How to fit a TomTom ONE replacement battery
There are two key things to replacing the old dead battery:
1. Finding a suitable supplier of the new battery which is compatible with the original.
2. Finding the correct security tool to undo the security bolts holding the back of the Tom Tom in place.
Disclaimer: You may invalidate your warranty or guarantee by opening the TomTom unit, however given due care and attention, and the correct tools, replacing the battery is a fairly easy job, and can be done in about 15 minutes. You have been warned! If you are unfamiliar with working inside electronic products and their components, seek help from a friend who is more confident with this kind of thing.
Removing the TomTom back with the correct Security Tool.
WARNING: Before you start, make sure you have done the following:
1. Backed up the contents of your TomTom, i.e. everything on the SDRAM Memory Card.
2. Unplugged any charger unit.
3. Turned off the TomTom unit.
4. Removed the SDRAM memory card from the memory slot so as to prevent any potential damage to the card. Nothing is likely to happen, but better safe than sorry.
The trickiest part of replacing the battery is that TomTom have rather sneakily used special security bolts to hold the back onto the TomTom which for V1 models require a special hexagonal Allen-key type tool, but they have a central stud which prevents a normal hex allen key tool being inserted. This means the corresponding male tool bit must have a hole in its middle (see the pictures of the tool sets below).
I suspect this is done so that us average Joe's don't like the look of it, and think "Oooh, that looks a bit tricky, I suppose I had better send it to TomTom (or one of their dealers) to replace the battery and pay them an exhorbitant fee plus postage for the privelege!".
Having said that you might be able to find a local dealer who is willing to replace the battery for you cheaper than the total cost of getting the parts to do the job yourself. Bear in mind that the alternative of sending your TomTom away may involve additional delivery insurance costs!
So unless you have one of these special security tools (or know a friend who does) you will need to order a small tool set at the same time that you order the battery. I found a 33-piece toolset at which cost £8.99. I considered this was O.K, given that there were a good variety of bits in the set, and these could come in handy in the future, given that more and more products are being fitted with security type bolts.
Maplin part GU60Q 33-piece Security Bit Set
Note: The smallest size Torx key security bit in this set is size 8 (the Torx keys are the star-shaped bits in the row nearest to you in the photo below, with the size 8 at the furthest right).
The 2nd row from the front is Allen-key style security keys, which are the main ones you use for TT One.
The first step is to remove the four angled rubber grommets protecting the security bolts. This is done by gently prying them out with the tip of a small screwdriver.
Once removed you have access to the security bolts. You have turned off the unit, and removed the SDRAM Memory Card haven't you?
Undo the security bolts using the correct size and type of security tool bit. In fact I found very slight differences in the size of the bolt hex opening, which meant I had to use different tool bits for different bolts! Nice quality TomTom (not)!!
Once all four bolts are removed carefully the back off. Note from the photo below that there is a fairly short lead on a connector attached to the loudspeaker in the back of the case, so don't rip the back off or you'll damage the lead or connector. While working I simply unclipped the connector so that the whole back could be removed and put aside. Don't worry, the connector can only be inserted one way around due to keying, so it ensures you can only reconnect it the correct way.
Removing the Old and fitting the New Battery.
Inside there is some black tape sticking the battery lead to the PCB (printed circuit board). Carefully lift the tape off the board with your fingers (don't use any sharp implement as you could damage the circuit board).
Disconnecting the battery plug should be done carefully because the plug and socket look similar - do not accidentally pry the socket off of the board. You might break off the solder connections when all you wanted to do was remove the plug. Gently unclip the battery connector from the socket on the board, by pulling the plug away from the socket. Note: Some Tom Tom models have the battery plug/socket mounted horizontally against the circuit board (as shown in the photo above), while some have it mounted vertically. Basically you should pull in the direction the wires come out of the plug.
The photo below shows the new battery in place because I took the photo after I had removed the old battery. Anyway, the old battery was stuck down very firmly with a kind of cushioned sticky-pad. This required considerable effort to remove the old battery from the unit, and I had to use a wide-tipped flathead screwdriver blade to gently but firmly prise the battery and sticky-pad up and off the battery mounting pad. Be very careful not to force or break the case or the surrounding components. As the sticky-pad starts to lift and come away it will get easier to lift off, so do it nice and slow and easy.
Once removed, you need to take the double-sided sticky pad off the old battery, and fix it to the backside of the new battery.
Tip: (from Eric Woolford in Australia) Thanks for your article as I managed to change out my 720 Tom Tom battery. Just one technique that I learnt over the years is to use a plastic knife dipped in some olive oil then to push behind the battery. This will lube the adhesive as the knife passes behind. By doing this it will not cut any circuitry that may be behind the battery and will prevent the adhesive from grabbing once apart. I found that most of the adhesive stayed on the circuit board. In order to stick the new battery down, I used a couple of
small dots of clear silicone.
Warning: Before you go sticking that new battery back into place, check its positioning very carefully. My new battery was very slightly larger dimensions than the old battery, and it only just fit into place in the recess on the inside face of the case back when the back was replaced (see 2nd pic below). The first time, I just stuck the battery into place without realising, and the back would not seat down properly, so I had to remove and reposition it again.
Do you see how the case back has a battery recess lip? Look just to the right of the circular loudspeaker, and you can see a rectangular lip and then two slightly more raised L- shaped lips. It's the higher raised lips that the battery has to sit between, otherwise the back won't go on properly.
With the battery back into position, you can;
• plug the battery connector back in paying attention to the correct way around,
• re-affix the black tape to hold the lead to the circuit board
• reconnect the loudspeaker connector lead (if you undid it)
• re-insert the SDRAM memory card ready for a quick test
Now, before replacing the back you should try turning on the TomTom. Usually new batteries are only slightly charged (perhaps only 1/8th or 1/4 capacity), so don't expect it to be full, but hopefully there will be enough charge for the TomTom to start up and show that it is working ok.
So that's it. If all is well turn it off again, and put the back into place, being sure that you don't trap any of the wires where they might get squeezed, then fix the back with the bolts, and put the rubber grommets back in their holes.
IMPORTANT: Put the unit on charge for a full 24 hours to bring it back up to full charge. Next day leave the unit on for several hours so as it runs down. The unit should stay alive for several hours. Drain the battery totally. Recharge to full and then drain again, before final charge.
Doing this is the best way to "prepare" the new battery for a long life.