What bulb with my m*g 2D 8,4v battery

Dutchman · Jan 7, 2008

I ordered this battery http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3985
from Kai. A German Flashaholic advised me to use the Pelican 3854 bulb.
The article he provided me with came from this forum and it only discussed batteries upto 7.2V. Hence my question

Thanks for your help

Kees

WildChild · Jan 7, 2008

Dutchman said:
I ordered this battery http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3985
from Kai. A German Flashaholic advised me to use the Pelican 3854 bulb.
The article he provided me with came from this forum and it only discussed batteries upto 7.2V. Hence my question

Thanks for your help

Kees

Those bulb are often used with 6 NiMH batteries that give over 8.4V when freshly charged... Voltage will drop under load. Same thing should happen with those Li-Ion cells.

2xTrinity · Jan 7, 2008

Dutchman said:
I ordered this battery http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3985
from Kai. A German Flashaholic advised me to use the Pelican 3854 bulb.
The article he provided me with came from this forum and it only discussed batteries upto 7.2V. Hence my question

Thanks for your help

Kees

Kai is reporting the peak voltage of the battery pack (8.4V fully charged) which is unusual. Most of the time, LiIon nominal voltage refers to the average votlage delivered by the battery throughout the runtime (keep in mind, that it will decrease continually) -- so normally 2xLiIon is considered 7.2V.

cfromc · Jan 10, 2008

Be careful with the ROP-Hi 3854 bulb. I have 2 of Kai's D cell L-ion batteries and the bulb exploded when each cell was fully charged. I was not careful watching the charger and both batteries were actually charged to 4.21 volts. I replaced the bulb and let the batteries sit for a few days. Since then I have used the light a couple of times for a minute or two each time and no problems yet. In the future I will be terminating the charge at 4.18-4.19 volts and letting the batteries sit for a day or two before using the light. I have used the ROP-Hi with fully charged 18650s at 4.20V each and never had a problem. These D cells certainly don't sag as much as the 18650s did but they also offer double the run time. My guess is that the D cells at 4.20V each (8.4 for the pack) are at the very edge of instaflash territory.

RoyJ · Jan 10, 2008

cfromc said:
Be careful with the ROP-Hi 3854 bulb. I have 2 of Kai's D cell L-ion batteries and the bulb exploded when each cell was fully charged. I was not careful watching the charger and both batteries were actually charged to 4.21 volts. I replaced the bulb and let the batteries sit for a few days. Since then I have used the light a couple of times for a minute or two each time and no problems yet. In the future I will be terminating the charge at 4.18-4.19 volts and letting the batteries sit for a day or two before using the light. I have used the ROP-Hi with fully charged 18650s at 4.20V each and never had a problem. These D cells certainly don't sag as much as the 18650s did but they also offer double the run time. My guess is that the D cells at 4.20V each (8.4 for the pack) are at the very edge of instaflash territory.

Yeah, I think the lack of sag is probably the cause (or a bad bulb). There're tons of people running 7 rested ni-mhs with no problem (initial V should be atleast 9V).

cernobila · Jan 10, 2008

I am going to be using the same outfit once all the bits get here. Anyone tried the Philips 5761 with these Kai D Li-ions?

robm · Jan 10, 2008

cfromc said:
In the future I will be terminating the charge at 4.18-4.19 volts and letting the batteries sit for a day or two before using the light.

The output of LiIons doesn't change through 'resting' like NiMH, apart from the first few minutes off the charger when they cool.
See here and here.

I am going to be using the same outfit once all the bits get here. Anyone tried the Philips 5761 with these Kai D Li-ions?

The 5761 is very sensitive to over voltage, and would expect this to instaflash without a soft-starter - especially if the light has had any resistance mods done, and if it has it may still :poof:

even with a soft starter!

cernobila · Jan 10, 2008

[QUOTE/]The 5761 is very sensitive to over voltage, and would expect this to instaflash without a soft-starter - especially if the light has had any resistance mods done, and if it has it may still :poof:

even with a soft starter![/QUOTE]
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I will be using a stock standard Maglite with the spring shortened a little. To what level should I charge the twin pack to avoid the instaflash.

divine · Jan 10, 2008

My 6 NiMH D cells read 7.98 volts a day after being off the charger.

robm · Jan 11, 2008

cernobila said:
I will be using a stock standard Maglite with the spring shortened a little. To what level should I charge the twin pack to avoid the instaflash.

Unfortunately the only way to know exactly is when you blow your first bulb, and that was too high. So start low (with some half used cells) and work up.
FYI I have run a 5761 with 2 18650 cells in a standard Mag, and it didn't flash, but YMMV.

cernobila · Jan 11, 2008

robm said:
Unfortunately the only way to know exactly is when you blow your first bulb, and that was too high. So start low (with some half used cells) and work up.
FYI I have run a 5761 with 2 18650 cells in a standard Mag, and it didn't flash, but YMMV.

I measured my 2x C Mag at the bi-pin adaptor and it was 8.26V. This works just fine with the WA1111 lamp but what would happen if I were to simply change the bulb for the 5761?.....

robm · Jan 11, 2008

From LuxLuthor's tests - Destructive Incan Bulb Tests - Updated 1/7/08 (Info Added)

The WA1111 flashed at 8.3v, and the 5671 at 7.9v. Although this is only one set of testing, it does indicate that the WA1111 can be overdriven more than the 5761, so just because the WA1111 is OK, the 5761 may not be.

cernobila · Jan 11, 2008

robm said:
From LuxLuthor's tests - Destructive Incan Bulb Tests - Updated 1/7/08 (Info Added)

The WA1111 flashed at 8.3v, and the 5671 at 7.9v. Although this is only one set of testing, it does indicate that the WA1111 can be overdriven more than the 5761, so just because the WA1111 is OK, the 5761 may not be.

Yes I have seen this data, I can also run my Maglite on two 18650's which would measure between 8.3 and 8.4V at the bi-pin adaptor fresh of the charger, so in theory the 5761 should flash as well with these cells......The ROP High seems a safer bet, yet not always.....

jimjones3630 · Jan 13, 2008

8.4vbat is what I get with 2 emoli cells which don't sag and use an NTC to drop vbulb to 6.9v which is safe for 5761. NTC cost $1 and cures instanflashes.

https://www.candlepowerforums.com/threads/177344

cernobila said:
Yes I have seen this data, I can also run my Maglite on two 18650's which would measure between 8.3 and 8.4V at the bi-pin adaptor fresh of the charger, so in theory the 5761 should flash as well with these cells......The ROP High seems a safer bet, yet not always.....

pertinax · Jan 14, 2008

Try the WA 1274.

LumenHound · Jan 14, 2008

cernobila said:
I measured my 2x C Mag at the bi-pin adaptor and it was 8.26V. This works just fine with the WA1111 lamp but what would happen if I were to simply change the bulb for the 5761?.....

cernobila: have you read mudman cj's Discharge data for Phillips 5761 on AW's new C Li-ion cells thread?

What bulb with my m*g 2D 8,4v battery

Dutchman

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WildChild

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2xTrinity

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cfromc

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RoyJ

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cernobila

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robm

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cernobila

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divine

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robm

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cernobila

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robm

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cernobila

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jimjones3630

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pertinax

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LumenHound

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