Just filmed an hour long presentation for a local charity without pauses. Half way through I notice there's no battery life icon top left. I was in the correct display mode and the icon HAD been there at the beginning. Just wondered if I have accidentally disabled it some other way than the display mode? Before anyone asks I was using a third party DTSE battery however the battery function has always shown up OK and now I am back at base I can't reproduce the problem at all. The icon stays on all the time.

Incidentally does anyone know a high capacity EXTERNAL rechargeable battery pack that could be used to provide 7.2 volts direct? Many thanks.

The one big drawback with third party batteries, besides the amount of charge they can hold, is that they are frequently not programmed to communicate with the camera properly. I have the same problem with third party batteries with my Panasonic GH cameras. You can not trust the battery indicator at all. Just learn how long they can last and then try to keep track of how long you have used them. I only use JVC approved batteries with my JVC cameras.

Thanks William, the genuine JVC BN-VF823U costs a ridiculous £100 in the UK, whereas I bought TWO higher capacity Chinese DTSE clones WITH external chargers for less than £30. from Amazon.
None of the batteries including the JVC give anywhere near accurate time-remaining indication so I was using the battery bars as a guide only. What I'd like is an external pack for such occasions where an extended record time is contemplated.

My JVC SSL-JVC50 is 175 euro but I got a swit s-8I50 which was about 50 euro cheaper and twice as big, the advantage of the swit battery is that it has a connector that allows me to plug in a videolight while the batter is in the camera, maybe swit has some battery solutions for your hm170?

It's a bit strange, the battery icon and time remaining appears for a few seconds but then disappears never to be seen again with one particular battery clone however I found an external 12v 6.8 mA/hr lithium ion battery pack and charger for just over £30 (meant for a portable remote cctv camera).
It even came with a dc power lead which was a bit short so I replaced it with a 1m cord. So now I have the original JVC battery installed with the external pack in my bag. I get a battery time read out courtesy of the installed battery which is continuously topped up/assisted by the external Li-ion pack. Seems to work fine.