Occasionally I am forced to use my observatory Windows PC when not observing. This involves reeling out a 240V lead to the obs. I have thought of having a 12V batt and inverter in the obs to run the PC for brief periods occasionally.
I already have a solar panel keeping a small 12V SLA battery charged for the alarm - Can I charge two different sized batteries at once - I expect I should just wire another charge controller/battery in parallel with what is there? Is this right??
If they are both 12V and wired in parallel permanently theres no issue.
If the two batteries hold different levels of charge voltage when connected it will cause a current flow from one battery to the other which could be problematic.
If I had a separate charge controller (like this one) on the second battery (there is already one on the first) - this would stop any flow between the batteries shouldn't it??
Depending on the panels capacity and its charging voltage and mechanism, you may be able to put a diode in series with each charging feed.
That way the batteries are isolated form one another, but can be charged.
The diode will have a 0.7v drop so this may cause problems, in any event if the charging circuitry requires voltage sensing of the battery then this may be a problem.
At least make sure the batteries of the same type of battery - say SLA.
If it were me - I would buy a second charger or make a dedicated circuit to handle the charging depending on what is in the system you have.
With the second regulator, hopefully nothing. As long as the panel is providing sufficient amperage to charge both batteries, then there should not be a problem. The solid state regulators are a much better unit than the older mechanical / solenoid units.
Avoid trying to charge two different amperage batteries from the one regulator - the regulator will turn off when the smallest battery is charged.
