How would you use 90V panels off-grid?

[cdevidal]

Found a great deal on some 90V panels but I'm scratching my head on how to best use them when most off-grid chargers top out at 48V. I'd need to buy them in bulk, 28 panels, and they're 90W each, so I'd have 90V at 28A.

I suppose I would just use an MPPT, something like this, correct? Specs indicate they can handle the higher voltage.

http://www.amazon.com/TRACER-3215RN-Solar-Charge-Controller/dp/B008KWPGAE/ref=cm_cd_al_qh_dp_t

I'm not sure yet what they'll be used for, but probably for a well pump. It's like a solution looking for a problem

What would you do?

[Wy_White_Wolf]

Yes, you will need to use an MPPT charge controller to the battery. But that controller is not large enough to handle all 28 panels.

28 * 90W = 2520W

2520W / 24V = 105Amps

WWW

[Sunking]

You will need to use a MPPT charger on a 48 volt battery bank. At 48 volt you will need a 2520 watt / 48 volt = 52.5 amps. So you will need at least a 60 amp MPPT charge controller. Too much power for 24 volts.

[SunEagle]

Found a great deal on some 90V panels but I'm scratching my head on how to best use them when most off-grid chargers top out at 48V. I'd need to buy them in bulk, 28 panels, and they're 90W each, so I'd have 90V at 28A.

I suppose I would just use an MPPT, something like this, correct? Specs indicate they can handle the higher voltage.

http://www.amazon.com/TRACER-3215RN-Solar-Charge-Controller/dp/B008KWPGAE/ref=cm_cd_al_qh_dp_t

I'm not sure yet what they'll be used for, but probably for a well pump. It's like a solution looking for a problem

What would you do?

Who makes a 90watt panel with a Vmp = 90v and Imp = 1amp?

[Wy_White_Wolf]

Who makes a 90watt panel with a Vmp = 90v and Imp = 1amp?

If memory serves me, someone was making panels that you stuck directly onto metal roofing that had those specs. The panels were like 10" wide but 10' long.

WWW

[cdevidal]

Yes, you will need to use an MPPT charge controller to the battery. But that controller is not large enough to handle all 28 panels.

28 * 90W = 2520W

2520W / 24V = 105Amps

WWW

Hmm? 2520W / 90V = 28Amps. What am I missing here?

[cdevidal]

Who makes a 90watt panel with a Vmp = 90v and Imp = 1amp?

28 cent a watt:

http://sunelec.com/tianwei-90w.html

[cdevidal]

You will need to use a MPPT charger on a 48 volt battery bank. At 48 volt you will need a 2520 watt / 48 volt = 52.5 amps. So you will need at least a 60 amp MPPT charge controller. Too much power for 24 volts.

Hmm? I'm talking about 90V/28A going into the MPPT. The one linked in the OP outputs to 12V or 24V.

[Wy_White_Wolf]

Hmm? I'm talking about 90V/28A going into the MPPT. The one linked in the OP outputs to 12V or 24V.

And when the MPPT does it's magic on that 2520 watts it'll be 105A at 24 volt or 52.5 Amps at 48 volt.

WWW

[SunEagle]

If memory serves me, someone was making panels that you stuck directly onto metal roofing that had those specs. The panels were like 10" wide but 10' long.

WWW

Actually according to the link that the OP provided these panels are 1300mm x 1100mm with a Vmp = 97 and Imp = 0.83.

[SunEagle]

28 cent a watt:
http://sunelec.com/tianwei-90w.html

I never heard about them but @ 28cents/watt they are low cost. Hopefully they aren't low quality.

[Legacy]

I am guessing these are liquidation prices as the company web site is no more and the German
distributer web site is gone as well, probably not much of a warranty so I guess you take your
chances.
Company name for the panels is Baoding Tianwei Solarfilms Co.Ltd

[cdevidal]

And when the MPPT does it's magic on that 2520 watts it'll be 105A at 24 volt or 52.5 Amps at 48 volt.

WWW

Now I understand. You're speaking about the output.

[cdevidal]

So how about four of the controllers in the OP?
Max. PV input power: 12V/ 390W 24V /780W

2,520W total array power / 780W maximum controller capability = 3.2 controllers needed

7 x 90V panel @ 1A = 7A and 630W going in, 24V @ 26.25A = 630W going out. (Minus overhead.) Divide the battery bank by four, and voila.

Actually I like this over one massive controller since it adds redundancy. A controller goes down and I'm only operating at 3/4 power instead of zero.

[cdevidal]

I am guessing these are liquidation prices as the company web site is no more and the German
distributer web site is gone as well, probably not much of a warranty so I guess you take your
chances.

Yeah I figure, as much as I'd be saving it's a pretty good gamble.