Upping the Burn time on a DX Bike light... feasable?

[cookeaa]

My DX Bike light (SKU 25149)apparently has a 4 cell (18650) battery but is claimed to be only 8.4V am I right in assuming it is wired as two pairs of batteries in Parallel and then the paired cells in series (assuming the cells are 4.2V not 3.7V) I'm half considering making up a 6 cell pack in the same configuration to give me increased Burn time.

Will it work? And what would be the best cells to use?
Would I still be able to charge the pack using the charger supplied with the light?

Any thoughts?

 

[Doh!Nut]

The pack is a 7.2v pack 8.4v is the charge termination voltage.
Yes the pack is two strings of two in parallel 2S2P
Yes changing it to 2S3P would increase burn time.

You could use the same charger
You could use any of the 18650 cells on DX
You could get all protected ones and then solder them together but I would go to all-battery and get a ready made pack with a proper multi-cell protection circuit board.
I would also get a proper charger as (I understand) that the supplied DX charger is only a power supply and relies on the safety circuit to terminate the charge, rather than the charger terminating the charge and the safety circuit being for safety.

 

[yellow]

search for "BP945" on E-Bay and get a 6600 mAh camcorder battery pack.
together with a charger (or use Your camcoder equipment), and a "charging cradle" where You solder Your wires on.
So You do not have to mod the pack in any way and can use it, charge it with the charger, ...

has all the protection drivers inside and overall is better than soldering around individual cells

 

[cookeaa]

Thanks for that... The BP945 battery looks like the ideal solution in some ways, some deals to be had on fleabay. I might give it a whirl…

My other thought was making up my own battery enclosure (similar to what a fair few others seem to have done looking about) to house 6 x 18650 cells, giving me the flexability to reconfigure the connections (should I every require it for a future project) and charge the cells in a standard charger outside of the enclosure, but by the time I've built all of that I may as well go with the camcorder battery, still it's fun to make things…

 

[Wuss912]

search for "BP945" on E-Bay and get a 6600 mAh camcorder battery pack.
together with a charger (or use Your camcoder equipment), and a "charging cradle" where You solder Your wires on.
So You do not have to mod the pack in any way and can use it, charge it with the charger, ...

has all the protection drivers inside and overall is better than soldering around individual cells

i would think something like this would be better still... http://cgi.ebay.com/Li-Ion-18650-7-...ultDomain_0?hash=item5ad060c4c9#ht_1307wt_686

 

[Luna01]

search for "BP945" on E-Bay and get a 6600 mAh camcorder battery pack.
together with a charger (or use Your camcoder equipment), and a "charging cradle" where You solder Your wires on.
So You do not have to mod the pack in any way and can use it, charge it with the charger, ...

has all the protection drivers inside and overall is better than soldering around individual cells

Hi, yellow. I also found a Battery Charger for BP945, but is not on eBay, it at uxsight, and its price is more low. Here is the link: Battery Charger for BP945


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