Need to know what batteries to use for a modded BTU Shocker

Batteries and Chargers Rechargeable Batteries
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Tom E is kindly modding a BTU Shocker for me to XM-L2 U2 1C’s and a resistor mod to bring the stock BTU driver up to 4.7A. The stock BTU driver drops down from turbo to high after 3 minutes, but I’m a little worried about voltage sag when it is at turbo. I believe the battery carrier is 2 parallel 1 series (corrent me if I am wrong), so voltage sag might not be as big of a deal as I am worried about. Currently I have protected 3400 mAh Panasonics, protected 2600 mAh Sanyo’s, protected 2800 mAh (4.3v) Sanyo’s, and Samsung 2000 mAh 22 amp INR’s that I can use in it.

Do you guys think I will be OK with any of the above batteries? Should I only use the Samsung INR’s? I could also get some Panasonic NCR18650PD’s that do 10 amps, however, they would be unprotected….which frightens me in a LiCo battery.

Here is a picture of the battery carrier:

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The carrier is in 3 series. FWIW I use Samsung 2600 or Sanyo 2600 in mine.

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I use protected KeepPower 3400’s in mine.
If you use unprotected batteries, you may need to use magnets since they are shorter.
I tried using AW IMR’s in my BTU. They work, but they are really loose in the carrier.
It feels like one good bump would make them shift and lose contact.

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at 4.7 amps I think you should use high current batteries or you will get some voltage drop and a decrease in output

the inr 22 amps batteries would be my first choice since you already have them

btw all size cells fit in this

im using fasttech ncrb 70mm long cells in mine and they are snug

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https://www.fasttech.com/products/1141104

This exact model i guess?

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yes sir

when i say snug - they took some mild convincing to get in - i would never force a cell into a carrier thats too small - wouldnt want to damage the pcb - but with the springs compressed all the way they fit ok

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Thanks!

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Well I guess these INR’s I bought for no particular reason will actually have a use now. I wish the NCR18650PD’s could be had with protection circuits…

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If you want to save a bit of money, these are 3100mAh instead of 3400.
However the NCR18650Bs can handle about 6.6A, while the NCR18650As can handle 6.3A.

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http://intl-outdoor.com/2-pcs-panasonic-ncr18650pd-2900mah-protected-battery-p-671.html
protected PDs but not cheap, got some callie customs protected for about same price.

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Ahhh thanks for the link. My buddy who sells batteries told me some reasons I now forget why those cells aren’t good with protection circuits. I will have to ask again and get back.

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Just want to clear some things up, INR/ICR/IMR batteries can be used for well over 10A discharge rates, good quality cells can go 20A+ (and this is for an 18650).
Panasonic NCR18650PD are the highest current handling battery in Panasonic’s ‘NCR’ line, and dont have protection because it will most likely kick in at around 7A, while the battery itself can supply up to 10A.
Panasonic NCR18650B are next, able to supply just over 6.5A.
And then there are NCR18650A (which I find the cheapest for my needs), which have a maximum of around 6.2A and a lower capacity than the NCR18650B cells.

The NCR line is a high current line, so whichever one you have they will be able to supply a pretty high current.

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ncrbs will give you 4.7amps no problem and probably very safely - cells might get a little warm but thats normal…

i would expect you would see voltage drop below 4v under that load rather quickly even on fresh cells… maybe even in as little as 2-5 minutes

at 4.7amps the Vf of an xml2 is probably somewhere around 4v (perhaps other members can chime in here if this is not correct - i am going by memory here)… so you would notice a sort of “direct drive” taper as your batteries are depleted

would the voltage stay higher for longer with an imr? i dont know… they are less capacity so they will be drained quicker

i think some real world test are in order

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I use the NCR18650A in most of my lights, best bang for buck I think.

On a side note, any more details on the resistor mod for the Shocker? I’ve just got one with some XM’L2’s on the way :slight_smile:

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I’m having mine modded by Tom E. I’m not really sure what resistor(s) need to be swapped. I’m sure he could point you in the right direction if you PM’d him.

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I’d do the same if i could, however return shipping from Aus would cost more than the light itself :frowning:

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just a noob question. But are all these the direct drive models?

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The DRY driver is direct mode, the BTU driver is regulated. My mod, using a driver from IOS (Hank at Intl outdoor) works in direct drive mode in this configuration of 3 cells in series, 3 LED's in series. So, all resistance must be reduced to get super output.