Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Long times on 3,3V per cell in winter months
#1
There will be a long period in winter months, about three months, where my powerwall will have to stay at 3,3V per cell. Is that bad and should try to keep it in higher voltage?
Reply
#2
If they are LiFePO4's, that should be fine. But if they are the other chemistries, you might want to bump them to 3.7V for long term storage.
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 Discord Chat (channels: general, 3d-printing, linux&coding, 18650, humor, ...)
(this chat is not directly affiliated with SecondLifeStorage; VALID email req'd)
Reply
#3
No Lithium Ion. I think its better and either way no problem if i do so. There would not be much energy i can store in this time. Will see if everything is running. Thanks Korishan.
Reply
#4
3.3 Is not a problem on LiIon either.... Questions is just why to drain them that low Tongue
Maniac_Powerwall 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
I do not have enough panels or capacity untill now. But we will see how things go :-)
Reply
#6
For storage, a couple members of this forum actually recommend storing in the 3.3 to 3.4V range, myself included. https://secondlifestorage.com/showthread.php?tid=7441
Formerly known as Dallski
Reply
#7
Ok, always thought 3.7V-3.8V would be perfect.

Another question 3.3V would be equal to about what DOD? 90% or 80%? Does this depend on the used cell?
Also 4.0V would be what SOC?
Reply
#8
3.3V is maybe 3% State of Charge? It's very low. If you do store your battery at this voltage, make sure to disconnect any loads, especially if using a high-powered BMS. Even a 1 miliamp draw will eat more than 2 Amp Hours over the course of 3 months.
Formerly known as Dallski
Reply
#9
Problem storing that low is that you have no capacity left... = YOU MUST crosscheck the cells every other day. Because there is no headroom with capacity just slightest self discharge will drain them to dangerous voltages below 2.5-2.8v. Thats also one of the reasons you shouldnt store them long term unattended at that low voltage....

I dont recommend storing it like that for any period of time unattended. You save more grief going up above 3.6V. Of course once again with no load.
Geek 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


Who read this thread?
41 User(s) read this thread:
James-w (09-08-2019, 08:14 PM), ajw22 (09-08-2019, 10:30 PM), stevelectric (09-09-2019, 08:50 AM), Generic (09-11-2019, 04:05 AM), Scottietheyoung (09-10-2019, 10:21 AM), Wolf (09-09-2019, 10:57 AM), clupton (09-09-2019, 02:48 PM), chuckp (09-11-2019, 12:35 AM), Katarn_89 (09-12-2019, 03:43 AM), kevinjaye (09-08-2019, 06:26 PM), OffGridInTheCity (09-09-2019, 01:33 AM), Funkadelicious (09-13-2019, 06:28 PM), 3xtr3m3 (09-08-2019, 10:31 AM), Emiel (09-13-2019, 10:09 AM), juanjo57 (09-08-2019, 11:39 AM), 100kwh-hunter (09-09-2019, 06:09 AM), Lucan (09-10-2019, 09:06 PM), winny (09-09-2019, 09:35 AM), Maniac_Powerwall (Yesterday, 05:22 AM), Jim Jr. (09-09-2019, 12:47 AM), Riplash (09-11-2019, 02:14 AM), Bubba (09-09-2019, 10:29 AM), jesusangel (09-08-2019, 04:38 PM), The-J-Man (Yesterday, 11:29 AM), jdeadman (09-10-2019, 12:45 PM), PAF (09-09-2019, 07:28 AM), A + A (09-08-2019, 09:56 PM), Korishan (09-10-2019, 07:34 PM), Majorphill (09-11-2019, 01:53 AM), Sean (09-11-2019, 12:08 AM), Geek (09-12-2019, 12:57 AM), SWEwall (09-10-2019, 04:23 AM), Ibiza (09-10-2019, 06:18 AM), jonyjoe505 (09-09-2019, 03:26 AM), Dala (09-10-2019, 05:52 AM), gpn (09-11-2019, 01:56 AM), jm1 (09-09-2019, 12:14 AM), Oz18650 (09-12-2019, 08:52 PM), ChrisD5710 (09-10-2019, 11:34 AM), Ivo Staelens (09-08-2019, 04:23 PM), daromer (09-10-2019, 05:09 AM)

Forum Jump:


Users browsing this thread: 1 Guest(s)