TomTom ONE LE - battery life

[sparky672]

Wouldn't it use more juice turning it on and off due to obtaining a SAT lock every time?

Probably.

But is it a significant amount? Enough to notice a difference in battery life?

I doubt it, IMHO.

 

[Jim101]

Is it possible to make an external battery pack to plug into the TT when you are "Walking around" with it? If it could use an easy to get/cheap to buy, like AA's, it might work....I have one for my iPod. Any ideas?

Jim

 

[sparky672]

Is it possible to make an external battery pack to plug into the TT when you are "Walking around" with it? If it could use an easy to get/cheap to buy, like AA's, it might work....I have one for my iPod. Any ideas?

Jim

There are threads here that discuss that exact thing.

If you get 4 AA batteries and use the expensive rechargeable type, you'll get another couple hours.

 

[Smokiewolf]

What kind of external "battery pack" can you buy that plugs into the Tom Tom?

 

[sparky672]

What kind of external "battery pack" can you buy that plugs into the Tom Tom?

Anything with a standard USB port.

They make these for iPods but with a TomTom, you would probably want to use rechargeable type batteries. The TomTom will use a lot more power than an iPod.

 

[Delexed]

Better life: plugged or unplugged?

Assuming one is making trips primarily of less than an hour, is it better for the battery (life) to always plug in or to operate on battery until run down?

 

[y0bailey]

I just built one of these battery packs. Here is a how-to: Charges my Zune, and I tried it out on my TomTom and it works great.

I finally got a zune battery extender up and running. I am bored and on winter break so I have been practicing my soldering skills and trying to use my noggin and make a charger. Here goes, this is windy.

I went through my battery box and found 4xAA 1.25v nimh cells. If you run these in series that will give you 5v of juice. (4 times 1.25 = 5v yay!). Bought the 4xAA battery box w/ switch for $1.99 at radio shack and soldered it to an old female usb jack (This battery box runs them in series for you, so no soldering directly onto the batteries).

http://www.radioshack.com/product/i...ry holder&kw=battery holder&parentPage=search

I just plugged my old ipod into it and it showed the charging icon beautifully. I then plugged my Zune in and the charging symbol only showed up for one rotation, then stopped. My guess is that it is slightly undervolted and the zune is confused. I am draining my zune down to 3/4 power now, then plugging it in while the zune is off to see if it will actually charge.


Day 1: After all night waiting to see if this works I have good news....it does!

I played a full video, losing about 3/4 to 1/2 charge. I then plugged in the zune to my battery extender, powered down the zune, and checked back a few hours later. It is sitting at near full power! This bad boy works!

I have a few thoughts. It is likely that this is putting out right under 5v. I found some good information that highish quality rechargable Nimh batteries are fairly good at putting out 1.2v till the bitter end. This gives me 4.8v of charge, and 2500mah of backup power with no external circuitry. I only have theories to why the zune doesn't actually show the device as "charging" while the battery pack is attached. It is probably because the voltage is slightly on the low side, and the zune probably uses all 5v the USB can supply. Not getting all 5v = not showing the charging sign (despite the battery pack still supplying power)

I did a little more research and it is "possible" that the zune battery could actually charge the battery pack if the pack lost all of it's charge. Unlikely, but I am going to install one little piece to not let this happen. To avoid this a simple diode from radioshack can be installed.

http://www.radioshack.com/product/index.jsp?productId=2062577&cp

Day 2:

Alright so everything is finished! It is 100% working!

I installed the diode today, then repeated my "movie test" with the exact same settings. After the entire movie was complete I checked the battery level, and I am happy to report it was showing a little GREEN fully charged battery! So after 1.5 hrs of movies the Zune was still 100% charged. I will be leaving town till wed so I won't have any time to do further testing such as total time it will run, but despite the "battery charging" icon not working it is 100% functioning!

Here is a pic of the final setup. I am not going to bother making it look better, because frankly I don't care about appearance just function!

Final parts list

1) radio shack "battery holder." I used 4xAA, you can use 4xAAA if you want a smaller less powerful charger. (In theory this is a 2500mah charger. I believe the default Zune battery is around 800mah (correct me if I'm wrong) so this should "extend" for about 3x the normal battery life)

2) 1 diode linked to above. This is just for safeties sake...I'm not sure it is 100% necessary. I am no engineer so who knows, it is just good information I found on the web. Plus it's $1.50!

3) 4xAA RECHARGEABLE nimh batteries! This is crucial so you don't overvolt your Zune. The nimh batteries give off 1.2v, while the standards give off 1.5v. Make sure you read the information off the battery before you attempt this!

4) Female USB port. I found mine in a box full of old crap.


Directions to make:

1) Solder battery holder red lead to diode (in the direction shown in the picture), then to the red lead of the USB female connection. Repeat with the black lead but no diode needed.

2) Insert batteries.

3) ?

4) Profit!

Let me know if you have any questions! I am no engineer so if this explodes your Zune you can only blame yourself for listening to me! That being said as far as I can tell this is going to be safe and not harm your Zune in any way. I have been using it for 2 days an no side effects.

Day 3: Ummm this thing will give me at least 40 hrs of music play....I gave up after getting that far. Pretty bad assed.

 

[sparky672]

I just built one of these battery packs.

I just plugged my old ipod into it and it showed the charging icon beautifully. I then plugged my Zune in and the charging symbol only showed up for one rotation, then stopped. My guess is that it is slightly undervolted and the zune is confused. I am draining my zune down to 3/4 power now, then plugging it in while the zune is off to see if it will actually charge.

I have a few thoughts. It is likely that this is putting out right under 5v. I found some good information that highish quality rechargable Nimh batteries are fairly good at putting out 1.2v till the bitter end. This gives me 4.8v of charge, and 2500mah of backup power with no external circuitry. I only have theories to why the zune doesn't actually show the device as "charging" while the battery pack is attached. It is probably because the voltage is slightly on the low side, and the zune probably uses all 5v the USB can supply. Not getting all 5v = not showing the charging sign (despite the battery pack still supplying power)

I did a little more research and it is "possible" that the zune battery could actually charge the battery pack if the pack lost all of it's charge. Unlikely, but I am going to install one little piece to not let this happen. To avoid this a simple diode from radioshack can be installed.

2) 1 diode linked to above. This is just for safeties sake...I'm not sure it is 100% necessary. I am no engineer so who knows, it is just good information I found on the web. Plus it's $1.50!

3) 4xAA RECHARGEABLE nimh batteries! This is crucial so you don't overvolt your Zune. The nimh batteries give off 1.2v, while the standards give off 1.5v. Make sure you read the information off the battery before you attempt this!

I am an engineer...

I'll just comment on something you mentioned. For charging to occur on anything from car batteries to small electronics, you do need the voltage slightly higher on the charger than the battery being charged.... otherwise you could create a situation where the drained battery is charging the charger.

I would hope that the circuit in the Zune, TomTom, iPod, etc. would prevent the device itself from supplying power back into the USB bus. However, not seeing the Zune indicate charging mode is most likely due to the lower voltage of your charger.

You seem to have figured this out on your own so I'm only confirming.

I would suggest finding a schematic online of another home built USB charger. I do believe there is a bit more to the charger circuit than only a single diode. Personally, I believe it would be better to use more batteries to boost the Voltage (also get more mAh as a bonus). Than add a circuit to regulate the voltage down to something in the high end of USB's voltage range... 5.2 Volts, perhaps? However you could compare notes to see how others have been doing it.

 

[y0bailey]

Hey Sparky. Good comments, and luckily I thought about all of them before.

The purpose of the diode is to prevent any juice running from the zune/tomtom back into the charger. It is a one way street. That will prevent any leeching back into the batteries from the device.

Also the batteries inside the zune/tomtom are all 3.7v lithium ion batteries. So as long as 1 of the battery cells doesn't completely die, the battery pack will always be putting out a higher voltage than the battery in the zune/tomtom.


I did try to boost the voltage to the zune up to 6v and it still didn't show the device as charging. This problem occurred with a large amount of 4th generation ipods, and it ended up being that they would charge but they needed to be plugged into the computer to actually show they were charging.

Like I said, build at your own risk, and please more criticism. I want to know if the design has any flaws that I haven't addressed. I know there are more complex designs out there, but this one costs $3.50.

 

[sparky672]

Like I said, build at your own risk, and please more criticism. I want to know if the design has any flaws that I haven't addressed. I know there are more complex designs out there, but this one costs $3.50.

What may seem like useless for lack of understanding may protect your device from accidental damage.

What's in the more complex/expensive circuits that's missing from yours?

 

[y0bailey]

There are 2 different types.

One type uses a boost regulator to take AA's up to 5v steady. More expensive, requires more parts and a few of them are harder to find. The design uses 2 standard 1.5v AA's.

The other types use either 9v or 9v+AA's and adds resistors to bring it down to 5v. Wastes energy and 9v's don't provide very much juice in terms of mah's compared to AA's.

My design is simple as hell, but depends heavily on the quality of your rechargable AA's. I wouldn't stick a no-named brand in there. My friends multimeter showed this thing putting out 4.7volts at best, and dropping down to 4.5 volts at its worst (when the batteries have lost most of their charge). Luckily that is still above 3.7v's the lithium ion battery in the devices need. The battery choice saves the need for more expensive circuitry.


For me this is only used for long road trips (for my mp3 player so I can watch videos), or long plane flights. It would be perfect for the occasional long hike with your tomtom. I don't use it day to day, and I always make sure my rechargable batteries have adequate charge.

 

[sparky672]

There are 2 different types.

One type uses a boost regulator to take AA's up to 5v steady. More expensive, requires more parts and a few of them are harder to find. The design uses 2 standard 1.5v AA's.

The other types use either 9v or 9v+AA's and adds resistors to bring it down to 5v. Wastes energy and 9v's don't provide very much juice in terms of mah's compared to AA's.

My design is simple as hell, but depends heavily on the quality of your rechargable AA's. I wouldn't stick a no-named brand in there. My friends multimeter showed this thing putting out 4.7volts at best, and dropping down to 4.5 volts at its worst (when the batteries have lost most of their charge). Luckily that is still above 3.7v's the lithium ion battery in the devices need. The battery choice saves the need for more expensive circuitry.

For me this is only used for long road trips (for my mp3 player so I can watch videos), or long plane flights. It would be perfect for the occasional long hike with your tomtom. I don't use it day to day, and I always make sure my rechargable batteries have adequate charge.

It seems like you did your homework. I'd also stay away from the design with two AA's because it won't give you very many mAh either.

It's not practical for walking due to weight, but if you just need extended power away from your car or home (for biking perhaps), you can hook a female lighter adapter to any 12 Volt battery. Then use your TomTom car charger cord. Total cost is $2.85 without the battery or zero if you have a socket already.

https://www.tomtomforums.com/showthread.php?t=4626