I’ve flown my Hubsan Q4 rather a lot now as I’m currently on my third battery. For the benefit of anybody also looking to fit a replacement, here’s how easy it is. You don’t even need any tools.
All you need is a Hubsan Q4 battery, part number H111-04. I got mine from Robot Birds for £3.95: [link]
The first step is to remove the white plastic bodyshell, which is done by gently prising the two plastic clips at the front of the Q4 free from the PCB.
It’s easiest to remove the front clips first as they can be gently pushed out and up over the PCB. You may be able to move the white plastic body backwards which helps a little.
Once the front clips are out, slide the shell forwards and up to free the two clips at the back, taking care not to break them.
Now pay attention to the orientation of the battery and the wiring which we are about to remove.
Now unplug the existing battery from the PCB, making a note of the orientation. It does have + and – printed on the PCB to help though.
The battery is attached to the top of the PCB using nothing more than a sticky pad. Take a last look at how the battery is fitted, then just gently pull it free.
Remove the backing paper from the new battery. At this point I put the waxed paper onto the old battery so that it wouldn’t stick to anything. Please dispose of the old battery responsibly, don’t just bin it as it is lithium.
With the new battery all ready to fit, this is the point where you think, “where did it actually go on?”. My advice is to place the battery where you think it should go (look at the earlier pictures), but DO NOT press it down firmly. In other words, trial fit it, then put the white plastic shell back over the top to check that you have it in exactly the right position. There isn’t a lot of spare space, so it needs to fit right.
Once you’re happy with the fit, push it down on the sticky pad and connect the power lead. Make absolutely sure the polarity is right as it is very easy to break the connector if it is the wrong way round. There is a + and – printed on the PCB, plus you can have a look at the old battery as the leads are very stiff and it will have kept its shape.
Then tidy up the wiring by doubling it up as in the picture, or just copy how the old battery looks. There isn’t much space, so it needs to be neat and tidy.
Finally, put the body shell back on, reversing the procedure you used to get it off. Push the back clips in first, slide and clip the front ones in.
That’s all there is to it. You should now have a fully working Q4 again.
It was at this point that I switched it back on and wondered why it didn’t work any more. Obviously you need to charge the new battery before you can use it.
30 minutes later and I’ve got a zippy new Q4 flying around the room again. No more heavy throttle stick and 2 minute flight times. Like I say, I’m on my third battery, so they must be a bit marginal on the current drain to be wearing it out so quickly (or the charger is rubbish). Either way, at £4 at time I can’t really complain as this one will last a few more months.