Dave's Build Thread


MASSIVE restock of EV Batteries at www.batteryhookup.com 5% coupon "POWERWALLS"

Daveyboy

Member
Joined
Aug 6, 2017
Messages
91
Hi everyone.

I've been meaning to do my build thread fora while now, but build progress is slow. But as they say, slow and steady wins the race :D

I learned about using 18650s for home storage probably a year ago now when I stumbled on one of Pete's videos. I watched them all and thought "Damn. I could do that!"

IF ONLY I COULD SOURCE BATTERIES!!!!

So I thought i'd give it a go trying to find these old dead laptop batteries. After a lot of calling around, I found a few sources that could provide a few dozen packs per month for free. It got me started.
After a few monthsI had a few lucky wins of a hundred or so packs, and with a local powerwall enthusiast selling me some of hispacks, I soon had enough for my planned build.

Planned build:
14s80p,
>1700mah per cell
48v 4000w MPP off grid inverter
8x solar panels (250w)

It will be installed in and on my Garage. Its an odd shape garage. Double length, not double width. Really impracticable for cars, but great for sticking solar on the roof. I can fit 8 panels on one side and its almost perfectly south facing and about 40 degrees, which is pretty good for UK.

My house is grid connected. Electricity and Gas. I mainly want to do this because of my bitter disappointment in the lack of drive of government to clean up our power generation, coupled with the fact that the landfilling of these batteries is nothing short of complete tragedy.
Anyway,I've got gas heating as well as electric heating in a loft conversion. Water is heated by gas with option to be electrically heated.
I really want to take selected circuits in the house and have the option to select solar/battery instead of mains.
And depending on how much solar power i have I want the option to use excess power to heat the water.
No plans for solar heating, or solar powering the range oven or the one electric shower.

But if this all works, I will be looking to install more panels on the roof of the house.

I started my journey withthe battery though. Using only 3 opus testers. Like I said. Slow and steady.
I want something with easy maintenance. Single 80 cell packs look like a pain to work on when something needs fixing. I'd rather work on a single 20 cell pack. So I chose that as my form factor.
I wanted something pretty secure to the wall and didn't want to just sit them on a shelf, so I drew up a bracket and had 56 of them printed. It took 3 prototypes to get it right, but they are strong and I really like the way it looks.

Keith sorted me out with some white sleeves to give it a unique look. Well worth it!

I've decided to go tab welding route instead of soldering. I have done one test pack. It's not as easy as I thought it would be.

So as of right now, I decided to weed out the <2000mah cells. Only because I'm confident I can get enough packs to be picky and I've noticed after a 3 month sitting test, its the <2000mah cells that drop voltage the most. I personally think they will be the problematic cells in the future. So out the came. Its left me with only 14s60p though. Thats ok. Slow and steady.

I got my panels yesterday. (Thats what inspired me to do my build thread).
I'll be installing them myself once I've got the mounting hardware for a pantile roof.
I'm yet to order an inverter.
I think the (industry standard?!!) MPP solar 48v 4kva or 5kvawill be perfect.
Need to find an electrician that would be know what i'm trying to achieve here though and make sure its all wired up safely.

I'll update when there's something worthy of an update, but I am going to be taking my time with this. Most of my spare time is actually allocated to decorating my house. It was quite the project house when we bought it. But I hope to get this battery operational over the summer.

Oh. How about some pics...

image_cwhthz.jpg
The intended target - my garage

image_odmwgi.jpg
Cells that passed the tests

image_rdpiti.jpg
My Design of a 20 cell pack wall mount

image_yyqoei.jpg
Wall mount printed

image_kzzrcw.jpg
First trial of welding fuses

image_tnombd.jpg
Packs mounted to wall (and I love how it looks :D )

Let me know if you have questions etc, I know this intro doesn't have much detail in it.
Cheers
Dave
 

Sonic01

Member
Joined
Sep 19, 2017
Messages
125
ah i meant to ask you about those cool little holders you had for the packs! i might adjust that STL for 40p if you dont mind :) credit you you of course.

how are you printing them?
 

Daveyboy

Member
Joined
Aug 6, 2017
Messages
91
Sonic01 said:
ah i meant to ask you about those cool little holders you had for the packs! i might adjust that STL for 40p if you dont mind :) credit you you of course.

how are you printing them?

Go for it!
I paid a local print shop to do mine. I've got too much on right now to spare time setting up a 3d printer. :rolleyes:
The only thing i'd say is make sure you print them on their side such that the grain is from top to bottom when they are on the wall and not grain left to right. I learned this the hard way as it isn't strong and WILL break along the grain of the print if sufficient force is applied. Mine snapped when taking a pack out, as the holder needs to flex a little.
I had mine printed in PLAat 25% infill. Plenty strong now. Would def hold your 40p packs.
And if I was to print them again, I would recess the screw holes a little deeper to allow screws with a thicker head to sit further into the holder.
 

Daveyboy

Member
Joined
Aug 6, 2017
Messages
91
UPDATE: Just ordered my inverter. All of a sudden, this is getting real!!!
 

Daveyboy

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Joined
Aug 6, 2017
Messages
91
zag2me said:
What are you doing for bus bars?

Nickel strips.

I've got a lot of 8mm x 0.1mm nickel which should be good for 4 or 5 amps. So my plan is to run 4 strips per 20 pack, so 5 cells per strip. Should be ok for 1 amp per cell, even though I don't plan to go anywhere near this high.
Now due to my 20 pack style and that there are currently 3 packs in parallel for 60p, I will run the nickel busbar above and below the pack to I can join the pack below to the string. It will just be a plate with a hole in it. Probably made from copper with the nickel strips soldered to it. Or brazed if required. I plan to work out the method within the next few weeks.
 

Daveyboy

Member
Joined
Aug 6, 2017
Messages
91
I've made some progress recently. I've completed the Pack connection for the first row. So that's 14S20P that can be used. Honestly, I'm regretting the 20 cell pack strategy. Each pack took an hour to finish. Its a combination of spot welding and soldering. I presume I could have done an 80 cell pack in about the same time. Hey ho. I still like the way it looks.
now have aVoltacon 4048MS, so basically a pip4048MS. Only went with that because I got it cheaper than the pip on an auction.
I've ordered:
-35mm2 battery cable,
-lugs,
-crimp tool,
-stainless nuts and bolts for terminal connections,
-40A DC breaker for the solar, 125A DC Breaker for battery connection,
-DIN rails,
-2x 15mm x 3mm copper bar as my main busbars left and right side of the wall.
-MC4 Connectors,
-Cable trunking
And got 6mm2 solar able from sonic (cheers dude)

I've also mounted a monitor next to the inverter ready for a pc.I'm looking at options for that. Will probably get a second hand NUC as they are pretty small and low powered.
Also yet to order BMS.


image_xkkcsb.jpg

image_ydtxdn.jpg
 

Korishan

Moderator
Joined
Jan 7, 2017
Messages
6,879
Looking good. Nice list of parts on order.
Altho, 1 thing to state, Stainless Steel is probably not the best. However, if you are only using that to clamp two pieces of copper together (or tinned copper), then that's fine. Just don't try to rely on the SS to carry the current ;)

Waiting for the next phase of the build :)
 

Daveyboy

Member
Joined
Aug 6, 2017
Messages
91
Korishan said:
Just don't try to rely on the SS to carry the current ;)
Good point. I did consider this andbelieve I don't need the bolt to carry current. The cable should be good for 200A and I'll only ever be putting a max100A continuous through it. But sizing the terminal for 200A just requires that the contact area with my busbar should exceed 35mm2, which it had better do! I'll measure themwhen they arrive.

Korishan said:
Waiting for the next phase of the build :)
Me too!!!


On a separate note - I'm off to Goodwood Festival of speed tomorrow, purely to get my eyes on the Tesla Model 3. First time in Europe I hear. So exciting!
 

Daveyboy

Member
Joined
Aug 6, 2017
Messages
91
The 35mm2 crimp lugs finally arrived today, so I was able to terminate the battery cables. Rigged it up and switched it on. Apart from the one teething issue with the inverter being in parallel mode, which I don't want, its all looking good. WatchPower sees the inverter and reports status ok.
So with that milestone done, I have ordered the BMS. It took many hours of deliberating, but I've opted for the Batrium 14x longmon starter kit (no shunt). I also ordered a spare longmon, you know...just in case I break one.

I plan to just run the garage off grid for a while before getting electrician in to wire up the house for it. It will give me an opportunity to feel out the battery and make sure its performing well enough for the larger load.
 
Joined
Mar 7, 2018
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With the 4048MS would that be enough to run the house ? The fridge compressor is the main issue in my mind, not on it's own more of the case when you have the kettle on (2kW) a couple of lights, the computer, etc. so you have an extra 400W, at 2.4kW the inverter is nice and happy and then it get s a kick in the nuts with the fridge switching on..

I tried out running the saw on a 2.2kVA UPS as it has a soft start and it started up, then freaked and overloaded and switched off out because of the reactive power from the motor. That was without trying to cut anything, hence my question about fridge compressors and a like with inverters.

What is the largest or most challenging load any powerwallers are running on which units ? Appart from the large 10kVA units :)

Did you get to see the M3 ?
 

Daveyboy

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Joined
Aug 6, 2017
Messages
91
completelycharged said:
With the 4048MS would that be enough to run the house ? The fridge compressor is the main issue in my mind, not on it's own more of the case when you have the kettle on (2kW) a couple of lights, the computer, etc. so you have an extra 400W, at 2.4kW the inverter is nice and happy and then it get s a kick in the nuts with the fridge switching on..

I tried out running the saw on a 2.2kVA UPS as it has a soft start and it started up, then freaked and overloaded and switched off out because of the reactive power from the motor. That was without trying to cut anything, hence my question about fridge compressors and a like with inverters.

What is the largest or most challenging load any powerwallers are running on which units ? Appart from the large 10kVA units :)

Did you get to see the M3 ?

It sure won't be big enough to run the whole house. I've got an electric range cooker that could potentially call for 7kw of power will all ovens switched on simultaneously and I have a 9.5kw electric shower. So those items are certainly not within the scope of the 4048MS. But everything else.... my honest answer is I don't know if 4kw is enough for peak loads. I've certainly never see my power meter go over 4kw, but it might be more frequent than I realise. So my plan has always been to have switches for each of the house circuits so I can manually change from Genset to Mains. That will give me the freedom to play power manager :D

I've worked with motors before, and typical starting current is between 6 and 8 times running current. My kitchen fridge frezer is taking about 100W when runningso I don't epect it to pull more than 1000w even when starting from warm. I do have a fridge freezer in the garage, which I can run some tests on. Really need to get me a plug-in watt meter!

The pip inverters can also give 2x surge current for a few seconds. SoI could be nearthe rated 4000w and switch on the hoover and exceed the 4000w for a couple of seconds and it shouldn't cut out. But again, I'll be testing all this, as therory and practice often don't agree.

Yes, I got to see the model 3. Sat in the driver seat, and sat in the back. I'm in love and I want one :D
here's a pic I took. You like Teslas?

image_rsonuc.jpg



So more playing today. I hooked up 2 of the panels and stuck them in the garden, resting against various tables and kids toys!
It works fine and was putting charge into the batteries. I'l keep an eye on voltages until the bms arrives.
I then really wanted to see some AC output but I don't want to unwire the garage consumer unit, so I pulled the breaker out and connected the inverter to the circuit using a suicide cable. Its just testing so....
But yes, it all works. Runs the fridge fine so far. Now i'm looking at VPN options so I can monitor it from my sofa :D
So far, its great to see my house baseload drop a lot already. It appears that the garage takes quite a bit of juice!

image_jshzqo.jpgimage_aewzbi.jpg
 

Daveyboy

Member
Joined
Aug 6, 2017
Messages
91
I left the garage to run over night. Voltage steadily dropped down to 48V and at 9am, sun came up and started charging. Such a good feeling!! Now want to see how quickly the batteries charge to full.
 

hbpowerwall

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Oct 7, 2016
Messages
2,068
Black inverter looks good!
 
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