Red led flicks

[adayismo]

I bought this extra battery http://http://cgi.ebay.es/ws/eBayISA...m=290226562264 but when I plug it into a3 the red led start to flicking (on-off-on-off)..

What's hapening?

[nivlacbot]

Once again.. for want of a more helpful response. The red light flickering means... not good.[biggrin]

Check the specs... with the power adapter. Your link is broken... and I would be wary of e-bay offerings.
I know that it doesn't help much...

[Chorca]

Depending on how fast it's flickering, i'd make sure the voltage and current are close to the power adaptor. If it's flashing on and off that could mean that it starts the charging process, but when the rapid charging begins, it's pulling too much current for that battery pack to supply, which then causes the player to interpret the loss of current as the plug being pulled, and it stops charging.

The flashing would mean it's in an cycle of pulling too much current, and the battery building up enough current to make the player think it's plugged in and try charging again. That's the best I could come up with, the manual doesn't specify anything for a flashing light.

[quatermass]

I've been experimenting with various power supplies for my A3.

I made up this:

http://mytriops.com/mypics/a3power.jpg

Rechargables
If I use a set of 4x Ni-MHi AA cells @ 2700mAH then I get a varying 4.6-4.9V on charge mode or steady 4.77V when A3 is on. This seems to cause the A3 red LED to flash. But it was charging as after an hour it stopped flashing (but no green light came on) and when I powered up the A3 it had all 4 green bars lit up when before it was 3.

So I think in my case the A3 is detecting the incoming voltage is low and complaining via the flashing. The flashing is too regular to be due to a fluctuating voltage I think.

Interestingly the A3 thinks it's on battery when I switch on the A3 with these batteries plugged in. But if I switch it on when they're not plugged in and then plug them in, it thinks it is now on the adaptor. Battery drops to a steady 4.6V.

Also if I switch it off when these batteries are plugged in, then the A3 turns off and then comes right back on again! But now it thinks its on battery power. But it is draining the external batteries!


Without knowing the A3 chip that is used to charge the battery and regular the power fed to the A3 circuitry I can only guess why. But I tried putting 100uF and a 10nF capacitor in parallel across the plug in case it was electrical noise getting injected. But this didn't help.


AA Duracell Alkalines
If I use 4xAA basic Duracell alkaline batteries (~1000mAH) then the output is 5.98V off load. But once its plugged into the turned off A3 it drops to 5.02V. The red LED flashes away and then the LED turned green after a time.

Though if I turn on the A3 whilst these batteries are plugged in, the A3 thinks its on internal battery just like the rechargeables.

If I power up the A3 and then plug in the Alkalines, then it happy to power from that.
If I power off the A3 and plug in the Alkalines, then the voltage is varying from 4.8 to 5.5V. Much faster than the LED red light that is flashing.

(AA alkalines don't last long as they're only 1A/H. But I was interested in seeing how they performed.)

I think all this varying voltage is confusing the hell out of the A3 internal battery charger and the A3 computer reads this to display its power bars, etc.. It may very well be that when the external battery voltage falls, the A3 thinks the adaptor is turned off and back on again.

But I don't know what its doing to the internal charger when it thinks it's on battery when in fact the external battery is still plugged in. It's certainly drawing current.

My A3 original power adaptor gives out 5.03V on load and I bet the A3's internal battery charging device needs it to be this exact.

So I say don't switch on the A3 with a external battery pack plugged in. Only plug it in after the A3 is switched on.


So if want a fully working replicate of a Mains adaptor as a battery, you must use a external battery pack which gives out exactly 5V. My various external power supplies that give out a constant 5V work 100% with the A3.

So my best guess is that we need a 8V battery pack with a low forward voltage drop out regulator circuit to give the A3 a constant 5V @1A

(most of the 78xx voltage regulators I looked at, that can handle a minimum of 1A need a min. 8V on the input side.)

Or I guess you could live with the odd goings on if you use one of these unofficial 'eBay' battery packs.

In a nutshell, the A3 power in socket isn't designed take a fluctuating 5V supply which an external battery pack may do. :D