More battery charger, voltage shunt reference.

Well, I do resent your idea that I'm trolling. I was sincere about seeing how you would approach the simulation.

I can wait until you cure your compatibility problem.

It's not that simple. The battery with a simple internal resistor will snap between the charging and non-charging voltage instantly. That is not what a battery does. After charging, the terminal voltage relaxes to a lower value over some time. Similarly, upon charging the terminal voltage does not rise to the desired value instantly. There is a time constant both ways. It is a chemical thing. Spice that. It makes a difference in your bang-bang switching.

The solar panel is more like a voltage-limited current source. When open circuited and at low light levels, it works very well as a light detector by reading its terminal voltage but it won't produce much current. At high insolation, it becomes a current source. This is not the same as sweeping the source from from 0 to 22V. When attached to a battery it becomes a variable current source depending on the amount of insolation. Spice that.

You really are in the dark on this, aren't you?

Insinuate that I am a troll again and I'll go away.

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.

5 minutes to enter. Then some time to play with it.

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.

600mA short circuit current is not especially impressive. Allowing for imperfect alignment with the sun and shading it is likely to be under the C/100 indefinite charge rate for a typical 40Ah car battery.

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!

've never used it, so it's on you to find the spec sheet and gauge its suitability for your purpose.

"Instructions: How to Charge:? Connect the 12V rechargeable battery, the solar panel and any load application. Note: Always connect the battery first.? When the solar panel is connected to the charge controller, the charging LED will light to show that the 12V rechargeable battery is receiving a charge from the solar panel.? The charge controller provides the following system protections:1. Over Discharge Protection - When activated, the "low voltage" indicator will light and the charge controller will shut off the power output to prevent damage to the battery. Note: If this occurs, disconnect all load applications.2. Overcharge Protection - When activated, the "high voltage" indicator will light and the charge controller will shut off the power input from the solar panel to the battery. Note: If this occurs, disconnect the solar panel from the charge controller."

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.

13.0 volts sets the final current limit from the battery's point of view. for the circuit components (...): a bridge rectifer from said transformer connects to the +&- rails. a pnp to220 (Tip42) device's emiter connects to the + rail a 1k resistor connects from the + rail to the pnp base the pnp collector connects to a 1n4002 diode. the other end of the 1n4002 goes to the output. the collector of a 2n3904 npn to92 device connects to the base of the pnp device. the npn emitter connects to a small schottky diode and the other end of the diode connects to the output. a 220 ohm resistor is connected to the + rail and the other end connects to a 15v zener. the other end of the zener connects to the - rail which is also the negative output. from the zener/220 ohm junction a 100 ohm resistor connects to the base of the npn device. From the base of the npn device a 1.8k resister connects to the - rail. That should do it. The 1.8k resister does some fine tuneing to 13.0 volts. The circuit basically tracks the up&down of the rectified 60 cycle so be carefull to not put a capacitor in the circuit. The battery (this is lead acid) does the deciding as far as current goes and 13.0 volts seems to saturate at ~0.1 amp with the voltage returning to ~12.6 after the charger is removed.

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.