Need to wire solar panel direct to battery?

[RobPlatts]

I'm considering fitting solar panels and the local electrician (Turkey) has suggested they need to be wired directly from the regulator to the battery bank. If I do this I will be bypassing the power meter shunt and, whilst the voltage will still be measured, the charge in/out will not. A language barrier is preventing proper explanation and wonder if anyone could suggest why the local chap is proposing this?

 

[Norman_E]

That is how I would wire them. Do you really need to be able to see how much charge they are providing, as the voltmeter will tell you what you really need to know? Another issue is that the shunt may well be fitted after the main circuit breaker, thus connecting the solar panels via the shunt would mean that they would be switched off, and no longer charge the batteries if you turn off the main switches when you leave the boat, which would defeat the object of fitting them.

 

[RobPlatts]

Thanks Norman, that's useful - I think you've probably explained exactly why the electrican wants to wire them this way. The main reason for fitting the panels however, is to reduce our reliance on the generator each day when living on the boat, rather than using them to keep the batteries topped up whilst we are away. I do like measuring the amps in and out as the voltage reading alone, when charging is active, won't indicate the current state of charge.

 

[VicS]

Unlike Norman
Id expect to see the battery monitor shunt directly connected to the battery on the negative side and the isolator switch to be in the positive connection but you dont tell us what battery monitor you have.

I'd then wire the solar panels directly to the battery positive terminal and to the shunt on the negative side so that the charging current passes through the shunt.

Perhaps you should investigate the position of the battery monitor shunt and the isolation switch. You can then decide if the panel has to be connected as the electrician suggets or if it can be connected so that the current passes through the shunt.

 

[RobPlatts]

Thanks Vic, this also is useful. Currently the shunt is on the postive side but following your post I read up on the monitor (Sterling Power) and it can be wired either way. Happy days!

 

[pappaecho]

Assuming that you have a proper regulator, the voltage of the battery will tell you the relative state of charge. I have tested with and without shunt fitting, and we appeared to get lower input with the shunt in place. This was done measuring the current flow

 

[VicS]

Thanks Vic, this also is useful. Currently the shunt is on the postive side but following your post I read up on the monitor (Sterling Power) and it can be wired either way. Happy days!

Ive not looked at the Sterling one before! ...

How you connect the solar panel then depends on the position of the battery isolator switch relative to the shunt.

If the switch is between the battery and the shunt then you have to do as your electrician suggests.

If the shunt is connected directly to the battery and the isolator is downstream of it then you can connect the panel to the shunt so that the charging current goes through it. Just as is shown on the diagram for the Sterling unit
Mr Sterling seldom shows isolating switches in his wiring diagrams !

How is you shorepower charger wired in. Does its output go though the shunt.

Sterling shows the charger and the solar panel wired in to the same point.