Battery mAh and Voltage Q about Ultrasound

[ThreeQuadFive]

Hello all.

I did some searches but didn't find the answer I was looking for (*ignores the forum waving its hand*).

I have a couple of battery holders...2AA, 4AA, and an 8AA which I think I need to take back because I thought it was a slim 4AA but woops :)

I also have some rechargeable batteries I bought last week or so.
They are of the Duracell brand, and are rated (each) 2650mAh. The battery states further: AA/HR6/DC1500 iMH/1,2v (so...1.2volts each).

Reading up on the Ultrasound info, it looks like a max of 10 volts can go in..but what about maH? I see the trustfires are 900mAh each, totalling 1800mAh, but i'm not sure if two of these rechargable batteries would be overkill...and before I try it out and fry my board, I wanted to ask first :)

[Lord Maul]

mAh is a measure of battery life, not power. It stands for "mili amperes hours"

[ThreeQuadFive]

Ah, so in that case, would it be ok to use just two of the AA's then or would that be seriously underpowering things??

[totuss]

yeah 2 AA's would only be 2.4v , u generally need to supply a min of 1 volt more than the led wants (the led driver will consume this)

so for a lux 3 , k2 , soul p4 for e.g
its 4x AA's or if u are tight on space 4xAAA's or 2x AA size trustfires
AA's would have a longer runtime
AAA's and trustfires about the same runtime
trustfires are recomended for U.S 2.0 for their power stability.

u could maybe even run a lux5 with 2x trustfires tho its cutting it fine
lux 5 needs 6.85v and 700mah

example
so 4x 1.2v 1000 mah AAA batteries wired in SERIES would give 4.8v 1000mah
4x 1.2v 1000 mah AAA batteries wired in PARRALLEL would give 1.2v 4000mah

an led needing 1000 mah and a battery pack suppling 1000mah and the correct voltage would last approx 1 hr, an led needing 700mah would last 1.4 hours (1hr 24mins approx)

so u need to balance the led requirments (voltage and mah) and space available (how many batteries of what type u can fit in to provide enough voltage) with how much runtime u want (the mah of the batteries divided by the mah needed from led = approx runtime), its a trade off

anyway hope this helps you to decide wich power option to go for.
but from what it sounds like u have at the moment u would be underpowered useing 2 of the duracells
i think 2 trustfires should be ok the ultrasound will burn off extra voltage as heat tho so dont wrap the board up cosy
good luck and mtfbwu

tot

[ThreeQuadFive]

So 4 of the AA's @ 2650mAh is OK though? That won't kill it or anything?

[Lord Maul]

No, you're fine.

[totuss]

yup thats what i run in my 1st custom hilt ,u will have great run times too :D

[Jedi-Diah]

"mA" is current but "mAh" is a measurement of capacity. It gives you an idea of how long it will last. AA and AAA batteries have the same voltage but the AA lasts longer than the AAA because it usually has more "mAh".

Its kinda like "miles per gallon" (or maybe the size of the gas tank). It doesn't tell you anything about how much power or speed a car has. It just tells you how far it will go on a tank of gas.

The higher the "mAh" the better but it usually means a bigger battery and less space in your hilt.


So 4 of the AA's @ 2650mAh is OK though? That won't kill it or anything?