Mini PM Generator - Need some advice

[veggie]

Hello electronic experts !

I came across this mini PM generator and I wonder how I can get some usable power out of it.
The unit is an Altronic 24 volt PM alternator which puts out wild unregulated power from 2 pins on the external connector.
I have very little information about this unit, but the cutaway picture in the install manual does show two wires coming from the stator to the external connector.
Performance is rated at 30 volts maximum, 4 amps, at 2000 rpm.
These units are used to run ignition systems on large engines in remote places. I suppose they also keep the starting batteries charged while the engine runs for hundreds of hours at a time.
I do not have a regulator for this unit.

My question....
Would it be practical to think that I could put a rectifier in the output lines of the unit to get a pulsating DC supply, then connect an inexpensive 10 AMP 24DC solar charge controller to the rectified power....for batter charging?  or...would the pulsating DC power confuse the little charge controller being that they usually receive a steady DC flow from solar panels  ?

Veggie

[BruceM]

Hey Veggie,
Some info is needed. If this was intended as a DC charger, I would expect 3 phase output with 6 diodes to rectify, as is done in auto alternators.
So only 2 output wires seems very odd.  If this is a two pole motor, your single phase output is just 33 Hz.

You say it only gives 4 amps at 2000 rpm; that is pretty disappointing but at least you don't have to worry about stressing the charge regulator.

I would guess that some of the very cheap on/off controllers (non-pwm) would work with this just fine with the bridge rectifier as you suggested.
The controller will turn on during the downswings, and turn off on the upswing if the battery voltage gets too high.  If you open the lid on these units you can find the pots which allow you to adjust the off voltage and hysterisis, usually.  They are handy for $15 or less.  There is no need for PWM at only 4 amps of charge unless you have a miniature battery.

Here's what I'm suggesting if it really is 2 pole, 4 amps 33 hz output. I've modifed these before so know the circuit inside well:

http://www.ebay.com/itm/20A-12V-24V-Solar-Panel-Charge-Controller-Battery-Regulator-Safe-Protection-B2-/111719625949?hash=item1a030234dd:g:P4IAAOSwu4BVp7tL

A simple PWM controller will likely work better if you have a very small battery or 3 phase AC.  It will limit the real current to the battery to maintain the voltage instead of just pumping a charge into it and then turning off when battery voltage is "full.  I haven't tested this or others priced down to $8. 

http://www.ebay.com/itm/Renogy-5A-Solar-Panel-Off-Grid-12V-PMW-Battery-Charge-Controller-for-RV-Boat-/271469556792?hash=item3f34d8b438:g:L-IAAOSwX~dWr~Wa

[mike90045]

before a charge controller can work, you do need to smooth the pulsing DC output with a choke and caps in a PI network.  Solar charge controllers expect to see PURE DC from the panels and have no provision for ripple

[veggie]

BruceM,
Yes, only 2 output wires and 2 poles. I do have the perf curve and yes, only 4 amps at 2000 rpm. Only good for starting battery maintenance on long run systems.
Funny you should suggest this controller...
http://www.ebay.com/itm/20A-12V-24V-Solar-Panel-Charge-Controller-Battery-Regulator-Safe-Protection-B2-/111719625949?hash=item1a030234dd:g:P4IAAOSwu4BVp7tL

I have 3 of them 

----------------------------------------------------

Mike90045,
That was what i was afraid of, I do not know who to build a ripple control circuit.

veggie

[BruceM]

Mike-  Many of the simple PWM or on/off designs are very low power and operate off of the battery side.  The on/off types just turn on a low side MOSFET until the battery reaches the set maximum voltage (you can open them up and find the pot to change this). The varying input voltage should not bother them and it is not necessary to filter the rectified input, though EMI (high frequency interference) may need to be filtered with a small common mode choke and small caps if operation is irregular.  Putting small 0.1 uF caps in parallel to each diode in the bridge will often reduce EMI dramatically and for a couple dollars.

Plenty of folks here have used even the more advanced solar charge controllers with lumpy (rectified) DC instead of clean PV DC.  Often, they work just fine.

[veggie]

Thanks BruceM and Mike,

One way to find out....    Hook it up.   If/when I do get to it, I will be sure to post a pic/video.
It really is a cute little unit,... I now have to decide if the 4 amp 24 volt output is worth my time ?
As you pointed out earlier, it's hard to find a useful application for a 100 watt output.
If it were driven my a water stream (creek or river) then 24/7 at 4 amps would add up to something useful.

Veggie

[mobile_bob]

there are little simple 2 wire alternator regulators on the market to do what you want.

most of them need 28vdc open circuit to charge a 12volt battery.

let me see what i can dig up
bob g

[mobile_bob]

http://www.ebay.com/itm/VOLTAGE-REGULATOR-for-MTD-Cub-Cadet-with-Briggs-Stratton-Small-Engine-Motor-/251967426255?hash=item3aaa6dcecf:g:macAAOSwXeJYLhsZ

this is one that probably would work,  you connect your alternators two posts to the two yellow wires, and the red wire goes
via a fuse holder to charge your battery.  and the case is grounded to the battery negative however you want to do that.

ebay and look for "lawnmower" regulator

wouldn't these work?

bob g