Although a kill switch is the best protection for your Rampage, a voltmeter like one of these Hobbico Voltwatch units is also great for monitoring the charge level on your receiver pack.
Simply plug the Voltwatch into the third channel port on your receiver and it will show you the level of charge via LED lights. Once the LED turns yellow, it's time to bring your Rampage in for a charge or fresh receiver pack.
By the way, if you purchase a Voltwatch on Amazon, please use one of the links in this post and I'll earn a small commission from Amazon.
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