How did you pick your battery?

[MikeGrahamT21]

2 minutes ago, pocster said:

Ok . It’s a rare example but has happened .

pw low . Se full . Discharge se into pw . If pv generation is greater than 3.68 pw will charge at 3.68 ( it’s max ) . Se can’t soak up extra over 3.68 as it’s discharging . ( or not if pv is 3.68 or greater - but it is in ‘discharge mode’ not ‘charge from solar ‘ ) .

Google tells me ‘ pass thru ‘ does exist and allows charge / discharge simultaneously 

 

Does sound very much like a lag in one of the monitoring clamps, check with manufacturer to see if theres any newer firmware to reduce the polling interval.

[Gill]

4 hours ago, pocster said:

certainly talk to your DNO - they can give you an indication of what you can have also ask them about various battery option

Well that didn't go well. They want a g99 application from an installer that requests a 'budget quote' for a particular configuration. So I need to overspec a system before they will give any indication of what is possible. 

[Pocster]

31 minutes ago, Gill said:

Well that didn't go well. They want a g99 application from an installer that requests a 'budget quote' for a particular configuration. So I need to overspec a system before they will give any indication of what is possible. 

DNO’s can vary on their attitude .

Looks like you take the whip from your DNO like I did . Get that g99 in and see what happens .

[Dillsue]

2 hours ago, Gill said:

Well that didn't go well. They want a g99 application from an installer that requests a 'budget quote' for a particular configuration. So I need to overspec a system before they will give any indication of what is possible. 

You don't need an installer to submit a G99, in its straight forward to do yourself. If you want 7 kw to use in the house then apply for 7kw and see what they come back with.

 

If its a no then you can-

Ask then to reinforce the grid so you can export 7kw

Implement an export limitation system

Use the 3 phase supply youve got

[SteamyTea]

4 hours ago, MikeGrahamT21 said:

 

How can you possibly charge and discharge something simultaneously

You can be filling a bucket from a tap at the same time as water leaks out of a hole in the bucket, Dear Liza.

 

I think the question is wrong.

5 hours ago, pocster said:

Why can’t my SE dc battery charge and discharge simultaneously ?

What do you really mean, or have noticed to make you think this.

Edited May 15, 2023 by SteamyTea

[Pocster]

2 minutes ago, SteamyTea said:

You can be filling a bucket from a tap at the same time as water leaks out of a hole in the bucket, Dear Liza.

 

I think the question is wrong.

What do you really mean, or have noticed to make you think this.

Because if I set SE to discharge it won’t charge from PV . It’s one or the other . As I said there are ways to reduce this . The main reason is I wish to top up the pw as this is what feeds the house directly .

The neat way to reduce this is set SE to charge only from clipped . That way SE and PW can potentially charge simultaneously .

As the sun is out by end of day ( when pv is minimal ) I get SE to discharge . As PW will be full or near full that goes to the grid . 
Rinse and repeat ( until winter )

Currently SE and PW are set to never charge from grid - been like that for 2 weeks now . 😎

Admittedly it is like managing a mini power station ; dealing with varying demands . SWMBO is WfH today so it’s a trickier test ! 

[PhilT]

6 hours ago, MikeGrahamT21 said:

there is absolutely no point in going AC Coupled, due to the fact you will lose a lot of energy through inverter efficiencies

Not necessarily. It's the battery discharge vs charge inefficiency which loses the most. I have separate AC/DC battery inverter and the losses from PV to battery feed are around 3%. A small price to pay for being able to use basic (and inexpensive) non hybrid HD Wave inverters that enable PV optimisers to capture a lot more solar on my 'difficult' roof. But you could go with something like an HD Wave with Storedge Hybrid module plus LG Res batteries, but I believe that would be considerably more costly

 

[Dillsue]

5 hours ago, pocster said:

Why can’t my SE dc battery charge and discharge simultaneously ?

I assume that you meant why cant your INVERTER charge and discharge simultaneously as in charge the battery and feed power to the house/grid/PW, which it can.

[Pocster]

7 minutes ago, Dillsue said:

I assume that you meant why cant your INVERTER charge and discharge simultaneously as in charge the battery and feed power to the house/grid/PW, which it can.

Yes ; sorry - you are correct .

Because as you state in effect it does that on the PW side no issue .