48V charging via ST generator and solar charge controller (no ST mod)

[oiler]

with the Flexmax control panel but it only takes a few seconds to change the charge amps. Just put a little chart on the wall with what you need from each source....

That would work fine for me, but how would my wife remember to do all that.   As it is, she can't start the Listeroid alone consistently, which is why I'm building an electric start.   It's going to be hard enough for her to remember to oil it!     Don't you guys have problems like this, too?!  

I do!!!!!!!

[Tom Reed]

I think my wife would just let the batteries go flat before she'd even consider starting the listeroid. I've tried giving lessons, however we didn't get to far.

[d34]

I think my wife would just let the batteries go flat before she'd even consider starting the listeroid. I've tried giving lessons, however we didn't get to far.

we may have the same wife  ... or maybe they are sisters 

[mbryner]

Hello Gentlemen,

Since I started this thread, here's an update.   I've only been on the forum occasionally in the past 6 months and I've missed it.  

Our house construction is nearing completion and hopefully we'll move in in the next few weeks!      The construction crew wouldn't even know they were off-grid if they didn't see the solar panels.  I didn't have time to think about this thread until recently...

The power system functioned flawlessly until about 2 weeks ago when we had our first early autumn rain.  The tile guys had 500 W halogen bulbs burning brightly all day, etc.   The solar panels couldn't keep up in the cloudy weather of course.   So I had to start the Listeroid 6/1  when the batteries got down to about 60-70%.   It charged the batteries at max charge rate back through the Outback inverters.   But, whenever the guys would try to start a big saw, etc., their equipment would kick-off because of too low voltage.    Now I'm getting leery of living in my house, having low batteries because of rain, and not being able to run, say, the vacuum because the generator is running.

So, I'm going back to my original plan of faking out a charge controller into thinking it's getting DC from panels when it's actually getting rectified current from the generator.    I'm installing a few breakers at the generator to select between 230 VAC and 120 VAC output.   Then I'll take the 120 VAC output to a high current bridge rectifier, then through an inductor/choke filter.    V DC should be close to 120 V, correct?   (i.e. Should be close to the RMS AC Voltage after going through the choke.)   To get even lower voltage, I'm adding a tiny key-ring loop to the governor spring on the Listeroid, effectively decreasing spring tension which would decrease RPMs, but would be simple to change back to normal voltage.   A rheostat on the field winding would work too if I find the right one.    I ordered the rectifier and it should be here in a few days.

Never did find a transformer (see a few pages back): the shipping was always the deal killer.

Still don't know about limiting the charge current, but what harm can I do by hooking it up?   If the Outback MX80 draws too much current, the Listeroid will bog down, voltage will drop and the charge controller will eventually disconnect.   Of course, if no one is watching to turn it off, it would try to reconnect and would cycle like that continuously.   Using a 2nd charge controller would be another option, but the PWM controllers won't work because they only limit current to a certain point, then disconnect.   From the TriStar-45 manual:

"If the solar input exceeds 100% of the controller's current rating, the controller will reduce the average current below the TriStar's rating. The controller is capable of managing up to 130% of the rated solar input. When 130% rated current is exceeded, the solar will be disconnected and a fault will be indicated. The input FET switches will remain open for 10 seconds. Then the switches are closed again and charging resumes. These cycles can continue without limit."

Updates will be posted in the next few weeks as I experiment again.

I know, you guys are saying, "he didn't fix the dumb thing already 6 mos ago?!?  

If you want to see pictures of the house (from about a month ago):
http://www.docbryner.com/4images177/details.php?image_id=8390

Thanks,

Marcus

P.S.  mobile_bob, I still have that big Variac.   Thought I'd use it for something, but never did.   You still interested?

[Ronmar]

That is going to be a lot of ripple rectifying single phase 120VAC to DC.  I will be curious to see how it works out feeding your inverter.

[mike90045]

Don't the outback inverters have chargers in them ?  What model inverter ?

[mobile_bob]

Marcus:
nice to see you back, alive and kicking!

trying to remember the variac, was it the three phase unit?

bob g

[SteveU.]

Hi MarcusB.
Your house pictures are looking great. A very Swiss-American home! Just had to get the tractor in there too, eh?
The kids are sure getting bigger too.
Looking forward to seeing pictures of your mass hearth wood heater.

Regards
Steve Unruh

[Tom Reed]

Marcus,

Welcome to my world. We've got a 3.4 kw solar array on the roof and s listeroid 6/1 too. Ours was used without the solar panels for 99% of the construction because we mounted the array on the roof. The system is currently setup to charge through the out back vfx3648 inverters that are wired out of phase to feed a standard utility panel. The only real problem we encounter is that if the micro wave or jet pump turn while the generator is running it will lower the voltage enough to cause the inverters to drop out of charge mode and then in a minute they will reconnect. I had expected the inverters to come with "Generator Support" however although the menu item is there it is not functional. Had the generator support  been functional when the load exceeded the max amp set point the inverters should have synced to the generator and switched to inverter mode until the load dropped and the inverters would return to charger mode.

I have contacted Outback about this without reply and am quite disappointed in how they have handled this. I've even wrote a correction to Home Power magazine about their article stating that the Outback inverters will do generator support and no reply from them either.

So assuming you have outback inverters you are stuck as am I. Please keep us informed as I am thinking of doing something similar to you with our system.

[mbryner]

Hi Tom,

hee hee, we have exactly the same setup.   What kind of charge controller are you using?   Can it handle high voltage V(oc)?   I just drove through Hopland a few weeks ago.

I can't be out at the house jobsite every day, so having the solar panels working was a necessity.   My contractor doesn't know much about electricity (funny, huh?), so he couldn't be starting the Listeroid every day and throwing switches.   Yes, if only the inverters would drop charging mode and go back into inverting mode when you turn on a heavy load, but my guess is they can't sync fast enough.   Here's my current plan:

So, this long thread started because I wanted to get away without making a ST head mod,   but it looks like a system of 2 breakers  will be necessary to convert between 120 and 240 V operation because transformers are expensive.  One breaker can jumper U3/U4.   The other breaker has to be a double pole breaker: one pole to connect U1/U4 and the other pole for U3/U2.   Make sure you *never* have both breakers switched on at the same time.    In both cases either U3 *or* U4 can be neutral, and don't bond neutral to ground except at the main panel.

The 120 V option completely bypasses the inverters, with output going to the high-current bridge rectifier.   Here's the one I bought (1000 Volt, 100 Amp):  
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170546493063    
It's 3 phase but will work fine for single phase also.   I have a giant old transformer for a filter choke to smooth out the ripple that ronmar was alluding to.    Geno a few pages back confirmed that the Outback charge controllers can handle rectified DC.    The whole thing is a couple more switches/breakers than I wanted but it is cheap to implement.

The 240 V option is for emergency feed to the main panel and back into the Outback inverters (i.e. the current setup).

Marcus

p.s. mobile_bob:  yes, 3 phase 9.7 kva autotransformer    See page 10 of this thread or:  http://www.microcogen.info/index.php?topic=500.msg8470#msg8470
Come pick it up!

[Jedon]

Marcus,
Your house looks great!
I want to charge from my 6/1 through my ST-5 to a TS-60 to my batteries to supplement my PV and hydro when needed so I'm glad you guys are figuring it all out for me!
-Jedon

[Tom Reed]

Hi Tom,

hee hee, we have exactly the same setup.   What kind of charge controller are you using?   Can it handle high voltage V(oc)?   I just drove through Hopland a few weeks ago.

I have a MX60 and it can handle 140vdc max. Which is just a smidgen short of what is needed, it sometimes blows the 60 amp breaker on a cool bright day when the batts are low. I'm still trying to decide what is the best way to charge the batteries given the equipment I have.

Our houses are very similar too. During construction of our house the st5 was wired for 120 vac with a 4 plug receptacle for power. I trained the contractors to fuel and run the genny. They picked it no problem. Are you in Hopland often? I work at home so let me know if we can meet.

[mbryner]

Hello gang,

So, I finally have some real data for you to peruse.  I've slowed down the Listeroid to about 550 (?) rpm using a tiny key-ring in the governor mech (just lengthens the spring) for when it is in "120 volt DC charging mode."  (See my last post above.)  This makes the output voltage about 80 V DC after going through the bridge rectifier.   The large choke was essential.   Without it, the charge controller seems to "hunt".   It would load down the Listeroid with up to about 1500 watts, then drop the load immediately, and repeat.   With the filter choke, the MX80 charge controller pulls about a 1600 watt load and holds it well.  1600 seems to be the max because the voltage drops as the engine is loaded and rpms drop.   Every little while the charge controller lets off the load and (I assume) checks the battery status.   Perfect.   When it is drawing a load, the engine rpm's drop to about 480.   I'm just counting the exhausts puffs per min and multiplying by 2.   You'll notice I gave up recording the Hobbs meter, because at the lower rpms/voltage, it runs slower, too!

The engine seems to be quite efficient at this slow speed and load.  (Anyone know what the rated HP is at this speed? Are there any downsides to running the Listeroid this slow?)  The fuel efficiency compares very favorably to other published results on Utterpower.  Overall, I am very pleased!    Pictures will follow when I have a chance later tonight.

		Total Run	Fuel tank	Kwh	Total kwh		Hobbs
Start	0955		10 gal				201.3
	1925	9.5 hr	8 gal	16 kwh	16 kwh		209.0
End	2215	12.3 hr			19.8 kwh		211.1

		Total Run	Fuel tank	Kwh	Total kwh		Hobbs
Start	0755
	1505	19.47 hr	6 gal	11.3 kwh	31.1 kwh
End	2230	26.88 hr	~4.5 gal	11.6 kwh	42.7 kwh

Results at 6 gal mark (more precise):

Average charge rate:	31.1 kwh/19.47 hr =	1.60 kw
Average rpm: ~480
Fuel efficiency:	19.47 hrs/4 gal =	4.87 hrs/gal
		or 0.205 gal/hr
	31.1 kwh/4 gal =	7.76 kwh/gal
		or 0.129 gal/kwh

Results overall:

Average charge rate:	42.7 kwh/26.88 hr =	1.59 kw
Average rpm: ~480
Fuel efficiency:	26.88 hrs/5.5 gals =	4.89 hrs/gal
		or 0.205 gal/hrs
	42.7 kwh/5.5 gals =	7.76 kwh/gal
		or 0.129 gal/kwh

All measurements at ~1780 ft above sea level,
performed 10/24/2010 + 10/25/2010

[Tom Reed]

That's very encouraging! Now that generator season has started for us I'm thinking real hard about converting my ST5 to DC also. I'm planning to pull wires for each pole and rectify the 60vac and feed that straight into a MX 60. Done this way I shouldn't need the choke and also should be able to get full rated power out of the engine. I'm thinking things could be switched between dc & ac with a 4 pole transfer switched although I haven't worked out the schematics yet.

The occasional shutdowns you are getting is when the charge controller re-sweeps the "Panels". You can set this value to a real high number to stop that as it is really not needed as the MPPT is always the same. My MX60 will also do a restart about every 30 min and that setting can be changed too. Do you feel that the MPPT function is correctly/effectively limiting the amps pulled from your system?

[gregger2k]

Hey guys, sounds like fun.
I would try the Outback's MPPT 'U-Pick VOC% mode' and change the percentage of VOC to find a setting that will load the generator to where you want. Since you are using a choke input filter you do have some source resistance but not quite like a solar panels more constant current output.

Maybe you could contact Midnight Solar about their new Classic controller. They have a high voltage model that might work well with rectified generator output. They say it will do everything else (even talk to you) I think the controllers are almost out of vaporware!!!

Greg