Kid PV input size.

[exsadlow]

Hi I'm Ed
I bought the Kid solar charge controller using the sizing tool..but unfortunately i sized the battery bank wrong at 48 V instead of the 12 V that i have...i have 3-230Watt 24 V panels at the moment i have 2 connected in series to the controller charging 12 V batteries...so the question is if i connect the 3rd in series will it hurt the controller or will the controller limit the current to a 30 Amp Max to the batteries or will it blow the fuse..adding the 3rd panel to this system would be nice in cloudy conditions...
Temagami Ont.

[TomW]

Ed;

According to Ryan from Midnite The Kid will limit the output to the 30 amps it is rated for if you feed it excess wattage.  Likely still need to stay within the input voltage specs.

I will try to find the link to that recent post.

The quote:

The Kid will be fine. You can grossly overload the kid with PV and it will simply put out 30 amps.

Down near the bottom of this thread:

http://midniteforum.com/index.php?topic=1919


Tom.

[vtmaps]

so the question is if i connect the 3rd in series will it hurt the controller or will the controller limit the current to a 30 Amp Max to the batteries or will it blow the fuse..adding the 3rd panel to this system would be nice in cloudy conditions...

I presume that your Voc is about 37 volts per panel.  Three in series would be about 111 volts.  I doubt it gets cold enough in Ontario to exceed Vmax on the controller.

However, raising the input voltage on the Kid will make it less efficient (=more heat = less than maximum current).

Consider the classic 150:  It is often quoted as having a 96 amp maximum output current.  That is correct for an input voltage of 90 volts and a 12 volt battery.  If you raise the input voltage the rated output current goes down.  I haven't seen power curves on the kid, but if it behaves like the Classic you may not get your full 30 amps as you raise the input voltage.

Another consideration is that these numbers we're talking about are LIMITS.  Is it a good idea to run things at their limits for long hours? 
Here's a quote by Robin, one of the founding engineers of Midnite.  He is talking about running a Classic 250 at its LIMITS.

I would not put more than 3000 watts on the Classic 250 myself. It will just run hot. That is never a good idea to run the controller flat out at its maximun day after day.

--vtMaps