On-grid domestic battery storage

pile-o-stone

1961Nick wrote: »

I've had batteries for 183 days & have recorded 122 cycles. Even with overnight charging in winter, that figure won't rise beyond 250 cycles pa. That should mean that at worst it'll take 16 years for the batteries to reduce to 80%.....easily solved by adding another battery.

If you mean adding another battery to the exist battery array, then take into consideration:

"As batteries naturally age, their voltage levels reduce. If the age gap between the old and new battery is too great, the optimal performance of the new battery may be compromised because it will operate at the same level as the existing unit."

https://www.bimblesolar.com/GW2500-BP-PYLON-WG

Zarch

Exiled_Tyke wrote: »

Apologies for being unclear. It was £3k for the battery system. So the VAT would have been £600. The two new panels came to £700 which I was happy to pay as it avoided the 20% VAT rate on the battery.

What did the battery system consist of?

As you've got Solar Edge for you original panels i'm assuming you needed another inverter as well as the battery itself? What inverter model was included?

And who supplied and did the install?

Thanks.

1961Nick

pile-o-stone wrote: »

If you mean adding another battery to the exist battery array, then take into consideration:

"As batteries naturally age, their voltage levels reduce. If the age gap between the old and new battery is too great, the optimal performance of the new battery may be compromised because it will operate at the same level as the existing unit."

https://www.bimblesolar.com/GW2500-BP-PYLON-WG

Used pylontechs will eventually appear on ebay for a couple of hundred pounds & that's what I'd be on the lookout for.

zeupater

1961Nick wrote: »

Used pylontechs will eventually appear on ebay for a couple of hundred pounds & that's what I'd be on the lookout for.

Hi

Okay, that helps with mitigating underperformance issues on the additional new batteries, but how do you determine the state (cycles/expired duty) of the pre-owned batteries at time of purchase to ensure that they don't have a similar negative effect on your existing batteries? .... or are you simply trusting that the used batteries will be cheap enough that the capacity dilution effect will be worth it whatever the status?

HTH
Z

1961Nick

zeupater wrote: »

Hi

Okay, that helps with mitigating underperformance issues on the additional new batteries, but how do you determine the state (cycles/expired duty) of the pre-owned batteries at time of purchase to ensure that they don't have a similar negative effect on your existing batteries? .... or are you simply trusting that the used batteries will be cheap enough that the capacity dilution effect will be worth it whatever the status?

HTH
Z

Firstly, I'd try to determine how many cycles they'd already logged & also the voltage with full charge.

My batteries were fairly early US2000B Plus's so it's highly probable that used ones would have less cycles anyway & the dilution would be on the additional battery/batteries. Moving to the Octopus Go tariff & charging overnight during winter increases that probability.

joefizz

1961Nick wrote: »

Firstly, I'd try to determine how many cycles they'd already logged & also the voltage with full charge.

Most of future failures or 'spares or repair' will be failed cells or failed capacitors, both easily checked and repaired with a modicum of knowledge (and a bit of safety sense).


Most of the drop offs will also be failed cells in the banks and the replacement cells are reasonably priced or if theres enough demand there will probably be a return of post fix service.
It will depend on future pricing of course but completely replacing the cells in one of the pylontech shouldnt cost more than a couple of hundred quid.



The inverter/battery hardware and setup is the expensive bit. Its why I went for the pylontech, the firmware is good enough to manage the mismatches plus easy enough to take one offline to check/repair/replace.



Some good videos on youtube now about repairing/salvaging tesla batteries, give it a couple of years and there will be same on pylontech etc.

Ive been replacing the rechargeable cells in cheap power tools and have a 20 year old rechargeable dremel that really just uses AAs in its 'power pack'. Ive replaced those at least twice and that was before AAs with solderable tags were readily available.

Exiled_Tyke

Zarch wrote: »

What did the battery system consist of?

As you've got Solar Edge for you original panels i'm assuming you needed another inverter as well as the battery itself? What inverter model was included?

And who supplied and did the install?

Thanks.

You are correct a new inverter was needed: Solax X1-AC-3.6, with the Solax 6.3kWh Triple Power battery and BMS. They could have installed a hybrid inverter to take from the new panels as well as look after the battery but this would have worked out more expensive.

Small local firm did the installation.

Solarchaser

Ebay is awash with pylontech at the moment, and for the first time this year, the price is coming back down to the £750 mark for multiples of the us2000 (2.4kwh)

mmmmikey

Looking for some help here...


We've previously discussed the tactic of switching something on in the early evening to overcome the threshold at which the battery starts discharging, and then turning it off and relying on the hysterisis to keep the battery going.


Any ideas on a converse process to get the battery to start charging in the morning on days like today where there isn't quite enough solar power to get the battery to start charging, but enough to keep it charging when it has started? The obvious solution would be to reduce the base load by switching something off, but my base load is so small that there isn't really anything I can think to switch off. I suppose I could go into the garage and flick the switch on the consumer unit but that is hardly convenient and seems a bit extreme.



I'm clutching at straws a bit and the only thing I can think of is to do something with the current clamp to temporarily make it think there's more export than there is?


Any suggestions welcome, thanks, Mike

1961Nick

mmmmikey wrote: »

Looking for some help here...


We've previously discussed the tactic of switching something on in the early evening to overcome the threshold at which the battery starts discharging, and then turning it off and relying on the hysterisis to keep the battery going.


Any ideas on a converse process to get the battery to start charging in the morning on days like today where there isn't quite enough solar power to get the battery to start charging, but enough to keep it charging when it has started? The obvious solution would be to reduce the base load by switching something off, but my base load is so small that there isn't really anything I can think to switch off. I suppose I could go into the garage and flick the switch on the consumer unit but that is hardly convenient and seems a bit extreme.



I'm clutching at straws a bit and the only thing I can think of is to do something with the current clamp to temporarily make it think there's more export than there is?


Any suggestions welcome, thanks, Mike

This is a tough one. You've already considered the only sensible option which is to temporarily reduce the load.