When to change the battey
mosquito56
Posts: 387
·When is the time to change the battery. I noticed yesterdy the 3.3 output was 3.35 and everything seemed to be working. I have 3.28 today and things are getting strange. Infinite loops are not repeating but about 5 times.
· I think I am drawing down the battery but not sure. Any ideas?
·I am using rabbit 9V batteries.
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Mosquito: An animal which buzzes in your ear and never stops. He may byte you, he may nibble you, but you will know you were bit.
Technologically challenged individual, Please have pity.
· I think I am drawing down the battery but not sure. Any ideas?
·I am using rabbit 9V batteries.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Mosquito: An animal which buzzes in your ear and never stops. He may byte you, he may nibble you, but you will know you were bit.
Technologically challenged individual, Please have pity.
Comments
If a new battery resolves the problem, and re-testing with the old brings the problem back again you know you've found the problem.
(b) It is not easy to find out how much is left in a battery. You can meassure the current wrt a certain load (i.e. 100 Ohms). A still useful 9 V battery will deliver 90mA. The voltage should be in the range of the nominal voltage. (Note that the nominal voltage of 9 V rechargeable is NOT 9 V but 8.4 V (= 7X1.2)). The open circuit voltage is of little value, except to distinguish an absolutely full battery from an abolutely empty one... E.g for an 1.2 V cell:
Full: 1.35 V
Empty: 1 V
(c) have a look at a typical discharge diagram of a sixpack of NiMH AA cells. You see that the factual voltage depends heavily on the drawn current - which is a consequence of Ohm's law, obviously.
Post Edited (deSilva) : 1/4/2008 5:30:47 PM GMT
P.S. I changed the battery and everything is fine. The servo was drawing down the voltage. Still curious what is min voltage for the prop.
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Mosquito: An animal which buzzes in your ear and never stops. He may byte you, he may nibble you, but you will know you were bit.
Technologically challenged individual, Please have pity.
Post Edited (mosquito56) : 1/4/2008 5:39:58 PM GMT
If you use 5V and 3.3V regulation, 4xAA cells will not be enough! You have to use 6 of them (=7,2).
As I rarely had a need for exact 5 Volts I use unregulated 5V voltage from the raw 4x1.2 batteries and regulation for just the 3.3V. The voltage from the batteries is between 5.2 and 4.7 V which is fine for most applications. (servo, LCD display,..) ...
My other power supply comes from an USB HUB (well to be honest sometimes also directly from the Notebook...)
You need:
- a small veroboard
- some header pins
- a surplus USB cord
- a 3.3V regulator (LM33 e.g. also an SMD type in DPAK housing will do fine)
- two 100nF caps
- one LED
- one 470 Ohms resistor
Solder the headers and the other parts onto the veroboard
Then cut the USB cable and identify Vss and Vdd; solder both at the right place onto the veroboard and fix them with some hot melt adhesive
But first make a drawing of how it shall be arranged on the veroboard in the first place
There are lots of instructive possibilities how to make errors here.
- Which end of the USB cable?
- Which side of the Veroboard to use? When you twiddle around with the header pins you will find that they best fit soldered in a way that the copper of the board looks up. But there is not enough space for the other parts between the veroboard and the breadboard where this power supply shall be plugged into .. so best put them atop, SMD like
- There is generally no need for 100µF or above electrolytes to buffer the 3V output
- You can put the LED at 5V or at 3V; or take two...
Post Edited (deSilva) : 1/5/2008 5:57:18 PM GMT
When the batts go flat, the app, which is a game, keeps restarting faster and faster until it stays off.
Virand:::: What does the BOE enable pin do? Feel free to disregard question as I always get a long answer on why didn't I just look·it up from others. I could but don't want to.
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Mosquito: An animal which buzzes in your ear and never stops. He may byte you, he may nibble you, but you will know you were bit.
Technologically challenged individual, Please have pity.
Note that any additional current load (LEDs!) will reduce the terminal voltage..
When the Propeller stops working from them the batteries should be generally still "as new"