Max charging for safety.

[Contest1]

Boat with 2x100 ah plus 100 ah starter battery. Is it OK to connect a 200w solar panel to an existing 9amp trickle charger.
The boat has a I or 2 or both switch.
It a pals boat and he says the existing mains charger is marked as 9amp max?
I was thinking it a very small charger for such a large battery bank.

 

[PaulRainbow]

Boat with 2x100 ah plus 100 ah starter battery. Is it OK to connect a 200w solar panel to an existing 9amp trickle charger.
The boat has a I or 2 or both switch.
It a pals boat and he says the existing mains charger is marked as 9amp max?
I was thinking it a very small charger for such a large battery bank.

How do you mean, connect it to the mains charger ?

200w will need a controller.
It's OK to connect that to the batteries.
Without knowing more about the boat, it's use and it's power requirements i't hard to be 100% certain, but it could well be the 9a mains charger is a waste of time.

 

[Contest1]

How do you mean, connect it to the mains charger ?

200w will need a controller.
It's OK to connect that to the batteries.
Without knowing more about the boat, it's use and it's power requirements i't hard to be 100% certain, but it could well be the 9a mains charger is a waste of time.

I should have said in addition to the 9 amp charger. The solar panel will have a separate controller. His load is around 5 amps including the fridge. He is doing OK when on shore power but thinks he can might cruise off the grid occasionally. I did point out the 24 hour availability of mains power and the likely hood of requiring the engine to top up.
We cruise from the Costa Blanca so fairly reliable solar power most days ��

 

[PaulRainbow]

I should have said in addition to the 9 amp charger. The solar panel will have a separate controller. His load is around 5 amps including the fridge. He is doing OK when on shore power but thinks he can might cruise off the grid occasionally. I did point out the 24 hour availability of mains power and the likely hood of requiring the engine to top up.
We cruise from the Costa Blanca so fairly reliable solar power most days ��

In that case, the solar controller should be connected to the batteries, fused close to the batteries too. It won't bother the solar system what output the mains charger is. The mains charger will likely struggle to keep up with demand when onboard and put anything much into the batteries, but the solar will possibly make up the deficit. Probably suck it and see, keeping a close watch on battery voltages.

 

[William_H]

A 200 w solar panel is very likely to be one of those made for domestic PV systems ie max voltage 40v at max current around 5 amps. If this is the type it means he will need an MPPT type controller to get something closer to max 10 amps into the 12v battery system. A cheap controller will just see max 5 amps and see a lot of power lost in the panel. ol'will