Your Home Base Load / Background Power Draw

[Dillsue]

1 hour ago, Radian said:

Never seen the overnight load fall away so distinctly.

Isnt that the usual curve for the orange gas generation?

[Onoff]

1 hour ago, Radian said:

Remarkable recent data from Gridwatch:

 

 

Never seen the overnight load fall away so distinctly.

 

Are we all turning into our dads going round switching lights off and moaning?

 

I am!

[Onoff]

1 hour ago, Radian said:

 

While connected in parallel the terminal voltages are obviously identical so it's impossible for one battery to be over or undercharged. Current will just share out safely between them. However, I would make sure both batteries had the same terminal voltage before joining them as the above only applies when the voltages are exactly the same.

 

As I said the lower Ah battery can over discharge though. 

[SteamyTea]

1 minute ago, Onoff said:

switching lights off and moaning

Lights!

You were lucky.  We had to sit around a smouldering rag.

[Radian]

9 minutes ago, Dillsue said:

Isnt that the usual curve for the orange gas generation?

 

I only started taking notice this month and noted approx minimums around 3AM:

 

1/4 28GW

2/4 26GW

3/4 25GW

4/4 24GW

 

TBH it probably tracks overnight temperatures more than anything else.

[Onoff]

2 minutes ago, SteamyTea said:

Lights!

You were lucky.  We had to sit around a smouldering rag.

 

8 of you were there, in one shoe box?

[SteamyTea]

1 minute ago, Onoff said:

 

8 of you were there, in one shoe box?

Yes, and the baby.

When I say rag, what I meant was a used candle wick that had passed though the dog.

[Radian]

3 minutes ago, Onoff said:

 

As I said the lower Ah battery can over discharge though. 

 

No, so long as battery chemistries are identical (they absolutely have to be to do this!) the SOC is identically proportional to terminal voltage. If the smaller AH battery were to lose charge more it would drop the voltage at its terminals and this would cause current to flow in from the larger AH battery so restoring the balance. The charge shifts around but still equates to the sum of the two AH's overall.

 

[SteamyTea]

11 minutes ago, Radian said:

so long as battery chemistries are identical

Why does the chemistries have to be the same.  Is it because single cell voltages are different between chemistries?

[Nickfromwales]

20 minutes ago, SteamyTea said:

Why does the chemistries have to be the same.  Is it because single cell voltages are different between chemistries?

Wouldn’t it be better matched? eg similar will exchange charge at the same pace?

[Radian]

15 minutes ago, SteamyTea said:

Why does the chemistries have to be the same.  Is it because single cell voltages are different between chemistries?

Yes, even SLA batteries can vary a bit - especially from manufacturer to manufacturer. But you're getting into third-order effects with that.

 

What can go wrong is if some of the cells become sulphated and present a relatively high impedance. Charge will still circulate but I2R losses will take place inside the weaker cells and put an unnecessary drain on the better battery. That could be either the larger or smaller capacity battery or even two supposedly identical capacity batteries so paralleling definitely needs to be done with healthy batteries.

[MikeSharp01]

On 04/04/2022 at 16:48, Radian said:

but I2R losses will take place inside the weaker cells and put an unnecessary drain on the better battery

Sounds like a case for some intelligent electronics - surely you can organise a battery management system can deal with these, and other, effects.

[SteamyTea]

3 hours ago, MikeSharp01 said:

Sounds like a case for some intelligent electronics - surely you can organise a battery management system can deal with these, and other, effects.

Diodes, they can do everything.

https://en.wikipedia.org/wiki/Diode

Just got to pick the right ones

[TonyT]

Battery management system would be my choice rather than a diode

[SteamyTea]

2 minutes ago, TonyT said:

Battery management system would be my choice rather than a diode

They will have diodes in them doing the work.

probably more than one.

 

I want one of these, as it sounds impressive.

https://en.wikipedia.org/wiki/Cockcroft–Walton_generator

 

[dpmiller]

^ that's just a tripler from an old telly.

[MikeSharp01]

1 hour ago, SteamyTea said:

Diodes, they can do everything.

I was always told by a famous - now rather late, professor who taught me a thing or two that one should never go into any electronic situation without a pocket full of diodes - 1N4001 is my usual tipple but then I am a bit AC/DC.

[TonyT]

I think I was using IN4007 when my sae envelopes from cricklewood electronics arrived after a long wait, those were the days waiting to see if the postman had delivered when I came back from school…

[SteamyTea]

8 hours ago, MikeSharp01 said:

I am a bit AC/DC

Ah, the change, from analogue to digital

[Onoff]

7 hours ago, TonyT said:

I think I was using IN4007 when my sae envelopes from cricklewood electronics arrived after a long wait, those were the days waiting to see if the postman had delivered when I came back from school…

 

They're still going strong. I just received a delivery from them. I've a half finished (no surprises there 😂) mini drum synth sitting here and a second one to build.