RC Tank Warfare community hobby forum

Has anyone put a low battery indicater in there tanks that would flash a Led when the battery is about to get to low I know they have them for LiPo packs but is there any for the 7.2v NHMH packs . I was running my tanks at a WW 2 War reenactment the last two weekends and had them shutdown and restart when battery was low would like to have a Led flashing low battery then could drive tank to motor pool and change out to fresh battery pack .

Jimmy

If anyone has the answer, post it up!! I would love to install something like this.

Rob G

Thats a good idea Jimmy
Stevie

I have found a circuit that would work but im no good at doing a pcb board for it I can solder on the parts from a kit anyone got the know how and would like to try this . Not shore if it would have to have reworking to work on 7.2v Ni-MH packs .

http://www.whatcircuits.com/display-related-circuits/indicator/low-battery-indicator-with-led-flasher/


Jimmy

ok I found this .

http://store.autospeed.com/Items/14444?&caSKU=14444&caTitle=LED%20Battery%20Voltage%20Indicator%20Kit

jimmy

I have a suspicion that this idea might not work well in practical use.  I think one of the 'good things' about NiMh batteries is that they hold their terminal voltage right to the end of their charge, so my guess is that it would be practically very difficult to give you the sort of early warning you require with NiMh on a tank that is taking a high current - I reckon you would get an indication about the same time the motors stopped turning.  More experienced people may prove my theory wrong though, and for the price it wouldn't be a major expense for you to try the circuit to see. 

Its just my understanding, and I am more than happy to be corrected, I was under the impression that the expensive, matched cell, Nimh's give out a high voltage briefly, then a long term consistent voltage, then a sudden drop off. The problem would be detecting the point at which the drop off in power occurred.

...but what do I know.. !! : (

Rob G