Using complete toolpacks to build a powerwall

So I have had this idea that I would like a powerwall which serves many purposes.

I bought into quite heavily one type of 40v toolpack battery, which I also can power a mower, strimmer and mine and my wife's ebikes.

Kind of irrelevant which battery it is but it comes in 2.6ah and 4ah at 40v nominal 10s2p inside.
They were sold by b&q in their Macallister brand (blue and grey, then later black and blue)
homebase under qualcast (green and black)
and now argos under spear and Jackson (black and red)

Ive been buying these 2nd hand off ebay whenever ive seen them for cheap with the idea of putting new cells in failing ones but mainly using them on my ebikes until they do fail and they have been great.

So I already have a plastic printable design to hold the battery to the bike (or anything else)
So I plan to make a structure that I can pull the batteries out of when I need them for mowing or cycling.
This will have the ability to charge and discharge the batteries on rules so that
no battery is trying to charge or discharge at the same time
the fullest battery charging to full (to ensure I always have one I can take out when I need it) (maybe 2)
It will know my solar output (3kw array) and will know if my car (leaf24) is plugged in and will charge if there is excess solar but only if the car isn't charging.

please let me know of any potential worries people can think of here and I will try to post some build photos as I go.

in the 4ah flavour I have 24ah.
in the 2.6ah type I have 10.4ah
this is approx. 1.2kwh so far
I also have about 8 empty cases with the bms' that I intend to put new cells in too.
I have plenty of chargers and simplistically I am going to go with simple double throw relays hopefully will ensure they are never short circuited. (also they will be fused on the dc side)
Later I would like to investigate whether the batteries could be charged by a non-oem charger so more slowly, or turn down the oem charger. My aim is to never have to open the toolpacks up. The chargers I am not so precious about.

reserved

reserved as well

reserved as well greedy I know

Do you have data logging from your solar set up ?
A power wall is only useful if you have spare power to charge it, so you need to understand what you may have available after any direct usage, car charging, ebike charging etc.
It will help you design your set up.
No point in building a 10+ kWh power wall if you only ever have a max of 5 kWh surplus !

whereswally606 said:

So I have had this idea that I would like a powerwall which serves many purposes.

I bought into quite heavily one type of 40v toolpack battery, which I also can power a mower, strimmer and mine and my wife's ebikes.

Kind of irrelevant which battery it is

Click to expand...

Until that form factor gets discontinued.

ONE+ is my reco for repurposing tool packs.

Top quality cells, and

Ryobi has committed to consistency for many decades, if not "forever"

https://pvoutput.org/list.jsp?id=67748&sid=60211

this is my solar output historically. It had gaps in the data early on due to a flaky wifi reception which ive solved now using powerline ethernet devices. collected using eversol on a raspberry pi by smoller.

yes I agree its important to commit to something where you can keep buying them but I have found that I will be able to pickup old packs and recell them if they get completely discontinued.
both macallister stopped and then changed the colour and started again, homebase when under so green packs are likely last of there kind but the spear and Jackson black packs are still obtainable from argos, and ive got lots from ebay in 4ah from recently all new.

I also like the worx powershare packs, since I have a hydroshot and a drill. I am trying to stay within one battery ecosystem to increase their utilisation.

Id also like to try building this power generator with the potential to step up the volts to 400v to supplement my leaf in a kind of range extender device but I'm not sure yet of the finer details on doing this. There is a company in Liverpool that produced h2 based generators for env200 (which is a gen1 leaf in van form essentially) so it can be done but as to the details im not sure on that yet.

looked at ONE+ system. I like it but its all 18v so need 2 minimum for my ebikes which is a bit more faff than id like.