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diy solar

DIY, Low Cost Generator From Vehicle Alternator (Alternating Generator)

You are one of the few people on any forum that I've seen mentioning that to properly measure the resistance of a high current cable you need to use high currents. It's something I do as a matter of course but I wonder how many people here are aware of it.
 
@Jetenginedoctor not a slight on you in any way. Just noting it for reference for future discussions on potential incidents with parallel. You sound very much on top of your situation doing all the right things to correct your predecessor.
 
The MOST I'll do is make a suggestion, and only if you ask what we think...

You are one of the few people on any forum that I've seen mentioning that to properly measure the resistance of a high current cable you need to use high currents. It's something I do as a matter of course but I wonder how many people here are aware of it.

I'm one of the few people that both home and business rely on high amp cables I built, and I found every way possible to screw it up! ;)
 
@Jetenginedoctor not a slight on you in any way. Just noting it for reference for future discussions on potential incidents with parallel. You sound very much on top of your situation doing all the right things to correct your predecessor.

Please excuse the defensive posture, I've been on both sides of a flame war having been off and on internet forums for more than 20 years.

I'll point out again that the story I'm telling is about my 2015 model year 5th wheel RV/camper. These are the "house batteries" that provide DC power to all of the lights inside and outside of the trailer, control voltage for the refrigerator and HVAC, ventilation fans for the kitchen and bathroom, and hydraulics for the slides and landing gear/jacks. A single 12v group 27 battery is provided by the dealership, and is adequate for operating the landing gear and slides a time or two during setup, and a few hours of lights and furnace before the battery is pretty well pooched. You need to plug into shore power for sustained use of electrics, as this battery along isn't enough to get you through even a single night of boondocking.

Anyway, RV electrical systems use a "converter" to charge the house batteries. The cheapest converters just produce a single "float" voltage. Better chargers have two or more charging modes including bulk, absorption, float, and equalization. You can hear the converter change between the modes from time to time with changes in load, with a change in cooling fan speed and brightness of incandescent bulbs. I believe that there were a lot of high resistance connections in the original owner's "installation" that kept the second battery from ever fully charging, and the converter stayed in bulk charging mode much of the time due to the "charging" current not falling below whatever the amperage setpoint to take it out of the higher voltage charging mode, resulting in electrolyte loss and associated damage. When I removed the vent caps, the water level was a good inch below the tops of the plates in the first battery. I added distilled water to bring the electrolyte level to just below the bottoms of the wells and connected that battery by itself to charge. A few days later, I measured capacity and it was just above half of what it's rated new, and I figured the damage was done. I put it in one of my old Mustangs as a starting battery, it petered out a few months later. No big loss.

Anyway, I'm pretty sure I just threw away all of the cables that I took off. I wish I had them so I could take photos, just for a goof. I bought a half dozen or so '00' cables in 18" lengths from Tractor Supply when I wired up the quartet of Group 31s. I originally had them paralleled in a ladder configuration with the load and ground attached only to the first battery in the string. I later realized that even in spite of the much better cables I used, there would be a difference in how "charged" the four batteries would become, so I moved the ground cable to the last battery in the string. My thought was that way each of the batteries would always have 3 interconnect cables worth of voltage drop, regardless of position, instead of zero, two, four, or six.

I don't know the specifics of the converter in my trailer, but I suspect it to be mid-grade at best. I'll eventually move to Lithium batteries, possibly with a focus built converter. But for now, I'm intrigued by the idea of building a gasoline powered DC generator to maintain charge on the house batteries and using the big Trip-Lite inverter as backup power.
 

How about 24 Volt, 600 Amp, http://www.prestolite.com/pgs_produ...tail_id=42086&item=1287170&product=Alternator

I usually just hit the Lester catalog and hunt up what I need.
The cases are consistent up to 48 Volts, doubling common rectifiers get the DC part done, and if I need a rotor, stator or voltage regulator I just order it unless I'm trying to do something specific like water generator.
 

Great suggestion, and it's affordable!

All joking aside, I'll probably keep an eye out for some of this style of alternator to tinker with, but one of the more pedestrian variants. A 200 amp 12 volt unit would probably be a perfect compliment to the equipment I already have, but 24 or 48 volt would be ideal if and when I ever decide to drop coin on upgrading the electrical system in this camper (or more likely, the next one.)

I wonder if anyone reading this has any knowledge, first hand or otherwise, about what would be the quietest "cheap" engine to pair with such an alternator? Otherwise, what would be some effective measures one could take to attenuate the noise of a single cylinder, air cooled small gas (or diesel?) engine operating at moderate output in a campground setting? If there's one thing that's nice about the little Chi-com generator I carry, its that it's reasonably quiet. However, its output is only about 2000w, and I'm not confident in the output quality or longevity of the engine or electrics. The big Tripp-Lite inverter, on the other hand, should be damn near bulletproof (it weighs a good fraction of what the generator does.) I don't have it in front of me, but if memory serves, this is the inverter I've got.


Granted, this is not a pure sine wave inverter. I've got a smaller 500 watt inverter that I could rig up to cover that need for sensitive loads. Considering this cost as much by itself and weighs nearly as much as the Chinese inverter generator, I'd be willing to bet the power produced is at least as good, though I should dig out my scope and try to figure out again how to run the damn thing and have a gander at the waveform to see.

Has anyone here used the Tripp-Lite industrial inverters and have any feedback on the quality of power produced?

BK
 
You are one of the few people on any forum that I've seen mentioning that to properly measure the resistance of a high current cable you need to use high currents. It's something I do as a matter of course but I wonder how many people here are aware of it.

To measure this resistance, are you passing high current through and then measuring the voltage drop and calculating resistance?
 
To measure this resistance, are you passing high current through and then measuring the voltage drop and calculating resistance?

That's the 'Proper' way.

You can go low budget and look for restrictions/resistance with infrared imaging which is fairly commonly available, or you can check with a 'Heat Gun'/thermal probe.
Terminals are by far the worst offenders, so for about $30 a 'Heat Gun' (infrared) let's you check terminals in use.

IMG_0255_zpspjlysgx5.jpg

The gray thing between watch & induction coil in this picture...
No insults about my crappy looking experiments... :(
Time the rise in heat and you can *Roughly* figure losses.
In this case, I was trying to (roughly) figure magnetic energy transfer rate to the steel core in the induction coil.

I heat treat metals, so getting away from electrical resistance or flame,
Going to electro-magnetic induction where only the target part heats.
Electro-magnetic induction cook tops work the same way, and it's suprising how effective it can be.
 

Great suggestion, and it's affordable!

All joking aside, I'll probably keep an eye out for some of this style of alternator to tinker with, but one of the more pedestrian variants. A 200 amp 12 volt unit would probably be a perfect compliment to the equipment I already have, but 24 or 48 volt would be ideal if and when I ever decide to drop coin on upgrading the electrical system in this camper (or more likely, the next one.)

I wonder if anyone reading this has any knowledge, first hand or otherwise, about what would be the quietest "cheap" engine to pair with such an alternator? Otherwise, what would be some effective measures one could take to attenuate the noise of a single cylinder, air cooled small gas (or diesel?) engine operating at moderate output in a campground setting? If there's one thing that's nice about the little Chi-com generator I carry, its that it's reasonably quiet. However, its output is only about 2000w, and I'm not confident in the output quality or longevity of the engine or electrics. The big Tripp-Lite inverter, on the other hand, should be damn near bulletproof (it weighs a good fraction of what the generator does.) I don't have it in front of me, but if memory serves, this is the inverter I've got.


Granted, this is not a pure sine wave inverter. I've got a smaller 500 watt inverter that I could rig up to cover that need for sensitive loads. Considering this cost as much by itself and weighs nearly as much as the Chinese inverter generator, I'd be willing to bet the power produced is at least as good, though I should dig out my scope and try to figure out again how to run the damn thing and have a gander at the waveform to see.

Has anyone here used the Tripp-Lite industrial inverters and have any feedback on the quality of power produced?

BK

I bang the salvage yards, big trucks COMMONLY used 200-300 amp versions, and almost everything up to 48 volts is common cases.

For $20 core charge, it's only 'Junk' until someone finds a purpose for it.

That 'Junk' riding lawn mower...
Vertical shaft engine mount, frame.
Add a tongue to steer it, strip off the steering wheel support, seat, etc.
Get rid of the drive, transmission etc. And put some front wheel size tires under the back,
Mount alternators vertical, nose down, and add several, you can squeeze 3 or 4 on the average flat folded metal deck/frame, and your drives align with engine, now you need belts.

A self contained pull around generator that will make enough power to do what every you want.
You can even get froggy and make a hood for the generators.

Total cost, belts, wires, nuts & bolts, maybe another multi-groove pulley for the engine.
The 'Looks' depend entirely on what kind of a hood you make.
Mine has a rack for 30 gallon propane tank, I dislike gasoline going bad, cleaning tanks & carbs, so for $130 I converted to propane.

If you stumble onto a 110vac generator for cheap, just plug it into the frame, hook a belt to it.
Engine speed & pulley sizes determine the cycles per second (60 hZ USA standard).
Pulley size is usually 1:1 since most 110vac generators were direct shaft drive...
 
I have about 4-5 gallons of fuel that sat in a tank for the boat for years and it has oil added to it. I've been wondering how best to convert to DC w/o destroying any engine I care about. A salvaged alternator would be one piece of the solution. I love your DIY spirit @JeepHammer !
New question, @JeepHammer . I just replaced a perfectly working garbage disposal because the aluminum ring holding it in place corroded. Is there a way to convert that to something useful?
 
I'm in the process of building one. Talked to an old timer from Alaska. He could get 10k+ hours out of common China Honda clone engines. The secret is RPM. Its a light duty engine. You can't go too slow or you can damage the crank but 2000 RPM is great on those engines. Modest power and long life.
Another gentlemen from smokstak, now dead I think, use some sort of sulfate to clean the engine out during break in. He would open the case and empty out all the metal he could find which apparently is a lot. Throw in a powerful magnet and would end up getting over 5000 hours out of those 6.5 HP predator generators, thats 3600 rpm. Imagine a oversize motor, loafing around at 2000 rpm on a better quality fuel like natural gas or propane. Makes it very easy to repair.
Scaling the rpm to the alternator output is important. That way you can run it slow and save fuel or add some rpm for extra amps. Fuel efficiency will be lower unless you splurge for a quality inverter and most of all a quality alternator. Belt loss is also dependent on type. Timing belts is something I see used a lot.
 
Hello,

This type of thread is one I have been looking for, for years now! Thanks so much for starting this!!

I have some questions..

Ok here is my issue I have a small 11HP Kubota Diesel engine that I am driving a 160A GM alternator from an Escalade. I have removed the regulator and the Diodes and have a external Bridge and control the rotor field with a PWM controller up to ~12V. Here is my issue, when I turn the field up with NO LOAD on the stator and crank the engine to full speed Alternator is turning about 10,000 RPM (a guess). the Stator gets HOT! Why is this?? Now again no load on the 3 Phase Diode bridge.... the open circuit voltage is 130V! So no IR losses... What making the Stator gets so hot?? Are there any alternators out there that don't have the problem? It seems the Ford 1G alternator does not have this issue as much, maybe because of its large fan... Dunno... but does someone know what going on here?

thanks!!
 
Hello,

This type of thread is one I have been looking for, for years now! Thanks so much for starting this!!

I have some questions..

Ok here is my issue I have a small 11HP Kubota Diesel engine that I am driving a 160A GM alternator from an Escalade. I have removed the regulator and the Diodes and have a external Bridge and control the rotor field with a PWM controller up to ~12V. Here is my issue, when I turn the field up with NO LOAD on the stator and crank the engine to full speed Alternator is turning about 10,000 RPM (a guess). the Stator gets HOT! Why is this?? Now again no load on the 3 Phase Diode bridge.... the open circuit voltage is 130V! So no IR losses... What making the Stator gets so hot?? Are there any alternators out there that don't have the problem? It seems the Ford 1G alternator does not have this issue as much, maybe because of its large fan... Dunno... but does someone know what going on here?

thanks!!
My guess is that you've essentially turned your alternator into an induction heater. By spinning the rotor at 10000rpm with full field current, you've got a powerful high frequency alternating magnetic field. The stator is like the pan on an induction cooker. Stator cores are laminated to reduce eddy currents and therefore heating losses, but that doesn't completely eliminate it.
 
Hello,

This type of thread is one I have been looking for, for years now! Thanks so much for starting this!!

I have some questions..

Ok here is my issue I have a small 11HP Kubota Diesel engine that I am driving a 160A GM alternator from an Escalade. I have removed the regulator and the Diodes and have a external Bridge and control the rotor field with a PWM controller up to ~12V. Here is my issue, when I turn the field up with NO LOAD on the stator and crank the engine to full speed Alternator is turning about 10,000 RPM (a guess). the Stator gets HOT! Why is this?? Now again no load on the 3 Phase Diode bridge.... the open circuit voltage is 130V! So no IR losses... What making the Stator gets so hot?? Are there any alternators out there that don't have the problem? It seems the Ford 1G alternator does not have this issue as much, maybe because of its large fan... Dunno... but does someone know what going on here?

thanks!!

Jacob is dead correct. The electro-magnetic link is flipping poles fast enough to create induction in the steel frame of the stator. Slow that puppy down! Or cut WAY back on the rotor power so the magnetic field isn't so strong...
 
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