Immersun before batteries

alford

Hi, I’ve just had a pylontec battery system added.
The problem I have is the immersun mk 1 is reacting
quicker than the battery system and using the spare
electric to heat the water, instead of changing the
batteries.As I would prefer to charge the battery first
and then heat the water.Is there any way to do it in that
order. Thanks Paul

mmmmikey

I had issues with getting a SOLIC immersion controller and PowerVault battery systen to work together and my initial solution (now superceded - see below) was just to switch them on and off manually. Not too inconvenient for me but it worked, although I can see this wouldn't be workable if you're out during the day (I'm retired). Unfortunately I don't think there's a good way to do this automatically yet - unless someone else can help?

At the risk of pouring on the doom and gloom there's another issue to look out for. You can get the situation where the batteries charge first but under certain condtions the immersion controller then uses the energy stored in the batteries to heat the water.

My solution to this has been to ditch the immersion controller altogether and to move to metered export. This only works for me because I'm on an E7 tarriff and I can buy electrcity overnight for much the same as I can sell spare electricity during the day via the export tarriff. That is, using the SOLIC doesn't save me anything over heating the water using paid electricity because I can sell the "free" energy I would otherwise have used for water heating, cancelling out the addtional cost. All a lot more convenient.

You might find a way forward (unless you're already on E7) is to switch to a tarriff like Octopus Agile and ditch the Immersun altogether. Sorry this doesn't really answer your question but at least it gives you another angle of attack.....

pinnks

Just guessing but you can set the immerSUN mkII (and I think the mkI) to require a minimum export before it switches on. I assume the battery charging system does something similar. If so, try setting the immerSUN to a higher figure than the battery charger...

alford

Thanks for the replies.I am about to move onto the octopus go tariff.
As I receive 50% deemed export it goes against the grain to export electricity and import gas or am I just being tight��.
Thanks again for the replies

Solarchaser

Can I ask what battery system you are using?

I ask as I have a sofar and it responds pretty blinking quickly.

I'd imagine you can set the immersun to have a 100w minimum threshold before engaging, and if the battery system responds at 0w then it should always take priority as pinnks said

alford

I have a sofar battery charger with two
3.5 kWh pylontec batteries. I’ve had a look at
the immersun mark 1 manual and as far as I
an see there are no threshold to set.

pinnks

I Think you are correct. I found my old MkI manual and can't see an option either. It must have a threshold though as the philosophy was to ensure zero import. The default on the MKII is 50W, so my guess would be that the MKI had the same threshold. If you can set the battery charger to less than 50W you might be onto a winner, otherwise it could be worth upgrading to a new immerSUN - I see they are being marketed again with a new version...

mmmmikey

Good to hear the newer devices allow you to set the thresholds.

At the risk of sounding negative, a word of caution here. The issue I had wasn't just the threshold in Watts, timing comes into it, as well as calibration of the sensors.

Suppose, for example, the battery has a threshold of 50W and the immersion controller 100W. The sun comes out from behind a cloud and you would expect the battery to start using the power first, and the immersion controller then do nothing as the power is going to the battery. But if the immersion controller software means it samples the output from the panels before the battery controller software it will grab the power first even if the threshold is higher. This effect can end up being a bit random depending on exactly how the two devices sample the power from the panels. And keep in mind too that the immersion controller and battery will probably be using current clamps which aren't particularly accurate at these low levels, which can lead to seemingly random effects.

The bottom line is you may find getting the 2 devices to play nicely together is a bit hit and miss.

Having said that, I hope you do find a solution that works and if you do please post back as this is an issue that has vexed others here.

mmmmikey

alford wrote: »

Thanks for the replies.I am about to move onto the octopus go tariff.
As I receive 50% deemed export it goes against the grain to export electricity and import gas or am I just being tight��.
Thanks again for the replies

Hi, just for clarity here and using my own tariffs as an example......

I have opted for metered export which is an option available because I have a smart meter. I get 5.24p per kWh for export, so using solar power to heat my water costs me 5.24p per kWh (because it reduces my payment by this amount)

But if I heat the water using cheap rate E7 electricity overnight it only costs me 4.9p per kWh.

So in my (tight fisted ) case I'm actually better off exporting the solar than using it for heating water.

Obviously you need to check your own tariffs here and I have to say my combination is probably unusual. But if you are able to get metered export and buy cheap electricity at night, even if you're worse off per kWh you may never save enough to pay for a MkIi Immersun......

Reed_Richards

What a device like the Immersun needs to know is:
1) You are exporting power to the grid.
2) Your battery is not discharging.
If both those conditions are satisfied then it is safe to switch on whatever power-hungry thing is being controlled. If the battery starts to discharge or you start to import power from the grid then the controller needs to switch off the thing it is controlling. I am not aware of any controller with the ability to tell whether a battery is charging or discharging.

mmmmikey

At the risk of labouring the point about tariffs this is worth looking at:

https://www.edfenergy.com/for-home/energy-efficiency/smart-meters-and-feed-tariff-changes

Devices like the Immersun largely pay for themselves by using "free" electricity from your solar panels. This electricity is only free if your export is deemed because you get the same payment whatever you export.

But, like them or loathe them, smart meters are well on their way to being rolled out and an effect of this could well be that we all end up on metered export whether we want to or not - as per link above. Even if you decline to have a smart meter installed (a right you currently have) you might be cutting off your nose to spite your face as this could limit your access to the most favourable tariffs.

So although I've been a big fan of them in the past I suspect the future market for Immersuns etc. is going to die very soon and I would think carefully before inversting in a new one or spending too much time and effort getting it working alongside your battery (apart from the fun of the technical challenge )