but that is it. not been wiring any new stuff so theres not been much call for the inverter, on service change outs, I just grab the 1800 and clip it to the truck battery and the way I go. well with the motor running, found out what not running it ment once:roll: and with a stock 104 amp alt. if you load it it will kill the motor:cool:


Ok enough for now.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Thanx, Wayne! I'm not going with multiple batteries, as I don't intend to do all-day work from it. My main reason for the second battery is to limit the length of run of the large conductors.

One battery should do well for the occasional ground-rod drive with my Bosch rotary hammer, but I may consider two batteries. If I have local power, I don't need the inverter, so no AC charging.

I think it's time for me to find a local truck parts and accessories shop. I have looked for high-capacity alternators, but the Ford ambulance setup was for twin alternators.
 

hurk27

Senior Member
Thanx, Wayne! I'm not going with multiple batteries, as I don't intend to do all-day work from it. My main reason for the second battery is to limit the length of run of the large conductors.

One battery should do well for the occasional ground-rod drive with my Bosch rotary hammer, but I may consider two batteries. If I have local power, I don't need the inverter, so no AC charging.

I think it's time for me to find a local truck parts and accessories shop. I have looked for high-capacity alternators, but the Ford ambulance setup was for twin alternators.

Look for Ford big rig truck parts, some will have very high amps, you might have to make brackets, and or change pulleys, but it can be done, the Delco that was in the 2006 Chevy express, was huge, and they had fabricated the brackets, but the factory did it, so it was under warranty, well until it got smashed, yep it was hit on that side of the motor:mad:

because I don't do many new wire Jobs now, I just used about 10' of the 3/0, I found some very heavy duty batter clamps, and soldiered them to the end of the cables, the other ends terminated into stainless lugs on the inverter, so when I need it, I just get it out and set on the front of the engine compartment, and clip it to the battery, but I was messing around with a 1675 watt heater to see if the alt would keep up, well in about 5 minutes the engine just sputtered and died, I tried to crank it and nothing, never had a problem like that with the 3600, we ran 2 or 3 drills off it, saws, chargers, radios, lights, and never had a problem, most GM alts, are current limiting, not sure about Ford, but you cant over load the alt if it is. the ballast resistors are to not starve the truck electrical, GM knew what I was wanting to do so when they installed the 285 amp alt, they built a freewheeling bridge, with one side from the rectifier going to the truck battery, and the other side going to a large bolt in 250 amp fuse holder then to a binding post with a 3/8" bolt sticking up, which is where I connected my stuff to. very nice of them, when I called the engineer up there, he said he wanted a report on how well it worked because they said they might want to offer it as a package deal for construction vans and trucks, to offer 120 power without a generator on the engine, which I guess was an option at one time, but was third partied out. the hydro assist front drive didn't last to many problems, so that was removed, but the locker rear end is now becoming a standard for all construction vans and trucks, tried to push for using Goodyear Work Horse Extra Grip tires as standard but they thought nobody would like the small added noise level they caused, I personally don't mind it as those tires really grabbed to get me through the mud and snow, and would just bend over a 16 penny nail, with that titanium belt they used, and 100k miles per set of tires wasn't bad either, so if I ever get to order a new one, it will be just that if they still offer it.

One thing I'm sure you already know, don't spare the dielectric grease on any connections by the battery's or under the hood, don't take much to cause a bad connection at 12 volts.:D
 

tallgirl

Senior Member
For a vehicle, I'd go with a pair of 8D-class batteries -- nice, low center of gravity and usually more manageable than anything you'd find in a 240AH class. Which sounds like golf cart batteries.

For the conductors, 4/0 fine strand "Welding Wire". My source is these guys if you want real cables that are going to work -- http://www.mavericksolar.com/ And forget using do-dads and hoo-has from an RV supply. By the time you piece together all the transfer pieces / parts and get a proper 4 stage voltage regulator, you've spent more than you would on a proper inverter. I'd go with an OutBack VFX2812MT -- you can also get that from Maverick.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Hey, Julie, long time no see, and thanx for the response!

We can't afford new equipment, and we already have the AIMS inverter. I've decided to place the second battery close to it, so I won't need more than one or two feet of large conductor.

I think 1/0 will be plenty, as I don't expect to use more than one tool at a time, and driving ground rods with the Bosch is probably the biggest and longest-time load the setup will ever see.

I'm not trying to choose between a deep-cycle/starting marine battery and a slightly-higher reserve capacity straight starter battery. I've read that combo batteries are compromises.

I am going to see if I can find the Ford part number on the alternator, so I can look up whether it's a 95a unit or larger. If it's that small a capacity, I will look for a larger replacement unit.

If it's 130a or larger, I won't bother. I'm not worried about the alternator being large enough to power the inverter completely. I just want to recharge the second battery between uses.
 

tallgirl

Senior Member
It's been a while! My former employer decided I'd passed my "Best By" date and invited me to seek gainful employment elsewhere. In the middle of an economic depression (don't buy the "recession" nonsense). I do a lot of solar work these days.

1/0 is mostly so-so, unless the 2500VA on the inverter is "peak" and not what you actually plan to use. The issue is voltage drop, in spades.

"Combination Batteries" are mostly a waste of time and money -- unless you're comfortable replacing batteries on a regular basis. Which you likely will wind up doing if you charge and discharge the batteries more than once a day.
 

markstg

Senior Member
Location
Big Easy
I'd hate to see how long ya'll would talk about this if ya'll got together with some of TallGirl's Home Brews.:)

Excellent info.
 

tallgirl

Senior Member
I'd hate to see how long ya'll would talk about this if ya'll got together with some of TallGirl's Home Brews.:)

Excellent info.

Didn't you and I conversationalize about meeting in New Orleans (I assume that's the "Big Easy" in your sig) over a beer or five? I know there were several regulars I discuss Adult Beverages with more than once.

And feel free to PM me with solar questions.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
My former employer decided I'd passed my "Best By" date and invited me to seek gainful employment elsewhere.
Their loss, definitely!

1/0 is mostly so-so, unless the 2500VA on the inverter is "peak" and not what you actually plan to use. The issue is voltage drop, in spades.
No, it's rated at 2500 watts continuous; the peak power rating is twice that. However, the input current being dependent on the load, I don't anticipate ever hitting the max.

The Bosch is a 11227e, rated at 8.8a, my Milwaukee angle drill and my Hole-hawg both use less. Only my DeWalt miter saw uses more (15a), and that will rarely be inverter-powered.

"Combination Batteries" are mostly a waste of time and money -- unless you're comfortable replacing batteries on a regular basis. Which you likely will wind up doing if you charge and discharge the batteries more than once a day.
Withstanding constant discharging/recharging is supposed to be the fort? of deep-cycle batteries, but I get the impression that a starting battery is more capable of inverter demands.

I did find out that my alternator is what's called a 'large-case 3G' unit, and is rated for at least 130a, so I don't need to upgrade it for my use. I'm debating adding an isolation rectifier unit, or even an isolation relay.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Me again. I'm getting there. Now, the next question: For the direct battery-to-inverter OCP, would I be better off using a 200a breaker, one of the 200a ANL fuses, or a 200a terminal fuse?
 

iwire

Moderator
Staff member
Location
Massachusetts
Do you plan on blowing the fuse so often the extra expense of a breaker is worth it?

One of my truck amps needed 60 amp OCP off the battery, I just used a standard NEMA 60 amp 250 volt fuse holder screwed to the fender under the hood. I used a cheap 60 amp cartridge fuse.

The dampness did not seem to bother it but you could get fancy a put a shield over a 200 amp 250 volt fuse holder.
 

hurk27

Senior Member
Do you plan on blowing the fuse so often the extra expense of a breaker is worth it?

One of my truck amps needed 60 amp OCP off the battery, I just used a standard NEMA 60 amp 250 volt fuse holder screwed to the fender under the hood. I used a cheap 60 amp cartridge fuse.

The dampness did not seem to bother it but you could get fancy a put a shield over a 200 amp 250 volt fuse holder.

I used a 250v 300 amp time delay (3600w@13.6) as these inverters can surge when starting a motor, and like Larry said, many will be double the rated output I.E. 5kw, but for the most part its only for a few seconds. kind of like doing a 430 application, where the conductor can be for the rated load but the OCPD is set for the fault current, also unless your running multiple battery's, most battery's will limit most of the surge current, even 2 battery's will provide some limit, but @ 200 amps, a time delay fuse would be the lowest cost way to go. 2500w@13.6 is about 183 amps, so a 200 time delay should work, 250 TD should be ok for a fault and still provide a good margin to prevent surge current tripping. remember a faulted wet cell can provide over 2k amps on a bolted fault depending upon the battery size.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Do you plan on blowing the fuse so often the extra expense of a breaker is worth it?
No, but if you saw how inexpensive they are (ebay: search "200a breaker" and skip the typical ones we usually use),you might reconsider. That's why it's not a no-brainer for me.
 
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