Battery/generator project

[Fordguy64]

Hey guys! I've been a member for a while just reading and learning and I've finally picked up a good motor for a small battery charger that might turn into a chp.. I found 2 semi truck apus that both had kubota z482 diesel motors. Both were said to run but had been sitting inside for a few years. I gave 200$ (us) for each unit. Got them home and had the one running the next day it's a direct drive 3600 rpm 7500watt unit. Runs and generates just fine. The other unit is a 2600rpm belt driven 4000 watt unit. Although generator doesn't work(ordered a capacitor for it yesterday hopefully that will fix it) either way I think I'm going to sell the 7.5k unit and use that money to build the battery charger. I have a 24v battery bank at 840ah I have hooked up to solar panels and it does just fine in the summer but its pretty cloudy here in the winter. I am not off grid or remote by any means but Id like to be self sufficient. So I plan to do the 110-555jho alt and a voltage reg to recharge the batteries when needed but I'd still like to swap the belt and have the 4k gen head if it was needed.(assuming I can fix it cheap) ill get some photos up in a day or 2

Feed back is welcome
Rob

[Fordguy64]

Also looking for some clarification on a few things.. Why not just get a leece Neville 24v alt with a good regulator and just use it instead of the 12v Jho version? Next is what actually controls the alternators out put? Changing the voltage on the sense with change the voltage out but how are the amps controlled? I've been playing with the idea of making my own regulator. There is a guy in here I believe thaT has made a very nice engine controller alt controller that I would like to use somemofmhismideas but on a much simpler scale.

[Fordguy64]

so this is the one with the bad generator it revs at 2600



this is the 3600 with the 7.5k gen head

[Fordguy64]

Also I need thoughts on an alternator that can put out 160 amps at 24v

[mobile_bob]

the only reason to go with the 110-555jho (12volt nominal) for 24 volt battery bank charging relates to higher efficiency over just using a 24volt alternator.

the reason basically comes down to this,

for an automotive 24volt alternator to begin charging or rather charge with significant amperage
at engine idle, it has to have more turns of wire in the stator, more turns equates to higher resistance and higher inductance, both of which have a non linear relationship to losses.

when we use the 555jho we use a stator that is designed to charge at 12volts which requires about half the wire, which means about half the resistance and lower inductance. 

now in order for the 555jho to generate at 24volts nominal we have to spin it faster, which in our application really is not an issue as we can set the pulley ratio to whatever speed we want and we run at a fixed speed.  we don't need the alternator to charge at engine idle and also at road speeds like an automotive application.

that is the short of it, 

now having said all that we still need to provide for a 12volt field when we are charging at 24volt nominal... while this might seem odd when it comes to automotive it is not at all unusual in other generator/alternator applications where the generated voltage can be much higher than the excitation voltage/current.   for instance the st7.5 has something like 60volts and a couple amps and can produce 240vac as designed.  many large generators might have a 240vdc field and several thousands of volts on the output.

as for a 24volt 160amp alternator, you could go with that without any problems, however it would likely be a bit less efficient, but i don't know without knowing which one you are thinking of... but generally speaking if it is an automotive alternator it will be less efficient than what was previously discussed...

it depends on if efficiency is the most important consideration?

fwiw
bob g

[Fordguy64]

Efficiency is important for sure. Just thought things might be easier in my situation to use a single alt instead of trying to drive 2 on the same bank. I've got an 840ah battery bank at 24v manufacture recommends the max amps at c/20. That's 168 amps. Also the engine I have for this project is a kubota z482 that makes are 13hp at 3600rpm. Now I don't ever plan on running it at that high of an rpm. Maybe 2600 or so tops and from if seen it should make 4kw pretty easy at that rpm so I would like to get as close to that load as possible. 28v at 150amp is 4200w so maybe I can find a 300amp 12 alt? Then I should get about 150 amps out of it. Or I can run 2 of the 555s and have what I need. I guess the redundancy would be good to for back up.  I've found the 555s for 150 shippe on eBay. Supposed to be oem and not a copy. Anyone have any good sources for those alts?

[BruceM]

A max amps of c/20 for an 840ah bank would be 42 amps.  C/10 is more common, and would be 84 amps.
Maybe I misunderstood something...

[Fordguy64]

C20 should be 2x c10? I think that's how that works

[thomasonw]

Also looking for some clarification on a few things.. Why not just get a leece Neville 24v alt with a good regulator and just use it instead of the 12v Jho version? Next is what actually controls the alternators out put? Changing the voltage on the sense with change the voltage out but how are the amps controlled? I've been playing with the idea of making my own regulator. There is a guy in here I believe thaT has made a very nice engine controller alt controller that I would like to use somemofmhismideas but on a much simpler scale.

Rob:  Hello, great to see another Dc generator!   I would be the 'guy on the board . . ',   Just to let you know, I also made a slimmed-down version of that fully integrated controller / regulator to have just the regulator portion.  As before, its major feature is it monitors both Amps and Volts to not only make sure the battery is fully charged, but also allows you to accurately cap the load the alternators place on the engine - preventing any overloading.   

http://arduinoalternatorregulator.blogspot.com/

It is designed to support different battery voltages and field voltages, ala a 12v field and a 24v battery will work just fine.  Please feel free to use any part of the design you want, and if you have any questions  will be happy to answer them.  Also: am currently having a short run of 20x of these assembled, about 15x of them are spoken for already - if you are interested in one drop me a line.

And FYI, am also looking to do a short-run of the full controller as well in about a month.  These will not be 'fully' assembled, but will have all the SMT parts machine placed and re-flow soldered.  Will still need to hand solder on the high power parts, but the SMT work will get perhaps 85% of the components all done.

Best of luck, will be interested to see how it works out for you!

-al-

[Fordguy64]

Never put it together but I've been in touch with you already about a week or so ago. I'm on the waiting list for the full controller . Just here trying to sort it all out and make sure I get it all straight

[BruceM]

I checked and you're right Fordguy, 0.2 times the 20 hour capacity rate is the maximum charge rate Trojan allows for on it's bigger batteries.  The recommended charge rate is  0.1 times the 20 hour capacity or C/10 for the regular batteries. 

[thomasonw]

Never put it together but I've been in touch with you already about a week or so ago. I'm on the waiting list for the full controller . Just here trying to sort it all out and make sure I get it all straight

Sorry, didn't make the connection :-)   

-al-

[mobile_bob]

no reason to drive two 12volt alternators to charge the 24volt bank,
just use one of the 12volt 110555jho alternators and drive it fast enough to charge the 24volt bank

it will do so quite well at about 4500-5000rpm with more than adequate cooling, low field current and capable of 100amps at 28.8vdc continuous duty using something on the order of 35watts of excitation current (about 3.5amps at 10vdc).

i have tested to 130amps at 28.8vdc and the unit remains thermally stable, under the max heat rating, but figured 100amps probably means the longevity is improved by backing down a bit.

fwiw
bob g

[Fordguy64]

Well my thought with the 2 alternators was to bring up the amperage to allow shorter run times. But  maybe for now ill start with one and see how it goes

[Fordguy64]

So my latest thoughts for this system are:

1. Use system to charge my battery bank of 24v at 840ah with a 110-555 alt and maybe even 2 of them at some point. Use Al's smart dc generator to control that

2. I'd like to be able to drive a 5-8kw generator head also.

3. Use waste heat to heat dhw and maybe some of the house depending on run times in the winter and also the outside temp.

4. This is the one that I know least about and have only seen people talk about but have yet to see a system actually in use. That would be to drive an ac compressor to heat/cool. I've seen a few people talk about it on here but I have not seen any systems in use? Correct me if I'm wrong. Anyone seen any on another site? Links?

Obviously I wouldn't be able to run them all at the same time..

Thoughts?