4 D Mag search Lion/Lipo alternative to nimh

[mash.m]

Hello,

i am searching for alternative batteries then nimh for my actual project:

http://www.candlepowerforums.com/vb/showthread.php?t=186673

The Body is a normal 4D sized Maglite. i know that dx sells d-size lion batteries at the past. but at this moment i can´t find any seller. i don´t want to bore out my mag, so they must fit without any changes.

other ideas are welcome. i need the voltage of one cell (3.7 volts) and much current. goal is 3,7 volt an more then 15.000mah.

thanks,

markus

 

[mdocod]

tri-bore[edit sorry just noticed you don't want to bore... bah], 9 17670s, the good news is that charging will be pretty easy (no balance charging required if the whole pack is in parallel)... I have an idea for how to build the pack if you are interested.

If you use some quality cells like AW or Pila you should be able to get about a 13-14AH performance out of it(figuring ~2.5A output per cell to meet the ~22 amp!! demands of the light). The problem I see with this is that it isn't gaining a huge amount over the NIMH you are using currently, and the cost would be well over $100 to complete the pack after you figure in all the materials necessary to do it...

[edit in] I think you might be better off just holding out for some good D cells to become available somewhere, that would be so much easier as far as the pack building is concerned, and will give probably close to 20AH for the pack.

here's a 2xD "pack" you could take apart:
http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3985

 

[mash.m]

hello mdocod (stands for???),

thanks for your reply! of corse i am interested in your idea to build a lion pack .also the lion pack at kaidomain looks very interesting.
problem with high powered nimh cell is the selfdischarge, so i wan´t a lion pack.
in germany there are new mono d cells available like the enloop with low discharge, but after 3 charge and discharge they have only a messured current of 7ah and not 10ah that is printed on it!

thank you!

markus

 

[mdocod]

here's a NIMH options that will solve your self-discharge problems:
http://thomasdistributing.com/shop/...html?SP_id=&osCsid=bi4nl48h5j668p3k1mlbbuis13

it's been a LONG time since someone asked what "mdocod" meant.... I came up with it back when I was in my sophomore year in high school to use as my "online" "handle" for nearly everything. It means, "medium density organic compound of death." Whether or not that accurately describes me anymore is up for questioning (high school years = rebel, liberal, crazy, etc,) but I have stuck with it for sentimental reasons. I think the reason I came up with it, is at the time one of my big hobbies was building speaker cabinets, I used medium density fiber board for a lot of my projects, it sort of worked. lol.

 

[2xTrinity]

here's a 2xD "pack" you could take apart:
http://www.kaidomain.com/WEBUI/Produ...px?TranID=3985

At one point, Kai sold the same cels that make up these packs individually, with no protection circuits, for $15/ea. To buy the packs and break them will cost you $20/ea. The biggest problem I believe you will find is actually the wiring to get all of them in parallel. In order to pull it off, I believe it will be necessary to actually build and then shrink-wrap a 4-parallel "pack" with all the leads sealed up as part of it. If I were going to shrinkwrap such a pack though, I'd want individual protection on EACH cell in case of gradual mis-matching over time. IMO Kai should cell protected "singles" for $20, I believe most would prefer those to packs.

9x17650 will give you only about 60% the total energy of the Kai cells, which about the same as NiMH can give you, although you'd still have the advantage of massive reduction in weight.

 

[mash.m]

hi,

nobody askes cause anybody here knows, or no one interest?

thanks for the link to the nimh - good to know but not available in germany. do you think these cells have their ratet capacity of 10.000mah?
i think the kai lion are the better alternative for my. with two of these packs i get 20.000mah! i must do some tests with the lion cells i have and still hope that the voltage is enought for drive to fully brightness. if so i would give them a try! do you know shipping coats to germany at kaidomain? the four nimh´s batteries i used break down to under 4 volts under full load :thinking:

markus

 

[mash.m]

At one point, Kai sold the same cels that make up these packs individually, with no protection circuits, for $15/ea. To buy the packs and break them will cost you $20/ea. The biggest problem I believe you will find is actually the wiring to get all of them in parallel. In order to pull it off, I believe it will be necessary to actually build and then shrink-wrap a 4-parallel "pack" with all the leads sealed up as part of it. If I were going to shrinkwrap such a pack though, I'd want individual protection on EACH cell in case of gradual mis-matching over time. IMO Kai should cell protected "singles" for $20, I believe most would prefer those to packs.

9x17650 will give you only about 60% the total energy of the Kai cells, which about the same as NiMH can give you, although you'd still have the advantage of massive reduction in weight.

i think make a package with four cells is not the problem, also the wires. shrinking a protection is a must have! what do you mean with individual protection ? under/overvoltage, temperature? fyi: i know about handle lion cells...
do you have a link to these unprotected cells? i can´t find them!

markus

 

[dan_]

As far as I remember the actual capacity (talking about the ones in the link below) was more around 3A and not 5A. Maybe you want to do a search in cpf on kaidomains d-lion pack to find out more about it.

I was going to buy one of those http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3985
but for d-lion the capacity is fairly week.

Don´t know if the D-lion (the single ones) will be available again. Guess they had around 10A but were non protected cells.

(Btw. did you mill the head of the BigMag^3 by yourself?)

Cheers,
daniel

i think make a package with four cells is not the problem, also the wires. shrinking a protection is a must have! what do you mean with individual protection ? under/overvoltage, temperature? fyi: i know about handle lion cells...
do you have a link to these unprotected cells? i can´t find them!

markus

 

[mash.m]

(Btw. did you mill the head of the BigMag^3 by yourself?)

Cheers,
daniel

yes, i mill it by myself. it is the same like my bigmag², but much lighter.

markus

 

[mdocod]

you mentioned worrying about the Li-Ion not driving that thing full brightness... and that is something I would definitely be concerned about.. it might drive it full brightness maybe for part of the discharge... but you have some voltage dropping hardware in there, Li-Ion is only 4.2V open circuit fresh off the charger and will drop to about 3.7V or lower pretty fast under a stiff load, I'm not sure what the Vf is on the LEDs you are using, and if you were planning on leaving all those diodes in there, but this could mean dropping below your full brightness pretty fast..., you've been running 4xNIMH that probably hold above 4.8V through most of the discharge. Now that I think about this, I'm not sure it will work as you have in mind...

do you think these cells have their ratet capacity of 10.000mah?

here's some test results of the "C" size of the same type of cells:
http://www.candlepowerforums.com/vb/showthread.php?t=187271
they came in OVER their label capacity by a decent margin, very unexpected. I would have to suspect that the D cells will be close to their label capacity if not above.

 

[2xTrinity]

As far as I remember the actual capacity (talking about the ones in the link below) was more around 3A and not 5A. Maybe you want to do a search in cpf on kaidomains d-lion pack to find out more about it.

Not sure if you're talking about discharge rate (A) or capacity (Ah), but based on this graph the capacity rating is definitely 5Ah, and holds up quite well even at 15A draw.

It was the DX "C" cells that claimed to be 5Ah that were overrated from 3Ah.

 

[mash.m]

hey guys,

you are talking about two different cells. one time the lionpack at kaidomain and second time the accupower nimh cells...

i have ordered two packs of the lion batteries from kai. i will give them a try. yesterday evening i have testet with a lion pack, 4 cell parallel. it drives the flashlight most of the time to fully brightness so i am shure that the lion pack from kai is the right choice!

also i will order the accupower cells to test it. i will write down the results here when they arrived and tested.

thank you!

markus

 

[mash.m]

hi,

i have searched the internet for the accupower evolution d size batteries. but i can´t find them anywhere!?!
at accupowers homepage also nothing! how can this happen?

http://thomasdistributing.com/shop/...html?SP_id=&osCsid=bi4nl48h5j668p3k1mlbbuis13

markus