diy solar

diy solar

The "Meg" Build

Hedges said:
Testing a PV panel tester, you want same illumination for each test. If you don't have the lamp used for production testing, use the sun instead, intensity varies and without measuring you wouldn't know. Also, as panels heat up, their output changes. Read one panel over time and observe how much it changes - whatever variation is observed, don't expect two testers to differ less than that.

Need to switch panel between the testers several times and average multiple readings from each tester. Or put a different panel on each tester, read each one. Then exchange panels between testers and read again. If one panel consistently reads lower on all testers, it produces less. If one tester consistently reads low with all panels, its measurement is lower. Assuming several similar panels used, average of all readings by a given tester could be compared to the other testers.

A hand-held tester can't measure panel wattage under load, because it can't dissipate hundreds of watts. Same goes for automotive starting battery testers for cranking amps. It can draw "I" and measure "V" for a brief period; maybe that would read high because interconnect doesn't heat up; more likely low because a 100W 20% PV panel would still be getting 100W of heating, rather than 100W - 20% = 80W of heating.

I went through three Optima batteries in my Civic, each lasting about 20 months. The car would start eagerly time after time during the day, then one time nothing. Open circuit, voltage was around 12.5V. Headlights on, around 6V and a dim glow. Auto store battery tester showed 60 CCA (though obviously not "cold" cranking amps on a balmy day.) If the battery had actually been able to deliver 60A at 7.5V cranking voltage, 400W, it would have light the headlights just fine and held 12V. The switching load battery tester was not accurate. (I figure something inside the battery broke lose, leaving the tiniest amount of lead as an electrode.)
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you are wrong.. it has 3x 75a mosfets.. so it can. it only shorts the cells to get a reading, then opens the circuit then test again 15 seconds later... so very low duty cycle
 
Of course the day i split the series string on the ground mount/santan/Trina panels, i have rolling overcast all day.

I've also been having other problems with both inverters kicking over to Bypass/Grid power whenever a 3rd AC kicks on. Pretty bizarre because there is 13kw of available power, and all 3 units draw less than 5kw together, and the surge from 1 is wayyy less than the remaining 8kw. Hell I even use to run all 3 AC units on a single Inverter, and then some! So im going back and forth with Ian trying to figure it out. We originally thought it was because the unit was getting over 70*C, which was causing it to kick to Bypass because of temp, but apparently thats not so since I installed the window AC.

Any ideas? I did notice it has different firmware versions between the 2 units. No idea what that would do. Im wondering if I should pull off the communications cables and run them separately like when I initially put these both in action.
 
Lt.Dan said:
Of course the day i split the series string on the ground mount/santan/Trina panels, i have rolling overcast all day.

I've also been having other problems with both inverters kicking over to Bypass/Grid power whenever a 3rd AC kicks on. Pretty bizarre because there is 13kw of available power, and all 3 units draw less than 5kw together, and the surge from 1 is wayyy less than the remaining 8kw. Hell I even use to run all 3 AC units on a single Inverter, and then some! So im going back and forth with Ian trying to figure it out. We originally thought it was because the unit was getting over 70*C, which was causing it to kick to Bypass because of temp, but apparently thats not so since I installed the window AC.

Any ideas? I did notice it has different firmware versions between the 2 units. No idea what that would do. Im wondering if I should pull off the communications cables and run them separately like when I initially put these both in action.
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try running one inverter only that has the 2 ac
 
GSXR1000 said:
try running one inverter only that has the 2 ac
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That works just fine for some reason.

I just pulled the communication cables, shut off PV and AC power and rebooted them both. Now they work perfectly fine. I think the different firmware makes them think differently, so when they communicate they are just giving each other the finger and don't know what to do. Idk what could be going on, but it works now, so?
 
Lt.Dan said:
That works just fine for some reason.

I just pulled the communication cables, shut off PV and AC power and rebooted them both. Now they work perfectly fine. I think the different firmware makes them think differently, so when they communicate they are just giving each other the finger and don't know what to do. Idk what could be going on, but it works now, so?
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the shared neutral maybe causing feed back idk
 
They are still sharing the same neutral, just no communication and no 180* sync on the sine wave output.
 
you could try feeding only 120v from grid then parallel inverters at 120
 
Well, the best the SanTan panels could muster on string 1 was at 1:15pm with 179 watts per panel. Much higher, and almost matches the NOCT spec of 181watts. Im pretty satisfied with that.

Now rewiring the Sunpower panels on the roof is another story, and will be a little more difficult since they are physically bolted to the roof. Maybe I'll do that in a few months when it starts to cool down.

As for the inverters themselves, turns out I am still having Inverter #1 kick onto bypass whenever a load higher than 3kw is applied. But if I remove the Grid Input, everything is perfectly normal. This is becoming a real PITA trying to diagnose, because the LV unit doesn't just TELL ME why its switching over to the grid??
 
Sort of makes me glad I've pretty much decided on the LV6048 instead of the LV6548. Not that I'm trying to make light of your problems by any means. I hope you figure out what's going on, though I suspect that firmware difference may be part of the equation in some way.
 
Lt.Dan said:
As for the inverters themselves, turns out I am still having Inverter #1 kick onto bypass whenever a load higher than 3kw is applied. But if I remove the Grid Input, everything is perfectly normal. This is becoming a real PITA trying to diagnose, because the LV unit doesn't just TELL ME why its switching over to the grid??
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At the risk of sounding like a d1ck, is it too late to consider switching to Victron gear? Does your supplier sell Victron and would he consider giving you credit on your MPP purchases?
 
K8MEJ said:
At the risk of sounding like a d1ck, is it too late to consider switching to Victron gear? Does your supplier sell Victron and would he consider giving you credit on your MPP purchases?
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Lol, no offense taken. I didn't go to victron originally because it didn't do what I wanted, like prioritizing PV input first, then battery power, and at last resort switching to the grid if the battery voltage gets to a set point. And if victron could do that, im sure its tens of thousands of dollars lol. Ian at Watts247 doesn't sell Victron, but I have a feeling i might be asking for a refund in the near future if this can't be worked out. I dont see why this can't be fixed though, as it was working 100% perfect the first time around.

Edit: please enlighten me if I'm wrong about Victron capability, I just couldn't find the info when doing research on Inverters, and MPP/Growatt advertise it very easily.
 
Lt.Dan said:
Lol, no offense taken. I didn't go to victron originally because it didn't do what I wanted, like prioritizing PV input first, then battery power, and at last resort switching to the grid if the battery voltage gets to a set point. And if victron could do that, im sure its tens of thousands of dollars lol. Ian at Watts247 doesn't sell Victron, but I have a feeling i might be asking for a refund in the near future if this can't be worked out. I dont see why this can't be fixed though, as it was working 100% perfect the first time around.

Edit: please enlighten me if I'm wrong about Victron capability, I just couldn't find the info when doing research on Inverters, and MPP/Growatt advertise it very easily.
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Can you update the firmware on the MPP's to get them in sync?

In the Victron world, there are "out-of-the-box" or default options and then there are assistants and other more sophisticated things you can do. Right now I just have my system set up in a simple way. About the only time I'd want to prioritize PV input is when the camper is sitting in my driveway at home or in storage at some family owned property that has 120v in the barn I because beside (outside). I was told I could do this with a little bit of programming but just haven't gotten around to it yet. I have a few months of extra time coming up so maybe I'll give it a try to see if I can say for certain that it works.

That said, here is a link I found a few minutes on Google. I searched for "victron multiplus prioritization". For you, a Quattro might be preferred. Anyway, check it out. Read up on hub-1 and ESS configurations. I'll do the same. Might as well. Except, I'll have to get a Windows machine running because I think it requires VE.configure instead of just using VictronConnect.

Victron doesn't sell an all-in-one for the North American market yet. I wish they did. When I asked them, I got "we have some interesting and requested new products for NA coming soon" *shrug*
 
K8MEJ said:
Can you update the firmware on the MPP's to get them in sync?

In the Victron world, there are "out-of-the-box" or default options and then there are assistants and other more sophisticated things you can do. Right now I just have my system set up in a simple way. About the only time I'd want to prioritize PV input is when the camper is sitting in my driveway at home or in storage at some family owned property that has 120v in the barn I because beside (outside). I was told I could do this with a little bit of programming but just haven't gotten around to it yet. I have a few months of extra time coming up so maybe I'll give it a try to see if I can say for certain that it works.

That said, here is a link I found a few minutes on Google. I searched for "victron multiplus prioritization". For you, a Quattro might be preferred. Anyway, check it out. Read up on hub-1 and ESS configurations. I'll do the same. Might as well. Except, I'll have to get a Windows machine running because I think it requires VE.configure instead of just using VictronConnect.

Victron doesn't sell an all-in-one for the North American market yet. I wish they did. When I asked them, I got "we have some interesting and requested new products for NA coming soon" *shrug*
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Yes I'm currently attempting to get logs from both machines and send them to MPP. The end user can update them with a computer, but MPP must send you the files, they aren't readily available.

I'll do some more research and see what I come up with too, thanks!
 
Lt.Dan said:
Lol, no offense taken. I didn't go to victron originally because it didn't do what I wanted, like prioritizing PV input first, then battery power, and at last resort switching to the grid if the battery voltage gets to a set point. And if victron could do that, im sure its tens of thousands of dollars lol. Ian at Watts247 doesn't sell Victron, but I have a feeling i might be asking for a refund in the near future if this can't be worked out. I dont see why this can't be fixed though, as it was working 100% perfect the first time around.

Edit: please enlighten me if I'm wrong about Victron capability, I just couldn't find the info when doing research on Inverters, and MPP/Growatt advertise it very easily.
Click to expand...

Yeah unless you use their ESS you can't QUITE do that.. but I've gotten close by using the conditional AC connection feature where it connects to AC only if, e.g., the battery SoC is below a certain threshold. The only other way I know is to not use a closed system (don't let the BMS control the Victron) and set the charge voltage of the SCCs higher than the Quattro's... lastly, it may be possible with Node Red ... One day I'll play with that stuff.. it's supposed to be awesome.

Ah, yes, what @K8MEJ posted
 
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