Batteries - one for the techies...

[imamartian]

ok, i have a scalextric type car game, and i put in the batteries, and it was really good.... but then it went really slow... the batteries say (according to my tester) are at 1.43 volts.....

why do batteries at 1.5 volts work, but at 1.43v not work.... and how to use the remaining 1.4 volts?

 

[ColJack]

unfortunately, the batteries when tested with a standard multimeter will not be under load, so you will see the "resting" voltage..
when put on load the voltage will drop considerably..

put them back in the game and put the probes accross them while it's running..

 

[sparkyspike]

Have a look on eBay - you can get a Scalextric transformer for just a few quid.

 

[timtheenchanter]

doesnt take much for a dead battery, for example a car battery is 12.6V full, 11.9 is considered dead.
try this http://www.emanator.demon.co.uk/bigclive/joule.htm to suck every last bit of power from your battery.

 

[IJWS15]

You don't use the Volts, you use the Joules (energy) stored in the battery.

Unfortunaltly the no-load voltage tends to depend on battery design so even with next to no joules left they still tend to indicate a no load voltage of close to nominal. It takes a long time to get the last few joules out.

 

[maltaron]

A fully charged car battery is 13.8volts not 12.6 - 6 cells @ 2.3v
Its also worth noting that NiCd rechargables are only 1.2v fully charged against 1.5v for a new alkaline.

 

[timtheenchanter]

all the info I have ever read says 12.6 (6 cell @ 2.1V)
with 13.8 being a charging value.


# Quiescent (open-circuit) voltage at full charge: 12.6 V
# Unloading-end: 11.8 V
# Charge with 13.2–14.4 V
# Gassing voltage: 14.4 V

 

[maltaron]

I think the exact voltage of a lead acid cell is 2.2v, so we are probably both wrong. Not worth arguing about though, we agree on the proper charging volts.

 

[timtheenchanter]

fair enough...