Too high MaxaBeam current consumption?

[Lurveleven]

I measured the current used by my MaxaBeam (Gen2) when hooked up to a 12V 12.5A power supply through a cigarette lighter adapter, I got 4.84A on normal mode and 10.2A on high mode. The voltage from the power supply was 12.12V at normal mode and 12.06V at high mode, that means my MB used 58.7W at normal mode and 123W at high mode. That seems very high to me, is this normal or is the lack of voltage sag from a battery pack causing the high current? When looking at the stated runtime numbers and Ah ratings of the battery packs, I don't see how they can achieve those runtimes if the high mode is as high as on my light. They rate their Li-Ion pack 7.2Ah with 75 minutes runtime, but 10.2A for 75 minutes would require a 12.75Ah battery pack. I read that the NiCad pack uses 10 F cells so its voltage under load should be less than 12V.

Has anyone else done similar measurements? Anyone got a high current variable voltage PS they can use to test different current use at different voltage?

Does anyone know what the input voltage range is on the MB? I'm planing to make my own battery packs using A123 cells (4 in series). Does the light shut down before it reaches 8V?

Sigbjoern

 

[Ra]

Hi Lurveleven,

123watt indeed is quite a lot !! Even when we take about 85% for electronics-efficiency (mostly, the efficiency is about 90%) we're looking at about 105 watts provided to the lamp. Thats high, but not catastrophic: The gen-2 should switch back to nominal power after about 18 seconds to prevent the lamp from overheating! (with high-power mode set at continous: there also is the possibillity to set it to momentary-mode)


But high-power like this shurly shortens lamplife !!

If you don't have much electronic skills, just leave it the way it is: The high-power wattage is settable on the ballast, but you must know what you are doing !
Just don't use it at high-power unless you really want to impress friends, neighbors, animals, aliens and others..:duck:

If you use it, use it no longer then 10 seconds: pushing the "joystick" to the right a second time switches the lamp back to nominal power before timed safety steps in..
I'm sorry, but Maxabeam just isn't build to be a lumens-monster !!

I measured about 8.5 Amps on the high-setting of my MB..

As for your last question: The gen-2 shutts off when the voltage drops under about 9.5volts (give or take 0.5 volts..)

I think the voltage-range is 9.5 to 14 volts... (have to look up that one, so the 14 volt is taken on the safe side..)

I don't think using A123-cells for a battery-pack is not a good idea, better use 18650's..


I hope this is sufficient to answer your questions..


Best regards,

Ra.

 

[SDS]

Hi Sigbjoern,

Your current draw looks OK to me. The Nimh pack on mine gives me 5.4 amps on low.

I built and use a LiPoly pack (4 series x 2 parallel with protection circuiting) which has a fully charged load voltage of 14.8v . I haven't experienced failure after a year of use. Component life may be reduced but it is BRIGHT.

Li-ion 123's in a single series pack won't handle the current draw unless you set up 4 or 5 series packs in parallel. Several people have posted threads on CPF as to their attempts to build re-chargeable Li-ion packs for this light, and I wouldn't recomend it for safety reasons, unless you have an electrical engineering background.

Enjoy your light.

Steve

 

[Lurveleven]

Thanks for the very useful information. A clearification about the cells I'm planing to use, it is not the small R123 cells, but these high current cells. Even a single 4S1P package is able to drive the MB at high power. They have less Wh/L and Wh/kg than 18650, but are safe in use and have superiour cold performance (which is very important to me). And now that I know that the MB shuts down at 9.5V I don't need to add a LVC to the battery pack.

Sigbjoern

 

[Ra]

Whhoww,

Those are some powerfull cells !!!

Yep, you're right, that would work !

Thanks for sharing the info..


Regards,

Ra.

 

[LuxLuthor]

Thanks for the very useful information. A clearification about the cells I'm planing to use, it is not the small R123 cells, but these high current cells. Even a single 4S1P package is able to drive the MB at high power. They have less Wh/L and Wh/kg than 18650, but are safe in use and have superiour cold performance (which is very important to me). And now that I know that the MB shuts down at 9.5V I don't need to add a LVC to the battery pack.

Sigbjoern

Are they making them available in a test/developer scenario that I saw on the other web page?

 

[larryk]

Lux, it is more economical to buy a 36 volt DeWalt battery pack and take it apart for the ten A123 cells inside. They cost about $ 130.00 on Ebay. These cells can really crank out the amps are much safer than other Li-Ion batteries. One problem is they charge up to 3.6 volts and discharge to 2.5 volts. And you will need yet another charger for these cells, or a lipo adapter like the one in the link.
http://www.slkelectronics.com/lipodapter/index.htm

 

[Phased_Array]

What is the successful configuration of a LiIon battery pack for the Maxabeam? I tried 2-in-parallel , protected AW 18650's 3-in-series, but kept blowing the protection circuit in the middle batteries.

 

[LuxLuthor]

Lux, it is more economical to buy a 36 volt DeWalt battery pack and take it apart for the ten A123 cells inside. They cost about $ 130.00 on Ebay. These cells can really crank out the amps are much safer than other Li-Ion batteries. One problem is they charge up to 3.6 volts and discharge to 2.5 volts. And you will need yet another charger for these cells, or a lipo adapter like the one in the link.
http://www.slkelectronics.com/lipodapter/index.htm

Yeah, I have been waiting for Hyperion to have the relatively free upgrade process setup for the 1210i to charge those new cell types.

It's not gonna be long before the makers of these Lithium phosphate cells figures out who is snapping all them up, to get a better market on them...even this $79 has turned out with most all cells working

I have read on RCGroups that these cells are lasting 1K-2K charges in Dewalt drills...and much safer--without the lithium combustion issue. Apparently many are getting them now at BigERC.com

 

[Lurveleven]

I bought them in 4S1P Solderless Power Tubes packs here. They also sell loose cells at $15.5. The cells should not be soldered, so I think Solderless Power Tubes is the way to go with these cells.

Schulze sells chargers that are able to charge these cells (from firmware version 8.41).

Sigbjoern

 

[Lurveleven]

I received my A123 pack today. A single pack had no problem running the MaxaBeam. The current was a little lower than from my PS though, 4.6A (normal) and 9A (high).

The battery pack weighs 12 oz, is small enough to put in my jacket pocket, and should be able to power the MB for 30 minutes in normal mode. In many situations 30 minutes is more than enough, and then this is a much lighter option than the PeakBeam Li-Ion pack. If I need more runtime I can just add some more packs.

Sigbjoern

 

[Phased_Array]

Lurveleven,
Went to the web page... Exactly which setup did you get?

 

[Lurveleven]

Lurveleven,
Went to the web page... Exactly which setup did you get?

Sorry for the late answer (was on Easter vacation). I got the the 4S1P pack (i.e 13.2V 2300 mAh).

Sigbjoern

 

[ShortArc]

Lurveleven,
What run times are you getting with the pack?
Regards,
Willem.

Sorry for the late answer (was on Easter vacation). I got the the 4S1P pack (i.e 13.2V 2300 mAh).

Sigbjoern

 

[Lurveleven]

I haven't tested runtime yet since I don't have the charger yet (I'm waiting for the new Schulze). I estimate I will get 30 minutes on normal mode with my pack.

Sigbjoern

 

[ShortArc]

Thanks Sigbjoern.
The reason I was curious is the difference in low cut off voltage between Gen 2 & 3. Your Gen2 has a lower and supposedly adjustable cut off voltage. This would make your run times longer, linear with voltage I would assume?
My Gen3 cuts out at 10.6V, resulting in the 4S2P pack giving me 1:06H run time. Recharge time with the T.M.E. Xtrema was approx. 30mins. Let me know what you come up with once you receive your charger.
Thanks.