Mag 5C w/NiMH and 6V bulb

[bmsmith]

lemlux: No, that's one of the great things about this board.. everyone's pretty nice and sincere and willing to help each other out (in more ways than one). (Thank God Craig seems to be recovering well.)

I wonder, though... are the NiMH cells that Trinity imports actually different in design/technology from other "consumer grade" NiMH cells? Maybe lower resistance designs that allow 30 Amps of draw without melting or exploding? I'm not sure I'd try to draw 30 Amps from a Radio Shack size C NiMH cell......

Oh well... late night thoughts. Time for bed.

- Brian

 

[Nerd]

I tot that the RC scene has been using motors that draw 30 amps continously for 5 mins < ? Those double/triple/quad wire motor winding method are very power consuming.

 

[lemlux]

bmsmith:

Re the R/S C NiMH cells: I've read that most consumer NiMH cells aren't being overstressed at loads of up to 1.0 * C. I've gone somewhat over that without killing batteries.

For instance, I have two PT40's in which I drive a ceramic potted Carley 3.5V 2.30 A Halogen with 4 AA 1800 mAh NiMhs that voltage drop to 3.9V when fresh. (Edit) (2.30 A / 1.80 mAh) = 1.28 * C. This T-1 1/2 bulb envelope is narrow enough that it hasn't damaged the reflector for the run times of up to 5 minutes I used them for.

 

[Velcro]

Originally posted by bmsmith:
lemlux, yea that reflector is pretty terrible, isn't it? Hmm, it's probably not worth my money to even bother. I just looked at my 3D Mag and it's pitiful with the rings and non-circular shape.

<font size="2" face="Verdana, Arial">Hmmm, my 3D beam is completely circular.

Greetings,
Velcro

 

[lemlux]

My reason for not going over 10W with the Mag reflector is that I guess 10W is at the upper limit of its temperature tolerance.

I just bought a 20W Sl-35X with charger but w/o 5 D cell battery pack for $46 on EBAY. I was delighted to avoid paying for a $57 NiCad pack when I have cheaper alternatives.

The SL-35X and my Mag Charger with 11 to 20 Watt W/A T-2 1/4 bulbs will be my big-gun aluminum flashlights in the up to 20W category.

 

[lemlux]

Gandalph:

I, too, have used a MagCharger battery in a Mag 3D with bulbs drawing between 0.85 A and 1.70 Amp. It's a sensible arrangement.

If I were to buy a replacement for the Mag Charger 2.2 A pack which costs about $28 on line I'd get a SL-20X 2.5A pack which costs costs about $36 on line. (Both before shipping).

 

[bmsmith]

lemlux, that's interesting and useful info about the 1.0-1.3 * C not overstressing normal NiMH's. Now let's get a 6V 8.5Amp bulb to go with those 8500 mAh D cells!! Haha.

Nerd, you are correct about the motors and the amount of power that they draw in RC applications. I have an electric boat with twin 17x3 motors wired in series and two 7.2V RC2000 NiCd packs in series that drains those packs in about 4 minutes. I think that calculates to around a 30 Amp draw or 15 * C. The packs are sometimes too hot to even hold in my hand after a run. It was for those high-Amp discharge reasons that many people were skeptical that NiMH would work well at all for RC main power batteries since NiMH cells have a higher internal resistance than NiCd's. Maybe the RC industry is large enough to push Sanyo and Panasonic to redesign their cells to handle the 20+ Amp draw that is asked of them. I'm not really sure the RC industry has enough clout to do that, though. This was why I asked if there is a difference in technology/design of the RC3000 and RC3300 series of sub-C NiMH cells vs normal off-the-shelf-at-RadioShack C-size NiNH's in the blister pack on the battery rack. But I'm probably asking this in the wrong forum. lemlux's response leads me to believe that there is indeed a difference between the RC industry NiMH's and the consumer-level ones, but it's beyond the Amp draws being discussed here for flashlight use.

Velcro: Want to trade? Just kidding.

- Brian