NeilP wrote:ok, thanks
is that on that site or elsewhere
I didn't look.
I haven't got the time at the moment to draw one up but its basically part of a linear power supply design of which there are hundreds on designs on the net normally fed from a transformer but could be fed from a switch mode supplys output.
Ah, ok, i mis understoodI thought you menat you had seen one somewhere there, no problem
That said I have a linear power supply that supplies some of my amateur radio equipment thats capable of 25A output and drops similar voltages and its well heatsinked . I built a 40A one and it definitely needed to be fan cooled and used 8 * 2N3055 transistors.[/quote]
I had started building a 12 volt 20 or 30 amp variable supply many years ago for a 70cm rig...(was it a Pye Vanguard...cant remember), and that too had a bank of 2N3055's as the output...but there again I was never good enough with theory to get the design correct, and all our ham radio club members were all in to the modern Icom and Yeasu black boxes, so the project was never finished.
If you're going to go linear, just get a bunch of PTCs and put them in parallel until you get the desired charging current. Cheap and easy. Not terribly precise, but I don't think precision is what you're going for here. Just a tangential suggestion...
PTC's? but no, I already have these supplies and the idea is to use them as a second charger to suplement my pair of Meanwells that are at home. I have a good charge system , just wanted to have a backup for free or nearly at the farm workshop as well as one at home.
Thinking just maybe a big rheostat from a theatre or similar, so I can have a variable resistance...start it high and bring it down, once the initial connection current surge that trips the supplies out has passed