SparkyLabs

yes I have the diode on the coil. again I suspect spikes from the ignition system. I am wondering if it was damaged via the gate its +-20 V max and full on at -4 V, perhaps there have been high voltages hitting it (the TL084 used to drive it is connected straight to the "12" volt supply from the battery not via the regulator. I'm considering a 1/1K voltage divider.

the dynamo feild coil is being PWM from a mosfet that has a breakdown voltage of 100 V, This not only has to work on paper but in real harsh life conditions as its going on his car and if it breaks on the other side of the country I won't exactly be able to help ! I/We are considering taking something from the original design in which the field coil is control by a (type of) relay with a resistor over it's switch, this means that the coil always get some power although not always all of the power as the switch opens and closes. May this would help stop spiking in the coil ? apart from the fact we think it may eliminate some of the ripple we are getting

you do not require an MPPT, an MPPT is a device used to maximise the efficiency of the battery/solar panel charge circuit, what need apart from an MPPt if you choose to use one (the cost generally outweighs the benefits but its on my projects to do list) is a grid tied inverters. In the uk it is illegal to use these devices unless they are approved by your local electricity supplier, this rules out homemade designs unless your going to go through aproval process costing many more times than a simple comercial 400 W grid tie inverter. The bottom line: buy one if you so wish in accordance with your power supplier. the other option is a large battery (mine will hold up to 1.25 Kw but then its only 40W panels) and a 1.5 KW inverter, you will have to switch from the inverter back to the grid when the battery goes flat, this is far more economical and simpler a solution

well the 3 A load could do with some protection.

I'm drawing up to 3A to supply the field coil of the dynamo, about 10 mA of this goes through the regulator to power the pic. I've been wondering what size inductor I could use to help as well.

unles plainly staed on the supply that its power output is what you observed I would send it back, sounds like a bit of a joke

I building a powermanagement circuit for a friends vintage car. It all works fine but for the fact that it has a life of about 15 minutes after which succumbs to ignition spike destruction. the 78L05 reg in particular packs up. Any recomendations on filtering out the spikes from the ignition circuit to protect my circuit ?