How to harness an 80 Volt panel

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How to harness an 80 Volt panel

Postby Bob James » Tue Jan 31, 2017 8:14 am

I have an 80 volt output panel capable of about 7 amps.
I have a 24 Volt system of lights and batteries .
How do I get the 80V down to 24V efficiently so I can connect it to my charge controller ?
Last edited by Gordon-Loomberah on Tue Jan 31, 2017 10:43 am, edited 1 time in total.
Reason: fixed spelling in subject
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Re: How to harness an 80 Volt panel

Postby Gordon-Loomberah » Tue Jan 31, 2017 10:41 am

Welcome to the Energy Matters Forums Bob :)

When you say 80V panel, is that Voc or Vmp?

In any case, you need an MPPT charge controller, which will step down the panel voltage to the battery voltage. You need to make sure it has a high enough maximum input voltage to handle your panel in cold weather, so Voc + say 5V.
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Re: How to harness an 80 Volt panel

Postby Bob James » Tue Jan 31, 2017 6:41 pm

No idea . Thats about 80V on the mutimeter with nothing connected ,does that help?
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Re: How to harness an 80 Volt panel

Postby Gordon-Loomberah » Tue Jan 31, 2017 7:00 pm

That will be Voc, ie open circuit voltage. Aren't there any specs on the back of the panel?
If Voc = 80V, then Vmp might be over 60V, and at 7A, that's one mightly powerful panel!
What brand and model is it?

Take care when handling 80VDC, it can give you a nasty shock if you make contact with + and -.
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Re: How to harness an 80 Volt panel

Postby APR » Tue Jan 31, 2017 7:09 pm

Welcome Bob.

As a matter of interest, what is the length and what is the width of the panel?
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Re: How to harness an 80 Volt panel

Postby lantern » Wed Feb 01, 2017 7:48 am

And how many cells?
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Re: How to harness an 80 Volt panel

Postby Bob James » Wed Feb 01, 2017 9:46 pm

Well I didn't remember that right did I so I am out on that I guess it must be about 1 amps max . Get myself confused with these things sorry. Stll the problem is how to use it with a 24 Volt system
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Re: How to harness an 80 Volt panel

Postby Gordon-Loomberah » Thu Feb 02, 2017 8:34 am

As I mentioned earlier, you will need an MPPT charge controller to use that panel with a 24V battery.
Just make sure it can handle >80V input.
There are many different brands available, but you do tend to get what you pay for with this sort of gear. El-cheapo junk from ebay may only be PWM type, rather than MPPT, despite the claims in some advertising.
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Re: How to harness an 80 Volt panel

Postby davidg » Thu Feb 02, 2017 9:10 am

Gordon-Loomberah wrote:El-cheapo junk from ebay may only be PWM type, rather than MPPT, despite the claims in some advertising.

Gordon is being too diplomatic ..... El-cheapo is almost always PWM and more often than not, total crap.

About the cheapest that works properly is a brand from china called EP-Solar which for what they are is pretty good, for simple system/s there not a bad option they generally have an input of 100Vdc and some of their unit's have an input of 150Vdc. Otherwise for quality brand names consider Midnite Solar or Outback Power and there are others.
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