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OffGridInTheCity

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Yikes... I did not know the midnites were so crummy... Just thought of another idea... I know you just bought that pallet of used cells but I noticed that you have a ground mount setup. Why not update the panels on the ground mount with some 'newer' ones like 380-420w 72 cell? you might have to buy new/longer rails but it appears you have the ground clearance to get another row also in landscape orientation. Could be a 50% bump from what you have for that one array.
The 16% loss is from the AIMS inverters - not the Midnite Classic Charge Controllers. The Midnites are in the top tier of MPPT efficiency as far as I understand. The existing arrays of 3s5p (285w) are of design to be near the max of the Midnite Classic 150s and the wiring I have in place. I don't believe I have significant loss of the incoming PV power.

Different size panels / wattage is not a clear 'win' (other than space perhaps) in that there would be expense/ripple affects - to physical framework, possibly the wiring, etc.... space is not the main issue. :)

Side note - the picture (12 posts back) shows the size difference between my existing Mono crystalline (black) and the recent Poly crystalline (blue'ish) 'backup generator' panel sizes - they are both 285w. In addition the Poly(s) weight 20lbs more. I never really 'got it' until this week when I see them side by side - its a significant difference.

I'm attracted to SolArks because they 'more' EMP hardened. I'm attracted to MagnaSine because they advertise 96% inverter efficiency. Both systems are a lot more $ than AIMs inverters.
 
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floydR

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check out the specs it is only an 8kw inverter off grid yes 12kw on solar minus what you are charging into batteries other things such as having problems starting high wattage/amperage items while off grid. etc reference
starting around the 3 minute mark he says he shut it down with his air compressor, then a couple seconds later he said is dryer shut it down
The inverter a good one but not for everyone, You essentially lock yourself into a 50amp service Ben also says
Later floyd
 

Solardad

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check out the specs it is only an 8kw inverter off grid yes 12kw on solar minus what you are charging into batteries other things such as having problems starting high wattage/amperage items while off grid. etc reference
starting around the 3 minute mark he says he shut it down with his air compressor, then a couple seconds later he said is dryer shut it down
The inverter a good one but not for everyone, You essentially lock yourself into a 50amp service Ben also says
Later floyd

A good point that most folks over look.
 

dali1972

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Sep 11, 2020
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I've become a huge fan of 'heat pump' technology as a way to get heat from electricity....
- Hot Water - We have a Rheemes 50gal hybrid (heat pump + regular elements) water heater which is mainstream/good-prices from Home Depot and very efficient in heat pump mode and maxes out at 450w (smaller inverter).
- Forced Air, whole house heat pump - We have a 4ton Lennox heat pump that works down to 30F/-1C with a max draw of 5000w (at 25F) - but typically runs around 3500-4000w while heating 2600sq ft house.
- Mini-splits are cool - I have a 9,000BTU on the trailer and it 'sips' power and is whisper quiet.
- Clothes Dryers - I have read about heat-pump clothes dryers. They max out at only 1,000w instead of the 4,500w of a normal dryer and 'reportedly' use only 1/3 the overall power of a regular dryer.
- Clothes Dryers - I have read about heat-pump clothes dryers. They max out at only 1,000w instead of the 4,500w of a normal dryer and 'reportedly' use only 1/3 the overall power of a regular dryer.

We have a AEG 7000 series heat pump dryer.... and not trying to be sexist, but my wife hates it and constantly complains about it. tumble dryer.jpg

So why is it bad...and why does she hate it so much.... simple, it as you say uses less wattage and the temp is much lower, this means that what would normally have taken 60 mins to dry in the old tumble dryer now takes roughly 3 or 4 times longer. Thus not sure it actually saves a great deal in money, and is certainly a pain, if you need something fast. PS - also bloody expensive to buy in first place...so honest opinion of ours.... DONT...save your money...buy more panels...and buy an ordinary one.
 

dali1972

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- Clothes Dryers - I have read about heat-pump clothes dryers. They max out at only 1,000w instead of the 4,500w of a normal dryer and 'reportedly' use only 1/3 the overall power of a regular dryer.

We have a AEG 7000 series heat pump dryer.... and not trying to be sexist, but my wife hates it and constantly complains about it.View attachment 24053

So why is it bad...and why does she hate it so much.... simple, it as you say uses less wattage and the temp is much lower, this means that what would normally have taken 60 mins to dry in the old tumble dryer now takes roughly 3 or 4 times longer. Thus not sure it actually saves a great deal in money, and is certainly a pain, if you need something fast. PS - also bloody expensive to buy in first place...so honest opinion of ours.... DONT...save your money...buy more panels...and buy an ordinary one.
One more point to add... my wife will only use our tumble dryer if we need to...otherwise its clothes line outside, or radiators. Its a last resort tool...not a goto machine. Thus her issue with the time to dry.
 

OffGridInTheCity

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Dec 15, 2018
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I'll measure them against a know good panel and see how they actually stack up.
1614561527618.png
38 of 40 panels tested OK....
- Reference panel (new) = tested 34v open circuit and 8a shorted circuit. Vmp spec = 31.3 * 8a = 250w
- Suntech panel (9yrs old) = tested 44v open circuit and 6.9a-7a shorted circuit. Vmp spec = 35.4 * 6.9a = 244w
So I'd say these are at least 90% original spec... the test method is a bit 'loose' is why I'm not claiming 97.6% as numbers show.
Suntech warranty on these panels....
1614561058558.png


Had 2 bad ones.
- Voc = 30v instead of 44v. This is likely a blown diode.
- Panel arrived *shattered*. It was the very last one (bottom of the 2nd pallet). Such a waste, glass all over, and cut my thumb!
1614560649177.png


All in all - I'd say it was a success ordering used panels as I got 38 of 40 that are fine and I think I can fix the 39th one.
 
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Solardad

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Oct 27, 2018
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38 of 40 panels tested OK....
- Reference panel (new) = tested 34v open circuit and 8a shorted circuit. Vmp spec = 31.3 * 8a = 250w
- Suntech panel (9yrs old) = tested 44v open circuit and 6.9a-7a shorted circuit. Vmp spec = 35.4 * 6.9a = 244w
So I'd say these are at least 90% original spec... the test method is a bit 'loose' is why I'm not claiming 97.6% as numbers show.
Suntech warranty on these panels....
View attachment 24060

Had 2 bad ones.
- Voc = 30v instead of 44v. This is likely a blown diode.
- Panel arrived *shattered*. It was the very last one (bottom of the 2nd pallet). Such a waste, glass all over, and cut my thumb!
View attachment 24059

All in all - I'd say it was a success ordering used panels as I got 38 of 40 that are fine and I think I can fix the 39th one.
Thoughts on how you are going to mount these if they are for temporary use?
 

OffGridInTheCity

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Thoughts on how you are going to mount these if they are for temporary use?
I have universal strut, bolts, wire, and connectors stored with the panels - wa la, a 'backup generator' package. The design/plan is to setup them up in the yard and wire them into the existing pv array combiner boxes to take the array from 13kw to 24kw. In winter time, the charge controllers have plenty of extra capacity due to low winter sun and this will get me near 1000kwh/month based on past 2 winters of data.
 
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OffGridInTheCity

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Was successful repairing the panel with bad diodes by installing a new diode box. And here's the final stash/resting place of the 42 * 285w = 12kw 'backup generator'. Phew - a lot of work to drag them under the house. If the worst should happen, I can drag them out into the back yard and have the potential to generate an extra 500kwh/month during the 4 winter months. :)
1617320041989.png
 
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