Batteries

[Joeboy]

That’s one heck of a price difference. There are cabling and isolator costs along with support frame build costs yet it appears to me that the BMS is already installed in the Pylontechs and that these batteries could be slipped in to one side. Essentially inline between the Pylontech stack and the off grid inverter, thoughts?

You've used the 8 pack price but you need 15 cells to make up a Pylontech equivalent in terms of voltage, so I make it about £900 for a 5kWh pack (similar to two of your Pylontech US2000).

Cheaper but not as cheap as you think and once you add the cell balancers, and all the faff, your probably better off with more Pylontechs.

My addled mind assumed that by running them off a spur so to speak then they would act as dumb storage with the voltage control being acted on by a combination of the Pylontech master battery BMS and the powerflow and limits by the Goodwe hybrid controller. If they are spurred off to the side off of the top and bottom remaining Pylontech battery connections will they not just settle at the Pylontech stack voltage? I alrady have the offgrid inverter hooked up to these points and power flows fine. Once again I am in unknown territory.

[SafetyThird]

To form a small 2.4 kWh one needs "The Pylontech battery has 15 cells in series, so 53.2V equates to 3.55V per cell" so what do you do if one cell fails ? How do you get the one, that failed cell out and is access easy without soldering around electronics ? Or can you just make an easy equalization charge ? Or just bring the the whole lot to the dump ?

There's a couple of videos on YouTube of people opening up their pylontech batteries after damage, the cells are all pouches so I expect it's possible to change out a single pouch cell if needed. Mind you, with a long warranty I'm hoping that won't be needed on the one's I'm about to start using

[Stinsy]

OP, Apologies for the seeming hijack, battery related though!

Ah = kWh ÷ V × 1,000.
My current stack is 14.4kWh @ 48v so 300Ah before any degradation or operational parameters set on it. Each unit of 6 cost me around £700 so £4,200/300Ah is £14 per Ah.
Today prices are around £800 per unit so £4,800/300Ah is £16 per Ah.
These sealed units on Ebay come in at £490 for a set of 8 at 102Ah. The fast charge rate is limited to 40A and DOD is 80% but other than that they look as if they could slip into my system.
https://www.ebay.co.uk/itm/265662358313 ... SwHUdiZycF
£490/102Ah is £4.80 per Ah
That’s one heck of a price difference. There are cabling and isolator costs along with support frame build costs yet it appears to me that the BMS is already installed in the Pylontechs and that these batteries could be slipped in to one side. Essentially inline between the Pylontech stack and the off grid inverter, thoughts?

I priced up these a few times. Plan similar to yours: whack a series string of 15x batteries in parallel to the pylontechs, let the pylontech BMS do the heavy lifting and get a simple balancer to keep the string in order.

However the price was always so similar to pylontechs that it wasn’t worth it. Once you consider you’ll likely have to buy 16x batteries and keep one spare and the benefit was wiped out.

[Joeboy]

OP, Apologies for the seeming hijack, battery related though!

Ah = kWh ÷ V × 1,000.
My current stack is 14.4kWh @ 48v so 300Ah before any degradation or operational parameters set on it. Each unit of 6 cost me around £700 so £4,200/300Ah is £14 per Ah.
Today prices are around £800 per unit so £4,800/300Ah is £16 per Ah.
These sealed units on Ebay come in at £490 for a set of 8 at 102Ah. The fast charge rate is limited to 40A and DOD is 80% but other than that they look as if they could slip into my system.
https://www.ebay.co.uk/itm/265662358313 ... SwHUdiZycF
£490/102Ah is £4.80 per Ah
That’s one heck of a price difference. There are cabling and isolator costs along with support frame build costs yet it appears to me that the BMS is already installed in the Pylontechs and that these batteries could be slipped in to one side. Essentially inline between the Pylontech stack and the off grid inverter, thoughts?

I priced up these a few times. Plan similar to yours: whack a series string of 15x batteries in parallel to the pylontechs, let the pylontech BMS do the heavy lifting and get a simple balancer to keep the string in order.

However the price was always so similar to pylontechs that it wasn’t worth it. Once you consider you’ll likely have to buy 16x batteries and keep one spare and the benefit was wiped out.

Yeah, that's kind of where I am in my head. I have made a stupid offer on 15 units, we'll say what they come back with. I like playing with stuff and that's the appeal (alongside the extra storage). Could easily stick another two US2000's up in that space and just use longer leads to hook it all up but that's too easy!

[Stinsy]

OP, Apologies for the seeming hijack, battery related though!

Ah = kWh ÷ V × 1,000.
My current stack is 14.4kWh @ 48v so 300Ah before any degradation or operational parameters set on it. Each unit of 6 cost me around £700 so £4,200/300Ah is £14 per Ah.
Today prices are around £800 per unit so £4,800/300Ah is £16 per Ah.
These sealed units on Ebay come in at £490 for a set of 8 at 102Ah. The fast charge rate is limited to 40A and DOD is 80% but other than that they look as if they could slip into my system.
https://www.ebay.co.uk/itm/265662358313 ... SwHUdiZycF
£490/102Ah is £4.80 per Ah
That’s one heck of a price difference. There are cabling and isolator costs along with support frame build costs yet it appears to me that the BMS is already installed in the Pylontechs and that these batteries could be slipped in to one side. Essentially inline between the Pylontech stack and the off grid inverter, thoughts?

I priced up these a few times. Plan similar to yours: whack a series string of 15x batteries in parallel to the pylontechs, let the pylontech BMS do the heavy lifting and get a simple balancer to keep the string in order.

However the price was always so similar to pylontechs that it wasn’t worth it. Once you consider you’ll likely have to buy 16x batteries and keep one spare and the benefit was wiped out.

Yeah, that's kind of where I am in my head. I have made a stupid offer on 15, we'll say what they come back with. I like playing with stuff and thats the appeal (alongside the extra storage).

Yeah, it’s a fun project. Don’t forget: studs, nuts, washers, crimps, cables, etc.

I really wish you could show a saving when all is said and done. But the truth is that pylontechs show astonishing VFM!

[Joeboy]

I priced up these a few times. Plan similar to yours: whack a series string of 15x batteries in parallel to the pylontechs, let the pylontech BMS do the heavy lifting and get a simple balancer to keep the string in order.

However the price was always so similar to pylontechs that it wasn’t worth it. Once you consider you’ll likely have to buy 16x batteries and keep one spare and the benefit was wiped out.

Yeah, that's kind of where I am in my head. I have made a stupid offer on 15, we'll say what they come back with. I like playing with stuff and thats the appeal (alongside the extra storage).

Yeah, it’s a fun project. Don’t forget: studs, nuts, washers, crimps, cables, etc.

I really wish you could show a saving when all is said and done. But the truth is that pylontechs show astonishing VFM!

This is me convincing myself, Had a quick look and ITS Tech have the US2000C's at £990 each incl vat. The C part is no use to me as I am limited by my B's. £1,980 for two batteries. If i could chuck it together for say £1,200 all in, that would be pretty good?
Thought you'd be at the Mall today?
P.S Alan, sorry for the horrendous hijack but it thought It was a too good thread for battery stuff to start another.

[ALAN/ALAN D]

Hello Gents
I am still in 16 Leisure battery mode on a 24 volt system.
Having got 33 panels on various systems / Grid export. My 900 LTR water tanks are at 85 Deg. C. at the bottom by 9 o'clock in the morning.
Next doors tank has also switched off. Just looking for bigger keep it simple battery system.
Is the “ 4-8PCS 3.2V 102Ah LiFePO4 Battery Pack “ the way to go.
How much looking after do they need. ? What charge / over charge limits need to be in place.
Many Thanks.

[Joeboy]

I am going to go and set up a new thread as I don't want to mess your one up Alan.

[Moxi]

JB wouldn’t four of those only be 12.8volt ?

Moxi

[Moxi]

Ok I’ve caught up on the various threads now but when I clicked on the link it said only two units left so I was ?????

Moxi