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Double alternator

MatthewWBailey

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Well the alt choice depends entirely on your load. If you have dropped to 2 service batteries you will have some surplus typically As the truck loads including all the lighting, are going to be under 30A @24v. So a 110A delco 28SI would have 80A available once the service batteries are peaked. Whatever house battery charge controller you use needs to be able to work with what y0u have leftover from whatever alt you choose. It may also need a little additional control to hold off the house battery charging until the service batteries stop drawing significant current. Is the Viltron charge current adjustable?

if so, i like the 28SI just because it is so available and serviceable…. With a little modification, a J180 alt can ride on the military mount. At keast for the A0.

what truck is yours again?


View attachment 934730
What's the feeling/feasibility of a pto-driven supplemental alternator/generator? I'm sensitive to 'vehicle specific systems' being used for anything other than vehicle propulsion, since that's rather critical. Having a big alt just to accommodate a habitat seems like an undue burden on the integrity of the vehicle's prime function (thinking like a designer). And even with the 200+ amp Alt upgrades, it still doesn't seem like enough.

I was thinking about driving a 570Amp 24v only Neihoff off the PTO. Looks like the shaft will need some TLC to rout it but looks doable. The new star PTO states a 50hp continuous rating. You only need the extra power when you're parked (if there's a habitat) and you can run the truck rpm any speed you like depending on the power needs. Those MRAP 570A alternators are cheaper than the 100a dual voltage units!! By half.

The scheme would still need an inverter (as opposed to a straight AC genset which won't work due to the need for rpm single set point) but you'll have that anyway. Then you never have to worry about the engine's alt and can just leave that to serve vehicle systems.

Or it could be a crappy idea. I've got lots of both.IMG_5924.jpeg
 

Ronmar

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70A@24v is 1960W. It looks like the plan for this is as a supplement to onboard solar and that is probably a comparable amount of power to what is on the roof. if sized correctly, the solar should meet all the typical needs, so this would most likely rarely be called for…

Best practice is is to keep separate service and house batteries so something drawing down the house batteries does not effect your ability to start and move.

it is also normal practice to draw from the service power system to feed the house system. Google “BIRD relay“. found on just about every pre solar motorhome as that was how you charge without a generator. Bird relays can also be configured for manual override to allow you to draw from house power to help start the vehicle if for some reason the service batts become depleted. We have an Incident Command Vehicle(motorhome) at work that has a start assist switch in the dash to manually control the bird relay. It also automatically connects the two systems for house charging once the alt floats up to full output voltage. Roof full of comms gear, no solar…

Of course the bird is only appropriate if the peak battery load from the house is lower than the alt output. With all electric habitats doing away with bottled gas and generator as power sources, and running a massive battery bank. A programmable charge controller is required in place of a Bird relay…

if I were going to hang a second alt i would probably find a way to hang it off the engine. Or couple it to an engine and create a standalone generator/APU…That PTO area is a PITA to work in, and I have only been trying to cleanup the plumbing and wiring:)
 

MatthewWBailey

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BIRD relay
That's neat. Looks like a typical DPST latching relay. I was thinking about a latching relay, in theory, to allow going back to 4 batteries, with 1 x 24v set isolated from the other for charging but both being available in the event of extreme cold starting. Then a controller or timer could just alternate which set is charged from the small 110a alternator.


That PTO area is a PITA
I was wondering if that's a better alternative than the pto. Maybe a 3cyl 900cc Yanmar diesel could run one of those Mrap 570's. I have an old one from a Polaris ranger thats needing a rebuild. It's a 25hp rating.
 
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Ronmar

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Well 2HP per KW for continuous power generation is a pretty good rule of thumb… 570A@28V is 15,960W. Nearly 16KW. Well thats too much for that engine at full load, and enough power to power 2 houses? You could charge EVs in the campground:)
 

MatthewWBailey

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Well 2HP per KW for continuous power generation is a pretty good rule of thumb… 570A@28V is 15,960W. Nearly 16KW. Well thats too much for that engine at full load, and enough power to power 2 houses? You could charge EVs in the campground:)
It's wrong IMO to charge EVs in that setting. The owners should be more prepared. I Will Not be an enabler! Besides the $/kw cost would bankrupt them.

Every time I try to find a new home for this yanmar, it's fails the grade. But 12.5kW max output is still a big number. The inverter I'd be using is only 10kw anyway.
 

serpico760

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Well 2HP per KW for continuous power generation is a pretty good rule of thumb… 570A@28V is 15,960W. Nearly 16KW. Well thats too much for that engine at full load, and enough power to power 2 houses? You could charge EVs in the campground:)
Well let's see I need a few dozen off-road lights all around, A kicking stereo with some woofers, and a winch... 570 should be good for that...
 

serpico760

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Well let's see I need a few dozen off-road lights all around, A kicking stereo with some woofers, and a winch... 570 should be good for that...
A neighbor of mine I just met has a line on somebody who's got a bunch of those! Trying to get him to join because he has a sweet 1990 M923 and until a few days ago he's never even heard of SteelSoldiers!
 

Ronmar

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It's wrong IMO to charge EVs in that setting. The owners should be more prepared. I Will Not be an enabler! Besides the $/kw cost would bankrupt them.

Every time I try to find a new home for this yanmar, it's fails the grade. But 12.5kW max output is still a big number. The inverter I'd be using is only 10kw anyway.
My backup generator for my house is a 6HP slow speed diesel spinning a simple 5KW generator head via belt drive. It will hold 3KW all day long at 3/8GPH… that gets me all my lights, reefer and well pump. Can run a stove burner or the microwave or an air fryer. Direct Electric hotwater is off the menu but at 2KW of electric load, I can harvest enough waste heat from the generator to heat a full 50 gal tank of hot water in a little over 30 minutes…
 

GeneralDisorder

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What was on the MRAP that they needed a 570 alt?
BIG 24v air conditioning system for the troop transport, large amount of HID lighting including joystick remote controlled spot lights, communications and Blue Force tracking gear, CROWS weapons station, active armor RPG countermeasures, Driver's Vision Augmentation System, Night vision systems, fire suppression systems, electro-hydraulic powered doors (https://www.controls.com/powered-door-system/)..... and so much more!
 

MatthewWBailey

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BIG 24v air conditioning system for the troop transport, large amount of HID lighting including joystick remote controlled spot lights, communications and Blue Force tracking gear, CROWS weapons station, active armor RPG countermeasures, Driver's Vision Augmentation System, Night vision systems, fire suppression systems, electro-hydraulic powered doors (https://www.controls.com/powered-door-system/)..... and so much more!
Geez. I guess that was a bad truck to have a failed neihoff regulator.
 
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