Suitable switch for isolating solar panels

[headlight]

I have 2 x 100 watt solar panels to a Victron 75-15 MPPT.
I want to be able to stop the panels charging my LifePo4 leisure battery.
Therefore I need a switch between the panels and MPPT.
Suggestions for a suitable switch please.

 

[Brains]

A VanBitz battery master.

Available from several online shops for around £70.
It has the advantage that one installed it will top up both leisure and engine batteries.

 

[Ditcha]

I have 2 x 100 watt solar panels to a Victron 75-15 MPPT.
I want to be able to stop the panels charging my LifePo4 leisure battery.
Therefore I need a switch between the panels and MPPT.
Suggestions for a suitable switch please.

I just use the cheapest 2p DC circuit breaker I can get my hands on works fine.

 

[MisterB]

I also have a 2 pole DC circuit breaker. .

 

[Revolvor]

A VanBitz battery master.

Available from several online shops for around £70.
It has the advantage that one installed it will top up both leisure and engine batteries.

OP is looking for an isolation switch.

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[headlight]

A VanBitz battery master.

Available from several online shops for around £70.
It has the advantage that one installed it will top up both leisure and engine batteries.

?
To disable my solar panels ?

 

[headlight]

Like below.

 

[Lenny HB]

Like below.
View attachment 902660

I would trust a cheapo Chinese one as a circuit breaker but as a switch it will be fine.

 

[headlight]

I would trust a cheapo Chinese one as a circuit breaker but as a switch it will be fine.

What amperage ?
Everywhere seems to be out of stock of 20amp ones so 32amp is the next size up.

 

[Lenny HB]

What amperage ?
Everywhere seems to be out of stock of 20amp ones so 32amp is the next size up.

Should be OK it will be the Sam contacts.

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[headlight]

Should be OK it will be the Sam contacts.

Cheers Lenny.
The reason for the breaker is I've been turning charge off on the Fogstar app to stop my solar from keeping my LifePo4 on float when the van isn't being used.
However recently I've noticed that although SOC has been around 80% when I park up in storage, both on the app and shunt, a couple of days later the app will still show 80%SOC but the shunt will show 100% SOC.
I assume that although the battery bms is stopping the battery accepting a charge the shunt is still registering what the solar is trying to put in ?

 

[DandG5515]

I’ve just got one like this between panel and controller

 

[1967bowesj]

You could also use something like this, then divert the unused solar to the cab battery when in storage cheap controller as not needing much charge but better than wasting it.

Heschen Universal Rotary Cam Selector Changeover Switch, SZW26-20/D202.2D, 660V 20A, ON-Off-ON, 3 Position 2 Phase 8 Terminals, with Master Switch Exterior Box (Standard Box) https://www.amazon.co.uk/dp/B097T3DXV8?tag=mhf04-21

 

[Lenny HB]

I’ve just got one like this between panel and controllerView attachment 902724

Those cheap battery switches get hot with current flowing through them if you are going to use a battery isolator switch use a Victron or Blue Sea.

You could also use something like this, then divert the unused solar to the cab battery when in storage cheap controller as not needing much charge but better than wasting it.

Heschen Universal Rotary Cam Selector Changeover Switch, SZW26-20/D202.2D, 660V 20A, ON-Off-ON, 3 Position 2 Phase 8 Terminals, with Master Switch Exterior Box (Standard Box) https://www.amazon.co.uk/dp/B097T3DXV8?tag=mhf04-21

Those are a better option.

 

[1967bowesj]

Those cheap battery switches get hot with current flowing through them if you are going to use a battery isolator switch use a Victron or Blue Sea.

Those are a better option.

They should be, you told me to use them lol, works perfectly as a two way splitter

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[Lenny HB]

They should be, you told me to use them lol, works perfectly as a two way splitter

Don't remember that, I found out when doing Tam's install as he bought a couple them, warm with only 30 amps flowing through them they are supposed to take 300 amps.
Cranking the terminals up to far higher torque than you should they were much cooler but that was only at 30 amps.

 

[headlight]

You could also use something like this, then divert the unused solar to the cab battery when in storage cheap controller as not needing much charge but better than wasting it.

Heschen Universal Rotary Cam Selector Changeover Switch, SZW26-20/D202.2D, 660V 20A, ON-Off-ON, 3 Position 2 Phase 8 Terminals, with Master Switch Exterior Box (Standard Box) https://www.amazon.co.uk/dp/B097T3DXV8?tag=mhf04-21

I've already got a Battery Master fitted that keeps the cab battery charged.

 

[headlight]

Those cheap battery switches get hot with current flowing through them if you are going to use a battery isolator switch use a Victron or Blue Sea.

Those are a better option.

I've ordered a dc circuit breaker

 

[DandG5515]

Those cheap battery switches get hot with current flowing through them.

Not the case with mine, I'm running 10amps through a switch rated for 300amps. But I don't always buy the cheapest.

 

[Lenny HB]

I assume that although the battery bms is stopping the battery accepting a charge the shunt is still registering what the solar is trying to put in ?

It can't do that as there won't be any current flowing through the shunt.

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[headlight]

It can't do that as there won't be any current flowing through the shunt.

That's what I thought but it's done it the last 2 times it's been parked up.
Before that it worked fine.
The shunt SOC should actually fall as the leisure battery discharge is on so it's running the Battery Master and a bit of parasitic drain.

 

[Lenny HB]

That's what I thought but it's done it the last 2 times it's been parked up.
Before that it worked fine.
The shunt SOC should actually fall as the leisure battery discharge is on so it's running the Battery Master and a bit of parasitic drain.

Will be interesting to see what happens when you put the switch in and set the BMS back to normal.

 

[headlight]

Will be interesting to see what happens when you put the switch in and set the BMS back to normal.

It's the only thing I can think of doing.
Nothing in my set up has changed so it's odd.

 

[Peavy]

The shunt SOC should actually fall as the leisure battery discharge is on so it's running the Battery Master and a bit of parasitic drain.

And the Victron would also drain some.

 

[1967bowesj]

Don't remember that, I found out when doing Tam's install as he bought a couple them, warm with only 30 amps flowing through them they are supposed to take 300 amps.
Cranking the terminals up to far higher torque than you should they were much cooler but that was only at 30 amps.

Not the Red switch the 3 way double pole switch, you always give good advice!!

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[headlight]

What used to happen is that I would turn charge off in the battery app on my last day of a trip so what I used the last day and night wouldn't be replaced.
I'd park back up in storage with the SOC showing as say 80% on both the shunt and app.
Whilst not being used for a couple of weeks the shunt SOC would slowly drop as the Battery Master and a bit of parasitic drain took a few amps.
The app SOC would remain the same as the BMS can't detect small drains below 1 amp ( I have found that my BMS doesn’t detect drains of 1.5 amps or below ).
When I then used the van again the app would still show the same SOC as when I parked up but the shunt SOC would have dropped as it had detected the small drains caused by the Battery Master and parasitic drain.
What has happened the last 2 trips is that although when I've parked the van up charge has been turned off, after a couple of days the shunt SOC shows 100% SOC whilst the app SOC shows 80%.

 

[Lenny HB]

Very strange.

 

[jezport]

I put an inline fuse in

 

[eddie]

I have 2 x 100 watt solar panels to a Victron 75-15 MPPT.
I want to be able to stop the panels charging my LifePo4 leisure battery.
Therefore I need a switch between the panels and MPPT.
Suggestions for a suitable switch please.

Turn the off in the app

 

[headlight]

Very strange.

Yes it's weird.
It's only done this the last 2 trips.
Since fitting the LifePo4 at Xmas the shunt has worked as expected.
It is only the past month that it has behaved strangely.
Nothing has been changed or altered on the system.