24v controller

[RobT]

Sorry Guys, I still need some input. First, thanks to all for helping on the first post. ibedonc even found the original schematic, which helped a lot, since mine wasn't complete.  Now, the mods have been made to go from 12v to 24v. I also want to go from a 20amp load capability to 60amps!  My sparse knowlege leads me to think that if I change D2 to a 70 amp rating and parallel four 40 60v/40amp Mosfets in place of Q2, it should work. Big question is will it?  I can't find big-amp P-channel Mosfets, only in N-channel, but I have no idea about changing the ckt to fit, so the thinking is to parallel the 40 amp Fets to carry the 50-60 amp load.

Thanks again for the input! It's worth a mint to those of us who are still on the steep part of the learning curve!   Rob T.

[Tom in NH]

This is the nice little controller that Forrest Cook designed. I suggest you ask him about modifying it to 24 volts. He has always been very helpful when I asked him questions. You could probably upgrade it to 60 amps by buying three of the controller kits and paralleling them together. If you intend to use the dump load enable circuitry on the board, you'd have to tie the three together somehow. I bet it would work with a three input AND gate. --Tom

[ibedonc]

the mosfet is a .02 ohm on res. ie very low , so very low watt dis as heat  and it is a 74 amp device , you could easy just parallel another one on a bigger heat sink and it would be fine  that would make you on resistance .01 ohm they are also under $4 for fet

at digikey

I am making a board , going to use them with my soar panels I am making

[ibedonc]

they cannot be N 's in this design

try this

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=265014&Row=280003&Site=US

[ibedonc]

Rob use this for D2

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=269599&Row=138971&Site=US

[RobT]

Thanks!  I've 'spoken' to Forrest, and he has confirmed the suggestions for converting to 24v although he hasn't actually made up a 24v board.  The idea of just parallelling two IRF 4905's seem to be the way to go.  I'll try it and see.

Thanks for the input!  Rob T.

[Opera House]

Be sure to check for gate voltage.  Many have a max spec of about 20 volts on many fets and a 24V system could see almost twice that.  This could be fixed by changing R18.

[Nando]

I can not read the circuit, if you send it to me directly, I will check it and give you the equivalent circuit using N type Mosfets.

Regards

Nando

nando37 at comcast dot net

[ibedonc]

also another thing I noticed is that transorb device is a TVS . and that would have to be changed to a 30 v part