Success! Youtube vid showing whole system

[Tom Reed]

Just curious, is the mx80 sweeping the supply source for the mpp? And what voltage does it settle in at? The reason I ask is by default I think sweeps the panels every 20 min or so to to determine the mpp. When you turned up the governor it may have tried to hold the old mpp. Powering on the mx80 after the engine is up to speed should reset it and perhaps it will run ok at the higher rpm.

[mbryner]

Hmmm.  Worth a try.  Thanks.  I'll report later tonight.

[mobile_bob]

while for the most part i would agree with what Steve and others have related about heat concerns, we also have to bear in mind
that it is very hard to hold your hand on something that is even 125 degree's F for 10 seconds,

most modern transformers are wound with class H insulation, and have a temp rating of around 180 degree C, which is blistering hot

i don't think you are anywhere near the upper end of the rating as far as temps go, however anything you can do to keep them cool
would surely work to make them live longer and be safer, at least i would think.

on thing you might consider is orienting them so that the heated airflow rise up through the center and around the out side of the toroids, so instead of mounting them vertically, mount the horizontally.

those little muffin computer fans can also be used to move some air over the cores, they come in 12, 24 and even 48volt nominal
and draw so little current that it is hard not to use them.

in reality the toroids should all be mounted inside a steel cabinet, so maybe an old computer case? or a junction box?

as for something to adjust the output down, maybe a simple reostat in the 150watt class maybe 20-30ohms?

or even a fixed power resister with an adjustable tap, that way you can adjust to fit your need and lock it there?

just some idea's fwiw

bob g

[bschwartz]

http://cgi.ebay.com/OHMITE-RHEOSTAT-10-OHM-225-WATT-PART-1256-NEW-/220708968949?pt=LH_DefaultDomain_0&hash=item33634799f5#ht_500wt_932

I'd think this should do the job, and it's CHEAP.

[gregger2k]

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.

You ought to be able to dial in the voltage drop % you want under load then run at whatever rpm you want. Like Tom mentioned you want to get up to your desired speed before engaging the MX.

[Ronmar]

After the internal videos I did, I wouldn't run mine below 600 under load without some additional oiling.  I really think it is the velocity of the dipper sweeping thru the oil th at causes it to be slung all over.  Turning the dipper sideways may help with oiling at lower RPM.  Raising the oil level by overfilling the lower sump so it keeps the upper sump at a higher level will also sling more oil...

What is your target voltage output to the charger?

[mbryner]

Target voltage is anything over 60 V DC but under 140.   It doesn't really matter, as long as it is sufficient for charging 48 v system and under 140 VOC max input of the MX80.   I'd be running full speed if it weren't for trying to decrease the target voltage a little for safety margin.   It seems w/ this modified setup w/ isolation transformers and good choke that the filtered output even at full 650 rpm is 120 V DC.    Ronmar, I keep thinking you are probably right that the low rpm's combined w/ significant load caused insufficient oiling and the big end failure.

Gregger2k, thank you very much for the "U-pick VOC%" suggestion.   That just might work and allow 650 rpm.   I'll set it to 77% to start, since that is the suggested sweet spot for solar panels (remember I have 3400 watts of solar panels hooked in, too).   

Brett, I bid on the rheostat.

The wife didn't want to go camp at the powerhouse tonight.   She felt cozy at the house in town, so I can't test it until tomorrow sometime.

[mbryner]

Today I tried changing the U-pick VOC% option, using multiple settings and input voltages of 120+ VDC at 450 rpm, and ~90 VDC at 650 rpm.   At an input voltage of 120+, I had to set the VOC% option to about 60% before it would charge decently, but then that setting would be all wrong for charging by solar panels in daytime.   Setting to about 75% yields about <1000 charging watts.   If use input voltage of 90 DC at 650 rpm, I can't get it to charge at over 1000 watts no matter what I set the VOC% at.    Oh well.   On the positive side, the toroid transformers run much cooler at the higher rpm.   I'll try changing the field voltage next.   Someone poached that Ohmite reostat at the last second on e-bay.   Dirty bidders...

[mobile_bob]

the ad copy on that reostat stated he had 100 of those things, you might contact the seller to see if this is so.

bob g

[bschwartz]

http://cgi.ebay.com/OHMITE-RHEOSTAT-10-OHM-225-WATT-PART-1256-NEW-/320631909911?pt=LH_DefaultDomain_0&hash=item4aa726ae17#ht_500wt_939

Try again? 

[wrightkiller]

http://www.mouser.com/Search/Refine.aspx?Keyword=%22OHMITE+RHEOSTAT+10+OHM+225+WATT

[bschwartz]

Have you looked at their prices 
$162.30

[vdubnut62]

I know this is off topic, and I will be good after this. Promise.
Marcus, sounds like you have been Sniped! For future reference, try Auction Sniper, it will bid automatically in the last few seconds of the auction, just input your max amount, and forget it. Plus you don't even have to bid, which sometimes avoids  a bid war. They do charge a fee, but it is very low, IIRC I've paid $10 in 10 years for the service. Oh, you get 2 or 3 FREE snipes to try it out.
Ron

[bschwartz]

I've happily used this one for MANY years.

http://www.sheaware.com/Download/BSII/bs2info.htm

I think it is a one time cost of $15

[mbryner]

There were more of those Ohmite rheostats, like you said.  I bought it with buy it now.   I always thought sniping was a dirty way to win auctions.   

Like I just wrote on another thread, if this rheostat doesn't do the trick, maybe I'll get a Xantrex C40 and charge through that.   It's current limited to about the correct load for a 6/1 and not too expensive.