Will this keep it simple??? (why-or why not, please?)

[64ragtop]

I'm just getting into this whole ebike thing, getting bits and pieces together, I realize that the
SLA cells that I already have may not keep me satisfied for very long, but they'll have to do for
the startup. After reading numerous posts here and elsewhere, I'm getting very interested in
the DeWalt 36 volt packs and using them as found. Just charge 'em up and plug 'em into the bike
ride til recharge is needed and recharge with the DeWalt charger.

That plan seems too good to be true! All that would be needed to make it happen would be proper
connectors to the battery and wiring to the bike. Need more runtime/range - wire up two or three
battery holders in parallel and double or triple the amp hours of the system. Simple, quick, and easy,
than but not so cheap as SLAs. Heavier than, but not so expensive as more advanced technology.

Reading the posts here, dealing with cell balancing and so many other issues, makes me think that
this plan is just too simple to actually work as it seems to me that it ought to. So would one of you
madcat battery mavens kindly enlighten my ignorance and explain why my idea is impractical / stupid.

If ya can do it without damaging my fragile ego, I would appreciate it.

Thanks for any and all responses - and my ego can take it if I get to learn something in the process.

 

[Anonymous]

.

 

[Drunkskunk]

You pretty much need a minimum of 3 to work with any useable range. 1 might get you around the block. 4 to 6 is best

As far as better technologies, fear not. The Dewalt packs are made with A123 cells. Right now, these are the most advanced cells available to the public. they do weight a bit more than a other lithium technologies, and the plastic battery housing is a little bulky, but as a power source, they are about the most advanced battery out there.


So yes, it is almost that easy.

 

[julesa]

You pretty much need a minimum of 3 to work with any useable range.

Another problem is the expense of buying a charger for each battery, or having to rotate batteries in the charger before you can ride again.

And then if you want to ride somewhere that's near the end of your usable range, charge for a few hours at that location, and then come home again, you have to carry a bunch of chargers with you.

I'd take apart the Dewalt packs and build a pack that I could charge all at once without any intervention, like with Gary and Richard's BMS kit:
http://www.tppacks.com/proddetail.asp?prod=EBKE%2DBMS%2DKit

And buy a reasonably powerful but still portable charger:
http://www.batterymart.com/p-battery-defender-48v-3_5a-battery-charger.html

Or maybe just buy a cheap prebuilt pack from Ping or Headway... you won't get the same amps as from the Dewalt packs, but not everyone needs that kind of power, especially if you only have a 20A controller.

Last I checked, the cheapest the 36V 2.2Ah DeWalt packs were going for on Ebay was around $140 each including shipping. Five of those would give you 11Ah of juice for $700 plus somewhere around $250 for Gary's BMS and a nice charger. If you think you might someday upgrade your controller to a high amp model, this might be the way to go. If not, you can get a 20Ah Ping pack (almost double the range) for probably around $500-600 including shipping, BMS and charger.

 

[dogman dan]

With a 20 amp controller, all you need is the Ping. But If you plan on big upgrades, then you need A123's. Of course a good Ping battery will not be hard to sell later, but you won't get all your money back out of it.