Homebrew backup genset

[The Wizard]

If you don't care about your battery life, or excess heat, you can just charge directly from the rectified alternator... but it will kill your batteries MUCH quicker.

You can also build, or buy, a much heavier duty rectifier/regulator/filter network, and charge through that.

Charging into a battery bank fixes those problems. No matter how dirty the DC coming into the batteries is, coming out it's flat and clean (or at least close enough to not overwork your inverter).

...DC generator. The alternator on automobiles has a DC output, but it usually is not particuliarly "clean" DC. The car's battery "smooths" this DC signal out somewhat. So car alternators run by a Briggs & Stratton will work OK to charge batteries, but DO NOT try to run DC equipment directly from it, without having a battery as a signal pulsation dampener.
Additionally, charge rate also affects battery life. To keep from killling your batteries prematurely, do not have a charge rate greater than C/4. The solar panel/offgrid folks consider C/10 to be about the best compromise between charge time vs battery life.

If you are going to run your house while also charging batteries, you will be using an AC generator and a battery charger, or invertor/charger.

So it can be done feeding into a battery bank just being aware that pushing too many amps through will significantly shorten battery life?

And I'm still not sure if I'm understanding very well about using electronics while charging the batteries with this home made 12v generator battery bank set up. If the 12v dirty electricity is produced and fed into one end of say a 4 bank system and the load is coming off the other end is it still a no go to run the generator to charge the batteries while a load is still pulling power off of said batteries? I understand that some of the energy being produced will bleed off down the connecting cables while the generator is running but I was thinking that it would be buffered by continuing to pass through the batteries down the line.

Thanks for all the information and thanks for speaking slow and using small words, I know I'm kind of hard to teach sometimes

[randy]

So it can be done feeding into a battery bank just being aware that pushing too many amps through will significantly shorten battery life?

Keeping it simple, yes

If the 12v dirty electricity is produced and fed into one end of say a 4 bank system and the load is coming off the other end is it still a no go to run the generator to charge the batteries while a load is still pulling power off of said batteries?

That depends. Easiest way to tell is to stick an oscilloscope on the output and see what the output wave looks like. (wait, everyone doesn't have an O scope in their basement? )

I understand that some of the energy being produced will bleed off down the connecting cables while the generator is running

Not so much "energy" but the format (shape/timing) of that energy as it passes through the system.

but I was thinking that it would be buffered by continuing to pass through the batteries down the line.

Again that depends on variables such as the generator's output (wave shape, voltage, current) and the capacity of the batteries relative to the generator output.

[randy]

Oh, and what Chris said while I was typing my reply!

[The Wizard]

Thanks guys, one more favor to ask, can someone provide me with a link to a 12v regulated charger, I started googling it and all I'm seeming to find is various AC to DC regulated chargers. At least some type of similar product so I know what I'm looking for.

[Termite]

You need to be looking at RV supply, alternative energy supply places etc..

Or for that matter, you can really easily make one with $50 worth of parts and an hour or so.

I would not encourage him to build a full wave adjustable rectifier, unless he's "feeling froggy". Too cheap and easy to buy one.

Put a relatively cheap regulated charger at the input side, between the alternator/generator and the batteries. This will fix issues with battery life, heat, and surging/dropping/spiking on input.

That would be my recommendation, also.


Ideal setup:
Buy a Xantrex Freedom SW-2012 inverter/charger. Link It has a 2000 watt pure sine wave output, a 30amp tranfer relay, and a 100 amp 3 stage battery charger that can be set for flooded cell, gel cell, or AGM batteries.
Have a battery bank consisting of eight L16 flooded batteries in series-parallel for 1600 amp-hrs @12vdc.

Have a high quality 5000 watt generator, with a full power switch so that you can set the output for full power single phase 120 volt.

You now have a kick-ass backup genverter system.

[The Wizard]

I dont suppose something like a motorcycle or snowmobile R/R would do the job im looking for would it?
http://www.trailtech.net/electrical/ele ... -rectifier
Or
http://www.extremescooters.biz/12v-rect ... lator.aspx

[Termite]

Its not the rectifier that you want to build, its the limiting/shaping/filtering circuitry that's cheaper to build than buy. Or rather to assemble from prep built subcomponents.... And presuming you are doing so instead of buying a high quality heavy duty regulated smart charger.

Our posts crossed. See edit above.

[Termite]

I dont suppose something like a motorcycle or snowmobile R/R would do the job im looking for would it?
http://www.trailtech.net/electrical/ele ... -rectifier
Or
http://www.extremescooters.biz/12v-rect ... lator.aspx

NO.

Those are for taking the output from an ignition coil, and charging a battery in a scooter, utralight aircraft, snowmobile, etc.

[The Wizard]

Got it, thanks
/runs off to do more research/

[Termite]

Since posts and edits got crossed above, I'll re-post this:

Ideal setup:
Buy a Xantrex Freedom SW-2012 inverter/charger. Link It has a 2000 watt pure sine wave output, a 30amp tranfer relay, and a 100 amp 3 stage battery charger that can be set for flooded cell, gel cell, or AGM batteries.
Have a battery bank consisting of eight L16 flooded batteries in series-parallel for 1600 amp-hrs @12vdc.

Have a high quality 5000 watt generator, with a full power switch so that you can set the output for full power single phase 120 volt.

You now have a kick-ass backup genverter system.

I'm not joking. If you are willing spend about $6K, this is the way to go. You could even step up to the SW-3012 for a few hundred more.