I am soldiering on with my trusty RU990 as I can't find anything better at a sensible price and in all honesty it does exactly what I need.....

I know this has been raised many times but I've never seen a definitive answer......battery life with 4 AAA ni-mH was abysmal - typically lasting less than one day - so with some minor battery compartment modifications I managed to squeeze a 5th battery in and added a diode in series so as to limit the voltage gain to around 0.7V, I also made a delta-V cut off charger to suit the higher voltage.

But even though the battery voltage is 6.0V the display icons are down to 2 bars and as soon as it drops to around 5.4V the bars are either 1 or "LOW" and it switches off / re-boots.

I've removed one of the motion sensors so it only switches on when shaken rather than just touched and the batteries are definitely not discharging as they re-charge very quickly and yes, I have tried more than one set of new batteries both 900 and 1200mAH capacity.

Current consumption is around 180mA on full brightness and 250uA "off" so 900mAH batteries should last for weeks !

This cannot be right, the problem seems directly related to the battery voltage itself - presumably there isn't an option for selecting primary or ni-mH batteries is there ?

The device shows
RU990 v1.0
Application version App. 3.8.17
Database version v3.42 EA
Bootloader version Boot V4.31
Free memory 99%

Really would appreciate some help here
thanks

Anyone ?

Maybe even the increase in voltage is throwing its curves off (it's expecting closer to 4.8V for the internal battery pack, not 6.0V)?



Perhaps there is an issue with voltage droop under load with your cells?

Thanks for your reply but rest assured the batteries are good as are all the connections.
Just to be sure I also tried a set of new batteries which made no difference.

At 4.8V it won't even power up ........ my parents have a totally un-modified and never tinkered with RU980 which exhibits the same behaviour - down to one bar after a days' use but the battery voltage (measured whilst the backlight is on) is good.

With my added battery (5 ni-mH = ~6V) it still shows 4 bars after 3 days use without charge !

With the extra battery added it finally died today - well it suddenly went from 4 bars to "LOW".

4 days use without re-charge is a miracle

Is it possible that the firmware has somehow got corrupted - and if so how can I re-flash it .....or even better hack it to alter the voltage levels ??

I found the firmware files on this site and down-graded to 3.8.1.6, connected the Pronto to a stabilised variable power supply and started reducing the voltage 0.1V at a time.....

5.4V 4 bars
5.3V 3 bars
5.0V 2 bars
4.8V 1 bar
4.6V  LOW
4.0V  switch off

Increasing the voltage in 0.1V steps the result was similar but 0.1V higher for each step which seems about right to give some hysterisis.

I then up-graded to 3.8.1.7 again and the results were exactly the same.

Does anyone know what the voltage / bar relationship should be ?....and is there any way of changing it.

Seems like powering with Ni-mH / Ni-cd is running pretty close to the wire to me as 4 cells would give 5.6V max dropping to 4.4V min (1.4 to 1.1 V per cell)

Also, what is the highest voltage these will safely run at......with 5 x Ni-mH the fully charged voltage is 5 x 1.4 = 7V........In theory 4 fresh Alkaline batteries would give 4 x 1.6 = 6.4V.....I don't want to risk blowing it up as they don't seem to be available any more !!!

Thanks

any updates please

I managed to find another one (TSU7000 / RU980) on fleabay and guess what....the battery bar issue is exactly the same :( ....this is somewhat disappointing

Any further thoughts....it is definitely not that the batteries are going flat - far from it as they all remain at 1.2V (and are new as well).....is it possible to alter / hack into the firmware code and change the setting ?
Surely I can't be the only person who finds it ridiculously irritating to HAVE TO re-charge it every night .... and as I have now had a total of 4 TSU700 / RU980 / RU990 units they can't all be faulty !