Give Eric a chocolate cigar
good eye 4 sure
thanks
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- op amp comparator circuit
Give Eric a chocolate cigar
good eye 4 sure
thanks
looks like a go I think
made correctiobs as per eagle eye Eric
added couple of LEDs just to be sure I have current flowing.
circuit would keep cycling -- duh??
got to thinking that using the op amp comparator circuit it would sense whan the batteries are low then turn on the charger.
all well BUT the charger would output up to 13.5 v thus triggering the op amp circuit off
then the batteries wouldn't be fully charged but the cycle would start all over again.
got to moving parts around etc.
came up with a frankienstein circuit (its close to halloween)
tried numerious combos and this works great.
could lower the base resister as it is really low in current??
haven't tried in LT spice (the LEDs don't light up in spice.)
used Tina and works great
any comments
still woundering why a 15v zener is nly one that seemed to work?
There is yet another route that you could take in the application:
When the sun comes back out the solar panels will began to charge the battery again. The idea behind the charger would only be to keep the system functioning until the sun comes back out. What would work is to lower the voltage on the charger down to 12 volts and have the circuit maintain the battery state until the solar cells can charge the battery again. The only thing that the charger will have to maintain is a 12v 1amp pump and the 100 or so ma used by the controller. sort of like a reversed ups system. you would have to incorporate a indicator lamp to let the user know that the system is drawing power from the household. Basically to warn the user that if it's sunny out and the light is on then something is wrong with the solar panels. The main thing is the frost protection, if the battery dies and the circuit doesn't have the juice to run the pump and keep the water circulating then the pipes will burst.
Last edited by cbiblis; 26th October 2009 at 06:27 AM.
One small problem
a battery charger usually outputs 13.5 volts or there about so it can charge the battery.
If 12volts were used as the output the battery wouldn't charge or not charge fully.
You need to at least 13 volts or so.
at least thats what I an lead to believe.
been wrong before..
have solution to keep charger on until fully charged instead of off on off on due to the monitor reading the battery voltage as well as the charger voltage.
but if you remember, i didn't want it to fully charge just charge enough to sustain the pump and circuit for enough time for the sun to come back out. This circuit would defeat the purpose of having a solar array. The idea is to get power for free and use power only when i have to. As it stands, the system that is in place now would take a week or more without sun to deplete the battery. If then after that time the charger were to kick in and fully charge the battery then if the next day the sun comes out for a week, that is a week of lost solar power. My solar array produces 14.5 @ 6amps in a 7 hour day this would charge the battery to its full state.
I'm not saying that the charger idea wouldn't work for my application just that it wouldn't help with the efficiency that i'm looking for. If it's to late in the project then i will make due. However if this could solve the issue then it will only benefit me. As for the parts, i would like to order from the electronicgoldmind that you suggested in another post. I have surfed around in there and if the shipping is quick enough then i found myself a new supplier.
Last edited by cbiblis; 26th October 2009 at 02:38 PM.
you can adjust for desired voltage
the monitor will monitor the batteries and turn on the charger at what ever voltage you adjust it for.
the over charge circuit is to prevent overcharging the batteries.
If you want the solar panel to charge the batteries then have the ac charger kick in if not enough sun then yes its doable
just a change over type circuit so if the batteries go below a set level then the ac charger kicks in.
Is this correct?
yes if the battery get below 12 volts then the charger should kick in and maintain the voltage at 12v. When the sun comes back out the solar arrays will put 14.5 v into the battery. this is when the charger should shut down. Basically if i read you post properly, that is the problem that you are having with the charger. When the battery senses that the voltage is down to 11.5volt the charger turns on but as soon as the 13.5 volts from the charger is sensed then the circuit will shut down. So to solve the problem we would set our high and low to 11.90v = on 12.10 = off Adjust the charger to charge at 12v with 1.5 amps.
yes just adjust the monitor for desired voltages.
Trying to get parts list from goldmine.
found an adjustable voltage reference as well as several opticouplers.. One is a HE PhotoMos . never heard of them?? AQV250
will get back to you later.
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