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Road Grime Road Cycling Forums forum - Topic - Powertap and Garmin 500

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Yo bisshes

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Powertap and Garmin 500

February 12, 2012 06:07pm

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Quote: lethoso

Quote: Rick_B

Yeah, I went looking for the EPX76's but couldn't see them. I used the A76's instead, which I read in a forum would also work. I'm 99% sure it is the batteries causing the problem.....I want my power readings back dammit!

http://data.energizer.com/PDFs/epx76.pdf

http://www.houseofbatteries.com/documents/A76.pdf

from the look of it the a76 might not put out enough volts.

I bought a couple of these from coles ($4 ea) the other day to replace my powertap batteries:

http://data.energizer.com/PDFs/357-303_EU.pdf

so far so good, but from the look of it they won't last as long as EP76s would.

You've too much power Lethoso, those A76 batteries won't be able to keep up for too long. D!K Smith's at Stafford always seems to stock a healthy supply of the EPX76's at around $20 each!

Pound for pound, the Powertap still seems the best value. But some say the hub ain't that aero - but when you are in the hunt for the win, it's time gaps and not power numbers that matter most.

Mighty the wheel is working again Rick. Rob wants to see you doing well.

Bill

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Powertap and Garmin 500

April 08, 2012 07:38pm Updated 08-04-2012 07:56 pm by Bill

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Many moons ago I worked in Tandy / ***smith (both woolworths owned). There are many battery numbers that have the same physical size of the a76. The most important factor, as far as a powertap goes, seems to be the type of battery. From the powetap manual:

Normal battery life in the hub is 400 hours of actual ride time. Use #357 or EPX76 Silver Oxide
type batteries and always replace batteries in pairs. Alkaline type batteries give shorter life and
poorer performance.

Silver oxide are better for devices that are not used all the time as they have longer shelf life and the voltage stays constant until they die where Alkaline allows voltage to drop as they go flat. Below is a list of batteries that have the same dimension as an a76 (LR44 is the most common)
Alkaline:
http://en.wikipedia.org/wiki/LR44_battery

LR44/LR1154
6135-99-792-8475 (NSN)
1166A
LR1154
AG13
157
A76

Silver oxide:

SR44/SR44W/SR44SW
6135-99-651-3240 (NSN)
SR1154
1107SO
1131SOP
SG13
S76
EPX76 (Energizer)
303/357

Based on the links to the energiser pdf's in the post above the epx76 is 200mAh (measure of run time) as opposed to 150mAh for the others but wether that makes it worth $20? SR44's are were around the same money as LR44, a76 when I was selling them.

mickncat

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Forum posts: 206

Powertap and Garmin 500

April 09, 2012 06:31am

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Sorry I read this thread a little late, I have been PT junkie for 2 years now. The issues you are having are all standard issues. Things I have found:

1. Make sure you don't touch both sides of the battery when installing them, the cheaper ones fail when you short them out.

2. Make sure when you wash the bike you take the PT off to ensure no moisture shorts the batteries.

3. When you have the batteries out, clean the connections and slightly bend them inwards to maintain good connection.

4. Always spin the PT when pairing it to your Device.

5. Don't lend you PT to anyone, as soon as you do there is an inbuilt device that makes the PT work perfectly until the exact moment they hand the damn thing back.

ojfluro

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Powertap and Garmin 500

April 09, 2012 09:58am

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I learnt the EPX76 lesson about three years ago. After the first set of batteries that came with the PowerTap died. I purchased some batteries from Battery World that were supposed to be the equivalent to the EPX76 but were simply useless. They were much less in cost but failed after a few hours.

Searching for somewhere locally that had EPX stock was interesting as Battery World did not sell Ever-ready. The local Amcal pharmacy (Torquay Hervey Bay) had two batteries in stock! Since then I have always had two EPX76 batteries stored on standby. The replacements are ordered when the old batteries are done.

Price wise the EPX76 from Amcal cost $6.90 each. They don't always have them in stock but if an order is placed the stock takes about two days to reach Hervey Bay.

Parso

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Powertap and Garmin 500

April 09, 2012 10:02am

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I went for a ride this morning and my power tap was not working, I do not have a manual (it will be the first time i read a manual, only because i love my bike so much i dont want to get it wrong!) so was not sure how to replace the batteries. Do you unscrew the hub? It would not rescan on my edge 500 so it must be the batteries.

lethoso

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Powertap and Garmin 500

April 09, 2012 12:33pm

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Quote: Parso

I went for a ride this morning and my power tap was not working, I do not have a manual (it will be the first time i read a manual, only because i love my bike so much i dont want to get it wrong!) so was not sure how to replace the batteries. Do you unscrew the hub? It would not rescan on my edge 500 so it must be the batteries.

you use the funny wrench thingo to unscrew the plastic cap, then pull out the little battery pod and replace them.

this clip shows it pretty well - http://www.youtube.com/watch?v=JA1i_3bJGqc

Parso

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Powertap and Garmin 500

April 09, 2012 03:26pm

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I worked out how to change the batteries but does anyone know who sells the spanner on the Goldcoast to undo the hub as it is too tight to get it with a shifter, it starts to tear the plastic hub.

M_Walker

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Forum posts: 434

Powertap and Garmin 500

April 09, 2012 03:52pm

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Quote: Parso

I worked out how to change the batteries but does anyone know who sells the spanner on the Goldcoast to undo the hub as it is too tight to get it with a shifter, it starts to tear the plastic hub.

While its rough it will get the cap off, I have used in the past a monkey wrench. Take your time as if it is not secured properly on the 2 flat side bits it will slip and it does hurt.

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