Deciding between batteries

[stas]

Hi,
I'm deciding on a battery pack for my hybrid aul canister and 18w light head light. The dimensions of the canister are approximately 3.18" diameter and 9" in height. I can either make a pack of 10D cells or 20C cells to get 10 Ah or 9.5 Ah respectively. I do not consider a .5 Ah difference important in the type of diving that I do. Other the that, is there a reason to choose one type of cell over another?

Also, on a separate note, I cant find almost any info on AUL lights on the web. I know they are out of business, but they also made a lot of lights at one time and its strange to me that its so hard to find info on them (like dimensions of their canister product line). does anybody have a catalog of theirs or a fact sheet?
Thanks Stas

 

[SoCalSwami]

is there a reason to choose one type of cell over another?

Would you rather pay now or later?
I ask because, you will find better long term results (longer run time and less weight) with Li-Ion batteries rathern than Ni-MH or Alkaline, but the up-front cost of Li-Ion is higher ($10 per 18650 cell) and requires (highly recommended) the additional cost of a balanced charger. Verse Alkaline which will cost more over the lifetime of your light.

The MSN divelight group has some great excellent presentations made by users regarding DIY battery packs.

You can see a small picture of my latest Li-Ion packs for the 35w hid I'm working on.
Picasa Web Albums - SoCalSwami - Lobster Illum...
They are double 4 cells packs in 2p2s (7.2V with 5.2Ahr) combined to give 14.4V at 5.2Ahr. You should be easily get 12-14V with nice run time based on the size cannister you described.

Mike

 

[stas]

It was my understanding that for the WA ballast, the voltage has to be very close to 12 V to function properly and Li-Ion packs ae higher voltage. Is this not the case?
Stas

 

[SoCalSwami]

That is unfortunate the voltage must be close to 12V. I would have assumed the ballast to act as voltage regulator and a 14V pack would be sufficient.
The voltages for 18650 cells are 3.7V increments (7.4, 11.1, 14.8)

I am now curious to hear others responses to your original question.
"Is it better to have more C size or less D size cells. Do they drain/charge any differently."

 

[Gary D.]

I use the batteries out of rechargable MagLites for four main reasons reasons.
They are always available in our Patrol Cars, size, good burn time and cost.

Gary D.

 

[stas]

Hi,
I would like to ask people's opinion on the following two battery packs:
10AH:
12V 10Ah NiMH Battery Pack for E-bike and Bike / Dive light - DV-12V9500

and the 12.6Ah
NiMH Battery Pack 12V 12.6 Ah ( 30x4/3A Cell) ) for Salvo HID Diving Light - BL-H12V4200S10P3

One of my specific concerns is that in the 12.6Ah pack, its three packs in parallel and I have read that due to how these batteries charge, there could be problems with undercharging which wouldn't be present with the other pack because its only one chain. Is that the case or is this not something I should worry about?
Other then this and the extra weight, is there any reason the 12.6Ah pack would be less preferred then the 10Ah.
Which one would you get if they both fit yur cannister (with the 12.6Ah one filling it out better).
I appreciate all the advice that has been given here already and ask for just a little more.
Thanks, Stas

 

[stas]

Anyone?