What is a good size Inverter for a Pinz at idle?

Dedicated to the memory and knowledge shared by Jim Mettler - All things relating to the flow of electrons in a Pinz.
Post Reply
User avatar
TechMOGogy
Canada
Posts: 2830
Joined: Wed Feb 01, 2012 11:39 am
Location: Ontario, Canada

What is a good size Inverter for a Pinz at idle?

Post by TechMOGogy » Mon Apr 21, 2014 2:24 pm

If I need to run a few household tools or accessories - what is a realistic size 24 - 120v inverter size that can be used at idle?
Did a search and got some general info but no specific recommendations (if it is even advisable)?
Thanks,
72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker

User avatar
Jimm391730
United States of America
Posts: 1456
Joined: Wed Apr 14, 2004 10:58 pm
Location: Idyllwild, CA

Re: What is a good size Inverter for a Pinz at idle?

Post by Jimm391730 » Mon Apr 21, 2014 3:03 pm

Inverter size is not/should not be related to "Pinz at idle". You would definitely want a 24V input inverter (it is half the current that a 12V inverter would draw). I routinely run a 700W microwave from an inverter, it draws about 50A from the batteries. If I did this for an HOUR, continuously, then maybe I'd need to run the engine to try to reduce the total battery draw (50 amps out, but some amps back in at the same time). But for an occasional, few minutes here and there use, any wattage inverter will be OK.

I just installed a 2400W modified sine wave inverter (Trace DR2424) in my truck; it is powered by an independent set of 100AHr batteries. But I used to have a 1500W Samlex inverter that ran directly from the chassis batteries and did microwave duty for up to 15 minutes, typically. (the Samlex is available since I have replaced it).

If you plan to use motorized tools you would probably want the largest inverter that you can realistically get (2400W or more) due to the startup and full load (even overload) currents. Although most inverters are rated at maybe 50% to 100% more power for a few to 30 seconds duration, you don't really want to be bumping into that over current condition very often, if possible. And the short duration current from the batteries might be in the 200A range for those few seconds; similar to cranking the engine. But that is exactly what the batteries are designed for.
Jim M.
712W and 710M

User avatar
TechMOGogy
Canada
Posts: 2830
Joined: Wed Feb 01, 2012 11:39 am
Location: Ontario, Canada

Re: What is a good size Inverter for a Pinz at idle?

Post by TechMOGogy » Mon Apr 21, 2014 3:24 pm

I put 'idle' in there as I thought full output of the alt. was available at idle so I could recharge batteries at idle if need be.
Is this not correct?
You could run the inverter for a while and then start the vehicle to charge the batteries
I also need a power source to run my smoker (auger and puter temp control) so I need a true sine wave inverter. Smoker = long cooks
72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker

User avatar
audiocontr
Canada
Posts: 1850
Joined: Fri May 01, 2009 1:30 pm
Location: Toronto Regional Area

Re: What is a good size Inverter for a Pinz at idle?

Post by audiocontr » Mon Apr 21, 2014 3:43 pm

i have one for sale. :D

Tested it via a power saw a few times and never used it again. All tests were at idle


viewtopic.php?f=5&t=8481&p=62287&hilit=inverter#p62287
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
2001 F250 Diesel and trailer

User avatar
Jimm391730
United States of America
Posts: 1456
Joined: Wed Apr 14, 2004 10:58 pm
Location: Idyllwild, CA

Re: What is a good size Inverter for a Pinz at idle?

Post by Jimm391730 » Mon Apr 21, 2014 6:50 pm

I put 'idle' in there as I thought full output of the alt. was available at idle so I could recharge batteries at idle if need be. Is this not correct?
Actually, I've never checked the alternator output "at idle"; only enough to know that it is charging the batteries.
But, if we assume that we can get all 30 rated amps from the alternator, at 28V, then the maximum power available is 30A * 28V = 840 Watts. So with that reasoning, you would never want to load an inverter with more than 700-750W (allowing for losses in the inverter). But as I said, that is what the batteries are there for -- to supply "short" durations of much higher power.

But wait, there's more! You can consider the average of your power: You can draw 1500W for 5 minutes, if you have 0W for the next five minutes (averaging 750W over the total ten minutes). This works, as long as your "draw time" does not drain the batteries to zero: you can't draw 1500W for hours (or even a few tens of watts for many days). But working with power tools, for example, a circular saw, you can make a 15 second cut every minute, hour after hour even if your saw draws 3,000 watts when cutting (assuming the alternator is putting out the full 30A). In fact, you can do this for an hour and still only draw down the batteries about half way, even with the engine off. That is why I suggested that you can use whatever inverter size you want.
Jim M.
712W and 710M

User avatar
edzz
United States of America
Posts: 1309
Joined: Tue Aug 11, 2009 12:13 am
Location: Coeur d'Alene, ID

Re: What is a good size Inverter for a Pinz at idle?

Post by edzz » Mon Apr 21, 2014 9:44 pm

My solution is to use a Honda EU2000i inverter generator, I can run my Ham radio equipment and the microwave without worrying about my battery's, along with being a source of 115 vac it also has a 12 vdc outlet. While not being as convenient as a vehicle installed inverter, for me the generator has proven to be a good choice. Up to ~ 8 hours on a gallon of gas and a very low noise level makes me happy, if longer run times are needed external fuel tank converters are available to use boat gas tanks to provide run times measures in days not hours.

Out of curiosity have you determined the estimated amperage you will require?

I also have a 1500 watt 24v inverter sitting on the shelf at home that I'd be willing to sell.
Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

crcpinz
Posts: 163
Joined: Wed Feb 09, 2011 5:05 pm
Location: Costa Rica

Re: What is a good size Inverter for a Pinz at idle?

Post by crcpinz » Tue Apr 22, 2014 6:38 am

My 2400w inverter (big and heavy) draws 24v from separate batteries that sit in a wooden box under the K's rear "shelf". These in turn get charged from the vehicle's alternator via a Newmar battery integrator. It works as good as it sounds, but I rarely use it for other than my radios. It probably delivers only about 1600w due to the size of the batteries, but it will run a small air compressor, blender, or water heater.
Si vis pacem, para bellum
1976 710K
http://www.facebook.com/profile.php?id=100000163282080

User avatar
Jimm391730
United States of America
Posts: 1456
Joined: Wed Apr 14, 2004 10:58 pm
Location: Idyllwild, CA

Re: What is a good size Inverter for a Pinz at idle?

Post by Jimm391730 » Tue Apr 22, 2014 2:29 pm

Now a blender seems like a valuable accessory! 8) :lol:
Jim M.
712W and 710M

User avatar
eToothpaste
Posts: 109
Joined: Wed May 02, 2012 10:22 pm
Location: Fruita, CO

Re: What is a good size Inverter for a Pinz at idle?

Post by eToothpaste » Sat Apr 26, 2014 11:34 am

Don't forget not to skimp on the conductor size from the battery to inverter! This is the problem with a lot of RV's that come with inverters from the manufacturer. And it was a problem with my solar setup when I bought the pinz. Might not be too big an issue if you're not using it very much, though. Now I'm not saying anyone is doing it wrong, I just want to give some info.

I won't bore you with calculations, but a 1500W supplied from a 12-AWG wire is losing 220W in the wire. At 10AWG, 140W loss. 8AWG, 90W. According to the NEC, you need 4 or 6-AWG at that amperage (75 Amps), depending on the type of insulation. But the NEC is just a "guideline". :lol:

Shorter cable is always better, too. I calculated with 12-feet, which is long for a Pinz, depending on your setup.
Matt

1972 710m

User avatar
Jimm391730
United States of America
Posts: 1456
Joined: Wed Apr 14, 2004 10:58 pm
Location: Idyllwild, CA

Re: What is a good size Inverter for a Pinz at idle?

Post by Jimm391730 » Sat Apr 26, 2014 11:56 am

I have found that the easiest way to get "large" gauge wires is to go to Walmart and buy a set of cheap #4 jumper cables. These are readily available, and can actually cost less than equivalent raw wire from other sources. But look carefully; the cheapest sets are barely #10 gauge.
Jim M.
712W and 710M

User avatar
milesdzyn
Posts: 550
Joined: Wed Mar 09, 2005 2:32 am
Location: Las Vegas, NV
Contact:

Re: What is a good size Inverter for a Pinz at idle?

Post by milesdzyn » Sat Apr 26, 2014 6:27 pm

TechMOGogy wrote:If I need to run a few household tools or accessories - what is a realistic size 24 - 120v inverter size that can be used at idle?
Did a search and got some general info but no specific recommendations (if it is even advisable)?
Thanks,
I have looked at what one needs in an inverter as function and necessity vs. need and desire. Unfortunately we keep getting sold on more is better here in the USA. Better to look at what you really need to determine what you should purchase.

My general rule of thumb, under 1000 watts use an inverter and over 1000 watts use a generator.

Even a dual battery system at 24 volts can't keep up with a heavy draw for any sustained time and the idle current can't keep up with a heavy draw of a 1000 watt inverter pulling max amps. Eventually over several cycles of drain and recharge, the weakest link, the batteries will succumb to a early death.

My setup uses a 24v 1000w inverter for use under power while driving, it will run my cooler and when needed any cooking appliance I own. While not under power I run a isolated separate system using a single 12v Battery charged by a 100w solar panel, running a 400w inverter for recharging batteries and running a laptop and some small appliances. Most of my needs are to recharge AAA and AA batteries as most of my lighting and various devices run on rechargeable batteries. I also have straight 12v accessory plugs throughout my vehicle for quick access to 12v power.

So my suggestion is to keep it below 1000 watts. As for product brand I suggest you go with Xantrex.

Miles
Lots of Pinz pictures here.......
http://picasaweb.google.com/pinzgauer.depository.1

'73 Pinzgauer 712M

Post Reply