Boro

iTrader: (1)

If a device uses an 8.4v 1600maH battery but runs better on 9.6v. If the maH was the same would it last longer, less or just the same?

Luminous

iTrader: (3)

power = amps x voltage

maH is energy (power capacity)

So, if it runs better at a higher voltage, assuming it draws the same current, then it will not last as long with a 1600maH battery.

RobsyUK

iTrader: (2)

I wold have said it wouldn't last as long. But then I don't known maths

Boro

iTrader: (1)

If it draws the same current and the capacity is the same how come it doesn't last the same amount of time? I'm guessing it's because the voltage is higher but can you explain why that is?

brendy76

iTrader: (6)

Mah is the figure you want to worry about when looking at longevity between charges, the higher the better.

Cockney Wideboy

iTrader: (2)

Assuming the power requirements of the device remains the same the upping the voltage would reduce the current required (Power = VxI)

Therefore if both batteries can deliver 1600maH then the 9.6V battery should last longer.

the mAh is what the battery can theoretically delivery of 1 hour...if you draw less than that the battery will last longer than an hour...

Boro

iTrader: (1)

Oh, two different opinions lol. Who's right? Haha

AndyC_772

iTrader: (2)

It'll last a bit less time, probably.

If it "runs better", I'm guessing you're talking about a motor rather than an electronic device as such. In that case, the higher voltage means the device will be drawing more current, and the mAh rating of the battery is a measure of how long it can supply a particular current for. More current = less battery lifetime for a given mAh rating.

Cockney Wideboy

iTrader: (2)

It may help if we know what you are powering..if its a striaght resistive load (i.e the power requirments remain constant) then increasing the voltage will reduce the current draw and therefore the battery will last longer

Boro

iTrader: (1)

It's an electric airsoft gun. So powers a motor yes.

Cockney Wideboy

iTrader: (2)

it’s been a while since I’ve looking into this sort of thing but I do believe that only if the load on the motor is increased will it draw more current...increasing the voltage will increase the speed of the motor but not the current drawn by it

Boro

iTrader: (1)

At the moment it uses an 8.4v battery which just about lasts the day. I'd like to put in a 9.6v which gives a higher rate of fire and better trigger response, but ideally don't want it to only ast half a day, for example.

Cockney Wideboy

iTrader: (2)

This is bugging me now and I’m beginning to doubt myself...it’s been a long time since i studied Ohms law, resistive loads VS inductive loads etc...

Maybe get a stop watch and time how long it lasts I'm almost tempted to dig out my old text books and re learn this stuff...as this proves you never know when it may come in useful

andy97

iTrader: (1)

A 9.6v battery with the same mAh will last longer because it's voltage will be maintained for longer as its replacing an 8.5 volt battery. So if the device stop working say at 7.5v. Then a higher voltage will sustain the device for longer.

gpssti4

iTrader: (6)

P=I*V

The battery with the higher voltage can supply more power and hence the motor will run faster (better?). This should be for a similar length of time as the lower voltage battery, maybe a little longer as the motor can work off a lower voltage, but it really depends on the battery type, i.e. with the old NiCd type rechargeables the voltage drops off less rapidly than NiMH. With a NiCd battery in my old bike lights from 20 years ago is would slowly get dimmer and dimmer over an hour or so, but newer NiMH batteries would work well for longer then go from bright to dim over a few minutes (bit like scoobynet these days!).

AndyC_772

iTrader: (2)

With a resistive load, the current is proportional to the voltage. V=IR. Increasing the voltage will increase the current.

Power would only remain constant if there were an intelligent controller in between the battery and the motor, maintaining a constant voltage at the motor. A crate of beer says there isn't.

AndyC_772

iTrader: (2)

You're right that most of the power drawn by a motor is a result of the mechanical work it's doing on its load - but if the voltage across it is increased, it'll exert more force on the load and therefore do more work. That in turn requires more power.

Boro

iTrader: (1)

I didn't think it would be this scientific lol. I was hoping for a unanimous yes or no lol

burbling1

iTrader: (1)

The battery will last longer but will the device your putting it in? Someones obviously designed this device to run on 8.4vs and your upping the vs so for the extra power is it going to shorten the life of your device. Im not saying it is but...

Boro

iTrader: (1)

Yeh that's a possibility but the weak link in the chain is the piston which is easily replaced and cheap. At that point I would upgrade it to a stronger type.

It's similar to tuning cars in some respects, it's just finding the next weak link and making it stronger and so on, etc.

11.1v Lipo would kill it quicker lol