More battery charger, voltage shunt reference.

In this case, a current source will do.

In this case, a voltage source will do. A small solar panel will make about no impression on the voltage of a car battery. A sinewave with offset would exercise the regulator nicely. Or a parallel RC would work too.

That circuit will work as first drawn first try. It's so simple it doesn't really need simulation.

But if it helps you understand it, by all means Spice it.

It doesn't need a detailed model of either to test the regulator circuit. The circuit is so simple it's not worth simulating, except maybe as a lazy way to calculate the resistor values.

Please show me your solution. I'm not trying to troll, but I have been accused of such.

Thanks.

That was nasty.

Maybe you should.

I don't need to. You are the one who suggested spicing it earlier. It is actually easier to breadboard and try.

Then why don't you man up and show us?

It was not addressed to you, John, so it is none of your business.

Yes. You and your ilk make it uncomfortable here for someone to express ideas (which you say you want but are very hypocritical). You really are the persona people in this group has come to dislike.

Because you don't matter.

I consider any solar PV panel under 1m^2 to be a toy. Solar PV sourcing currents of 10A and above or voltages in excess of 100v are serious PV.

Mine's only about a fifth of that area, but I don't regard it as a toy, I bought it for a purpose and it fulfils that purpose adequately. It doesn't need to be big enough to run a microwave oven or a refigerator, it just needs to be big enough to top up the van battery after having the main interior lighting on all the previous evening.

With 1.5 amps output, it is well suited to its purpose; it would have been a very expensive thing to buy if I had just wanted it as a toy. Horses for courses.

Yes, there's a better way. Buy a finished product with this purpose that has millions of copies in service with no problems. That would be the Schumacher SPC-7A, 12-Volt Solar Charge Controller. This is designed to be used with their higher capacity solar chargers. It's readily available and low cost. It is for LEAD ACID 12 volts!

I like to Spice things as a record of the design intent; we comment them and ID and archive sims as if they were formal engineering drawings. It's often easier to pick component values in simulation too, rather that using a calculator.

When you've worked on a few thousand circuits, many with other engineers, it's good to keep records.

George - I just finsihed the quest for a simple battery charger that you are enterring! Power zeners didn't work for me either and for the same reasons. I tried the LM317 a couple of different ways. It worked but not well. The results appeared to show too much effective series resistance in the LM317's output. From a later view, I suspect use of caps to provide a dc source was the basic cause. Basically, the final version assumes the transformer provides the current and choice of the 12v ac transformer specifies the current and the current limit. Now, the transistors do nothing but limit the output voltage.

Hul

George Herold snipped-for-privacy@gmail.com wrote:

Well, good for you. I'm sure that satisfies you OCD.

George - I forgot to mention the battery was 31 pounds. A slightly lite car battery.

Hul

Hul Tytus snipped-for-privacy@panix.com wrote:

The only obsession here seems to be your compulsive need to insult.

I'm not obsessive about electronics; it's too easy.

But good documentation makes sense. It avoids a lot of potential frustration and rework. It's silly to open a Spice file or a document and have to ask "What is this?" "Who did this?" "When?"

You wouldn't do very well in an EE class if you turned in lab reports without a title or date or your name on them.

You make a habit of it. The disease does seem to be catching.

It gets more difficult if you try to do it right. Making trivial modifications to an existing product so you can sell it to some customer as a custom solution is profitable, but the difficulty comes in selling something cheap and pricing it as if it were something expensive.

But it's a convenient excuse for getting low marks on a lab report that reported inadequate work.

Those who throw out gratuitous insults are unlikely to be overwhelmed with helpful responses. --

"Andrey Semyonovitch really was rather stupid; he attached himself to the progressive cause and 'our younger generation' from enthusiasm. He was one of the numerous and varied legion of dullards, of half-animate abortions, conceited, half-educated coxcombs who attach themselves to the idea most in fashion, only to vulgarise it and who caricature every cause they serve, however sincerely."

- Fyodor Dostoevsky