The Outhouse Powerwall


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

not2bme

Member
Joined
Oct 16, 2017
Messages
497
Thought I'd post my build even though it won't really be ready until this summer. But I figured I'd start posting my progress! Can't remember how I got started, but it was around mid-Oct and looking at Tesla powerwalls, and probably stumbled on hbpowerwall's youtube. My plan is to build an outhouse in the back and house all the batteries in it. My solar panels will be a ground mount but is basically laying on the lawn at the moment. By the summer I'll have the outhouse built and the solar panels mounted.

So far I've managed to build my first 7s60p pack. Here's what I'm using:

  • PIP2424LV from MPPSolar ($550)
  • 9x 245W used solar panels($50/ea)
  • 420 cells, roughly 3kwh of LG batteries mostly from alarmhookup to speed up the process (roughly $550)
  • Celllog 8M for BMS ($20)
  • 1S balancers (2x) to manually balance as needed. ($40)
My cells are arranged at 60p just because of the batteries I had at hand, but it seems the right way. I followed owitte's build in a way that I like to be able to increase the pack size as necessary by just adding more cells. But then I wanted a denser configuration, so instead I choose a rack style. I also brought both ends of the terminals up front, bringing one of the bus bars on the rear to the front. This allows me to front load the packs and not worry about anything in the back. Right now there's only one layer, but I am imagining at least two or three layers, with a copper bus bar running down each pack, so basically turning a 60p configuration into a 120p or 180p if need be.

Each layer of 7s60p is roughly 3kwh so I am planning to get to at least 12kwh by summer. My progress with the PIP2424LV so far is pretty abysmal. Partly to blame is the poor mounting of the solar panels, or lack thereof. Then there's the winter hours where I spend at least 18 hours on batteries. Combine that with that the PIP takes roughly 1200w to run, giving me roughly 2kwh of power out of my pack. So out of the 3kwh pack, I can barely run 100w continuously. I started with 6x panels, and I just threw another 3x panels this weekend, and it helped extend the running time during early and late day. Extending to 6kwh I expect to have most of these issues to go away as it allows me to be able to buffer at least one day of crappy weather.

I'm using a Celllog 8M as the BMS, and I'm planning on hooking it up to the ABB shunt trip breaker maybe next weekend. I calibrated it to match my multimeter and it seems to do a good job. I'm also using 2 1S balancers like owittes but I only hook up when I need to. Early on Pack 3 had an issue and it kept going out of sync, so the balancer seemed to balance it out pretty well. It balances at around 300ma at 100mv difference and increases with more differential. Then later I found the issue, I forgot to solder two fuses to the bar, so the pack was short 4 cells. After that it was fine.

image_quepjw.jpg


image_wcxwma.jpg


image_idxrkc.jpg
 

Korishan

Moderator
Joined
Jan 7, 2017
Messages
6,835
@wim: they are a short particle board shelf. I almost missed it, myself. You can see it barely on the left side under the mouse (black dome looking thing)

I agree with Stefaan and HBPowerwall (and anyone else who likes Stefaan's post); something falling in between the packs could get ugly. But, this is just a test rig and they won't be staying there. Perhaps the protective cover (maybe a piece of cardboard even) was taken off for the sake of the pictures :)

Nice clean look overall. I'd like to see how you build your outhouse (at first, I was wondering why you were putting a powerwall in an outside bathroom :p but that's what's you're calling the building the packs and hardware will go into)
 

not2bme

Member
Joined
Oct 16, 2017
Messages
497
Thanks all! Hehe it does look like it's floating! Yes there is a shelf there! I had to get it off the workspace since I couldn't do anything else if I kept it on the table. And yes there isn't anything on those containers other than pens and non conductive stuff! I removed those containers on the right already :) Anything falling down the middle will be unfortunate but not too critical, just 4x5 holders and pens. I use 2x1 spacers up front to protect the lugs from having anything cross connect or short accidentally by either bumping or touching anything conductive. Saw hbpowerwall's youtube on when he dropped something on them causing the short ;) On the right of the batteries is the PIP and a whole bunch of bussman fuses/disconnects/breakers but too ugly to look at since it's just a test bed.

Yes that's the plan for the summer to build the 'outhouse' :)
 

Wattsup

Member
Joined
Feb 19, 2017
Messages
512
Nice looking build so far ;)
 

wim

Member
Joined
Apr 6, 2017
Messages
556
Korishan said:
@wim: they are a short particle board shelf. I almost missed it, myself. You can see it barely on the left side under the mouse (black dome looking thing)

are you sure ?? Looks like a kind of anti gravity device to me... :D
 

not2bme

Member
Joined
Oct 16, 2017
Messages
497
Finally had some luck with batteries this weekend! Hopefully enough to build the next 3kwh! :angel:

Got a whole bunch of Lenovos. A majority of them are stuffed with Sanyo cells. I know they've been reported to be heaters, but has anyone been successful in using them in any large capacity?

These are reported to be UR18650FM and in the cell database to be 2600mah. I'm getting about 2400-2600mah on them.


image_pkasgg.jpg

image_psqovx.jpg
 

not2bme

Member
Joined
Oct 16, 2017
Messages
497
Completed my first month on solar! Did a data dump from the Watchpower software into excel. Generated a total of 89kw!! Got to thank this forum for all the ideas that I've been able to get!

Power output wasn't great but I didn't run it on full power because it isn't rigged up properly yet. I didn't have my kill-a-watt meters running on the right dates so I can't measure the utility usage so my rough figures would be about 30kw would have been used by the PIP and another 5kw to other losses. So I can only estimate that would make me generate around roughly 50kw of power! At around .18 per kw that would be a whopping $9 saved! Still awesome!

This was a really fun month! I got to say to everyone else starting out that it's definitely a waiting game to source all your materials. I don't think I was as aggressive in hunting for batteries as Pete but I must have asked everyone I know about it. In the end I was finally able to score another find last weekend to last me a while! Solar panels were the same, I scoured craigslist every day until I found them. In a way I'm glad that it was a 24v system since the packs are only 7s and I was able to build it quickly by cheating a little and bought it from alarmhookup when he had those lg batts. If it was 48v I wouldn't have jumped the gun, but I'm glad I did otherwise I would not have a functioning system today and only started to build my packs. I'm too impatient for that.

I did find that properly sizing your battery to solar panels to be quite crucial. I have way too many panels that I'm already fully charged before noon even though the packs are fully drained. I can't wait for the next packs to be done.

Going to be the last update for a while cause going to be traveling soon so this project will be on hold for at least a month.

Sitting above my current packs are the next 3kw packs all salvaged and waiting to be tested! :D

image_mtbalj.jpg
 

not2bme

Member
Joined
Oct 16, 2017
Messages
497
Been a while since I updated! Over the winter I had been busy sketching up my designs and waiting until the weather was cooperating. Unfortunately it rained every possible weekend and I didn't have any chance for progress until this month when I blew up my PIP. My design was to build something that was standalone and somewhat away from the house. I tried building it with the least amount of waste possible.


image_qqvwyf.jpg


I started on the foundation about two months ago using cinder blocks. This took me a while because first I thought about pouring concrete (even bought some bags of concrete mix) but ended up going the cinder block route. Ended up much easier and less messy.


image_lhlyec.jpg


Once that was done the rest just fell into place (I love drawing it up in CAD, it took most of the guesswork out!). Being a little guy, it did take me a while to frame it all up! :D


image_diroik.jpg



I tarped the entire frame as a moisture barrier and insulated the space with insulation. The weather during winters here drop below freezing often so this outhouse is going to keep warm and stay that way!


image_jwaqlv.jpg


The siding was made using imported european lumber and fine plywood (aka. shipping crates). Other than that the only thing I really bought from Home Depot were the 2x3s, 4x4 for the base and a bag of insulation material.


image_jtodlh.jpg
 

not2bme

Member
Joined
Oct 16, 2017
Messages
497
Thanks! I'm in New Jersey in the US.

Finished the whole thing last weekend so now it's all the wiring inside!


image_uxwsus.jpg


Below is my rack design using 1/2" EMT conduit. It's simple and allows adequate airflow while being cost effective! It really adds up every time I go to home depot! The bill of materials so far for this shed is a little over $200 even with using recycled stuff.

There's 6 slots allowing a max of 20kwh storage. I'm sure I can fit two more rows to get to 26kwh but with my current usage it's probably not necessary.


image_dkgdpn.jpg



image_bouqxj.jpg
 

not2bme

Member
Joined
Oct 16, 2017
Messages
497
Hehe for a while I did look around for one! But in the end I think building it was probably better! It's going to be the most insulated outhouse warmed by batteries! :D
 

not2bme

Member
Joined
Oct 16, 2017
Messages
497
Small update, I've been using this chinese BMS for a couple months now and although my packs seem to stay together fine without any BMS. Well this isn't more of a BMS than just an active balancer. So for the few months I had it working, even though I just knew it 'worked', I wanted to be able to log the data. It has a serial display board and I contacted the seller on aliexpress and she was kind enough to send enough details about the display for me to work with. It uses a serial TTL and I finally had the chance a couple nights ago to learn enough python to cobble together a script that I could run through telegraf and send the data to influxdb and display through grafana.

So for the first time, I can finally see it in action. I first put a cell that was over voltage by .2V, then another under .2V. In both cases it balanced it within 1-2 hours.


image_jwbtee.jpg

image_hplojg.jpg


I doubt it can balance fast if the packs were way out of balance, which means one cell isn't too healthy. What I really needed it to do was warn me if any cell went over or under voltage. Now I can monitor each cell group individually.
 

jesusangel

Member
Joined
May 28, 2017
Messages
277
not2bme said:
What I really needed it to do was warn me if any cell went over or under voltage. Now I can monitor each cell group individually.

Grafana hasalerts, it can alert you by mail, telegram and other systems if you have overvoltage or undervoltage on any cell.

Regards


image_lbwhwh.jpg
 

not2bme

Member
Joined
Oct 16, 2017
Messages
497

jesusangel

Member
Joined
May 28, 2017
Messages
277
not2bme said:
Thank you I will try that! Will it work even if the dashboard isn't running? I sometimes don't have the browser open on it.

Yes, for sure on Raspberry Pi and Linux system I've tried, I supose when you installs grafana on any system it configures some process to evaluate alerts, you don't have to be navigating the web, of course the PC or device in wich grafana is installed must be ON and receiving data, it also alerts you is no data is received for the evaluation period.

Regards
 

Korishan

Moderator
Joined
Jan 7, 2017
Messages
6,835
Interesting BMS.

Can you tell me the numbers on these two ICs? Curious as to what brains they are using for the logic


image_fgdsfq.jpg
 
Top