Circuit Breaker and Shunt Trip

Thanks to Rohan Wilschefski’s advice I found a second hand Merlin Gerin NS160 N circuit breaker from eBay. I then found a compatible 48V 30w shunt trip. This will allow the Batrium BMS to disconnect the Battery from the inverter in case of emergency such as Low Cell Voltage, High Cell Voltage etc.

Merlin Gerin NS160N

Shown here with 70mm sq cable lug

The shunt trip arrived today from the USA – even in the middle of the Corona Virus outbreak, international shipping is still quick!

fitted it into the circuit breaker and tested it. Everything works as it should.

Bus Bars

What a pain in the arse. I started by cutting 5 lengths of copper to around 41cm and filing the ends smooth. I then used the OEM busbars to mark the first and second hole positions. I then drilled out the holes with an 8mm drill bit. I repeated this over and over until I had a bus bar with 12 holes.

The to right hand side top bus bars will need to be slightly different to the rest due to the upside down top battery.
All 14S

Assembling the Lithium Tower of Power

Its time to assemble the Lithium Tower of Power!

I purchased 8x 1.2m x 6mm galvanized threaded rods from Bunnings at a cost of $3.77 each. I used some loctite on the end of the thread and screwed each of them into the mounting base. I hope its enough to hold when I tighten down the modules from the top with a nut.

I then stacked the modules. I will wait for the loctite to fully set before tightening down with nuts.

The Spacers

I realised the other day when stacking the modules that I didn’t have enough spacers. The spacers are required and sit at the front and back of each module. A client of mine – Scott from www.allwaterjetcutting.com.au said he could easily laser cut them if I provided him with a drawing. I photocopied two of the spacers and then set about measuring them with a vernier and documenting the dimensions.

Scott quickly provided a CAD version…

A couple of corrections and we ended up with a final drawing.

Today the spacers arrived and they are perfect.

The CAD Drawing

Here is the CAD drawing used to make the spacers. If anyone needs them cut, I can recommend Scott from www.allwaterjetcutting.com.au.

Video of the Spacers

I have recorded a quick video detailing the finished spacers

Fitting the Spacers to the Lithium Tower of Power

Bits n Pieces

One of the most time consuming parts of this project is researching and sourcing the required parts and tools. Hours of reading forums and watching videos! Making the wrong choice can cost $$ and time so I agonize over the choices. I decided to go big on the battery cable. Welding cable appears to be the cable of choice due to its extreme flexibility. The choices are 35mm sq. 50mm sq. or 70mm sq. I chose 70mm because I’m getting the 5kw inverter and may end up with another later on meaning massive amps. My next mission was to source 70-8 Bell Mouth cable lugs. On eBay these were selling for $60 each! I ended up sourcing from TLE electrical wholesalers.

The Busbars

I was able to locally source a 4m long 25mm wide 1/8” thick (3.17mm) piece of copper bar.

Nickel plating

I saw some videos on tinning copper and after asking about this in the second life storage forums I learnt about Nickel plating. I decided to have a go at making the Nickel solution and experimenting on small pieces of copper to see how it would work. I purchased a 100x100x2mm piece of pure Nickel from eBay and then created the solution using 2L of Coles brand vinegar and some SAXA table salt. I set my power supply to 5v and limited the current to 1amp and let it run for around 48 hours.

More Cells Arrived

Back in early January 2020 I paid for 10 Nissan Leaf cells from a seller in China. They were paid for on the 2nd Jan and shipped on the 8th January. Today, 3rd March 2020 they finally arrived. 10 modules bringing my total modules to 42 which will allow me to build a 2S6P pack with > ~14kwh capacity.

All cells arrived at ~ 6.4v or 3.2v per cell. Let the testing begin.