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.

 

[headlight]

That's interesting as I only ever use 20% of my charge too on my 105ah fogstar . Never get a chance to run it down more tbh. But might be worth me trying every so often.

On Friday, on Fogstar's advice, I depleted the battery to 25% by running a 1kw fan heater from my inverter.
Hopefully when the battery full charges from my solar the shunt and app SOC's will sync.
I'll then use the Victron solar app to disable charging with charge and discharge turned on in the Fogstar app and with any luck things will behave as they should.

 

[headlight]

One reason to have the charge and discharge switched separately is for when the temperature is below zero. You want to avoid charging below zero, but you will often want to use power from the battery below zero - to power the heating controls for example. Does that mean that a Fogstar battery will be totally useless below zero C?

Fogstar have a built in heater. It draws power from the charge source not the battery and warms the battery up to about 5c before the BMS will allow the battery to accept a charge.
Fogstar released an updated version of their app on the weekend.
On the new app you can only have both charge and discharge either on or off not one on and one off.

 

[autorouter]

Fogstar has a built in heater so it won't allow charging until the battery is up to 5 °.

So, I was wrong - if the app cuts off discharging and charging together, as stated, then the battery is totally useless below 5 degrees C, not zero.

 

[headlight]

So, I was wrong - if the app cuts off discharging and charging together, as stated, then the battery is totally useless below 5 degrees C, not zero.

The battery can be discharged when below 0c it just can't accept a charge until the battery is 5c.

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[autorouter]

On the new app you can only have both charge and discharge either on or off not one on and one off.

Charge and discharge either both on or both off.

The battery can be discharged when below 0c it just can't accept a charge until the battery is 5c.

Charge off, discharge on.

So, which is it?

 

[headlight]

Charge and discharge either both on or both off.

Charge off, discharge on.

So, which is it?

On the old app you could have one on and one off.
On the new app both on or both off.
I havent installed the new app but it doesn't matter as if charge is on but discharge off, old app, or charge and discharge on, new app, the battery will only accept a charge if it is above 5c.
If the battery is below 5c the built in heater will bring the battery up to 5c, enabling the battery to accept a charge, using the incoming charge to power the heater.

 

[autorouter]

On the old app you could have one on and one off.
On the new app both on or both off.
I havent installed the new app but it doesn't matter as if charge is on but discharge off, old app, or charge and discharge on, new app, the battery will only accept a charge if it is above 5c.
If the battery is below 5c the built in heater will bring the battery up to 5c, enabling the battery to accept a charge, using the incoming charge to power the heater.

If you get back to the motorhome and the temperature is minus 2̣̣̣̣̣̣̣̣̣°C, can the battery power the lights and allow you to switch on the gas heater whose control board is powered by 12V?

 

[unclestinky]

On the old app you could have one on and one off.
On the new app both on or both off.
I havent installed the new app but it doesn't matter as if charge is on but discharge off, old app, or charge and discharge on, new app, the battery will only accept a charge if it is above 5c.
If the battery is below 5c the built in heater will bring the battery up to 5c, enabling the battery to accept a charge, using the incoming charge to power the heater.

If you now have to turn off both charging and discharging, how can you control the amount of charge left in the Fogstar at the end of a trip? I would turn off charging on the return trip, however now the fridge will not be powered and when parked for a period the battery master won’t work. Am I seeing a problem that doesn’t exist?

 

[headlight]

If you get back to the motorhome and the temperature is minus 2̣̣̣̣̣̣̣̣̣°C, can the battery power the lights and allow you to switch on the gas heater whose control board is powered by 12V?

Yes, the battery can discharge down to minus 20c iirc.

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[headlight]

If you now have to turn off both charging and discharging, how can you control the amount of charge left in the Fogstar at the end of a trip? I would turn off charging on the return trip, however now the fridge will not be powered and when parked for a period the battery master won’t work. Am I seeing a problem that doesn’t exist?

I'm still using the old app which allows charge/discharge to be controlled separately.
Isn't your fridge powered by the starter battery when the engine is running not the leisure battery?
From now on I will be leaving charge/discharge turned on in the Fogstar app and turn charge off in the Victron MPPT app if I don't want the battery charging whilst the van is not in use.

 

[headlight]

autorouter from my Fogstar manual.