lipo alarm
Lipo Alarm Monitor for the HK450 Helicopter
I use a simple Lipo Alarm Monitor found on eBay, Balance Plug Type, as shown in image. Note the Pins!

Some have CLEAR Red LED’s some have RED Red LED’s
It’s quite simple these will scream “BEEP, BEEP, BEEP, BEEP” at you from across a football field to let you know that your battery has gone low and you need to land. You will hear it as these beep loud.
There are many types available for a few dollars on eBay, what you need to do is ensure that it is the type that plugs into your balance plug!
There is no use checking across the entire pack if one cell goes down then you kill your pack, so again make sure you get the one that plugs into your balance plug. Currently Hoby King do not have this type.
Regards
Elias Gourvelos (EatAtJoes)