THE LI-ion combat!!!
- Thread starter Doctorbass
- Start date
Doctorbass
100 GW
You want some paradox?
here it is!
----Doc production copyright---- 8)
here it is!
----Doc production copyright---- 8)
magudaman
10 kW
I would have to say that would be a amped up fight 
but A123 would crush that 18650 as it can handle more current making each hit count and could out out last it in stamina with over 1000 cycles. Hands down A123, now if it wasn't so expensive to sign over A123 to all my projects :-(
but A123 would crush that 18650 as it can handle more current making each hit count and could out out last it in stamina with over 1000 cycles. Hands down A123, now if it wasn't so expensive to sign over A123 to all my projects :-(
markcycle
10 kW
There no fight A123 win with the first punch BUT
A123 are the pipe dream of tomorrow
But I can get 18650's cells by the millions today create properly build packs and use them for about 3 to 5 years
My 120 cell 37 volt 27AH pack was put together for 700.00 pulls 35 amps if I want to with no problem. will last 500 cycles plus I hope (so far so Good) I charge it real slow overnight. But the most important thing is that I'm not carrying 40 pounds of lead have 50 mile range go 23 to 25 mph. The pack has less than a 2 volt sag at 20 amps and it didn't break the bank.
Let me know what a A123 pack with those rating will cost, not stripped from defective pack cells but real cost. When those cells come even close to 18650 cells in price per Amp hour then they are real and not vaporware.
The key to safety is a slow charge and not to overcharge, overheat or undervolt the battery. Not hard parameters to maintain with a good BMS and proper maintenance.
A123 are the pipe dream of tomorrow
But I can get 18650's cells by the millions today create properly build packs and use them for about 3 to 5 years
My 120 cell 37 volt 27AH pack was put together for 700.00 pulls 35 amps if I want to with no problem. will last 500 cycles plus I hope (so far so Good) I charge it real slow overnight. But the most important thing is that I'm not carrying 40 pounds of lead have 50 mile range go 23 to 25 mph. The pack has less than a 2 volt sag at 20 amps and it didn't break the bank.
Let me know what a A123 pack with those rating will cost, not stripped from defective pack cells but real cost. When those cells come even close to 18650 cells in price per Amp hour then they are real and not vaporware.
The key to safety is a slow charge and not to overcharge, overheat or undervolt the battery. Not hard parameters to maintain with a good BMS and proper maintenance.
xyster
10 MW
The A123 costs more to train than the fight purse is worth! Until that changes, for 1-3C battery packs the A123's is a pyrrhic victory.
markcycle
10 kW
Got a one time deal that will never be repeated
patrick_mahoney
100 W
efreak said:
They have risen by about $0.90 from $3.69 per 3.7V 2Ah 18650 cell to $4.59 (quantities of more than 100 cells pricing at all-battery.com). About 25% in about 12 months. But the capacity has gone up by 10% as well - you can't find 2Ah cells any more and now it's 2.2Ah, 2.4Ah and 2.6Ah.
There's a screenshot of the all-battery page from a year ago in this thread:
http://endless-sphere.com/forums/viewtopic.php?t=826
and then compare against today's page:
http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=1643
I put my 96 cell 44V 17Ah 18650 pack together for about $500 (including BMS, charger, bag, shipping, everything)... but I had to design and solder everything.
And there are still deals to be had if one is patient. They had a sale at all-battery.com with a 20% off coupon and free shipping over Memorial day weekend just a couple of months ago that took their "quantity of >100" price for 18650 3.6V 2200mAh tabbed cells to $3.67.
xyster
10 MW
I did like Patrick_Mahoney but with 300 of those same 2.2ah li-ion batteries, no traditional BMS, and 20 single-cell chargers. Total price for the 33ah 80v pack including the chargers was about $1200.
Patrick, could you give some details of what sort of charger/BMS did you use? This is looks like the biggest roadblock now for DIY ebike lithium batteries.
Anybody have any information on cells that have BMS built in? Like those:
http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=461
PCB there protects against undervoltage, overvoltage and overcurrent. But then I still have to have smart charger right? If I keep a cell at 4.2 volts indefinetly it will still explode?
Or maybe not. End charging current is specified as 0.01 mA and that's 0.001% of normal charging current. If that's correct, I can't see how that would heat/damage the cell. But on the other hand, it can't be right. Normal charge should be terminated when current falls to 10% of initial current, or in some other chargers 100 mA per cell. But is this absolutely necessary?
Another option would be to charge at say 4.0V instead of 4.2V. I've read
that this way batteries get charged to 80% of capacity, last twice as many cycles, and maybe end-of-charge checking would not be required?
Anybody have any information on cells that have BMS built in? Like those:
http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=461
PCB there protects against undervoltage, overvoltage and overcurrent. But then I still have to have smart charger right? If I keep a cell at 4.2 volts indefinetly it will still explode?
Or maybe not. End charging current is specified as 0.01 mA and that's 0.001% of normal charging current. If that's correct, I can't see how that would heat/damage the cell. But on the other hand, it can't be right. Normal charge should be terminated when current falls to 10% of initial current, or in some other chargers 100 mA per cell. But is this absolutely necessary?
Another option would be to charge at say 4.0V instead of 4.2V. I've read
that this way batteries get charged to 80% of capacity, last twice as many cycles, and maybe end-of-charge checking would not be required?
xyster
10 MW
tomv said:
The cells aren't at risk of exploding until charged beyond 4.5v. If left at 4.2v, li-ion/lipoly capacity degrades much faster.
tomv said:
This is what I do. I have enough capacity that I can charge to 4.0v per cell and still have 20 usable amp-hours on tap (between the 80%-full 4.0v mark, and the 3.70-3.75v 20% full mark). By using single cell chargers, I can balance the cells with every charge to whatever point I like. If I'm planning a long ride, I'll charge each 15-cell subpack to 4.15v. The other advantage of single cell chargers is the virtual impossibility of overcharge. The chargers can't charge beyond 4.20 volts because that's the only voltage they charge at. The disadvantage, of course, is having so many chargers to plug and unplug each time. But using blocks of Anderson connectors effectively reduces the number of plugs to deal with.
Similar threads
