hobbiest need help with a power switch \charger schematic

[cbiblis]

I have a solar water heater (differential thermostat, 12v 1amp water pump. When the temp in the collector is hotter then the water sensor in the storage tank the pump runs) powered from my solar array (16v @ 4 amps, running through a charge controller to a deep cycle battery).
The problem that i have is when we have a cloudy week the battery runs dead from running the water pump in the water heat design. The charge regulator will look at the battery as being faulted and won't restart the charge the need day. What i was wanting to do is build a circuit that will allow the solar arrays to do there job with out any outside assistance. However, if the battery reaches, lets say, 11v then i want to switch a battery charger on for enough time to recharge the battery until it has enough storage to handle another day of cloudy conditions and then continue with the normal cycle.
i have searched high and low and can't find a schematic for what i'm wanting to do. If you know where i can find a schematic for this project please leave a link. I would like to have the switch and a good battery charger in the schematic so that i can build the design to a pcb. it will need to source from a 120vac.
Thanks for any help you can offer.
I have a few 120v to 12v transformers rated at 100ma to run the circuit on. so just assume that the incoming power is 12v. The circuit should switch a relay to run the charger.

 

[MikeMl]

In this thread, I presented how to use a LM555 as a Low-Voltage CutIn, high-voltage CutOut switch. The trip points in the original post were very high, but can easily be customized for any voltages just by redesigning the voltage dividers. (see this other thread)


You would have to use the 555 to switch a DC relay which then switches the 120VAC, or use an SSR.

 

[cbiblis]

Thanks for the reply it will take me awhile to absorb the info due to my lack of knowledge outside of building thermostats but it looks like what i need.

 

[cbiblis]

hey mikemi, in the posted link you mentioned a schematic for a battery charger. would you mind posting that for me so i have a visual of what the circuit is doing? I'm really not asking for someone else to do the work for me. i just learn better from schematics. As a matter of fact, i always draw schematics to look at and study.