faulty controllers?

[sunny alex]

hello every one.

i need help in understanding this: our panels are rated 225w, Imp= 7.61A, Vmp=29.65v, Voc=36.7V

we have two such panels connected in parallel for max current of 15.22A.we measured it's Voc at noon here in nigeria to be 33.2V.

insolation here is 5.5hours.

our charge controller is rated for 20A/24V, panel voltage limit(over pressure) of 34V.

to our surprise the controller does not charge the batteries. (160Ah/12v x 2pcs = 160Ah/24V).

it seems the controller is faulty right?

please who has an idea what is wrong? three chinese controllers are not working, should i trust them? those are the controllers available here. the other types are way above budget.


prompt reply is appreciated.

[Mike90250]

Your Voc is 36.7V, and your controller max is 34V.

You apparently fried your controller with over-voltage

You need a new controller that can manage up to 36.7V, or you will burn it up again.

I would strongly suggest a Trace/Xantrex C-35 controller about $140usa

http://www.solar-electric.com/tracc35solch.html

it's OK to 54V input for your 24V system

three chinese controllers are not working, should i trust them? those are the controllers available here. the other types are way above budget.

Sorry, you get what you pay for.

[Sunking]

Agreed you exceeded your controller input voltage.

[john p]

Alex you question has been answered , But can you tell me if the controllers were MPPT or PWM type?

[sunny alex]

thanks

thank you for your answer. thanks also for replying to my email.

we usually have problems buying from america because they usually do not accept credit cards from buyers in Nigeria, because of scam apparently. so honest people pay the price. paypal is not available here either.

sending money by t/t for small amount involves large bank transfer fees.

but any way thanks for the advice, came in handy.

have a nice day.

Your Voc is 36.7V, and your controller max is 34V.

You apparently fried your controller with over-voltage

You need a new controller that can manage up to 36.7V, or you will burn it up again.

I would strongly suggest a Trace/Xantrex C-35 controller about $140usa

http://www.solar-electric.com/tracc35solch.html

it's OK to 54V input for your 24V system


Sorry, you get what you pay for.

[sunny alex]

thanks

Alex you question has been answered , But can you tell me if the controllers were MPPT or PWM type?

they were PWM.

thanks.

[sunny alex]

thanks

thanks a lot.

Agreed you exceeded your controller input voltage.

[Sunking]

they were PWM.

This is for a 24 volt battery system right? And the controller is made for 24 volt system right?

What I am having trouble understanding is ever panel made for battery systems Voc ratings are 18 volts for every 12 volts of battery. If you will note your panel Voc is around 36 volts as one would expect for a 24 volt battery setup. I find it hard to believe a manufacture would make a controller for a 24 volt system with a Max input voltage of 37 volts. That is just insane and very poorly designed. It should be able to tolerate up to 50 or 60 volts input.

[john p]

In my opinion there are just the worst PWM controllers in the world. as I have found over a very long time that even so so ones can take 20 to 30% overvoltage and the good ones like the old Steca and its Chinese copy can take 50% over voltage and over current. and without overheating.
The same cant be said for even "good" MPPT ones.
That is why I asked what type they were,,
But that low a tolerence is hard to understand unless the components inside are only rated at 24v????

[Sunking]

But that low a tolerence is hard to understand unless the components inside are only rated at 24v????

Yeah that is just blowing me away. That is the kind of ignorance and stupidity you would would expect from slacker college student senior project, amateur, or DIY. I just cannot comprehend a manufacture doing that.

[john p]

well sadly not all Chinese manufacturers are quality minded
old story shoe designer today electronics manufacturer tomorrow
I once saw in an amplifier that was of terribly poor design from China the use of a sardine tin lid bent in half and "glued" to a device to try and get heat away from a verry over stressed transistor. it still failed

[russ]

One time the company I worked for in India had 50,000 MT of steel coil on hand because they cheated a little too much on alloy and went under the negative tolerance limit.

It was perfectly good but useless for the high selling price extra quality pipe. We used that steel for many things building our own plants over the next two years but it was a very expensive screw up.

It was no accident - just trying to be too cheap.

Russ

[sunny alex]

thanks.

hi,
thanks for the hint.
well noted, i just needed to confirm. do you suggest that we use a MPPT controller for the specs of panel we are using?
225w, Voc=36.7, imp=7.61A, Vmp=29.56V, 2 pcs connected in parallel to get 15.22A
charge current.

battery bank: 160AH/12v x 2pcs in series= 160Ah/24V.
insolation : 5.5 hours

thanks,
guys.

This is for a 24 volt battery system right? And the controller is made for 24 volt system right?

What I am having trouble understanding is ever panel made for battery systems Voc ratings are 18 volts for every 12 volts of battery. If you will note your panel Voc is around 36 volts as one would expect for a 24 volt battery setup. I find it hard to believe a manufacture would make a controller for a 24 volt system with a Max input voltage of 37 volts. That is just insane and very poorly designed. It should be able to tolerate up to 50 or 60 volts input.

[Sunking]

Alex you can use either. MPPT controllers as a general rule can accept much higher voltages than PWM. However a PWM controller designed to work with 24 volt system has to be able to handle more than 37 volts, more like 50 or higher Voc.

[Mike90250]

hi,
thanks for the hint.
well noted, i just needed to confirm. do you suggest that we use a MPPT controller for the specs of panel we are using?
225w, Voc=36.7, imp=7.61A, Vmp=29.56V, 2 pcs connected in parallel to get 15.22A
charge current.

battery bank: 160AH/12v x 2pcs in series= 160Ah/24V.
insolation : 5.5 hours

thanks,
guys.

Well, if you have the budget, I would, but it will cost. Trace/Xantrex C-35 with panels in parallel, should be just able to hit equalize voltage, but a MPPT with your panels in series would be better.
But don't get the cheapest MPPT controller, use this site as a guide to buying one. You are in the range between the cheap and expensive, there are no mid-range MPPT controllers. You are at the max for the 15A morningstar (75V) http://www.solar-electric.com/mosumpsochco.html but it would still work, maybe throtteling back just a bit as it hits its limit.
Bluesky (57V max PV) is not a good choice, but the larger 45, 60 , 80 amp MPPT choices form Morningstar, Xantrex, Outback, and maybe Steca. Clones from flea bay, junk from china, well, you've been there.