Battery Shed Cooling

[Rover]

This could have gone under a different forum, but since the plan involves solar, thought I'd put it here

My battery shed with 8 6 volt FLAs and 600W of Solar on the roof, is going to get warm in the summer. I plan on installing a fan (14" automotive radiator fan 80W 7A@12V) to help bring the temp down

My current thoughts are not to to connect it to the bank. I have a 55W panel that I can't use for anything right now so I thought I'd direct tie to the fan, via a thermostat switch.

Since the current produced by the solar will be less than 80W draw of the fan and voltage may be a tad higher (~17V) ... Does anyone see any issues with persuing this route? I don't care if the fan spins a little slower.

Rover

[Watt]

With the current draw of the fan, you probably won't get to 17v. 

You are right, it will probably spin slower for sure.

It will work but I would make sure the fan can free flow.  I wonder too, can you cut a couple of blades off and still be balanced?  Would require less amperage that way.  At any rate, it should be fine. 

[dang]

If you must have a DC powered fan I'd be scouring eBay for RV style exhaust fans - Fan-Tastic, Maxxair & Ventline (in decreasing price ranges) have some advanced fans with tons of options - thermostatic control, rain sensors to close the dome, etc. I nabbed a take-off, a new fan an RV buyer wanted upgraded "Ventline 2501" 12V 0.5 - 5amp reversible model for for $50 delivered.

Would you consider trying passive first?  Mechanical thermostatic controlled skylight or gable 'window' vent using the below actuator or similar? Remember, to get the best chimney effect you'll need at least two openings, one low and one high...

Do you know whether the fan you're thinking of is a pull or a push fan?

A radiator fan is designed around pushing/pulling air through a multi-layered radiator - if allowed to run unloaded in free-air I'm thinking its outside its optimized blade profile design, plus its not a continuous duty motor. Really - the motor bushings are made for a couple hours usage weekly for summer season only. And if its an after market replacement, not OEM, all bets are off on how long until the motor burns the brushes or bearings out.

[Watt]

If you must have a DC powered fan I'd be scouring eBay for RV style exhaust fans - Fan-Tastic, Maxxair & Ventline (in decreasing price ranges) have some advanced fans with tons of options - thermostatic control, rain sensors to close the dome, etc. I nabbed a take-off, a new fan an RV buyer wanted upgraded "Ventline 2501" 12V 0.5 - 5amp reversible model for for $50 delivered.

Would you consider trying passive first?  Mechanical thermostatic controlled skylight or gable 'window' vent using the below actuator or similar? Remember, to get the best chimney effect you'll need at least two openings, one low and one high...

Do you know whether the fan you're thinking of is a pull or a push fan?

A radiator fan is designed around pushing/pulling air through a multi-layered radiator - if allowed to run unloaded in free-air I'm thinking its outside its optimized blade profile design, plus its not a continuous duty motor. Really - the motor bushings are made for a couple hours usage weekly for summer season only. And if its an after market replacement, not OEM, all bets are off on how long until the motor burns the brushes or bearings out.

(Attachment Link)

That heat activated window opener is pretty slick.  Have you tried one Dan?

[dang]

Wish I had - I've watched the price creep up from $32 to $50.

So far, my current out-building is a 10x20 tarp shelter that both ends open completely up for cross-ventilation, plus lets the mosquitoes browse easier. Once upon a time & far far away I had a 20x40 tin shed with doors on one end only - never again!

[Rover]

Well I've got the solar panel, and I have fan.. so might as well us them.

Dang, I've tried passive, no dice. The RV units are a possibility , but I already have the fan.

Rover

[ghurd]

I have a feeling it won't work as well as you hope... but would like to hear how it does.

Might keep an eye out for a treadmill motor, or maybe a 1800RPM 1/4HP 90VDC PM motor, then put a box fan blade on it.
G-

[Rover]

Yep, might as well.

Last year I had a modified 9" fan (one of DC clamp on types used in cars)  gable mounted to draw air out of the shed. The shed is only 8x16' and it seemed to make a difference. I'm hoping the larger fan will do a bit better.

Rover

[A of J]

One thinks you are over thinking the situation, batteries present a large thermal mass and do not  heat or cool quickly (by the environment).

How many hours per day is the sun on this shed? A sun roof, a second roof placed about 6" above existing is very effective and passive, shade cloth or a creeper on walls also passive and effective.

A of J

[Rover]

Hi A of J.

I know from experience that it routinely gets above 90F sometimes 100F in the shed for extended periods. The Shed is in the sun most of the day and has solar panels on the roof.

This is someting I have been dealing with for many year now.

Rover

[A of J]

My batteries are in a 9x6M shed and rarely go below 30C this time of year, yes it potentially affects their life span but that's life.

A of j

[kensue49]

What color is your battery building?
Paint it white. Put a 6 to 8" pvc pipe to your battery box, a straight run through the roof, paint the pipe flat black above the roof to create a draft. Place a vent on the side of the building that does not get sun at ground level and cover the vent with screen wire. This should allow a exchange of cooler air for hot air. You can cover the pvc with a chimney cap and seal the ground level vent or vent when it is cold with Styrofoam.
Passive will work. You will need a boot for the pipe or pipes. Two pipes at different levels will move a lot of air.
Kenneth

[Watt]

What color is your battery building?
Paint it white. Put a 6 to 8" pvc pipe to your battery box, a straight run through the roof, paint the pipe flat black above the roof to create a draft. Place a vent on the side of the building that does not get sun at ground level and cover the vent with screen wire. This should allow a exchange of cooler air for hot air. You can cover the pvc with a chimney cap and seal the ground level vent or vent when it is cold with Styrofoam.
Passive will work. You will need a boot for the pipe or pipes. Two pipes at different levels will move a lot of air.
Kenneth

Very nice suggestion and idea.  I think I too will do this. 

[Wolvenar]

I agree, I will be doing this also as I just moved my batt bank.

[Bryan1]

G'day Guy's,
                        This new 6x3 metre shed I'm building beside the house has those 'blueboard' cement sheet boards. Now they do a great job of repelling the heat and the best part is they are totally fire resistant too. Lately when it's been pretty hot here just walking in the shed it does seem that much cooler. Also we did find price wise it is comparable with steel sheeting and I know the new battery room will stay nice and cool too.....

Regards Bryan