External Battery Pack Garmin 500

[rob]

I have been using a Garmon 500 for training for the last few months and I intend to use it in time trials during the season.    Looking at the battery life I'm getting it will do a 12hr TT - just - but I would like to use it for the Mersey 24.

I have found this external battery pack :-

http://www.amazon.co.uk/Gomadic-Advanced-Garmin-compatible-Battery/dp/B0041L0NG0

Does anyone have any experience of this or could suggest an alternative ?

Thanks


Rob

[frankly frankie]

Is there something special about the Garmin 500 voltage requirement?  Won't any USB power pack do the job?  'Cos that's awfully big - it would probably power the GPS for a fortnight!

[Kim]

IIRC the Edges are fussy about what you do with the data lines to signal the presence of a dumb power source rather than a USB host.

[rob]

Is there something special about the Garmin 500 voltage requirement?  Won't any USB power pack do the job?  'Cos that's awfully big - it would probably power the GPS for a fortnight!

From what I've read elsewhere the 500 goes into sleep mode when you're charging so won't continue recording unless you have the right sort of connection cable.    This is where the technology gets a bit beyond me.

One suggestion I found said carry 2 500s and swap them over at 12hrs.   I think that's an expensive way of getting a solution.

[Feanor]

I can't really say about the 500, but the 800 is as un-fussy as it gets.

I can use any random USB cable from the rat's nest, and any random USB power pack or wall-wart, and it always Just Works.
It only goes into USB mode when connected to a USB host like a PC, as you might expect it to.

I borrowed a 500 once ( for someone else to use on a DIYxGPS ), and again, I just grabbed a random cable and a random USB power pack, and it Just Worked.
I may have been lucky, of course.

[jhob]

I made up a cable for my Garmin 500 as described here which I use with a little TeckNet battery pack. 

It's a reasonably compact and lightweight solution that by my reckoning would see me through a 600.  So far it has worked flawlessly.

[rob]

I made up a cable for my Garmin 500 as described here which I use with a little TeckNet battery pack. 

It's a reasonably compact and lightweight solution that by my reckoning would see me through a 600.  So far it has worked flawlessly.

Thanks.   I found your blog late-on yesterday but didn't make the connection.   Will give this a go.

Rob

[L CC]

I do similar- but my cable came from thing1

[jhob]

I made up a cable for my Garmin 500 as described here which I use with a little TeckNet battery pack. 

It's a reasonably compact and lightweight solution that by my reckoning would see me through a 600.  So far it has worked flawlessly.

Thanks.   I found your blog late-on yesterday but didn't make the connection.   Will give this a go.

Rob

I can't claim credit for writing the blog, I just followed the instructions - it does work though!

I'll be using mine on a 300 tomorrow.

[Polar Bear]

I am slightly confused by the need for a 'special' lead.   We have a 200 and a 500 touring.   If I connect either to my Easyacc battery the unit shows as charging and can be used for recording or following a route as required.   I am using the standard lead that comes with Garmin devices.

I am assuming that because the battery pack simply has + and - the device knows that it is a dumb feed.  Surely almost any usb battery will be the same?

A pair of those TeckNet battery packs would be ideal for touring.   One charging via the USB Werk whilst the other is proving juice for the Garmin and camping torches to boot. 

[L CC]

The 500 is a retro device, these days. It's special.

[Polar Bear]

But surely my 200 is more retro than the 500?

[fuaran]

No, the Edge 200 was released 2 years after the Edge 500. So it may have some improvements, even though it is a cheaper model.
Though I don't know if there's any difference for USB charging.

[Kim]

I am assuming that because the battery pack simply has + and - the device knows that it is a dumb feed.

My EasyAcc has resistors on the data lines to identify itself as a dumb charger (of various flavours on the different output sockets), it doesn't just put voltage on the power lines.

Just putting voltage on the power lines is what gets things into a muddle in the first place - with the data lines floating they expect a USB host to appear and tell them what to do.  Except the ones that don't.

[Polar Bear]

Ah, I see.   So the EasyAcc is in fact, clever.   Thanks for the explanation Kim. 

Are all EasyAcc power banks similarly clever do you know please?

[Kim]

No idea.  But it would be really stupid to design a USB battery pack that didn't do some kind of dumb-charger identification.  The ability to charge iPads is probably a good sign, as they're quite fussy about chargers.

[wajcgac]

From what I've read, how a device reacts to a particular charging cable can be affected by that devices firmware which would explain why some devices work with some cables and others not.

I've tried insulating the data connections on a standard USB cable and then connecting a battery to my Garmin 500 and it still goes in to charging only mode. This would confirm what has been said about connections requiring to be made as described in the link provided by

I made up a cable for my Garmin 500 as described here which I use with a little TeckNet battery pack. 

It's a reasonably compact and lightweight solution that by my reckoning would see me through a 600.  So far it has worked flawlessly.

I've ordered a couple of items from Ebay costing a total of £2 which should do the job without the need for soldering.

Mini USB Male to USB A female OTG adapter cable

and

Male to Male USB cable

I should have them in a couple of days.

[jhob]

I'll be interested to hear how you get on so do please report back

[Feanor]

A normal cable is just fine, so long as the battery pack does sensible things with the data lines, which all but the most rubbish will.

[Kim]

A normal cable is just fine, so long as the battery pack does sensible things with the data lines, which all but the most rubbish will.

The above article suggests not; the 500 appears to use the 5th pin on the mini-USB to determine whether it's connected to a charger, rather than the data lines?

[Feanor]

Yes, I saw that.

I've not investigated how this is terminated in battery packs, or how it is interpreted in devices.

Ah, it won't be, will it?
The battery pack end only carries 4 lines.

Bloody USB.
Why can't it just have a 25-pin D-type connector, where all we need to do is connect it to a 9-pin D-type at the other end;
and then spend all afternoon burning our fingers with various combinations of:

Crossover-or-not;
RTS-CTS pass-through, loop-back, or ignore;
DSR-DTR pass-through, loop-back, ignore;
Hardware or software handshake?
Baud? Start-bits? Stop Bits? Parity?
LLooccaall EEcchhoo OOffff??

[Kim]

Whoever came up with that was clearly a bastard.

[zigzag]

i've started this thread before pbp, and still haven't come up with simple solution to the problem. i've used a bodge which sort of worked, but would be delighted if there was a single usb cable that just works.

[Feanor]

I think that my previous post regarding a borrowed 500 'just working' must be wrong.
It must have been a 200, which possibly works differently.
USB dumb charging standards were evolving around that time.

The 500 looks like it needs stuff done in the cable, and I didn't use a special cable.

[wajcgac]

I'll be interested to hear how you get on so do please report back

Will do.

At the end of Joe's blog he says

Any combination of a USB Mini OTG cable or adapter and a USB-A male-to-male cable or adapter should work.

I reckon I should get the items by Mon/Tues next week and then we'll see if this is true.