I just bought a battery from you (NiMH 12V 2800 mAh). Should I charge it right out of the box, or use it as is, and wait till it runs out of power before charging it?
1 Like
Hi @dexter5!
Yes, before you use them for the first time, you need to charge your NiMH batteries fully. Please note that for new NiMH batteries, it is often necessary to cycle them at least three to five times or more before they reach peak performance and capacity. The first several times that you use your NiMH batteries you may find that they run down (discharge) quickly during use. Donāt worry, this is normal until the batteries actually structure internally.
1 Like
Thank you for that information! Iām glad I asked! I sometimes thought that it didnāt matter if or when I charged them.
1 Like
You are welcome.
I was just wondering if you might have any idea why my old battery (same as the one I just bought NiMH 12V 2800 mAh) went up in smoke a week ago? It was 3 years old and I have been using it on and off for the past 3 years. Do you think I did something wrong, or just that the battery has reached its age limit? When it died ( two puffs of smoke and an acrid smell), I was just running the two motors on my robot (EMG30s). I had just given the motors the command Serial.write(128) to get them to stop, going neither forwards nor backwards. Would that command have burned up the battery? Is Serial.write(128) a big āno-noā or something? Or is it a harmless, regular command? Or how about delay(5000)? I was trying to get the robot to pause for 5 secondsā¦would that have harmed the battery? The delay command came right after the Serial.write command.
Not sure if stopping the motors ( from full speed?) could kill NiMh batteries, but it can cause a big reverse voltage surge (like a ignition coil) if the motor controller isnāt prepared to block these.
Another thing I want to mention about NiMH batteries:
Back in the days, when NiCD was popular, we often heard the advice to completely discharge them regularly to avoid loss of capacity.
Donāt do that with NiMH!
Cutoff voltage should be ~0.8V/cell, depending on the current load.
1 Like
I was stopping the motors after a Serial.write(155) command, so not quite full speed. Is there any other way to get the motors to stop than using Serial.write(128)?
1 Like
If your motorcontroller has an āenableā input, you could use that to idle the motor. But you may loose some encoder pulses, when the vehicle keeps rolling.
Some dual-H bridges also have a ābreakā input. It shortcuts the motor windings, but keeps sending encoder signals.
1 Like