Bypass solar controller

[Vivid]

so my Blue Sky MPPT controller self destructed. I'm waiting to hear if the mfr will replace it. In the meantime, a question. Is it ok to connect the 280 watt panel directly to the battery (about 240 ah) for monitored charging in an emergency (failed controller) situation. I'm thinking the 30 v panel output will drop to battery voltage and the current will not exceed the panel's max. 8 amps which should not hurt the battery if I do not let the system voltage get over 14.6 or so.

[Stu Jackson]

Don't do it, you'll fry your batteries.

Installing A Small Marine Solar System Photo Gallery by Compass Marine How To at pbase.com

Scroll down and read "Do I need a Controller?"

[fallingeggs]

You won't go wrong following the advice of Maine Sail and Stu Jackson. In this case, you'll actually screw something up if you ignore it. You'll have to wait.


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[Jim Cate]

Stu, what harm will come from such usage if he monitors voltage and current? As he says, the panel voltage will be dropped to some reasonable value, and the max output of the panels will be less than 8 amps.

The reason I ask is that I have a bypass switch on our main controller, and we have it switched out for most all situations. Our Vmax is lower (~20 volts) and our bank a bit larger (440 ah), but I can't see what harm he will do... care to explain? We've been doing this for many years!

Jim

[daletournier]

What type of batteries? I'm no expert but if they are deep cycle lead acid batteries and the voltage dosent sit above 14.6 I don't think you'll do any harm....I wouldn't do this permanently, there is a reason we have regulators. I'd be more cautious with other types of batteries.

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[Maine Sail]

Originally Posted by Vivid

so my Blue Sky MPPT controller self destructed. I'm waiting to hear if the mfr will replace it. In the meantime, a question. Is it ok to connect the 280 watt panel directly to the battery (about 240 ah) for monitored charging in an emergency (failed controller) situation. I'm thinking the 30 v panel output will drop to battery voltage and the current will not exceed the panel's max. 8 amps which should not hurt the battery if I do not let the system voltage get over 14.6 or so.

You can do that in an emergency situation so long as it is closely monitored. You essentially become the solar controller. You do lose a proper absorption cycle but in an emergency you just need some juice so run the batts to 14.6V then disconnect the array.....

[svinshallah]

I just had the same problem with a Blue Sky 2000E controller failure after 13 years. Hooked 390 watts of 12v solar panels to 800Ah of batteries until the new controller arrived. There's not a whole lot of bright sun now in Panama, but the batteries never even got to 14.5.


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