jag said:
The two ways people posted using the DeWalt packs seem to be
1. Just harvest the cells, replace BMS
2. Use the complete toolpack with enclosure and everything.
Did anyone try:
3. Dissassemble toolpack, discard plastic enclosures, but keep BMS. Wire together into larger pack with a charging interface? Advantages for me would be:
+ Lighter weight and more compact. I'm planning to built a 2s2p from 4 28V toolpacks and put in a triangle framebag.
+ Can charge with a cable on bike instead of removing individual tool packs and putting in DeWalt charger
(How many connections does the DeWalt charger make to the pack? 2 or 3? )
+ Easy to occasionally check individual cell voltage manually to spot if DeWalt BMS appear to be failing.
(If the DeWalt BMS fails, but I spot it in time I can buy a separate BMS to replace it)
Experiences, observations or thoughts?
B.t.w. did anyone order from Toolking and ship to Canada? Any hickups?
The other place I can buy is from ebay seller "jeanclaudecayerent" in Ontario. Anyone has experiences with him? Looks like he has a power tools business.
Ok, I can be of some limited assistance here, I am about to do virtually the same set-up your describing with an Amped Bikes geared rear hub motor kit, but with 2s3p using six 28volt dewalt batteries in a triangle bag. I am also going to use kfong's interface boards as I have used with my dad's E-bike set-up which is a DD Amped Bikes rear hub motor kit. Dad's set-up is currently three 36volt dewalt batteries in parallel, and he has a fourth battery on the way. We have had good results with this set-up, but there have been several technicalities to work out along the way.
Are you using a kit that normally operates at 36volts? By running 2s 2p your true voltage should be 52.8 volts, so in my mind it makes a "sag resistant" 48volt set-up for years later when the batteries are operating at 80%. I am using a geared kit because I am wanting light weight over brute force, and hill climbing is 99% of what my hub motor will do, otherwise I will just be human powered, so I am wanting to keep the weight to a minimum.
I think you will find unless your doing around a 5 or less mile commute, that just four 28volt packs won't pack that much of a punch, depending on what your wanting.
If your wanting something pedal free for short distances, with a quick recharge time (you WILL however need one charger per battery to achieve this) of 30-60 min, then this will be fine, but it won't be a rocket, just a good steady short range power source.
If your going to be pedaling, I think you could easily double that range with out sacrificing top speed, but this will be a work-out, not just a joy ride
I think to get about 20 mph on the flats, you can expect 10-15 miles range with this set-up with most kits, maybe more with geared kits (remains to be seen at least in my personal experience) but if your going to be climbing a lot of hills, or wanting to max the speed, I think this amount of batteries might prove inadequate for anything faster/longer distance between charges.
I suspect for my own build that I will eventually be going for something in the neighborhood of 8-12 packs, 8 packs provided they are the same series/parallel set-up, will only make for a 7.2 AH battery, 12 packs a 10.8 AH battery.
IMHO, this is a great way to go, even if I end up going with something in the neighborhood of 16 packs since I can get the BMS + A123 cells at less than $5 per cell (on a good ebay deal) and in the end, I might end up trying something like you mentioned, making larger packs to go with the BMS and build them to the desired shape to keep compact and light weight.
I think best of all is the superior amount of recharge cycles the A123 batteries have. That is their main selling point to me.
I am also interested about other people's ideas for charging/building these cells into different sized packs, I am trying to keep everything at minimum cost, but also fastest recharge time possible, would want to stay under 2hr charging time to keep it feasible as a commuter.
Also, so far the only real problems with the dewalt BMS I have seen are the 15amp fuse (used only while charging) blowing on one of our older packs (2006 manufacture date, very easy to fix) also of note is the batteries only have a TWO YEAR warranty, where as the TOOLS have a three year, so it might make a difference which battery to buy on ebay if one's a 2006 and the other manufactured later.
Oh on another note, I don't have any personal experience with "jeanclaudecayerent" on ebay, however I have seen where he sells the DC9000 chargers for cheap, then charges about 3x the price of the item in shipping
, so just look closely at what your considering to bid on.
You can get good reasonable priced 28 volt packs on ebay, just have to watch for the better deals.
