Haste wrote:Would the 20ah version fit in falcon ev bag?
48V20Ah battery pack dimensions...
First pack: [ 279 x 178 x 75 mm ]
Second pack: [ 279 x 165 x 75 mm ]
The latest available: [ 300 x 185 x 75 mm ]
The latest detail coming courtesy of Judy Liu [ email@example.com ] and, if accurate, means fitting into the Falcon EV bag would be a literal stretch. A little something to consider.
cwah wrote:Thanks for this good feedback neophyte.
So at 7kg, the 48V20AH battery top at 137wh/kg. That's not bad at all.
Do you do 100% depth of discharge frequently? And how many C do you use usually?
cwah wrote:Yeah, I'm also considering lipo, but they require at minima 15% margin (high voltage / low voltage) capacity.
So a 140wh/kg lipo is equivalent to a 119wh/kg battery. (140wh-15%).
A 160wh/kg lipo is a zippy compact, and 160wh-15% = 136wh/kg usable battery.
The zippy compact would be preferable if they were cheaper. But they are also 20% more expensive than the NMC.
That's why I'm still hesitating
cwah wrote:Yeah, but the BMS is on the NMC side.
Without BMC the NMC battery would have higher volumetric density. They're also cheaper.
I'm just wondering how that extra payment on the lipo worth it. They zippy compact haven't been tested by a members. Maybe it has very short cycle/calendar life.
neptronix wrote:scorpion.. i do doubt they're using bmsbattery's cells
If you ever read some NMC spec sheets... well, they vary widely in every way. There are the Dow Kokam, which will do thousands of cycles, and can come in lighter than RC Lipo with discharge rates that are halfway decent at 2-4C..
Then it goes all the way down to.. worse than RC Lipo in density.. under 1C discharge.. 500 cycles or lower.. and poor quality, even poor safety.
The cells BMSBattery are using are at the lower end of that spectrum.
neptronix wrote:scorpion: cool.. your area could use that kind of work. Maybe one day we'll make a battery or two here in the US..
cwah: We'll see how it goes over the long term. Stuff from BMSBattery ( and many vendors like them ) is hit / miss. No quality control before they ship it out.. you are the QC
Neophyte wrote:I have two kits currently.
An eZee and a BMC.
Both installed on a Giant platform.
http://www.giant-bicycles.com/en-ca/bik ... 786/49386/
My two NCM packs I switch from one bike to the other as needed. Until I buy two more packs which I'll do soon.
In use I fully drain the packs about 30 percent of the time [ distances approaching 200 km ]. Daily average is in the area of 30 Ah used. And I always recharge immediately upon arriving home and, again, there's never been a problem.
The longest the packs have remained unused following being fully recharged is three days. The CA voltage reading, thereafter, still at 53.8V. My rarely used eZee LiMn pack doesn't fair as well when left unused.
Pack seen here…
As for C rate?
I set the CA current limit to 20A to remain in line with the pack's continuous discharge spec...
[ Maximal Continuous Discharge Current: 20Amps. ]
Despite the maximal spec...
[ Maximal Discharge Current: 40Amps. ]
eZee kit controller [ 20A ]
BMC kit controller [ 25A]
48V and 20A at WOT under ideal riding conditions without pedalling...
eZee : 40 km/h
BMC : 48 km/h
Again, no issues with the packs. Having performed flawlessly. Well constructed complete with protective padding. The included chargers functioning 100 percent.
And no major issues with BMSBattery as a company nor with any of the staff.
Will definitely continue to give the company my custom.
And, hopefully, we'll soon be seeing on the market packs hosting some of these claimed anode/cathode, etc. advancements that will, supposedly, yield energy densities up to ten times what we're talking about herein.
You just never know!
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