VSR and solar

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yerffoeg

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Some advice please about marine electronics please. It has been touched on before.

I have a house and start battery on my boat, connected by a BEP VSR. The alternator is given priority to charging the start battery. I have recently connected a solar panel, via a Victron PSM controller, to the main positive and negative bus bars. The solar panel charges the domestic battery, but not the start battery, if the boat is in its berth and not used for a while.

If I parallel the batteries (effectively turning the VSR off) would both batteries then get charged? Is there then any risk of overcharging the domestic? Your advice please. Vic, this is a subject that you know about!
 
yerffoeg said:
Some advice please about marine electronics please. It has been touched on before.

I have a house and start battery on my boat, connected by a BEP VSR. The alternator is given priority to charging the start battery. I have recently connected a solar panel, via a Victron PSM controller, to the main positive and negative bus bars. The solar panel charges the domestic battery, but not the start battery, if the boat is in its berth and not used for a while.

If I parallel the batteries (effectively turning the VSR off) would both batteries then get charged? Is there then any risk of overcharging the domestic? Your advice please. Vic, this is a subject that you know about!
Click to expand...

You could parallel the battery banks although not always the best of ideas. Your solar controller ( presumably you mean PWM) will prevent over charging

A dual sensing VSR is probably the best idea.

If just a question of maintaining the engine battery during long periods of non-use you could consider separate small solar panel.
 
Yes as Vic said if you connect solar to main + and-ve bus bars presumably this is connected to the house battery. It is likely that the VSR is single sensing expecting the engine battery to be charged first and when that is up to voltage then connecting house battery. So if house battery comes up to voltage the VSR will not connect the engine battery. A dual sensing VSR would work sensing when either battery is being charged. (above about 13.5 volts)
So yes if you hard wire or switch both batteries in parallel you will get solar charge to both batteries, however I would be concerned about leaving batteries connected that way. A failure of one battery could leave both damaged or at least unable to start engine.
I would prefer to see you fit another small panel for the engine battery. Or fit a controller with dual isolated outputs.
Of course much depends on panel size but I don't like the idea of relying on a VSR to connect a solar panel to different battery banks. The VSR will take some small current itself in sensing even more if it operates a relay. A small panel will keep a battery reasonably charged but may not get to 13.5 volts or so that a VSR will expect before connecting unlike an engine alternator with loads of volts and power. good luck olewill
 
Thankyou for your replies.

Paul, the two batteries are both red flash AGMs. The panel is a 20 w Ameresco rigid panel mounted on the pushpit, that can be tilted.

GEoff
 
yerffoeg said:
Thankyou for your replies.

Paul, the two batteries are both red flash AGMs. The panel is a 20 w Ameresco rigid panel mounted on the pushpit, that can be tilted.

GEoff
Click to expand...

If you had more solar i'd suggest a dual sensing VSR, but for your current setup a cheap and simple solution would be to fit a 10w panel to look after the engine battery when you're away from the boat. It wouldn't need a controller and if you're strapped for space it could be portable.
 
yerffoeg said:
Thankyou for your replies.

Paul, the two batteries are both red flash AGMs. The panel is a 20 w Ameresco rigid panel mounted on the pushpit, that can be tilted.

GEoff
Click to expand...

For such a modest solar panel, using a VSR is best avoided, in my view.
The current draw when the relay is closed could easily be 200mA, which equals 1 Ah over five hours of sunshine.
The panel can be expected to produce 5 Ah on an average summer's day. So the VSR might cut the solar yield by some 20 percent.
 
Sorry pvb, yes the start is a red flash, the domestic is by the same US company but is not a red flash (its still going strong after 15 years use!). Thanks again for the replies. I will probably then turn off the vsr (ie parallel the batteries) when using the solar in dock, or maybe get an additional panel.
Geoff
 
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