As the days draw in with less sunlight I want to charge an ac coupled
battery from solar PV panels without discharging my main battery. I can
easily do this manually when at home and don't want to invest in a solar
electricity diverter, far too expensive.

I have a voltage controlled switch but as the load will itself depress
battery voltage I can set a hysteresis to switch off at a lower voltage,
this may induce short cycling/oscillation.

OR I am thinking I may be better using the relay output to trigger a one
shot timer for 10 minutes and if the voltage remains above the trigger
point after the initial trigger to charge the battery for another ten
minutes USW. Ten minutes would consume about 200Wh which I don't mind
the main battery supplying should the sun get blocked..

I do possess an old Crouzet MUR1 which should do the job but the manual
I found online defeats me where I had no such problems 20n years ago.

http://innovistasensors.crouzet-control.s3.amazonaws.com/assets/library/datasheet/en/MUR1.pdf

For many years I used a two transistor home made Schmidt trigger and an
orp12 photocell. Yes thre was a bit of hysterisis, but if I removed it any
vehicle in the road with a strobing light on top swithed it on and off all
the time, wearing out the relay. Brian

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"ajh" <news@loampitsfarm.co.uk> wrote in message
news:koaov8FtsanU1@mid.individual.net...
> As the days draw in with less sunlight I want to charge an ac coupled
> battery from solar PV panels without discharging my main battery. I can
> easily do this manually when at home and don't want to invest in a solar
> electricity diverter, far too expensive.
>
> I have a voltage controlled switch but as the load will itself depress
> battery voltage I can set a hysteresis to switch off at a lower voltage,
> this may induce short cycling/oscillation.
>
> OR I am thinking I may be better using the relay output to trigger a one
> shot timer for 10 minutes and if the voltage remains above the trigger
> point after the initial trigger to charge the battery for another ten
> minutes USW. Ten minutes would consume about 200Wh which I don't mind the
> main battery supplying should the sun get blocked..
>
> I do possess an old Crouzet MUR1 which should do the job but the manual I
> found online defeats me where I had no such problems 20n years ago.
>
> http://innovistasensors.crouzet-control.s3.amazonaws.com/assets/library/datasheet/en/MUR1.pdf

I used to be able to solder simple things but lack of stereo vision
makes getting the wire, solder and iron in the same place a challenge.

A simple circuit running off, say, a 12V wall wart triggering a relay
with 230V 10 A contacts should be feasible. There's a repair cafe near
me next weekend and I'll see what the guys there think.

On 07/10/2023 09:28, Brian Gaff wrote:
> For many years I used a two transistor home made Schmidt trigger and an
> orp12 photocell. Yes thre was a bit of hysterisis, but if I removed it any
> vehicle in the road with a strobing light on top swithed it on and off all
> the time, wearing out the relay. Brian
>