I've searched around but can't find this anywhere. Got an '06 PSD with 2 batteries, one alternator (130 amp?). I want to put in a 1500 what invertor (probably behind the back seat?) for miscellaneous AC stuff. I have seen the general advice to use heavy wire like 2/0 to keep voltage drop down, but I'd like to know more about the battery setup.

1. Is one battery considered the starting battery, and one the auxilliary, or do both batteries do it all?
2. Is there an isolater already in the system to keep from uneven charging or to keep a weak battery from killing them both, or is there no need for that?
3. If there is no isolater, is that a recommended upgrade?
4. Which battery is best to hook up the inverter to?
5. Is there anything I should have asked but didn't?

Thanks in advance, and have a Harpy Halloween.

 

Big wire to prevent voltage drop is a secondary consideration. Remember that energy is conserved... if you're seeing voltage drop, you're losing energy somewhere. Guess where? Into the wire, as heat energy. Things then get hot and melt.

1. No, the batteries are paralleled and function as one unit.
2. No, see #1. No need for an isolator.
3. Personally, I'd suggest a continuous-duty solenoid instead to prevent voltage drop across the diodes in the isolators. However, shoehorning a third battery under the hood would be rough... you'd end up having to use a battery box elsewhere (maybe on the frame like the E-series vans?)
4. Doesn't matter, see #1. They're paralleled with sufficiently large cable that you're not going to have a problem.
5. Make sure you use adequate fusing. Personally, for my high-current installs (emergency vehicles and my POV), I use car audio supplies (I'm a dealer for Tsunami, so I can buy the stuff for reasonable prices).
Plan to keep your wire lengths as short as possible... you can run an extension cord off the AC side a whole lot easier (less voltage drop since it's 110).
Unless you're going to run a solenoid and a third battery, do NOT turn that invertor on when the truck isn't running, lest you find yourself unable to crank. Plan to wire up an upfitter switch for high idle/battery charge protect if you haven't done so already.

 

Thanks for the info!

1. As suspected.
2. Understood. Comment: I've read other threads about the horrors of having the batteries un-isolated, as when one battery loses a cell or is defective it may kill both batteries.
3. As to putting another battery under the hood, I can't see any chance of that. I can't even see where I could mount an inverter in the hood area, which is why I thought of behind the back seat. If there's a better spot, I'm all ears, mostly.
4. Roger.
5. Keeping wire length short - from battery to rear cab wall routed must be around 15' of 2/0. Is that too far? See #3.
6. The high idle upfitter is something I intend to do. I was also trying to figure out how to use an upfitter to turn the inverter on/off. (I'm going to apologize ahead of time for my ignorance) As I understand things, the upfitters are a max of 10 or 30 amps, so I know I can't run the power for the inverter through an upfitter, but is it possible to use the upfitter to turn the inverter on/off? At least that way I would not be able to use the inverter while the truck was off.

Thanks again.

 

2. Yes, that's correct. If one dies, it's going to kill the other. That's why you always replace batteries in pairs in these trucks. Unfortunately, they need to be in pairs to provide enough cranking current (especially when very cold) to crank over the high-compression PSD.
3. You don't want it under the hood anyway, it'll get way too hot. You might consider something in/under/around the center console, front seats, etc. Knocks 5-6ft. off your power run.
5. Your inverter is probably fused around 150A. (1500watts / 0.8 (inefficiency) / 12 = 156.25). I run 1/0ga. from the driver-side battery to the front wall of the bed in my 350CC at 150A with no problems and no undesired heating.
6. You could run a constant-duty solenoid rated for 200A to power the inverter itself. You might look at the inverter... some have remote control panels which offer a remote on/off. You could also "remote" the built-in power switch to a switch up front, but I wouldn't use an upfitter. That switch could be controlling logic at 1.8, 3.3, 5, or some other strange voltage. Frying things is bad, mmmkay? You could use a typical relay if you want... assuming the power switch is a typical SPST design, tie one side to common, the other to the normally open contact, an upfitter output to the coil, and the other side of the coil to ground... poof, upfitter-controlled inverter.

 

Thanks again! The inverter I'm looking at is the Vector VEC050D, specs:

Maximum Continuous Power: 1500 Watts
Surge Capacity: 3000 Watts
No Load Current Draw: .6 Amps
Maximum Efficiency: Approx. 87%
Input Voltage Range : 10.5 - 15.5 VDC
Output Voltage Range : 110VAC 60HZ
Under Voltage ShutDown: 10.0 Volts
Thermal Shutdown: Auto Reset
Wave Form: Filtered Modified Sine Wave
Internal Fuse: 30Ax6 Amp
Dimensions: 10"L x 3"W x 8.25"H
Weight: 8.4 lbs.

It does have a remote switch for ~$20, so that's a plus. Suggestion welcome....

 

Ugh, the Vector inverters suck. Don't plug anything you like into one of them... of the ones I've looked at on an o-scope, the "modified sine wave" is damn near a square wave (they used a stepped approximation... the Vectors don't have very many steps). This can create an issue with switching power supplies and some motors (motors rely on nice, smooth AC... stepped waveforms make them inefficient and cause significant heat buildup). Personally, I use a Samlex pure-sine 600-watt inverter... about $200 at my cost (distributor pricing). If you really need 1.5KW, you can get them in pure-sine... Samlex and Xantrex Prosine come to mind, but expect to drop $500-$1000.

What exactly are you trying to run? You might consider running a smaller inverter (like that 600-watt pure-sine Samlex) and carry a Honda EU2000i or equivalent for your big-smoke power needs.