Anotherpower.com Forum
Renewable Energy Questions/Discussion => Automation, Controls, Inverters, MPPT, etc => Topic started by: tomw on March 29, 2012, 01:49:28 pm
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Well, as some may already know I got a used BZ MPPT controller from Chris.
Installed it a few days ago during a long solar "vanishing" with lots of overcast and stormy skies.
It did a great job squeezing what there was out of the 4 Kyocera KC-130GT panels hooked to it. Taking a couple of PV amps and shoving 3 amps or so into the batteries!
It has been sunny a couple days now and this is where the rubber meets the road. Those 4 130 watt panels were pushing 540 watts plus through that BZ! 21 Amps into 25.8 volts at one point and probably more when I was not looking?
So, getting almost 4% over rated watts off those 520 watts of panels rather than the 80% of rating so I guess it works.
Just wanted to share that.
I knew it "should" work but now I "know". Can't wait to see the sunny day @-30F numbers next winter!
Considering a fresh one for the other 4 panels in the array. 4X 75 Siemens SP75's. Easier than installing more panels.
Tom
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tom-
that's awesome! mppt is a pretty cool thing!
i was against mppt for a while as prices were so darn high. i bit the bullet on a $300 mppt rogue controller last fall and have never looked back. the money aspect gets forgotten pretty quickly once you see the amps flowing. during low battery and cold conditions, i've seen over 420w coming out of my 390w array.
i think the best part about mppt is when you have panels in series. the high voltage allows charging to begin much earlier, and last much later into the day... even if it's just a trickle!
adam
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Cool Tom!
I have a Blues Sky 12V, a BZ250 HV , and the new Morningstar ts45 mppt . (all mppt). My new TS45 does about the same as what you are seeing with your BZ with 400W of panels (series to 24 nominal (around 40V Voc)) This will be going up to 600W this weekend.
The Blue Sky also does well with its 300W of panels
Unfortunately for me, I never was happy with BZ250, so its sitting on a shelf.
Rover
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Unfortunately for me, I never was happy with BZ250, so its sitting on a shelf.
Rover
Rover;
I would offer to take it off your hands but that unit is 12 volt only I think? :o
Tom
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I'll go check... but here is what I didn't like about it..
1. Since I graph my stuff I noticed , that once in a while it would drop out in full sun in absorb, for a few minutes
2. There are a lot of little black nuts that attach to screws separating the circuit boards, these have a tendency to just fall off and get lost (and the screw)
3. the little piece of plastic covering the LCD, just "fell out", doesn't hurt it.. but not there anymore
4. When cohabitating with my current sensors (Halls) in the same electrical panel, generated a lot of noise. (blue sky is in the same panel, no issues)
5. Switch on front panel is flaky.. meaning it prefers showing voltage rather than amps, (might be the opposite, can't remember)
I bought it new about 8 months ago. Ready to go for anyone that wants it (minus some screw and nuts, and the little plastic piece that covers the LCD)
Rover
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Yep, just checked the manual , 12V batteries only
Rover
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I shouldn't be so negative about the BZ :). It did do MPPT and that was obvious.
Although, temperature compensation was neglible, even though it had a temp probe (free air though, not bolt to battery). In comparison I can see the temp compensation from the ts45 .... comes down like little steps as the temp warms up
But for the price, (less than both the blue sky and obviously the ts45)
not bad.
Rover.
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Yep, just checked the manual , 12V batteries only
Rover
OK, otherwise I would hunt you down on IRC and call dibs on it. :o
Thanks.
Tom
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Nice thing about it is that it will take up to 150VDC in solar. Bad part is only up to 250W (total). Although I did have it running with 255W Solar... figure there is some fudge room.. regardless of the BOLD print in the manual.
The reason its not in use is that I have surpassed its capabilites.. hence the ts45.
Rover
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Are you getting those amp readings from the controller itself? I have read that even the venerable MX60 would incorrectly (optimistically) report it's own amps in some situations. Judging by my past experience with BZ, I would trust but verify ;)
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Are you getting those amp readings from the controller itself? I have read that even the venerable MX60 would incorrectly (optimistically) report it's own amps in some situations. Judging by my past experience with BZ, I would trust but verify ;)
Well, it seems to agree with my analog meters as well as the Doc Wattson on the solar.
Tom
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Hi Volvo Farmer
I have my own monitoring system... multiple hall efect sensors etc, that I can calibrate. I can't speak for Tom, but I do see what I see
Rover
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Those 4 130 watt panels were pushing 540 watts plus through that BZ! 21 Amps into 25.8 volts at one point
That's the beauty of the MPPT on either solar or wind - even on a cloudy day with the solar. Your bank can be low on voltage, which really cuts direct hooked panels back on power (especially if you got ~34 Vmpp and the bank is 10 volts below that). The MPPT gets the power out of them regardless of the bank voltage.
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Chris
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i was against mppt for a while as prices were so darn high.
Yeah, me too. For a long time I thought up every reason why I didn't need it. But after trying it it became pretty obvious that your RE system, without it, is pretty much like buying a car that can get 40 miles per gallon. But the car comes from the factory with one spark plug wire missing so it really only gets 30.
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Chris
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I'll go check... but here is what I didn't like about it..
1. Since I graph my stuff I noticed , that once in a while it would drop out in full sun in absorb, for a few minutes
2. There are a lot of little black nuts that attach to screws separating the circuit boards, these have a tendency to just fall off and get lost (and the screw)
3. the little piece of plastic covering the LCD, just "fell out", doesn't hurt it.. but not there anymore
4. When cohabitating with my current sensors (Halls) in the same electrical panel, generated a lot of noise. (blue sky is in the same panel, no issues)
5. Switch on front panel is flaky.. meaning it prefers showing voltage rather than amps, (might be the opposite, can't remember)
I bought it new about 8 months ago. Ready to go for anyone that wants it (minus some screw and nuts, and the little plastic piece that covers the LCD)
Rover
I'm all 12 volts here running a C40 but wish I had gotten an mppt. How much?
I was just looking at those a couple of days ago as everything I have is RV stuff. I've only got 170 watts so it's just the ting. I do paypal. Or it does me, not sure.
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How much?
Really depends.... ordered a BZ250 which is the lowest priced MPPT that I know of, ignoring fake ones on EBay, is roughly 125 to 150 US$. A step up in my opinion is the Blue Sky.. for roughly 220$
But.. these are pretty much limited to 12v Battery Bank... Although the BZ... has a solar top end this it much higher than the Blue Sky.
End of the day, I prefer the Blue Sky... better construction.. the BZ can be a bit flaky.
BUT.... If you are thinking of growing into the 400W+ realm.... there are a ton of better choices.... don't plop down $$$ for something you will replace in a year or 2 as you out grow the controller...
I have done this.. I have a Blue Sky and and A BZ... both are being replaced by a couple of Morning Star TS 45 MPPT. There are also other mppt vendors.. but I like the the first TS 45 I bought.. so that's my plug.
Rover
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My pickle is that I bought a couple 85 watt panels from sunelec a year ago and they, already, don't carry that model now plus they went nuts on shipping and want 100 bucks shipping on equivalent. I was just going to get one more as we almost had enough juice last summer but not quite. I hate to mix and match panels and I like that I can move these two panels around by hand that I have so to get that little extra juice the next best thing is an mppt. So I started looking for the cheapest and found the bz. $120-130
In a year or three I'll probably do a major upgrade and either go with brand name panels or make my own and then I'll need a better controller but I'm sure I can put the old stuff to use in my shop. Right now I just need something so we don't have to run the gennie everyday this summer to have refrigeration. I don't mind running it when it's cloudy or when we run the a/c but it urks me to run it when it's sunny. Gallon of gas a day for 60+ days. Even new retail the bz would save me a few bucks. So let me know if you decide to sell it.
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Rover said "don't plop down $$$ for something you will replace in a year or 2 as you out grow the controller"
Then Poorboy said "In a year or three I'll probably do a major upgrade"
and "Gallon of gas a day for 60+ days"
I agree with Rover. Get a TS-MPPT now.
Probably a good investment to get a stack of panels now.
Save some gas and gennie wear&tear.
Dollar per watt S&H will be a lot less with 4 or 6 panels than 1 or 2.
Might be worth it to borrow some money and pay interest, instead of pay S&H on 1 or 2 panels at a time while still buying more gennie gas?
G-
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Hence the user name. There is no investing, borrowing, interest for me these days.
But Rover saidReady to go for anyone that wants it
That's what I was going by but that was a couple of weeks ago and now it's not. No biggie.
I have had the very same model bookmarked at a couple of different sites for a few days now and will end up getting it. If I had a few hundred to spare I would do something else. Meanwhile this unit will help me out.