Recommend an isolator between my solar and Lithium battery

[gerry mcg]

I understand lithium batteries should no be stored at full SOC.
I’ve got an isolator between my B2B and lithium battery so I can choose when to charge the battery.
The “problem” i have is my MPPT is directly to the leisure battery - and consequently, in summer, the Solar keeps the Lithium battery topped up to 100% SOC when the van isn’t’ being used.
so i guess i should fit some form of breaker / isolator between hte solar and MPPT, or between the MPPT and the leisure battery.
I’ve got THIS between my B2B and battery - would similar be best (or recommend an alternative) and should i put it between the Solar and PPPT, or between the MPPT and Battery?
Cheers!
G

 

[Ditcha]

What Mppt do you have Gerry? If it's victron you can turn the charge off in victron connect

 

[Ditcha]

If its not victron you could also use a double pole dc mcb solely as a switch so cheapest you can find wired in between your solar and mppt.

Like this

 

[gerry mcg]

What Mppt do you have Gerry? If it's victron you can turn the charge off in victron connect

Its a Victron 75/16 bluesmart solar with a BT dongle… I wasn’t aware i could turn it off via the app

 

[gerry mcg]

Is it this toggle?

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[Ditcha]

Yes that's the one

 

[Mr Mousy]

Ditcha

This is what I need to do. How did you get the mcb fixed to the wall? Looking online I can’t see any mounting screws.

Thanks

If its not victron you could also use a double pole dc mcb solely as a switch so cheapest you can find wired in between your solar and mppt.

Like this

 

[Richard n Ann]

Ditcha

This is what I need to do. How did you get the mcb fixed to the wall? Looking online I can’t see any mounting screws.

Thanks

It will be clipped on DIN rail

 

[Reallyretired]

Or just use any switch. It doesn't need to be double pole but must be between solar and controller not controller and battery.

 

[Ditcha]

Ditcha

This is what I need to do. How did you get the mcb fixed to the wall? Looking online I can’t see any mounting screws.

Thanks

Just used standard din rail.

Din Rail Top Hat slotted TS 35x7.5 35 x 7.5 length 100mm QTY=1 00087622 | eBay

Part No :Top Hat Slotted 35x7.5mm. The coating thickness is a minimum of eight microns. A range of professional quality 35mm DIN Rail, available in standard or slotted rail and supplied in various lengths.

www.ebay.co.uk

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[activecampers]

You only need a basic switch from the panel to the controller. You want the controller powered, you do not want to isolate that (some can fail if they have solar input but not connected to battery)

You only need to disconnect one pole on the solar (though I do both as my 20A switch was DP). Its not a big deal, the solar just won't flow current once disconnected.

The panels will *tend* to be low current - so our 300W panels when generating lots are at 40v+ which is 9A - so a DC switch with the appropriate rating is enough.

Its worth doing as, say, you want to disconnect the LB its best to turn off the solar feed first. (and enable last)

 

[Pausim]

A battery isolator switch fitted to the battery negative terminal is cheap and effective. Type needed depends on the type of terminal but here is an example.
Amazon product ASIN B07J34S5DH

 

[autorouter]

A battery isolator switch fitted to the battery negative terminal is cheap and effective. Type needed depends on the type of terminal but here is an example.

That will certainly work, but I think the OP wants to disconnect the chargers but leave the habitation loads connected, which this won't do.

 

[gerry mcg]

That will certainly work, but I think the OP wants to disconnect the chargers but leave the habitation loads connected, which this won't do.

Yip, and the Liesure battery is under the driver seat, so the battery posts are inaccessible,
The battery terminals are also 6mm threaded screws rather than posts.
Turning off the victron charger via the app seems to work

 

[Ingwe]

I followed this thread with interest as my van, now fitted with two 110ah lithium batteries is stored indoors where the solar panel is inoperative but the return trips left the batteries fully charged. I raised this with the installers who said not to worry. The alarm and the tracker operated from the cab battery will, over time, reduce the leisure batteries via the Battery Master fitted before the lithium batterieswere installed.
And it’s true that it takes about four weeks for the leisure batteries to drop to about 85% SOC by which time it’s usually time for a trip where the batteries get used.

We still have never dropped below 80% SOC without ECU. Currently, (no pun inended) we’re parked up at a sunny site about 5 miles from home (don’t ask) and at about 4pm this afternoon, I’ll turn off the solar charger using the Victron app to prevent the any further solar charge before the short run home. The Victron b2b will still do its stuff on the short run home. But as we’re off to France in two weeks time, I’m not fretting about the high SOC in the period in between.

Incidentally the site we’ve been on for two nights has no ECU so we’ve been using LPG for the fridge, water heating and cooking. LPG is a getting harder to source around York but we'll have plenty to get over to France where we consider LPG is much easier to source.

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