NiFe battery pro's and con's
Cpfarr
Registered Users Posts: 19 ✭✭
Hi all, hope I'm not repeating a thread already here...
A little background; I've got a bank of FLA's and I've just had to remove one of my three strings due to five batteries going bad. I'm anticipating the need to replace the remainder of the batteries next year and I'm researching my options for battery types.
There seems to be a lot of half truths and salesmanship on the web pertaining to these batteries so... I'm trying to get some real world background from those of you who have experience with NiFe batteries. What are the pro's and con's of these batteries?
Thanks, Chad
A little background; I've got a bank of FLA's and I've just had to remove one of my three strings due to five batteries going bad. I'm anticipating the need to replace the remainder of the batteries next year and I'm researching my options for battery types.
There seems to be a lot of half truths and salesmanship on the web pertaining to these batteries so... I'm trying to get some real world background from those of you who have experience with NiFe batteries. What are the pro's and con's of these batteries?
Thanks, Chad
Comments
Quite a few discussion on the forum about NiFe (and also LiFePo).
http://www.google.ca/search?hl=en-CA&source=hp&q=site%3Asolar-electric.com+NiFe&btnG=Google+Search&gbv=1
Pro, is that they don't care if they sit for weeks on end, running between 30% and 80% of charge, which would destroy lead/acid cells.
Cons: high resistance, lower efficiency 70% vs Pb/H2So4 $85%, awkward electrolyte changeout every 4-7 years (it gets "poisoned" from atmospheric Co2) Much less energy dense, figure 3-4x the bank size for the same useful amp hours (you have to add ~30% more ah for the NiFe because of the higher internal resistance) so your 600ah Pb bank become a 900ah NiFe bank. Very wide voltage range from 10% to 100%, it will require inverters that will work over the large range, and chargers that can be programmed to fit the NiFe Charge Profile. 46V - 68V in my system. thirsty batteries,
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Pros:
1. Batteries were "free"; salvaged from railroad "wig wags". ("Still perfectly fine!")
Cons:
1. Tremendous voltage variation between charged and discharged.
2. Minimal real capacity compared to what was expected.
3. Slimy electrolyte compared to acid. Oozes out of the top of cells. (Yuk!)
3. A zillion interconnects required to make up a decent bank.
4. An environmental DISASTER to try and dispose of. (What exactly do you do with 100 useless cells on an island?)
I was able to dispose of them properly thanks to the Coast Guard, but otherwise would have been stuck with a horrible mess to clean up.
I guess I'm saying I'd avoid them.........
with the addition of a weak acid the KOH electrolyte can be turned into a Potassium salt with appropriate cautions taken to keep it off your skin. http://www.newton.dep.anl.gov/askasci/chem03/chem03011.htm
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
Or the electrolyte (KOH) can be diluted and used as fertilizer and soil acidity reducer. That's my plan.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,