Box Mod / Box battery advice

jono987

Another slight niggle with mine, i have noticed it has just started making a very light 'hissing' kind of noise when fired; just as the button is pressed but before the tank starts to make its noise. I think this may be rattlesnaking? Not sure

oska

I've not noticed that with mine. My Zmax used to rattlesnake but only after being fired, not before. Does it do it in both PWM and DC-DC modes?

jono987

Only when in PWM mode, is there any harm in me keeping it in DC-DC mode?  I still dont fully know the difference

oska

I'll be honest, neither do I really. The only thing I noticed is with a 1.4/5 ohm coil it's better in PWM but with a 1.7/8 ohm it's better in DC-DC.

Mostly it's been in PWM this week but if I fancy a stronger hit I switch to DC-DC.

Stuart

The chip in the sigelei 30w cannot give out lower than the battery voltage so it needs to pulse the voltage to give an effectively average lower output to match the selected wattage and coil resistance, this is known as PWM (pulse width modulation). This can result in a rattlesnake/rasping effect.

In DC-DC mode, it is a flat signal (no pulsing and no rattlesnaking) but can only be output at or higher than the battery voltage.

However, if you have PWM mode selected, as soon as the required voltage is above the battery voltage, it will automatically become a boosted DC output. So you only get PWM when required voltage is below battery voltage.

If you have DC-DC mode you will not be able to get a voltage below the battery voltage, no matter what the display says.

Described well below. It's a different device but the same chip. Watch from 23:46 for the relevant part.

jono987

Thanks for that Stuart, i returned mine today as the noise when in pwm was really annoying. My friend has also just got the same mod and his dosent do it.

oska

Another thanks, I had a look for IPV mini reviews as it's basically the same as the Sigelei and the PB one didn't pop up. Certainly gives a bit more info on how the chip performs, cheers.