question for C2 - batteries

johnlvs2run · Post by **johnlvs2run** » July 23rd, 2008, 2:00 pm

The battery on my pm3 is at 50 percent.
At what percentage should the battery usually be replaced?

What kind of D battery is recommended?

Is there a certain procedure to use when replacing the battery.

Citroen · Post by **Citroen** » July 23rd, 2008, 2:56 pm

You can change the battery without having to reset the clock and without losing any data in the PM3 memory if you're quick about it. (It takes about 30mins for all the capacitors to discharge completely.)

I'd fit stock alkaline D cells. Probably a pair of Duracells from Radio Shack.

You can run the batteries down until the PM3 starts warning about low power. Even then you can still row as there's just enough power generated from the flywheel.

If you hook the PM3 up to a live USB socket on your PC (or USB charger wall-wart http://www.rackmount-devices.com/045-3529.html) you can run without batteries.

PaulS · Post by **PaulS** » July 23rd, 2008, 4:21 pm

As the batteries do tend to last a very long time in a PM3, using a high quality Branded name that is less likely to leak is a good idea. I had some Panasonic Alkaline batteries that were funtioning just fine in a "Boom Box" show signs of leaking, fortunately caught it before it could damage anything, but it was completely by happenstance that I openned the compartment. 3 out of 6 had moderate to severe leaks.

c2scott · Post by **c2scott** » July 24th, 2008, 12:21 pm

You've got a long way to go between 50% and when the monitor will start complaining (you'll see a warning message when the monitor turns on). I do NOT recommend using USB power alone: if you use USB power alone, please leave a set of D Cells in the monitor (even if they're worn out it's OK). The PM3's may not run on USB power alone (it has to do with startup currents and the power supply components) but having some batteries in place solves this issue.

-- Scott

johnlvs2run · Post by **johnlvs2run** » July 25th, 2008, 2:52 am

Thanks much for all the helpful information.

Scott, do you have an idea of how low the percentage will go for the warning?

Also, if the warning came on at the start of a marathon, for example, would there be enough charge left to get through it?

c2scott · Post by **c2scott** » July 25th, 2008, 9:01 am

The warning would not come up in the middle of a workout: typically we do not show errors during a workout -- we would wait until it's over. If your model D or E generator is working properly then you would certainly make it to the end of a marathon.

If you were really running on dead batteries (ie the monitor would not come on until you row) and you rowed a marathon continuously, you would probably get through, but the bathroom break when the flywheel runs down would cause you problems... (try it -- take a battery out and row: it will eventually come on and count meters -- but it won't stay on when the flywheel runs down...)

johnlvs2run · Post by **johnlvs2run** » July 25th, 2008, 11:37 am

What I'm wondering is how low might the percentage go before getting the warnings.

5 percent? 30 percent?

Then when a warning comes on, does the battery still last for a couple of sessions after that?

Andy Nield · Post by **Andy Nield** » July 29th, 2008, 3:40 pm

You can change the battery without having to reset the clock and without losing any data in the PM3 memory if you're quick about it. (It takes about 30mins for all the capacitors to discharge completely.)

If you plug a usb cable in tothe pm3 you can take as long as you like

Nosmo · Post by **Nosmo** » July 29th, 2008, 4:57 pm

Andy Nield wrote:If you plug a usb cable in tothe pm3 you can take as long as you like

Just don't forget to plug the other end in or turn your computer on.

johnlvs2run · Post by **johnlvs2run** » July 29th, 2008, 5:08 pm

The battery did seem to maintain it's charge much better when I had it plugged to computer.

I've not bothered with that for quite a long time though, as the pm3 provides quite enough information on it's own.

Scott has assured me there is ample warning on the monitor, though at unknown percentages.
And the cost of the batteries is reasonable.