Help with modifying Dinotte 200L (AA) battery pack

[pcheninhk]

As the title suggests, I am trying to modify the battery to my Dinotte 200L battery pack so that I can have more run time. The Dinotte 200L AA battery pack is simply a 4 AA cell battery holder with a 9 volt type connector.

http://kc-bike.blogspot.com/2007/11/product-review-dinotte-200l-led.html

I have read a write up mentionig that a modification can be achieved by wiring two 4 AA cell battery holder together so a total of 8 AA cell can be used so the result is doubling the run time (please see attached link).

http://bike.duque.net/brevets-preparation.htm?pic=92

However, I was worried that the 8 AA cell (2 battery pack) might overload the lighting unit (i.e. from 4 AA [1.5V*4=6V] to 8 AA [1.5V*8=12V]). Could anyone please inform me that there is no need for my concern with the above setup? I just do not want to damage my Dinotte 200L unit by overloading it?

Lastly, if the above modification works, can I not simply buy a 8 AA cell battery pack with a 9 V type connector and use it like the above modification. Is there anything special about with the above modification that would allow me to use it on the Dinotte 200L that a 8 AA battery pack won't allow me to do? Please see link of the 8 AA battery pack.

http://www.radioshack.com/product/i...odsInSession=1&numProdsPerPage=60&tab=summary

Thanks for eveyone's input.

 

[Lynx_Arc]

as long as the two 4AA packs are in parallel should be ok..... buying a 8AA (series) pack wont work if your light doesn't have the right buck circuit to handle 10v you could toast it.

 

[pcheninhk]

Thanks for the quick reply. I am a noob and I cannot figure out why running parallel would work and not the prefabricated one? Wouldn't running parallel also generate a high voltage output? Please shed some light. Thanks.

 

[bbgobie]

Wiring in parallel means you add up the capacity and keep the volts the same.

Wiring in series means you add up the volts, the capacity stays the same.

Most premade battery holders are designed for series.

As long as you keep the voltage the same, you can pretty much do whatever you want.

 

[ncaudio]

2 packs in parallel-yes

I've run 2 standard dinotte AA battery packs in parallel connected to either a Dinotte headlight or taillight or both. The 2 lights and battery packs are on a helmet. If you're going to do this it's important to use batteries that test to similar capacity for all 8 cells and use freshly charged cells for both packs. The LaCrosse BC-700 battery charger/tester units can be gotten pretty cheap when on sale, Amazon had them for $24.98 each with free shipping a few weeks ago, I bought 2.

As long as the batteries are well matched, putting 2 packs in parallel can more than double the capacity since the current draw per pack is only half and batteries tend to deliver more power at lower current draws.

There is a guy that runs 3 packs in parallel, (don't remember where I saw it) but it might be hard to find 12 batteries that test to the same capacity.

 

[Zero_Enigma]

I did a pictorial write up on a HOW TO for this. Granted I own only the Dinotte tailight the front light uses the same 4 x AA configuration.

This is my webpage:

http://www.flickr.com/photos/49184877@N00/2736420310/

This is my original post :

http://www.bikeforums.net/showthread.php?t=441867


You can build up or improve on from here but this is the basics.

Enjoy.

 

[Zero_Enigma]

Pchen,

95% people can build this. At the most it'll take you 60mins if you're totally zoinked-drunk if you have all the parts at hand.

 

[znomit]

Running in parallel is kinda frowned upon because if one cell shorts the other battery pack discharges through it.

Why not run two packs with a switch to select which one is powering the light?

You could also go with 4 D cells (4x runtime).

 

[Zero_Enigma]

Running in parallel is kinda frowned upon because if one cell shorts the other battery pack discharges through it.

Why not run two packs with a switch to select which one is powering the light?

You could also go with 4 D cells (4x runtime).

I was going to suggest using a switch but the OP stated they are a newbie and I think my method is very newbie friendly on the most basic level without any soldering involved. Altho your method is good as well but an added extra step.

If the OP has two sets of new batteries chances are they would be balanced. ie. new NIMH or NIMH LSD cells. Or if the OP is a little advanced on the battery chargers and has a battery charger analyzer (ie. Maha C-9000, Lacrosse BC-900, Lacrosse BC-700 (cheaper version of 900 model that charges slower but with to my knowledge all the same analytical features as it's more expensive unit) the OP can check all thier cells and pick the ones that are in good health and same mAh capacity to use in thier DIY packs.

 

[Lynx_Arc]

if it was regulated he could use a diode on each pack to prevent backfeeding.

 

[ncaudio]

if it was regulated he could use a diode on each pack to prevent backfeeding.

Lynx-Arc, good idea for protection, but the downside is .6 V forward bias drop across the diode which means you would be throwing away some power and runtime. Running 2 packs in parallel is riskier if you have a cell short or put a cell in backwards, but a lot simpler and should extend runtime (compared to running down 1 pack then the other sequentially with a switch). I test all my cells, mark them and match them up within 100 Mah. The higher quality cells (Powerex Maha are what I'vé used and had good results with) seem to have very few failures of any type compared to Eveready and Duracell and the other off brand cells.

Most of the people here are technophiles and understand batteries, but the non technical masses don't want to take the time to learn the details, so a Dinotte with premade pack is probably better for them than dealing with packing cells in a holder, and wondering why they don't last that long ("they all say 2750 Mah on the side and I just charged them a month ago") much less paralleling AA packs, testing, matching, etc.

 

[pcheninhk]

Thanks for everyone's input, they are really helpful. Can the experts point me toward the "switch" (i.e. how it looks like and where to buy) and how it can be incorporated into the battery pack? My friend can probably help me solder if required. Happy Boxing Day!

 

[Lynx_Arc]

figure out how much current the light takes from a pack and find a SPDT switch. You can hook one lead of the same polarity from both batteries to each of the outside connections and the center connection to the light. Make sure you get a switch that can handle more current than you need..... If you light says 1 amp get a 2 or 5 amp switch etc. switches rated at more amps typically have less resistance in the contacts at heavy loads.

 

[Cemoi]

find a SPDT switch

SPDT :thinking:

 

[Lynx_Arc]

SPDT :thinking:

Single Pole Double Throw
means you take one input (Pole) and switch between two outputs (Throw)
some SPDT have center off also.