Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
18Kwh - 12v off grid Powerwall
#1
Photo 
Hi all, 

Finally starting my journey into a DIY powerwall. This will be intended for off grid solar with fairly small loads from two 700w inverters. Panels are 14 x 190w 

This is a low cost build intended for maybe 5kwh per day use , giving a few days power on dark rainy days. I'm not going 48v or even 24v as I already have two high quality synergex inverters. All lights and pumps are 12v etc. so really no need to spend up as their are no huge loads.

Regulators are 30a MPPT epsolar units that I can program the output voltages to fit lithium ranges. I'll be running four of them, I have two already and know they work together well. 

Basically a standard high efficiency  fridge , lights and a 42" LCD TV, pump etc is all I'll be running.

It will be a 3s x 720p so all up 18 x 120cell packs. Housed in a half height server rack.  

I will be monitoring the pack voltages using a sitmon PacketFlux unit, which I can graph and calculate usages , state of charge etc, also each pack voltage, with App/Sms alerting through PRTG. I can also control relays based on heat and voltage etc. great product that I've used before. Cheap too. 

Finally tested cells all loaded into my first pack tonight. Waiting on my glass fuses to arrive and will hunt down some bus wire :Smile   Now the real labor begins :Sad hey it's a hobbby right ? 
hbpowerwall likes this post
Reply
#2
How come you went with 3s instead of 4s? That doesn't leave you with much run time
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at https://discord.gg/c7gJ5uA
(this chat is not directly affiliated with SecondLifeStorage; VALID email req'd)
Reply
#3
(11-27-2017, 01:05 PM)Korishan Wrote: How come you went with 3s instead of 4s? That doesn't leave you with much run time

I looked at discharge graphs on low draw per cell, max my cells will see is 300mA . If you check out the amount from 4.1 down to 3.5v on these loads it looks like I'll get more.  The drop off from 3.5 down is quicker. What do u think ? I'm still leaning on 3s but ..... I'm open to suggestionsSmile
Korishan likes this post
Reply
#4
i think you are correct jestronix. At such low current the 3s would work fine and 4s you will loose on top end.
Just make sure to reduce the voltage drop due to resistance as much as you can. Otherwise you will end up with cut off to early
Korishan likes this post
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
Reply
#5
Just did a cell count, make this 20kwh ! Found one of my laptop packed had shorted on a bad cell, it melted the nickel buswire, acted like a big fuse. Anyway I'll see you in 6650 solder joints later ! Oh man what am I in for Smile
Reply
#6
(12-01-2017, 03:25 AM)jestronix Wrote: Just did a cell count, make this 20kwh !  Found one of my laptop packed had shorted on a bad cell, it melted the nickel buswire, acted like a big fuse. Anyway I'll see you in 6650 solder joints later !  Oh man what am I in for Smile

I wonder how many soldering irons you'll go through? Good luck.
Reply
#7
I would guess 0.5 soldering iron max! Smile I have done 10000 points atleast with mine and its still on same bare copper tip Tongue
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
Reply
#8
[quote pid='20595' dateline='1512098759']
   

Picked up an 80w iron today, perfect temp for a quick solder that sticks and doesn't heat the cells up much at all.  Slowly presoldering the packs. I'm in a bit of a rhythm now, 12 cells a day slow as it might sound adds up pretty quick when it comes to then soldering the packs, sneaks up on you. I'm in no major rush to do all 26 packs, as soon as I build 3 packs I can hook the solar up for low load and charge testing Smile 
[/quote]
hbpowerwall and Korishan like this post
Reply
#9
I've backed down to 80p packs, one reason being the rigidity of the 100p packs is not the best, as in there is far more flex than the 80p. Second is the weight makes 100p heavier meaning my digits are putting more pressure in cells and fuse wire etc. third they fit in those HP holders Smile
Wattsup likes this post
Reply
#10
@jestronix: You don't need to post multiple threads for the same project. You could of asked your wiring question here as it directly pertains to your build. Makes it easier to follow your build Wink
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at https://discord.gg/c7gJ5uA
(this chat is not directly affiliated with SecondLifeStorage; VALID email req'd)
Reply


Who read this thread?
100 User(s) read this thread:
hbpowerwall (07-01-2018, 03:37 AM), daromer (12-21-2017, 11:57 AM), mike (08-14-2018, 02:53 PM), 18650Shrink (11-27-2017, 01:16 PM), goodnowm (01-03-2018, 03:05 PM), BigBen (09-20-2018, 12:49 AM), NiVa (12-04-2017, 10:10 PM), owitte (12-05-2017, 07:51 AM), Majorphill (11-27-2017, 01:35 PM), ruby2 (12-23-2017, 04:18 AM), Korishan (07-01-2018, 12:27 PM), A + A (07-01-2018, 11:19 AM), PAF (07-01-2018, 01:06 PM), Wattsup (12-23-2017, 09:45 AM), eeesOap (12-03-2017, 08:36 PM), Frnandu Martiński (12-05-2017, 11:09 AM), eAnic (12-18-2017, 03:20 PM), jdeadman (07-02-2018, 04:12 AM), 2146 (11-27-2017, 03:38 PM), wim (07-01-2018, 05:14 PM), wimpie007 (01-28-2018, 07:54 PM), typ49 (12-23-2017, 11:25 AM), rebelrider.mike (01-15-2018, 01:26 PM), watts-on (07-01-2018, 07:22 AM), jesusangel (07-01-2018, 05:42 AM), Hanssing (12-03-2017, 06:18 AM), IronSky (07-01-2018, 03:51 AM), emmsee (07-01-2018, 07:16 AM), Stefaan De Ridder (12-22-2017, 12:57 PM), Chiptosser (12-05-2017, 03:32 AM), tremors (12-06-2017, 05:28 PM), brafi (01-07-2018, 01:34 AM), Jan Pieter van Zijst (11-28-2017, 09:33 PM), Eric Koshinsky (12-20-2017, 06:29 PM), KaminoReal (01-07-2018, 08:17 PM), KtB (12-01-2017, 03:57 AM), al4sound (06-22-2018, 01:49 AM), Seedser (12-06-2017, 01:51 AM), paraskevas (01-04-2018, 10:24 AM), Mazlem (12-05-2017, 06:58 PM), iceisfun (12-04-2017, 04:50 AM), Geek (07-02-2018, 01:45 AM), harrispp (12-05-2017, 05:17 AM), electricJolt (01-02-2018, 07:09 PM), Rad (12-01-2017, 07:26 AM), Jon (07-01-2018, 11:31 AM), Ivo Staelens (12-04-2017, 06:58 PM), jamesk9 (12-22-2017, 12:27 PM), Olberg (11-27-2017, 07:27 PM), floydR (12-05-2017, 03:29 AM), mickduc (12-04-2017, 12:21 AM), Learjet (12-24-2017, 12:32 PM), DarkRaven (12-04-2017, 09:53 PM), GFPowerBatteryIT (12-05-2017, 07:57 PM), Grumplestiltskin (12-01-2017, 11:52 PM), Trino Mendoza (01-01-2018, 04:51 AM), Thomas Koorneef (12-21-2017, 01:51 PM), burtyb (12-06-2017, 01:25 AM), zag2me (11-28-2017, 12:47 PM), priba83 (01-06-2018, 04:32 PM), James_H (12-08-2017, 03:37 AM), Matthew Oliver (11-29-2017, 09:12 AM), ap103 (12-03-2017, 12:00 PM), howiegrapek (12-22-2017, 02:40 PM), dougm352 (12-07-2017, 01:15 PM), cristof (12-03-2017, 02:12 PM), Oderus420 (12-22-2017, 03:15 PM), accoelho (12-07-2017, 10:52 AM), neurocis (12-22-2017, 02:23 AM), okent (12-06-2017, 04:13 AM), Elecjim (11-27-2017, 06:48 PM), not2bme (12-04-2017, 10:16 PM), paz45 (12-22-2017, 12:31 PM), CarelHassink (06-20-2018, 08:55 PM), sedorikku (12-01-2017, 07:58 AM), Dave Adams (12-05-2017, 01:04 AM), jbesedic (12-01-2017, 04:25 PM), Pavel Razzorenov (12-22-2017, 04:52 PM), Spkerking (12-21-2017, 03:57 PM), PowerLio (12-02-2017, 09:23 AM), Monsterhobby (01-02-2018, 07:16 AM), Joey Carson (12-02-2017, 08:52 PM), modido (01-01-2018, 09:36 AM), David Mire (12-31-2017, 05:25 PM), Stramon (06-21-2018, 02:07 PM), joeblogs (11-27-2017, 03:23 PM), jestronix (06-22-2018, 10:25 AM), Russ Britt (12-24-2017, 06:25 PM), Mark Kennard (12-04-2017, 09:24 PM), lula (12-23-2017, 12:19 AM), Mrbananaguy (07-10-2018, 12:02 AM), BGrillo (11-29-2017, 01:49 AM), bigblue (12-03-2017, 03:52 PM), putter32 (12-24-2017, 10:11 AM), Ross Brown (12-05-2017, 04:24 AM), PowerWally (12-20-2017, 08:26 PM), kristianyonuel (11-27-2017, 01:30 PM), Klommer (12-03-2017, 03:05 PM), nonopp4 (12-03-2017, 09:34 PM), AldigityLGR (12-02-2017, 06:45 PM)

Forum Jump:


Users browsing this thread: 1 Guest(s)