Norwegian 60kwh Powerwall SI8.0 REC BMS Leaf cells

Hi all,

I've been reading alot of the threads and thought it was about time to post about my project, and get some tips/help for my build.
Its based on 3 complete Nissan Leaf batteries + 3 modules, giving me 147 modules in a 14S42P setup. I will be using REC BMS and Sunny Island 8.0 battery inverter since i have a quite large solar system (22.8kwP BIPV) This will likely grow a little aswell, as i have access to very cheap solar (I sell PV through my own company in Norway)

I have seen 2ways of connecting up the nissan leaf batteries, but have not seen anybody using fuses between the series. As my battery has a very high capasity, i thought it would be good to include fuses between the seriesin the design. Any input on this would be much appreciated!





My plan for battery voltage is to keep between 3.65v and 4.05v. I would like to maximize battery life over capasity, thats the reason i'm building the battery so large.




For busbars, my plan is to use 4x15mm solid bar either copper or aluminium.

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Any preference between HRC fuses and MRBF fuses? The MRBF seems small and nice, but are actually close to twice the price. (i pay 5.5usd for 160a HRC fuses and 10.3 usd for the MRBF:
https://no.rs-online.com/web/p/centred-tag-fuses/0395872/
https://www.amazon.com/Blue-Sea-Sys...&keywords=MRBF+fuse+175&qid=1571793702&sr=8-2

Some pictures from battery picking:
Lifted the pack out from my trailer:



Open the cover:



Lifting the back half out of the encapsuling



Dismantling of busbar:





2 batteries stacked up

LOVE IT!

WOW!!!!

OMG ....quite an impressive powerwall. ^^

This is quite a setup I have a single car pack (using just 42 modules at 14s12p). I guess you are having a typo since you cannot end at an uneven number for your P or S without dismantling the modules?

Regardless the fuse - I doubt that you want the 160A fuse, since you won't be able to max out your inverter. I would suggest you go with some thick cables that can handle some peaks and reuse the main fuse of one of the batteries.

What I did with mine is re-use everything I could from the original pack. I ended up just buying cables from the bat and to the inverter - everything else was picked from the original battery. Here are some pictures of mine with a Battrium BMS (using Longmons since I originally planned going the 18650 route).








PS: Sorry for the mess

The inverter is rated to 9100w for 5 min and 11000w for 3 sec. What size of fuse would be recommended? @ 3.5v (lower than my plan) it will be 11000w/49v=225a. 250a fuse ok? MRBf fuses good stuff? Easy to get hold of 250a of those fuses. NH2 fuse holders are 4 times the price of MRBF holder.

sgrevskott said:

The inverter is rated to 9100w for 5 min and 11000w for 3 sec. What size of fuse would be recommended? @ 3.5v (lower than my plan) it will be 11000w/49v=225a. 250a fuse ok? MRBf fuses good stuff? Easy to get hold of 250a of those fuses. NH2 fuse holders are 4 times the price of MRBF holder.

Click to expand...

Presumably the inverter has it's own fusing. To me, I'd choosea fuse 'to protect the wire' from exceeding its max amps.

Yes, of course. On AC side, the inverter will be secured with a 40a fuse @230v. (max 9200w, and be limited to this in the software) Im thinking to protect the wires, but also internally in the batteries between the series, see the picture in first post.

For the inverter fuse, first I would look for the manufacturer's suggested value otherwise 250A HRC would be fine.
If you overloaded the inverter at either 9200W/5min or 11000W/3sec (225A), the time curve of the fuse would be longer & so would not result in nuisance blows.

Have you considered a 250A rated breaker with shunt trip? This way, your BMS can trigger shutdown if cells go out of spec.
If you can control the inverter & chargers via s/w you could get similar protection, but a shunt trip seems to combine the best features in one, eg:
- master system on/off switch (can use "fuse disconnect" units for this too)
- resettable (vs one time blow with fuse)
- can be tripped by BMS/controller

For the fuses in the battery, if you only have the one series string, then fuse = same as above. You might just use one in the middle of the pack?

I woudl go with an S3N ABB Breaker on that side rated at 200 or 250A. If you cant get that one look for S5N instead that is bigger.

Damn dude! I wanna drive to Norway and check out your powerwall! Looks really nice! Gj man!

Really want those Leaf packs aswell!

Which product are you selling in your company?

Anyways. I use the S5N ABB as Diy tech and repair on youtube.

https://www.schutzschalter-online.de/index.php
I bought my DC fuses from this german company! FH000 100A 3 pcs was like 4

I always wanted to take a look at your system so if you can be satisfied with ca. 1/4th of sgrevskott's Leaf pack maybe we could exchange a visit and discuss our systems

WuggyBuggy said:

Damn dude! I wanna drive to Norway and check out your powerwall! Looks really nice! Gj man!

Really want those Leaf packs aswell!

Which product are you selling in your company?

Anyways. I use the S5N ABB as Diy tech and repair on youtube.

https://www.schutzschalter-online.de/index.php
I bought my DC fuses from this german company! FH000 100A 3 pcs was like 4

Click to expand...

daromer said:

I woudl go with an S3N ABB Breaker on that side rated at 200 or 250A. If you cant get that one look for S5N instead that is bigger.

Click to expand...

Depending on location, the Schneider breakers with associated shunt trip can be found more easily than the ABB....

nice projec, in rec bms you just used 7 channel cells ?
i am about to start a project with 2 packs leaf but need to see what is the betther configuration any advice on these ?

Time to update the thread a bit. Things have been slow due to several other projects on the house. But set aside some time this week, an are now finished with dc side. 147 modules, bms leads, shunt, contactor, precharge, abb breaker and sma inverter wired. Went with 200a fuses, but do consider adding 1 Extra bridging between the series, would bring the fuses up to 400a(have spare copper busbar and fuses) All bus bars are 5x20mm copper, all dc wiring 95mm2.

Electrician will drop by tomorrow to connect AC side (due to regulations and insurance purposes)

Fire proofed the Battery by using rockwool in the shelfs, and buildt a crate of calsium silicate (5cm thickness). Expensive sheets atleast here in Norway. (300usd pr, i used 3 sheets!) Added some photos of the bipv from the house (40 panels south facing) and garage (24 north East and 12 south west + solar heaters)

Love your setup I have 45 panels for 12.85kw PV and I could do another 15 panels along the top of my fence around the back yard but the wife made me promise "NO MORE" at 45.... Do you have plans for more PV?

sgrevskott said:

Fire proofed the Battery by using rockwool in the shelfs, and buildt a crate of calsium silicate (5cm thickness). Expensive sheets atleast here in Norway. (300usd pr,

Click to expand...

Interesting as I have 10,000 18650 cells 'open to the air' under my house and have been considering what I might do. If I may ask...

What level of containment will this calsium silicate box provide and how did you determine it was a good approach? For example, will this contain a thermal runaway or is it more a slow/delay kind of containment.

FYI - I see Calcium Silicate on ebay - very expensive as you say and this is only 1" thick whereas 5cm = 2" - https://www.ebay.com/itm/313636977810