Battery Pack for Cordless Blower

[txmatt]

I know this isn't a flashlight topic but bear with me...

I recently picked up a Black and Decker cordless blower which does a surpisingly good job, especially hot off the charger. It came with 2 battery packs which are easily swappable. Each will run for maybe 5-7 minutes before they discharge enough to significantly reduce their power. I'm thinking of fabbing a new high capacity battery pack.

Connection won't be an issue as large spade lugs will suffice. A short cord to a belt loop clip or small fanny pack would be simple. So what batteries to use?

The OEM packs are 18V and I think maybe 1200 mAh NiCD's in 'em. One easy solution would be 15 NiMH AA's in maybe 4x holders. I could pop 'em out and charge them in an Accumanager. Also have an RC charger that will charge up to 14 cells in series at any settings I program. Could charge 12 in one shot and 3 in the Accumanger (which I charge my flashlight batteries in for required flashlight related content). Would likely just pick up an 18V NiMH charger, though.

Could up that to C or D cells (more expensive) but would be huge runtime improvment.

A small 12V and 6V SLA in series might work as well.

Any thoughts?

 

[BatteryCharger]

You could try to rebuild the stock packs with better batteries. Most things like that use sub C cells, which I believe are available up to 4500mah in NiMh. I plan on doing something similar with a cordless drill.

 

[Fallingwater]

Get some 8C LiPo cells for R/C models and build yo'self a 5s pack. You'll need to measure the blower's current draw to know which cells to buy. Warning: not cheap.

As for the AAs, they are a bad idea. They use NiCD cells in these applications because they handle high discharge currents better than NiMH. Using NiMH cells of a smaller size will only result in the cells overheating.
NiMH would be ok, but you'd need bigger cells.

 

[txmatt]

Don't they also use NiCd because they handle abusive charging/overcharging better than NiMh such that they don't have to spend the extra $ on a smart charger?

 

[Fallingwater]

Possibly.
Forgot to mention if you go the LiPo way you'll also need a charger. Absolutely don't charge a LiPo pack with the NiCD charger of your tool or Bad Things will happen.