What Charge Controller?

[Mike90250]

From the midnight site:
To ensure proper start up and MPPT operation, the minimum initial PV input voltage should be at least 30% higher than the highest expected battery voltage.

http://www.midnitesolar.com/productPhoto.php?product_ID=622&productCatName=Charge%20Controllers%20-%20Classics&productCat_ID=21&sortOrder=1&act=p

and it is supposed to have ethernet.

[MambaJack]

For simple usage it's fine. I bought one as a spare for my classic 200
Has ethernet, can use the Local App for control / viewing status.

Thanks Mike, Is there a way to confirm that this model has ethernet?

[MambaJack]

What's your charging voltage for a 24V bank ? About 32V for an EQ cycle. On a sunny day, your VMP is going to be only 33V. That's not enough for a MPPT to work well, so I'd think you have to have 2 in series. Your panels are an unfortunate voltage. Run the Midnight sizer again with higher ambient temps, and see if a single panel is enough voltage. I think it's marginal for hot weather, and you risk not fully charging when hot. So you would need a generator to top off for the last 2 hours daily in heat.

Yea, if .i put a single panel into the calculator, it shows all green.

[Mike90250]

Ah cool. Thanks for the advice. So my panels are VOC 41 and VMP 34.5. Does this mean running all 6 panels parallel into a combiner box?

What's your charging voltage for a 24V bank ? About 32V for an EQ cycle. On a sunny day, your VMP is going to be only 33V. That's not enough for a MPPT to work well, so I'd think you have to have 2 in series. Your panels are an unfortunate voltage. Run the Midnight sizer again with higher ambient temps, and see if a single panel is enough voltage. I think it's marginal for hot weather, and you risk not fully charging when hot. So you would need a generator to top off for the last 2 hours daily in heat.

[MambaJack]

Ah cool. Thanks for the advice. So my panels are VOC 41 and VMP 34.5. Does this mean running all 6 panels parallel into a combiner box?

[Mike90250]

yes, the midnight sizer can't anticipate panel losses in bus roof mounting, so you are likely OK. Also, with 24V battery, don't wire panels for more than 55V or so, that will keep conversion losses down. (and less heat in the controller)

[MambaJack]

For simple usage it's fine. I bought one as a spare for my classic 200
Has ethernet, can use the Local App for control / viewing status.

This seems like a great option. however midnites sizing tool is saying that the 2010 watts is excessive.
I wonder if this would ever actually be an issue with panel inefficiency, and the fact that i am mounting them all flat on a bus roof.
Thoughts?

[littleharbor]

Nice that you can run high voltage into it if you need to. If you don't need the high voltage input the regular Classic 250's are pretty pricy compared to the 150 and 200. The thing I don't care for is the 55 amp charging limit @ 48 volts.

[Mike90250]

Thanks, I will take a look.
Is there a specific reason i should run them all in series?
Are there any of the stripped down components that I will miss not having.

THanks,
dave

For simple usage it's fine. I bought one as a spare for my classic 200
Has ethernet, can use the Local App for control / viewing status.

[nwdiver]

Thanks, I will take a look.
Is there a specific reason i should run them all in series?
Are there any of the stripped down components that I will miss not having.

THanks,
dave

Not that I can really think of... it doesn't do boost so your string needs to have a higher voltage than the battery... I don't understand how that would really be useful...

[MambaJack]

Thanks, I will take a look.
Is there a specific reason i should run them all in series?
Are there any of the stripped down components that I will miss not having.

THanks,
dave

[MambaJack]

If you're running those panels in series (which you def should) and you don't need a lot of bells and whistles with your charge controller there's a strip down midnight classic on sale at sun elec and renvu for $360 and $290. Seems like an unbeatable deal.

Thanks, I will take a look.
Couple questions:
What is the reason that i should run them all in series?
Are any of the stripped down components of the controller big deals?
Characteristics of this SPECIAL EDITION:

[MambaJack]

If you're running those panels in series (which you def should) and you don't need a lot of bells and whistles with your charge controller there's a strip down midnight classic on sale at sun elec and renvu for $360 and $290. Seems like an unbeatable deal.

Cool, I will take a look?

Couple questions,
I definitely run them in series

[nwdiver]

Just purchased 6 335 Watt panels for my bus to charge 8 6v 235ah lead acid batteries setup in a 24v bank.
Was looking at an outback fm80 for a charge controller, would this work well, or is there a batter option?

Also, the reason for that much panel is not just to charge the bank, but to run my 12k btu minisplit ac during the hot hours of the day.

Thanks,
dave

If you don't need a lot of bells and whistles the Midnight classic 250 is on sale at renvu for $290.

[nwdiver]

Just purchased 6 335 Watt panels for my bus to charge 8 6v 235ah lead acid batteries setup in a 24v bank.
Was looking at an outback fm80 for a charge controller, would this work well, or is there a batter option?

Also, the reason for that much panel is not just to charge the bank, but to run my 12k btu minisplit ac during the hot hours of the day.

Thanks,
dave

If you're running those panels in series (which you def should) and you don't need a lot of bells and whistles with your charge controller there's a strip down midnight classic on sale at sun elec and renvu for $360 and $290. Seems like an unbeatable deal.