Fitting the MaxAmps 2600mAh Extended Battery to the a R Drone

Intro: Fitting the MaxAmps 2600mAh Extended Battery to the a R Drone

The A R Drone comes with a 1000mAh Lipo battery, but the short flight time of this cell quickly proves frustrating. At the time of writing, there is only one significantly larger capacity battery that I'm aware of that is ready to use, which is the MaxAmps 2600mAh pack sold at their site and through Amazon. The ad boasts 'guaranteed fit', which I expected would mean a guaranteed good fit, though in fact it turned out that it merely meant that you can get the hull of the drone back on successfully with the battery in place. The battery is actually a very poor fit - not one of its sides shares any dimension with the original battery compartment, and in fact it slides back and forth even when tied down by the velcro strap.

The impression that it would be a good fit was bolstered by an image of the product on the web sites that looks like the size and shape of the original battery, but which looks nothing like the battery that was delivered.

Whether it was the extra weight, or the battery sliding about in flight that caused it, or just an unhappy coincidence - our drone lost control and dived straight for the nearest wall when we first tried to launch and hover, with the Maxamps battery in place. Result, a broken cross piece and a long wait for replacement parts.

So this instructable will show you how to install the maxamps battery so that it doesn't slip whilst in flight and as a bonus you'll also see my hack repair of the central cross piece using JB Weld -- a stop-gap measure just to get back in the air until Amazon get the replacement parts back in stock. (Must have been a lot of people bought these for Christmas and have broken them already!)

Here is what the MaxAmp ad promised... a nice professionally finished product that looks to be about the right size and shape to be a drop-in replacement for the stock battery,

STEP 1: Comparing the Batteries

And here is what was actually delivered (right hand image.).  A short squat pack that looks like it must be made from two separate cells, held together with electricians tape.

The stock battery is on the left for a size comparison.  The drone's battery compartment is an exact fit for the stock battery, which means that the replacement 'guaranteed fit' battery is narrower, shorter, and therefore slides around under the accelerations of flight.

The replacement is also obviously taller, but surprisingly it does just fit under the hull, which I guess is what justifies the 'guaranteed fit' claim in the ad..

STEP 2: Mind the Gap

So here's the problem we have to fix - the gap at the side and the end of the new battery.  We'll fill that gap with foam...

STEP 3: Cut the Foam to Fit the Battery Compartment and the New Battery,,,

Cut the foam to fit between the battery compartment and the new battery,,,

The new battery doesn't fit with the existing velcro strap, so you need to strip your drone down to remove it and fit the replacement strap that came with the battery.  Fortunately I had mine stripped down already, to fix the broken central cross piece. I don't remember seeing it mentioned anywhere that you have to strip your drone down to fit the replacement strap.  It's quite a chore and requires a toolkit which the manufacturers sell on Amazon.

STEP 4: Repairing the Central Cross Piece

Like many people waiting for their replacement parts to arrive, I made a temporary repair of the cross piece using plastic epoxy to hold the pieces in place (it didn't make a very strong bond), and then covering the central area with JB Weld in order to give it structural support.  This was a lower extra weight compared to molding a support from PCL, and much faster than waiting the several weeks it takes for Sugru to cure hard enough to take the strain.  I don't expect this to last, but I want to get in the air again!

Comments

[XOIIO]

Just wondering, have you found or seen any other batteries that offer a longer flight time or should I shell out for a second/third battery?

[ChelseaM16]

Look on HobbyKing - they have two upgraded batteries that are exactly the same physical size as the stock battery (they use the same hardshell) I believe they have a 1500mah 20C pack and a 2500mah 15C pack.

[XOIIO]

How much longer does this battery last?

[gtoal]

Don't know, we never used it. The extra weight makes the craft unstable - maybe if the controlling software were modified to take into account more weight it would be OK.

[XOIIO]

Oh, really? The site says that its made for outdoor longer flight times.

even with it fitted it doesn't work? Prhaps I should just buy some secondary batteries

[gtoal]

Well, what happened was that when my wife flew it with this battery, it was unpredictable and sometimes darted off to one side. Definitely not bad piloting - she's pretty good with it. After the drone headed straight for the nearest wall and broke the central cross (which was expensive to replace) she decided not to take the risk of it happening again.

Perhaps with a large open space to practise in and a lot of time learning to compensate, it might have been usable, but we decided it wasn't worth the risk. The handling was very very poor.

I think a tweak to the software could make a difference, especially with hovering, but as far as I know neither of the sources of control software plan to make that change.

So yes, it flies, it just doesn't fly well. And without the mod to hold the battery in place it was even worse!

[XOIIO]

damn, thats sucky that theymislead you like that.

[gtoal]

Just to let folks know, we've now flown quite a bit since the repair to the broken central cross, and it is holding up well! I forgot to mention (though you can see it in the second image on the last page) that I used the quick-setting 5-minute version of JB Weld, and it seems just as good as the traditional style that takes half an hour to cure. It's holding up so well that we've cancelled our order for the replacement cross!