SparkFun Forums 

Where electronics enthusiasts find answers.

Have questions about a SparkFun product or board? This is the place to be.
By scotru
#107982
I've build a small project and have been powering it with a regulated USB rechargable, lithum ion battery pack:
https://www.shopfsp.com/ion-universal-m ... p/549.html

Sadly, part of my device has been reseting it self periodically and I believe I've traced the problem to the battery. If I supply 5V with a regulated plug in power supply, I have no problems (and also worked well with the sparkfun 5V VPack). I have very little hardware experience, does ripple or other problem with the 5V supply sound like a reasonable cause for this problem? Any suggestions for fixing it with the FSP battery?

Or what would sparkfun forum readers suggest as an alternative supply? My device draws about 150ma and I need about 4 hours operating time. I've looked at the NiMH 2-AA battery packs with VPack to get to 5V--but couldn't find a pre-built NiMH AA charging circuit that will fit in my very small case and don't have time to build sufficient quantity of custom charging circuits. I would prefer to charge in the device.

Also considering the LiPoly charger with my existing battery out of the FSP pack. Again, concerned about fitting the LiPoly in the case.

Any plus/minuses of these two options or other recommendations appreciated!
By PhatBob
#107988
That pack should be able to provide close to ten hours worth of power supply.
Have you got large enough caps eitherside of your voltage regulator?
By scotru
#108098
Just tried adding a 1000uF capacitor and didn't seem to help. I don't know if there's something funny going on the regulator inside the battery pack.

Battery life has been fine--not quite 10 hours, more like 6 (but I think there's step-up circuitry in the iON battery pack from 3.3 to 5V)--it's just that my device won't run reliably from the current from it...
By jremington
#108126
You might tell us what it takes to reset the device you are powering with the battery. Is it the brownout detector of a microprocessor or do you have reason to believe that the battery voltage actually goes to zero for a short period?

In any case, check of the battery output with an oscilloscope, while it is connected to the device and look for spikes.

Jim
By scotru
#108187
Thanks for the good suggestions.

With the help of an EE, using a scope, we found that the power coming off the regulator (DC-DC 3v to 5v converter) in the FSP iON Pack is VERY noisy. (Nearly a full volt variation)

Problem appears to be that I was near the high end of the voltage tolerance for my device (5.5V) and the noise was pushing me over it's tolerance periodically causing it to reset.

We inserted a diode in series with the battery and lowered the voltage enough that the problem appears to be solved. I still don't like the noise, but I think I'm going to live with it for now since the device seems to be working well now.