Thread: Mosfet Heating Circuits View Single Post

05-02-2010, 01:48 AM
 Harvey Gold Member Join Date: Jul 2009 Posts: 1,137
Thanks Glen,

As always I am impressed by your work

I was trying to do some basic calculations on how long your two batteries can sustain a 5.5 watt load. I come up with about 104 hours, does that sound right? They are each 12Ah batteries so there is 24Ah of charge in them. A basic DC breakdown is 5.5W / 24V = 0.229A. 24Ah / 0.229A = 104 hours.

So all we need to do now is run for more than 104 hours on those batteries and we have pretty good proof that we have extra energy coming from somewhere else And that's not even counting the lost energy in MOSFET or CSR to heat. Good Stuff!

ETA: Oh, I almost forgot - if we conclude that those Gel-Cell (edit: wait, those or Liquid Acid?) batteries are discharged when they reach 10V each, then that would be a drop of 4V over the 104 hours. That would give us a 0.0385V (38.5mV) drop per hour. So for the 5 hours we would have expected a minimum of 193mV drop not counting the energy spent on the MOSFET and CSR. Our results show only 110mV drop in that time frame, 83mV short of the linear projection. So you can see why we think we are getting energy from somewhere. Either that, or our battery discharge is not linear And BTW, it only gets better for us if we conclude the battery voltage should be lower than 10V when discharged (of course we all know that the battery voltage needs to be measured under specific load conditions)

__________________

Last edited by Harvey; 05-02-2010 at 03:44 AM.