Upgrading LED Lenser H7R batteries

[bwatkins]

Hi,

I've just ordered a LED Lenser H7R and and am already thinking about how to improve the burn time. I don't want to go the route of having a seperate battery pack on a belt as has been discussed here so I'm looking at modifying the existing battery holder to take a higher capacity.

The standard battery compartment takes 3 AAA's, so about 4.5v and 1000mAh, but I noticed from the pictures on the company website that the torch actually has "DC IN 4.8v" written on the side. 4.8v batteries are ten a penny in the radio control world and the come in all shapes, sizes and capacities. Is it as simple as just wiring a big 4.8v 4000mAh pack in to the LED Lenser's battery compartment? Or does the change in voltage and current mean the resistance in the torch needs to be changed? Couldn't I just put a stop on the dimmer to prevent it going to maximum?

You advice would be greatly appreciated.

 

[WyldOne]

Anyone able to shed some light? I'm in the same situation myself.

 

[jimpatrick]

. . . I noticed from the pictures on the company website that the torch actually has "DC IN 4.8v" written on the side. 4.8v batteries are ten a penny in the radio control world and the come in all shapes, sizes and capacities. Is it as simple as just wiring a big 4.8v 4000mAh pack in to the LED Lenser's battery compartment? Or does the change in voltage and current mean the resistance in the torch needs to be changed? Couldn't I just put a stop on the dimmer to prevent it going to maximum?

The LED Lenser H7 and H7R are very different. The H7 takes 4.5V (3*AAA) while the H7R uses a Li-ion or 4*AAA; 7.4V or 6.0V. I am assuming you are asking about the H7, not the H7R.

Three AAA are about 1¾"H by 1¼"W by ⅜"D. They weight 1.2 ounce together. The 4.8V/4A packs you listed are not AAAs, not even AAs, but 4/3A sizes; they are way bigger than AAA. Some of those packs are 'fat A' at an extra mm diameter. The overall pack size is about 2.6"H by 2¼"W and over ½"D. That NiMH pack is just over one pound weight! Don't think you want that on the back of your head!

It's all about tradeoffs. You could probably substitute a 4*AAA NiMH pack instead of 3*AAA alkaline, but gain little except recharging because NiMHs don't have the capacity of alkalines at 800 to 1200 mAh. If you change to AAs you give up light weight —for one thing, with NiMH you need 4 cells— but can gain capacity with some NiMH AAs as much as 2.7 mAh. If the extra 3 ounces doesn't bother, you might consider that. Unfortunately no combination or type of lithiums can get reasonably close to the 4.5V target, and I'd be afraid to try a 6V or 7V tow-cell on the H7.

 

[torukmakto4]

I googled, saw an H7R.2 with the Li-ion internal pack and 4xAAA tray, and an H7R with 3 NiMH AAA cells.

NiMH cells will hold a higher voltage under any reasonable load than alkalines. 1.5V is not a "nominal voltage" in the sense of rechargeable alternatives, it is closer to OCV. I don't think you would want to replace 3 alkies with 4 NiMH cells... not unless you know the driver and know there won't be smoke with a higher voltage. Besides, the H7R does run on 3 NiMH cells out of the box.

It should run fine on a 3 cell nimh pack or a single Li-ion.

Regarding the "4.8V" input connector as a sign of battery voltage compatibility, that may take a bit of research. If it is a charging connector, that voltage marking may not say anything about the driver's input voltage range. If it is for external power, you still need to be sure the full charge voltage of a 4.8V pack would be tolerated.