Originally Posted by
Plutonix
That is very reasonable, and one of the reasons I really like D. Is the upgrade program different than the trade in program? The website shows the 400L at $269 or $279 w/ trade in. Maybe the prices are not up to date.
I did some checking and you can build up a D cell based system very cheaply, but not from RS for the reasons mentioned (they prolly dont have 'real' D Cells):
4 D Cells = $26 and up (10,000 mAh)
Holder = $ 2
9V Clips= $ 3 (to wire a harness like shown above)
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Total $31 +s/h
If you needed a D Cell charger, add $15 for a cell charger, $25 for a smart pack charger (if you wanted to charge the cells in the holder).
There are several cell options: Tenergy and Powerizer @ 10Ah for ~$26; Titanium @ 12Ah for $28. As long as these are around 90% of the stated capacity (a quick stat from CPF) you'd still get about double the runtime for 2 light engines as compared to 2 sets of 4xAAs.
You could even go with AccuPower LSD D-Cells for $42 and still be below the $100 tipping point to upgrade 2 lights. It is only when you go to premium cells and deluxe chargers that it starts to not make sense unless you have other uses for them.
Could you post a link to the smart pack charger you mentioned? I would love to be able to charge my AA's in the pack, without taking them out, but I've never seen a charger that could do that, unless it was built into the light itself, for either AA or D batteries.
With the lith-ion, you also get 2 batteries, not just one, the 2 cell lith-ion is at least half the size (if not more) of 4 d cells, charges in the pack (maybe that's possible as you mentioned?), probably easier to mount on the bike, and going over bumps is not a problem at all.
Just...talking out loud here.