Gp2x Battery Draining Problem

[pferguso]

I am running into a rather unique problem here. I put in two freshly charged 2500 MaH Energizer batteries into my Gp2x. I play Nintendo for about 5 minutes and then turn the GP off. The next day, I go to power up, and the screen gets all washy like when there are dead batteries.

This happened to me on two separate occasions.

I think I might have put the batteries in there backwards once a while back. Could this have caused a problem like this? Am I going to have to go into this thing and replace a part on it?

 

[Destructo2000]

I don't know if putting the batteries in backwards could cause this, usually it doesn't even turn on if you do. I would recommend getting an AC adapter or a power supply. I just got mine from Radioshack today and it works great.

 

[imhotep]

Try a different brand before you give up. The Energizers may be at the end of their life.

 

[rokdcasbah]

do you have an ohmmeter? the resistance of my mk1 gp2x measured from the battery terminals is about 5.5k-ohm, but ONLY when the unit is switched on (no batteries in there for the tests, obviously). When the unit is switched off, I can't get a reading. Presumably there's close to infinite resistance in that case. If I switch the leads, I get a little over 13k-ohm, I'm guessing it has to do with diodes.

Anyway I'm guessing that, in your case, if an ohmmeter shows some resistance with the unit switched off, then it'd be possible for the batteries to drain. Of course, it's possible that the resistance is not infinite but some amount larger than your ohmmeter shows, in which case the test would be inconclusive.

i'm not sure what sort of current an ohmmeter uses to measure the resistance, but i think it's pretty small. in any case, to be safe, i wouldn't recommend applying the probes with reversed polarity unless you have to for some reason.

 

[Destructo2000]

I'd say if you don't want to buy an AC Adapter, try a different brand of batteries and see if those work. Also, try taking the batteries out when your not using them. I know it's a hassle, but hey, you do what works. Also, if you do get an AC Adapter, don't be like me and get a center positive one and and up returning it. Make sure it's center negative. I almost fried my GP2X that way.

 

[imhotep]

Is that avatar of yours on YouTube, pferguso?

 

[pferguso]

Thanks for all of the fast replies. I will probably get an adapter, but I am going to try some different batteries first.

And I don't know where this avatar came from, I just thought it was cool.

 

[imhotep]

All the best, hope you have some luck with it.

 

[shubox357]

i am having the same problem and i just got my gp2x today, i have not put the batteries in incorrectly and they are rechargeable batteries, 2650mAh, duracell. i have firmware 2.10. anyone else have the prob? maybe its just new consoles?

 

[Blah]

Some chargers don't charge batteries all the way. Try charging them twice.

 

[danny_galaga]

seems like the batteries the kid in your avatar is using have plenty of power. why not ask him what brand he uses (",)

 

[SiDCrAzY]

seems like the batteries the kid in your avatar is using have plenty of power. why not ask him what brand he uses (",)

I think its a she.

 

[gmiller1018]

Just remember that as the system sits, even if it is off the batteries discharge. The rate of discharge is related to the ambient temperature. Here is a quote from:

http://www.cobasys.com/pdf/tutorial/Inside...technology.html

Self Discharge



The NiMH batteries, like all batteries, have a certain level of self discharge that occurs when the battery is at rest. The self discharge characteristic typical of an available electric vehicle type battery module from Cobasys is shown in figure 6. The factors contributing to self discharge include the energy used by the oxygen cycle at high states of charge. The contribution to self discharge from the oxygen cycle is negligible below about 70% state of charge. Longer term contributions to self discharge are caused by chemical ion shuttles which continuously discharge the cell over longer periods of time. The rate of the self discharge is highly dependent on the temperature of the cell. Higher temperatures yield higher self discharge rates.

Figure 6. Capacity retention at several temperatures for NiMH EV battery



NiMH Battery Applications

 

[danny_galaga]

seems like the batteries the kid in your avatar is using have plenty of power. why not ask him what brand he uses (",)

I think its a she.

 

[thumpgun]

how old or your batteries ?, you can only recharge them so many times befroe they start to die...

 

[rokdcasbah]

as far as self-discharge, that looks like roughly 10% in 10 days at room temperature...enough to be noticeable but not a matter of national security or anything

pferguso, is it still happening? not having seen it, i think the most likely thing is it was a fluke or something battery-related. keep in mind that you want to discharge your batteries as much as possible before charging, which is tough on the gp2x since it stops working when the voltage gets too low, regardless of what's left in the battery. i usually put my "dead" ones aside and when i'm not playing, just put them back in and leave it switched on and take them out later. i'll probably get a battery clip soon and toss a resistor on, just to play it safe and not put undue stress on the gp2x.

like i said, if you want to be absolutely sure that you're not "leaking" current, get a cheap multimeter and check the battery terminals, with the unit switched off, to see if the circuit is open like it should be. either use the ohm fuction, or, most meters actually have a special function just for testing if a circuit is closed/open/shorted. my cheapo radioshack one does it. you can get meters on the internet for less than $5. it's also a good idea to get a multimeter because you can measure the voltage of your batteries before & after charging

but hopefully the problem hasn't repeated itself so all of this is unnecessary.

 

[Chronic]

keep in mind that you want to discharge your batteries as much as possible before charging

Actually, this isn't necessary with NiMH batteries. I even read an article stating it's not required with NiCad batteries (but who still uses those?). The memory effect myth stemmed from satellite systems which were exposed to solar radiation etc (which did cause a memory effect). What we generally term as memory effect is just the cell becoming less effective with age.

like i said, if you want to be absolutely sure that you're not "leaking" current, get a cheap multimeter and check the battery terminals, with the unit switched off, to see if the circuit is open like it should be. either use the ohm fuction, or, most meters actually have a special function just for testing if a circuit is closed/open/shorted.

This may not be an accurate indicator. I've hooked a 20K ohm load across a standard alkaline 9v battery and measured it's voltage regularly over a period. It took over a year for the cell voltage to even drop below 9v.
If you measure the resistance at the battery terminals and it's very low you may have a problem, but if it's relatively high it wouldn't cause batteries to discharge over night.


A good way to test your batteries is to put them under load and measure the voltage. Get yourself a 2 cell battery holder and a 5W resistor somewhere between 5 and 10 ohms. This will draw somewhere between 0.25ish and 0.5ish Amps when connected to the 2 NiMH cells (cells connected in series, btw). Hold your multimeter on the terminals and read the voltage with the load connected. If the voltage drops away quite quickly to a level below 2.3v, the cells may need replacing.

*disclaimer: I've never done this with only 2 cells, we check packs of 10x 1.2v 1500mAh NiMH cells in a similar fashion at work with a load of close to 1A. If the cell pack can withstand that kind of load for around 5 minutes, it stands a good chance of providing adequate battery backup for our equipment in case of a blackout.

*Also, be careful. The resistor may get hot.

One thing I believe is a problem for NiMH cells is being at a discharged state for an extended duration. If they're flat for too long they don't recover and wont charge properly. (or maybe thats Lead Acid and Lithium Ion types...)

 

[pferguso]

I tried some Duracells, and they last a long time. I think it was just crappy rechargeables I had. I am going to buy an alkaline battery charger. Alkalines just hold a lot more charge in them.

 

[rokdcasbah]

no, i meant to check the gp2x's batter terminals to see if the circuit was indeed open when there are no batteries in there.

you're absolutely right about measuring the battery voltage under load. the better the battery, the less it should drop (within reason i guess).

and i'm glad to know i was wrong about the nimhs having memory effect. i looked it up and everyone seems to be in agreement so, my bad.

pferguso, happy to hear you're not having problems. but alkaline rechargeables? i remember michael jordan pitching those in the 90s...they're still around though? the newer duracell or energizer nimhs are pretty good. rechargeable alkalines are not as good as the newer nimhs. the idea behind them was that you don't have to recycle them since they're not as toxic. but they're still batteries...it's not like you can plant one and expect flowers to come out of it.

but if you can get 'em for cheap, i guess there's no harm in trying them out.