GRS kitbuilt Peckett converted to battery r/c (now + video)

[ge_rik]

Got another 20mins out of her this morning before the protection board cut in. Looks like the battery monitor is a bit optimistic! In effect, if it drops below 100% then the batteries are about to die.

5h 20m seems pretty good, though.

Rik

[steampig]

... In effect, if it drops below 100% then the batteries are about to die... Rik

I eye-balled the discharge/voltage/current curves for these batteries available on the 'web. If the charge-lights on your board are simply measuring battery voltage, the charge results they report will vary wildly with the current being drawn at the time - in particular if little current is being drawn the charge will be greatly over-estimated. A give-away would be if the reported charge goes down mightily when the motor is turned on and then speeded up.

Is the only documentation for the board in the ebay listing you pointed to? The charge indicator should be 'calibrated' for some discharge rate, and if known you could wire a load at that rate and push-button test switch for when you want to check the charge.

I've used the voltage/current/discharge characteristics for monitoring alkali AA-cells in the radio-mikes of a PA system which were always running down on us - hasn't happened since Also got rid of the dud cells that people were just chucking back in the draw

[ge_rik]

Is the only documentation for the board in the ebay listing you pointed to? The charge indicator should be 'calibrated' for some discharge rate, and if known you could wire a load at that rate and push-button test switch for when you want to check the charge.

Hi
Yes - that's the only documentation.
I've only used the battery monitor when there's no load. Not tried it with the loco running.

Rik

[steampig]

Sometimes I wonder if the 0.5A charge limit you have noted is a consequence of the temperature-sensor having been cropped (if you have) - perhaps that falsely signals to the board the batteries are running hot, so it opts for safety?

Very successful project, however.

[ge_rik]

Sometimes I wonder if the 0.5A charge limit you have noted is a consequence of the temperature-sensor having been cropped (if you have) - perhaps that falsely signals to the board the batteries are running hot, so it opts for safety?

Very successful project, however.

Hmmm ... That's a thought. I'm just about to convert NiMh powered model to li-ion with thee 18650s, so might give it a try.

Rik