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Anyone want to share costs on batteries?

batalto · 2021-12-02T09:25:06Z

I am looking at beefing up my battery storage as the ASHP loves power, my solar is big and I have a cheaper overnight tariff. I've been reviewing batteries and settled on the Seplos Pusung 5kw batteries -They are LiFePO4, so very stable, they have good storage, 5kw and they can charge/discharge at 100A@51v so 5kw peak in and out. They are also stackable, so I could get 2 and have 10kw etc. I've also spoken to them and they've told me its $2100 (£1500) per unit for 1, $1800 (£1325) per unit for 6, and $1200 (£900) per unit for 12 plus $350 USD shipping per battery to the UK. If I get them in a big order, it works out very reasonable from a good supplier. I will also need a 5kw hybrid inverter, and this will be £600-£1000 My question is... is anyone else thinking about batteries? If you are, would you consider a bulk order to lower the costs? Using Octopus Go, I could realistically charge 20kW overnight at 5p/kW

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batalto

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Topic starter 24/09/2022 2:00 pm

Charger has now moved up to 3.5v, so getting there!

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE

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Transparent

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27/09/2022 11:10 am

This is now day-8 of @batalto top-balancing his first set of LiFePO4 cells, and a week since he posted here his calculation that it would be completed in another 29-hours 🤣

As all has been silent, so I'm assuming that the current is still running at the (max) 10A available from that power supply. And I remain quietly confident that my guesstimate of a fortnight's charging is closer to the mark!

On a related note, the crash in the value of the pound since last week's financial statement by the Chancellor has significantly raised the price of importing (heavy) cells direct from China.

Fortuitously I'd managed to complete another transaction and get a batch of 32 cells on a ship before the $-rate took a nose-dive. Phew!

Save energy... recycle electrons!

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batalto

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Topic starter 27/09/2022 12:55 pm

@transparent I'm in the USA, so no idea on the top balance. I'll be home tomorrow and will check then!

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Transparent

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27/09/2022 1:26 pm

Posted by: @batalto

I'm in the USA... I'll be home tomorrow

You'd better bring back as many dollars as you can. Joules are getting expensive.

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Derek M

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27/09/2022 7:37 pm

@transparent

Have you not heard, the pound crashing is of little or no consequence.

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batalto

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Topic starter 30/09/2022 2:59 pm

The battery box has arrived. I'll open it this evening to check everything and post some images for everyone. It's pretty chunky, but then again it's for 15kwh of battery. It weighs a tonne though and it seems built like a small tank

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Transparent

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30/09/2022 3:10 pm

So we know what you'll be doing all weekend @batalto

1: Have you viewed the YouTube video on this Mason box from Off-Grid Garage in Australia? There are some helpful comments uploaded by others which are worthwhile reading. They resolve several of the issues which he found problematic.

2: Whilst you're building this, could you keep in mind whether such a system might be useful to be built/used in a country which is recovering from a disaster. Ie if their mains grid was erratic and power was needed to get schools, hospitals and shops working, is the Seplos approach feasible? Or is too complex, requiring tools which are unlikely to be available?

When I say 'disaster', this could be natural (Cuba; hurricane) or man-made (eg Ukraine; war).

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batalto

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Topic starter 30/09/2022 4:00 pm

@transparent a few images of the unpack

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batalto

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Topic starter 01/10/2022 4:10 pm

Cracked on a bit today. Don't want to finish up as the batteries are STILL top balancing. However I've basically put everything together that I can. Seplos seems to have left out the RJ45 adaptor cable and the side clamps. Both not really an issue as I have an adaptor and I don't have any other batteries. However I might get more, so I might need those clamps.

One bag also split so there were some loose items in the box. No damage from them, but how hard is it to put things in a box Vs a bag?!

I didn't really use the instructions as they are quite light. But the videos online were fine to follow. I've got a few left over bolts which don't seem to go anywhere. It also looks like the fuse bolts were too long, so I swapped them for some short ones I had - not ideal if you don't have a small collection like I do.

To be honest, it was very straightforward to do. I only used a leatherman up to this point to make everything "finger tight". I'll make everything proper just before I finish up using my torque wrench which has an indicator.

So far 4 out of 5 stars. They are getting four as they are refunding me the difference for the adaptor. I'll let everyone know about the clamps etc. And I've also not turned it no, but can't see any issues with the BMS etc.

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batalto

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Topic starter 01/10/2022 6:50 pm

@transparent I think I've hit absorption on the batteries. Current has dropped to 0.63A and voltage is 3.6V. I don't have fine control, so I can only do 0.1V increments not 0.01V. So 3.6V it'll have to be. Means I can get the cells in tomorrow and finish up my build!

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Transparent

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01/10/2022 7:25 pm

That's good news @batalto I guessed a fortnight for top-balancing and it's been running 12 days since you succeeded in getting it to run at the full 10A.

I'm also amazed/relived that you've assembled the Mason-box with a Leatherman!

Whilst I would normally advise anyone to use the proper tool for each job, in this case you've succeeded with minimal tooling. That bodes well for using this box in locations which have been subjected to disasters.

You will, of course, still need to use the correct size spanner/wrench to tighten the bolts which carry electrical current, otherwise they could run hot.

And I suggest you find yourself a few spare fuses to put 'on the shelf'. If an installation error causes it to blow, then you don't want to be hanging around whilst you find another online. I think you'll have great difficulty finding one rated above 32v.

This post was modified 3 years ago by Transparent

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batalto

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Topic starter 01/10/2022 7:35 pm

@transparent you laid down the challenge for basic tools. 100% I'd say it's doable with a leatherman, Allen keys and a socket. At a push I guess you could use the leatherman as the socket/spanner but you couldn't torque properly.

I'll be probably putting it all together and tightening up tomorrow. The bulk of the work is done now. Realistically it's a couple of hours max in terms of work.

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