Battery Warning With Nimh Battery Packs


I'm curious about NiMH battery warnings from the EZ-B. As I'm using an NiMH battery pack to power a v4, I have the LiPo battery warning disabled from within the "Connection" control in EZ-Builder. I have never had my 7.2 NiMH run so low as to disconnect my EZ-B's connection and today it happened for the first time.

When the v4 disconnected from EZ-Builder, I thought this was due to a signal dropout. I power cycled the v4 and tried to re-establish the connection only to be greeted with the verbal "My battery is low" message. So does the EZ-B have a secondary battery warning system then, or have I missed something other than disabling the LiPo battery warning in the connection control?

I know a v4 shouldn't be powered with anything under 4.5 volts and didn't get the chance to see what the voltage was on my 7.2v NiMH before the v4 disconnected. Sorry if it sounds like a daft question, but this is the first time I have come across this and was curious.



So what exactly is your question? The ezb will spontaneously reset if the supply voltage drops below 4.5v regardless of the power source, that's a given... NIMH have a go/no go voltage threshold just like lipos.... Over discharging them will also damage nimhs.... I believe it is something like 1V per cell....

The secondary warning as you say is onboard the ezb itself.... If you hook up a battery with voltage too low the ezb will complain "my battery is low" even though not connected to ez builder


Don't quote me but I think you can disable the "secondary onboard warning" while in the ezb4 webserver settings....


My question was the one with the question mark...


So does the EZ-B have a secondary battery warning system...

I wasn't aware that the EZ-B had a secondary warning on the unit itself, that's what I was curious about. Pretty cool though. As this is the case and it's set for 4.5v, I wouldn't look to disable that. I've only started using NiMH packs with an EZ-B recently and and never connected a discharged battery to one, so this was new to me. I knew you could over-discharge NiMH packs even though I was told otherwise by someone else.

Anyway, thanks.


I had one 7.2v nimh pack (it was brand new) fail just recently because I inadvertently left it connected to one of my ezb's overnight.... In the morning it was of course completely dead.... Even a quick jolt of a 12V sla battery wouldn't bring it back to life.... The battery charger just flashed red indicating a damage nimh pack.... Had to toss it...


Damn, that sucks.

I should say that the guy who told me "you can't under-charge a NiMH" wasn't from this community, but from the seller I purchased the battery from.

A final question. What kind of NiMH battery meters are there available that can connect and talk to the EZ-B to give voltage info? I ask because I have 2 battery packs... one for the EZ-B (obviously monitored via the EZ-B), and one connected to a motor controller (unmonitored).


..... Actually I should have said over the years I have accidently killed a few nimh due to neglect (long periods of not charging them) or by accident.... If you let them discharge too far (as mentioned I believe 1V /cell) then they may not charge again.... Sometimes a 10 second jolt from a 12V battery will revive them... but that's hit and miss...


Okay. Good to know. I'll try to monitor my packs more carefully so I hopefully don't get to that point. It would be great if I could get voltage readings from my second unmonitored motor controller battery and write a script to give similar warnings like the EZ-b's monitor.


To add to this discussion; when the V4 fist came out and shipped, the first few of us who were lucky enough to get one were quickly aware of the dreaded female voice scolding us that our battery was low. There was no way to disable it as the power monitor and warning chant is coded into the EZB it's self somehow. It drove many of us crazy. It reminded me of my ex-wife nagging me to be a better person and be ashamed of what I've done. There's also an video out that DJ made for us on something (I forget what) with the voice chanting away in the background and DJ says "That's driving me nuts". LOL. Tongue Anyway, shortly after that the option was added in the EZ Builder software that resides on your laptop to disable this warning. At that time there was no way to keep the EZB to chant the warning untill it connected to the EZ Builder software and if that option was enabled th warning would then stop.

Fast forward to now.......... I read a post recently that newer V4 EZB's shipped have the option to disable the warning in the on board web server that resides on the EZB it's self. I haven't confirmed this and I don't know if the older V4 EZB's can be flashed to reflect this upgrade (if it actually is true). It doesn't bother me as I took steps to power my EZB with a plug in power supply and voltage regulator above where the point where the hag starts scolding me. *sick*



Nice post and very interesting indeed. I don't mind the warning voice too much, although like you say, it does nag a bit, but briefly on a different subject, I wish there was an option to swap it between male or female, especially on the "I am now connected to your network" phrase.

Back on topic again, and I will write a simple battery monitor script for above the 4.5v threshold for the 7.2v v4 battery (about 6v for a 6 cell battery) which will use my bots voice, but with the info that Richard gave, I want to now find a way to monitor the 12v drive battery via the EZ-B and write a similar monitor script like for the 7.2v. I know you use a mains supply to power your EZ-B, but do you, or anyone else for that matter, have any ideas on how I could accomplish this, or suggestions any magical devices I could buy that will monitor the battery voltage and send th info to an EZ-B?