how do i do this?

Merry Christmas

Fulthrotl

~Autocorrect is My Worst Enema.~
well, a bit of testing last night has been sad. the inverter keeps beeping off on both the induction cook plate,
and the 950 watt microwave. panasonic, inverter style, 120 volts.

i'll play with it today, but it looks like i'm getting low voltage on the supply, and it's turning off the output to protect the
batteries. assuming it's low voltage shut off, which i suspect is the case, who here has played with lithium batteries,
and what brands are you partial to?

i'm looking at Renogy. but a 3KW inverter will take two 170 AH or 3 100 AH to work. they are 20% off this week, but still....
they make a high end, and a cheap lithium. high end, four 100 AH batteries are $2,900.

what have you guys had success with?
 

cpickett

Senior Member
Location
Western Maryland
Occupation
Electrical Engineer
Our work trucks have 3kW inverters wired to the truck battery and guys run a microwave off them. I think the inverter enable signal is wired so the truck must be running. Sorry I don't have much more info than that, but at least I know it's possible.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
well, you have to be smarter than your hardware.

plug stuff in. turn on inverter. turn on jeep.
wait until dual battery setup decides to start
charging secondary battery. don't override it with
the instant connect button, dummy. take two or
three minutes. wait for voltage o sPod to go to 14.5.

this means both batteries and the alternator are at 14.5.

turn on microwave, induction cooktop, arc weld, whatever.

it all works.
 

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tallgirl

Senior Member
Location
Great White North
Occupation
Controls Systems firmware engineer
Any chance you can just configure your inverter to output 100V instead of 120V?

Cheers, Wayne

well, a bit of testing last night has been sad. the inverter keeps beeping off on both the induction cook plate,
and the 950 watt microwave. panasonic, inverter style, 120 volts.

i'll play with it today, but it looks like i'm getting low voltage on the supply, and it's turning off the output to protect the
batteries. assuming it's low voltage shut off, which i suspect is the case, who here has played with lithium batteries,
and what brands are you partial to?

i'm looking at Renogy. but a 3KW inverter will take two 170 AH or 3 100 AH to work. they are 20% off this week, but still....
they make a high end, and a cheap lithium. high end, four 100 AH batteries are $2,900.

what have you guys had success with?
Not undersizing the batteries, for starters.

Lithium batteries are the better bet because of the weight. It's been ages since I lifted ... by hand ... anything in those size ranges.

If you've got a meter with a "MIN" value, I'd put it on the DC input at the inverter, clear it out, start things up, then watch the inverter turn off. The "crack of the whip" is likely dropping the input voltage well below 10VDC with the loads you've described.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Not undersizing the batteries, for starters.

Lithium batteries are the better bet because of the weight. It's been ages since I lifted ... by hand ... anything in those size ranges.

If you've got a meter with a "MIN" value, I'd put it on the DC input at the inverter, clear it out, start things up, then watch the inverter turn off. The "crack of the whip" is likely dropping the input voltage well below 10VDC with the loads you've described.
battle born in sparks nevada makes a lithium iron 270 AH 12 volt battery that weighs 80 lbs.
i spoke with the technician, and he said it'll load bank 575 amps for 60 seconds. they test each one before shipping.
7 x 13 x 23 inches, mounts in any position. on sale this weekend $500 off. when i delete the rear seat with a
deck plate, near as i can tell, i'll have 9" in the part of the seat delete that isn't the footwells. one would be more
than enough. there is room for two in the space across the jeep. one is all i'd need for overlanding.

i have a 1/0 cable from the battery to the inverter, that runs under the seat. right under the seat, there is an
anderson connector. i could split it there, and use two more anderson connectors to charge and connect the
battery to the inverter. if i needed a longer run time than the battery was good for, i could disconnect the battery,
and hook the inverter directly to the batteries under the hood, and do 3KW with the engine idling for as long as the
fuel held out.

the whip is most surely cracking. as long as i let the engine idle long enough to connect the both batteries,
and the output voltage idling is 14 volts or more, it'll run the microwave at full power until the baked potato is
done. same with boiling water on the induction cooktop, and that is 1600 watts.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
It was… I just saw the alternator size on post one..:rolleyes:
this is what it is, but there is a flavor they make that does 340 amp for a few dollars more...
the main thing is it'll do 200 amps at 14.8 volts at a hot idle. just under 3KW. should do 2,500 W.
at idle, after going thru the inverter.


 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
this is what it is, but there is a flavor they make that does 340 amp for a few dollars more...
the main thing is it'll do 200 amps at 14.8 volts at a hot idle. just under 3KW. should do 2,500 W.
at idle, after going thru the inverter.


My original thinking was to simply change the pulley to a smaller diameter. Overlanding generally doesn’t run high engine RPMs, so the alternator should be fine with a smaller pulley getting you up to the 2200-2500RPM range on the alternator while your engine rpm is in the 700-1200 range, depending on the crank pulley size. I’m not sure what the ratio is now on your setup.
 

drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Engineer
... Overlanding generally doesn’t run high engine RPMs, so the alternator should be fine with a smaller pulley getting you up to the 2200-2500RPM range on the alternator while your engine rpm is in the 700-1200 range ... I’m not sure what the ratio is now ..

3:1 is pretty typical for automobiles. There's nothing in an alternator that stops and reverses direction every half-revolution, so it can safely turn at much higher speeds than a piston engine.

Putting a smaller pulley on a higher-output alternator is a recipe for belt slip -- less surface area available; more torque required.

Overlanding generally doesn’t run high engine speeds? Nobody ever puts it into low gear and puts the pedal to the metal to climb over an obstacle or up a steep grade? And what about all the rest of the driving? Never going to punch it to get onto a crowded freeway or pass slower traffic? I'd want to be sure that the alternator's not on the verge of a rotor burst when the engine's at redline or its governor speed.
2018-Jeep-Wrangler-JL-Capability-Engines-36L-Pentastar-V6-Engine.jpg.image.1000.jpg
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
3:1 is pretty typical for automobiles. There's nothing in an alternator that stops and reverses direction every half-revolution, so it can safely turn at much higher speeds than a piston engine.

Putting a smaller pulley on a higher-output alternator is a recipe for belt slip -- less surface area available; more torque required.

Overlanding generally doesn’t run high engine speeds? Nobody ever puts it into low gear and puts the pedal to the metal to climb over an obstacle or up a steep grade? And what about all the rest of the driving? Never going to punch it to get onto a crowded freeway or pass slower traffic? I'd want to be sure that the alternator's not on the verge of a rotor burst when the engine's at redline or its governor speed.
Maybe we are talking about two different types of off roading..
When I did it, yes we would gun it sometimes, but not continuously.
And I have never redlined an engine. Why abuse your stuff like that? In my book that’s just plain silly and a waste of resources.
What I’m suggesting is done frequently among some Jeep crowds and rock crawlers here. It keeps high output at minimum rpm’s. He is idling while he is cooking, not wide open redlining an engine.
 
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drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Engineer
Running an automotive engine at its redline isn't abusive, unless the engineer who decided where the redline would be got it wrong. Even running a modern (post-1996, give or take) engine over redline -- say, by putting it in neutral and putting the pedal to the metal -- isn't abusive. The governor (embedded in software, not a discrete device) will simply shut off the fuel when the speed is 5% over redline and turn it back on when it's 5% under. Engines make truly-hideous noises when operating in this speed-limiting mode, but it's harmless.

But when making a permanent modification, you can't design around what happens most of the time; you need to design for every possible operating mode. Unless you're okay with an occasional rotor burst when you occasionally punch it to get up a busy freeway entrance ramp.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Maybe we are talking about two different types of off roading..
When I did it, yes we would gun it sometimes, but not continuously.
And I have never redlined an engine. Why abuse your stuff like that? In my book that’s just plain silly and a waste of resources.
What I’m suggesting is done frequently among some Jeep crowds and rock crawlers here. It keeps high output at minimum rpm’s. He is idling while he is cooking, not wide open redlining an engine.
the lowly 3.6 isn't noted for huge horsepower, it just putters along. i looked at doing a pulley,
but it doesn't change the output rating of the alternator, just serves it up sooner. it does
save money however. rock buggies and such don't need that much electric, and they overall
run at lower speeds. i wanted 3kw at idle, and this is as close to it as one can reasonably get.

i've bought DC Power alternators before, and they work well.
 

Todd0x1

Senior Member
Location
CA
Have you considered a propane water heater? There are both RV style and some portable ones made for camping. I have one from Ecotemp, haven't used it yet though.
 

Russs57

Senior Member
Location
Miami, Florida, USA
Occupation
Maintenance Engineer
Comes a point where I have to ask "why not a generator"? The little Honda inverter based ones are very quiet, lightweight, with great fuel economy, and power quality is top notch.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Comes a point where I have to ask "why not a generator"? The little Honda inverter based ones are very quiet, lightweight, with great fuel economy, and power quality is top notch.
yep. they are excellent. i have two of them in the tool bin.
first is space. a JL jeep is not roomy. at all.
second is sound. i want something that can charge batteries, run small electrical loads silently

the i2000 honda can be yoked to make 4kw, resistive load anyway. a lot of stuff chokes them.
so, i'd have to bring both of them. two of those eats all the room in the jeep.

my needs are small 120 wattages, and the occasional big kahuna. as for the propane water
heaters, if i had to i could use one, but i'd rather not. the camplux is the same kind of thing.
they are big, and awkward. space is a thing. i've got a camplux electric water heater, and it'll
mount on the side of a zarges case, with the water tank inside, and it's self contained and
pretty effortless. with a bucketload of electrons, of course.

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