How to wire up batteries with both mains and solar charging

[MattS]

How should my batteries be wired up, if I have both a mains charger and a solar charge controller.

Two batters - starter and house. Currently connected via a 1-2-Both.

Sterling mains 4-step charger connected directly to both batteries.

Small 30W solar panel (and cheap solar controller) connected just to the house battery.

Is there a way of configuring this setup so that they don't interfere with each other and prevent optimal charging patterns etc.?

 

[PaulRainbow]

How should my batteries be wired up, if I have both a mains charger and a solar charge controller.

Two batters - starter and house. Currently connected via a 1-2-Both.

Sterling mains 4-step charger connected directly to both batteries.

Small 30W solar panel (and cheap solar controller) connected just to the house battery.

Is there a way of configuring this setup so that they don't interfere with each other and prevent optimal charging patterns etc.?

Sterling charger to both batteries.
Solar controller to domestic battery.

You could use a VSR between the two batteries, but only if you plan more solar really. Otherwise, something like a Victron ArgoFET for alternator charging.

 

[William_H]

Another alternative is to run the solar panel to both batteries via diodes. No controller. (diodes at the pos battery terminal so no fuse needed). OK for large batteries and limited solar power. The diodes can be silicon (ordinary) or better schotky type. volt drop will not matter much. You may find panel has a diode built in just connect another from the panel itself to other battery.
Mains charge as you wish will reduce charge current if batteries are found charged by solar. ol'will

 

[Stemar]

You can get a PWM controller for two batteries for not a lot or, I understand, an MPPT one for a small defence budget. I had the PWM one on Jissel for years and it worked well, charging the starter battery until full, then charging the domestic, on the basis that dim lights are an inconvenience, but not being able to start the engine could be serious. The output was permanently connected to the batteries. Alternator power was connected directly to the engine battery and via a relay to the domestic.