Adding batteries

[Nickfromwales]

2 minutes ago, pocster said:

Yes. I detect the envy on this forum already....

Greatness has been achieved whilst still living!

LOL  

[Pocster]

Yes - you all weep at MY cheap lecky . I can pick and choose a tariff that rather than ‘saves’ me money as conventionally ; I choose the one that makes me money .

An electric whore if you will . Highest bidder gets my goods .

[canalsiderenovation]

2 hours ago, SteamyTea said:

You still are.

 

But we are currently installing new capacity, on long term contracts, at £40/MWh.

So once the general public realize that, we could be into a couple of decades of fixed price power again. Will take another decade to get there.

Even when we had the 'cheap' energy over the last 20 years, people still think they were robbed.

(expletive deleted) them I say, let them get cut off or pay their share of the price.

Batteries at home are not going to reduce anyone's outgoings.

 

@canalsiderenovation

Have you thought, as an experiment, making your boat all electric and truly off grid?

Then plug your house into it.

 

@SteamyTea we just sold the boat at the weekend. Made a bit of profit but this is funding the patio areas, planters, porcelain and double garage - and hopefully we can save up enough to finally get the driveway/landscaping. 

 

We absolutely want another boat in the future but at the moment the priority is trying to finally get things finished. We are sick of looking at 20 ton of MoT, mud and mess outside.

[canalsiderenovation]

3 hours ago, pocster said:

Well - this ignores some things .

You could end up exporting at 35p a kw - like I do . I estimate I’ll earn £1000 a year from that .

 

Yes we are exporting on Flux at the moment and getting some good returns. 

 

[dpmiller]

22 hours ago, canalsiderenovation said:

We live next to the cheapest petrol station in the UK

 

OT, but how much are diesel and unleaded at the mo with you?

[joe90]

Just spotted locally unleaded and diesel the same price £1.44 🤷‍♂️

[SteamyTea]

Gasoline has an energy content of 9.5 kWh.litre^-1

Diesel is 10.7 kWh.litre^-1 partly why you get more mileage out of a diesel car.

 

Looking at confused.com's fuel price checker for my area.

 

UK prices as of Thursday 8 June

	Highest	Lowest	Average
Petrol	176.9p	129.6p	143.1p
Diesel	187.9p	119.6p	146.0p

 

The kWh price is between 13.64p and 18.5p, with an average of 15.1p for gasoline.

Diesel's kWh price is between 11.2p and 17.6p, with an average of 13.6p.

 

 

[canalsiderenovation]

1 hour ago, dpmiller said:

 

OT, but how much are diesel and unleaded at the mo with you?

 

I'll go check later. Earlier this week diesel was 130.9, I didn't check petrol as we don't use it.

[dpmiller]

4 hours ago, canalsiderenovation said:

 

I'll go check later. Earlier this week diesel was 130.9, I didn't check petrol as we don't use it.

certainly not the cheapest in the UK. Maybe the GB part of the UK? I passed two stations yesterday here both at the same 130.9...

[canalsiderenovation]

55 minutes ago, dpmiller said:

certainly not the cheapest in the UK. Maybe the GB part of the UK? I passed two stations yesterday here both at the same 130.9...

 

It was 129.9 for diesel recently, haven't been out today. It's been in all the national newspapers and TV channels in the past few weeks. Grindley Brook was famous, couldn't get out of our house down the lane  as it was chaos at the petrol station (our access is through the forecourt)!

 

Link to Scum article (sorry only one I could find at moment) https://www.google.com/amp/s/www.thesun.co.uk/motors/22355533/petrol-station-slashed-diesel-25p-litre/amp/

[JohnMo]

5 hours ago, canalsiderenovation said:

 

I'll go check later. Earlier this week diesel was 130.9, I didn't check petrol as we don't use it.

Was in town earlier, shell was 143p for diesel and petrol, Asda 141p diesel and 139p petrol

[Crofter]

On 14/06/2023 at 05:30, SteamyTea said:

Gasoline has an energy content of 9.5 kWh.litre^-1

Diesel is 10.7 kWh.litre^-1 partly why you get more mileage out of a diesel car.

 

Looking at confused.com's fuel price checker for my area.

 

UK prices as of Thursday 8 June

	Highest	Lowest	Average
Petrol	176.9p	129.6p	143.1p
Diesel	187.9p	119.6p	146.0p

 

The kWh price is between 13.64p and 18.5p, with an average of 15.1p for gasoline.

Diesel's kWh price is between 11.2p and 17.6p, with an average of 13.6p.

 

 

But in the real world you can't extract all the energy from petrol or diesel.

An ICE vehicle typically only uses about a third of the energy available in the fuel.

EVs are using 85%+

[JohnMo]

17 minutes ago, Crofter said:

But in the real world you can't extract all the energy from petrol or diesel.

An ICE vehicle typically only uses about a third of the energy available in the fuel.

EVs are using 85%+

Unless the electric comes from a renewable source, the electric car does no better than the ICE.  Electric vehicle only really win when the grid is renewable or a good percentage.

[Crofter]

3 hours ago, JohnMo said:

Unless the electric comes from a renewable source, the electric car does no better than the ICE.  Electric vehicle only really win when the grid is renewable or a good percentage.

Obviously it depends on the car but I've certainly seen this one debunked. Electric is simply a more efficient powertrain than ICE, and even with transmission losses tends to come out ahead.

And of course you get the benefit of removing the pollution from urban areas.

[JohnMo]

8 minutes ago, Crofter said:

Obviously it depends on the car but I've certainly seen this one debunked. Electric is simply a more efficient powertrain than ICE, and even with transmission losses tends to come out ahead.

And of course you get the benefit of removing the pollution from urban areas.

Removing pollution from urban areas is good thing in favour of electric vehicles.

 

Efficiency of power trains, an electric vehicle is basically a single speed gear train, so should always be efficient, than multi-speed transmission.

 

But getting back on topic, how do you add batteries to an AC PV inverter - instead of a hybrid inverter?

 

 

[SteamyTea]

47 minutes ago, JohnMo said:

 

But getting back on topic, how do you add batteries to an AC PV inverter - instead of a hybrid inverter?

Can you add them on the DC side, will need a charge controller between the modules and the batteries, but should need nothing between the batteries and a regular inverter, just a case of pumping in the correct voltages.

[Dave Jones]

16 hours ago, JohnMo said:

Unless the electric comes from a renewable source, the electric car does no better than the ICE.  Electric vehicle only really win when the grid is renewable or a good percentage.

 

leccy motors being an extension to the house/work battery systems via vehicle to grid will be a game changer.

[SteamyTea]

10 minutes ago, Dave Jones said:

 

leccy motors being an extension to the house/work battery systems via vehicle to grid will be a game changer.

Anymore than utility scale storage which will be cheaper?

[Radian]

13 hours ago, SteamyTea said:

Can you add them on the DC side, will need a charge controller between the modules and the batteries, but should need nothing between the batteries and a regular inverter, just a case of pumping in the correct voltages.

'Correct voltages' being probably something in the region of 120VDC to get the inverter to start up - which requires multiple series of typical battery packs. Then an external charge balancer for those. I doubt this could be cobbled together easily.

[SteamyTea]

10 minutes ago, Radian said:

Then an external charge balancer for those. I doubt this could be cobbled together easily.

I would have thought it would be off the shelf kit though.

You can get small, relatively inexpensive, full sine wave inverters, they would work, though not safe to connect to the grid supply.

[Radian]

25 minutes ago, SteamyTea said:

I would have thought it would be off the shelf kit though.

 

Unfortunately I don't think "we're there" yet. Browsing the market for raw LPF batteries it's striking how the pricing is on a continual downward slope - especially in the recycled EV sector. As tempting as it is to hack some of these bits together to make a DC coupled system on the cheap, I think it's still too costly even at half the price of commercial kit.

[SteamyTea]

1 hour ago, Radian said:

I think it's still too costly even at half the price of commercial kit.

I tend to agree, and usually only manage to burn my finger when doing electronic.

 

But I do wonder how difficult it really is.

[Radian]

On 17/06/2023 at 13:21, SteamyTea said:

But I do wonder how difficult it really is.

 

Well, here's a shot at it for you to contemplate, inspired by a 24V 100Ah LifePo4 Battery that can be daisy-chained (allegedly) to up to five batteries in series over on Amazon

The chemistry puts each cell at 3.65V max, with 8 cells per '24V' pack. That's 29.2V at maximum SOC. a total of 146V which should start-up most inverters and keep it going at above 120V until depleted.

Here, they even show a pretty picture of it:

 

 

Now that's as close as I've come to a plan for a DC system - but the MPPT controller that would regulate the charge for this particular setup isn't the kind of off-the-shelf item I see out there in the market.

If it was, it would have to play nice with the MPPT of the inverter and do its power-sharing without pulling the PV output down to its level

In my case a big old Buck Regulator to transform the approx. 250VDC from my PV down to 146V @ 10A which is reasonably do-able.

Alternatively, an AC coupled charger on the other side of the inverter would give more flexibility at a small reduction in efficiency. Either way a couple of Silicon Carbide Diodes could arbitrate the input to the inverter with a relay to manage when the battery is used.

So not something you could throw together entirely with off-the-shelf assemblies but the end result would be very handy: A 12kWh battery system for only £3,250 plus a few 10's of quid for transistors etc.

[Crofter]

It's hard to beat a DIY approach for LiFePO4. Get the cells and BMS from Alibaba (other vendors available), top balance the cells, and hook it all up. More configurable than a ready made unit, easier to repair if e.g. the BMS fails, and cheaper overall.

 

I'm not up to date with current prices but two years ago I built a 270Ah/12v pack for £407 including the BMS, shipping, etc etc. I had a few extras to buy but nothing much.

[Radian]

7 hours ago, Crofter said:

I'm not up to date with current prices but two years ago I built a 270Ah/12v pack for £407 including the BMS, shipping, etc etc. I had a few extras to buy but nothing much.

 

I guess that was for feeding an off-grid 12V inverter? Things get quite a bit more tricky interfacing with a grid-tied inverter. But 12p/kWh storage cost is still impressive when compared to the more usual 50p to £1 for commercial offerings.