Cavechat.org

So I'm making an external battery for my hammer drill - what's the best online store to get Li-Ion 18650 cells from? Keep in mind this won't be for a headlamp, so I don't need the absolute best. I just want something with decent capacity that's not going to explode on me (assuming I treat it right). I looked on batteryspace.com and megabatteries.com, but wasn't sure if there was a better place to go. Any recommendations?

This link was posted recently by Jeff Kruse in the ST-6 discussion.
http://www.candlepowerforums.com/vb/sho ... ew-summary

The author of the article notes that run time will depend on current draw and gives you a way to
determine which cells will be best for your application.

Thank you, some great info there!

I've had good luck with all-battery.com. They mostly carry the Tenergy brand cells, but they have some of the other big names as well. Also, I found that combined with a coupon code the price was unbeatable. I use high capacity Tenergy cells in my headlamp battery pack and have been pretty happy with them overall.

Lava wrote:So I'm making an external battery for my hammer drill - what's the best online store to get Li-Ion 18650 cells from? Keep in mind this won't be for a headlamp, so I don't need the absolute best. I just want something with decent capacity that's not going to explode on me (assuming I treat it right). I looked on batteryspace.com and megabatteries.com, but wasn't sure if there was a better place to go. Any recommendations?

Please be careful when using 18650 cells. They are generally a lithium-cobalt chemistry that can fail catastrophically when discharged at a high rate. 24 and 36volt drills can draw up to 15 amps which greatly exceeds the 1-2C discharge rate of most 18650s. Of course you can run a configuration like 10s2p to reduce the load on each cell, but then you run into problems charging the pack and cell balancing. I highly recommend using a chemistry that is capable of a high discharge rate like a lithium polymer or LiFePO4. Please feel free to PM me as I've built several high capacity battery packs for 36V Hilti drills. In fact, I'm building a 36V 15 amp-hour LiFePO4 pack right now for a customer.

LukeM wrote:I've had good luck with all-battery.com. They mostly carry the Tenergy brand cells, but they have some of the other big names as well. Also, I found that combined with a coupon code the price was unbeatable. I use high capacity Tenergy cells in my headlamp battery pack and have been pretty happy with them overall.

I second this. Used Tenergy 18650's in my latest 55 watt HID video light heads from all-battery. They are great!

I also use Tenergy 18650's. I get them from batteryjunction.com

jharman2 wrote:Please be careful when using 18650 cells. They are generally a lithium-cobalt chemistry that can fail catastrophically when discharged at a high rate. 24 and 36volt drills can draw up to 15 amps which greatly exceeds the 1-2C discharge rate of most 18650s. Of course you can run a configuration like 10s2p to reduce the load on each cell, but then you run into problems charging the pack and cell balancing. I highly recommend using a chemistry that is capable of a high discharge rate like a lithium polymer or LiFePO4. Please feel free to PM me as I've built several high capacity battery packs for 36V Hilti drills. In fact, I'm building a 36V 15 amp-hour LiFePO4 pack right now for a customer.

John, thanks for the heads-up. My drill already uses 18650s, I'm just adding a couple of parallel packs. Should be fine.