Voltage and Temperature Thresholds [Archive]

PleoWorldHostCami

12-09-2007, 10:25 AM

Should I wait for the battery to cool down before recharging it?
If yes, can I put it in the refrigerator to cool it down?

Where can I get extra battery?

Oneasiaweb

Hi oneasiaweb,

I have definitely been letting our battery cool before re-charging.

I would definitely NOT recommend putting it in the refrigerator! It really doesn't take all that long to cool down.

As of right now extra batteries and chargers are not available.. UGOBE is working very hard on getting Pleo out to as many people as possible and trying to work on extra batteries, chargers and other issues. We'll let everyone know when batteries and chargers are available. :D

Vicki12

12-09-2007, 10:51 AM

I've cooled it in the freezer for 5 min before charging. Not sure if it really made a big difference, but I never get a flashing red light saying the battery is too hot to charge.

cmadmacs

12-09-2007, 11:01 AM

Would the condensation cause corrosion in the battery?

BauerMECH

12-09-2007, 04:57 PM

Would the condensation cause corrosion in the battery?
Yes, I wouldn't freeze these packs.

dschenekl

12-13-2007, 09:09 PM

OK, in the RC world Nickel Metal Hydride batteries should be cooled down before charging. I believe the same holds true for Lithium Polymer and Lithium Ion batteries. Some people in the RC field use freezer packs to cool the batteries, however it is a real bad idea to do this if the battery wrap has any small spaces at the seams where condensation can accumulate. Since no other spare batteries are available from Ugobe at this time, I would say it is best to just let the battery cool off naturally to be on the safe side---My two cents

cmadmacs

12-15-2007, 01:24 AM

Also in the rc world they have little fans they place the batteries on to cool them down.

dschenekl

12-16-2007, 04:16 AM

Thanks, I forgot about this, duh.

I guess the holidays have taken their toll on me.

Oh well, I guess I will have to wait until Ugobe creates a personal assistant to help me remember stuff, do my laundry, and show up to work for me once in a while.

Pleo_Joe

12-16-2007, 12:49 PM

Regarding the voltage of the battery pack and Pleo's actions based on the voltage:
1 - a 6-cell NiMh pack will peak at well over 8 volts when fully charged (even though the 'nominal' is 7.2v, so the question is "What is the maximum voltage that Pleo will accept?"
1a - if the voltage is higher then the maximum acceptable volts, will Pleo reject it or will it accept it and harm the electronics?

2 - We know that Pleo can tell when the battery is getting low and will eventually go to sleep, so the question is "At what voltage does Pleo decide that it's time for sleep?"
2a - Considering all of the mechanical activity would surely cause voltage drops that would recover, does the voltage have to stay at the "sleep level" for a period of time before deciding to sleep? How many seconds?

3 - The thermal sensor is surely there to tell Pleo (and the charger) when the battery is too hot. What temperature is "too hot"?
3a - is there a temperature that is "too cold"? If so, what is that?
3b - Will Pleo operate if the thermal sensor is not connected?

I hope UGOBE can answer these questions.

Thank you and Merry Christmas!

PleoWorldHostCami

12-16-2007, 03:09 PM

I'll see if I can get any answers to these questions.

Marzipanlady

12-21-2007, 06:12 PM

I just got my Pleo today and look forward to getting to know my little green friend!

However, I am charging the battery as the manual instructs and after a steady red the charger changes to green within 20 minutes or so. I took the battery out and returned it to the charger which which is first a faint red and then a bright red. After that, it went green again. I hope I don't have to keep replacing the battery into the charger over 4 hours!

Question: Could the fact that the box was out in the cold for a few hours have made the battery too cold? The battery feels only slightly warm to the touch now.

Question: How do I know just when the battery is fully charged? It seems that some people's batteries were fully charged in much less than 4 hours!

kchamster

12-22-2007, 04:18 PM

For me for the first two charges I had to take out a few times and replace but on my third charge it went a steady 3 1/2 hours and then I got to play for about 1 1/2 hours :D hope this answers your question

BauerMECH

12-22-2007, 04:31 PM

I bet you will find if you'd go ahead an put the battery in Pleo, he'll play just fine. It seems some of the batteries are shipping partially charged. If you see the green, he's ready to go. ;)

pleoman

12-23-2007, 01:34 AM

I bet you will find if you'd go ahead an put the battery in Pleo, he'll play just fine. It seems some of the batteries are shipping partially charged. If you see the green, he's ready to go. ;)

I think they may well be shipping partially charged batteries because my first charge only took 2 hours and the next charge took 2 and a half hours.

ZED

12-24-2007, 12:55 AM

I too am curious.
Is the thermistor necessary for operation or just safe warranted operation?
Either way.. wondering what the output signal of the thermistor is under what circumstances.

pleohacker

12-25-2007, 08:10 AM

Just off the charger the pack reads 8.272 volts at 45 degrees C. At this temperature the thermistor reads about 4.5 K (with the resistance increasing as it cools) At 35C it is about 6.3K

This would make it 10K (at 25C) with a 3900K B-Constant, or a part like a Murata NCP21XV103J03RA
(as found at digikey.com)

the thermistor is required to regulate the end of charge and to force Pleo to sleep if the pack is getting too hot (guessing around 50 C) Hot cells can self destruct, so the thermistor is really needed.

ZED

12-25-2007, 02:09 PM

gracias

and some stuff to make the post long enough to meat posting threshold

ZED

12-25-2007, 07:21 PM

dont put it in the freezer.. there is a safe high and low temperature. Put the pack in the fridge and it'll end up forgotten a bit too long some day. Phone rings.. kid falls down.. all of a sudden you're in the grocery store remembering the battery is in the freezer.

a fan will do nicely... maybe cut away some of the plastic wrap in-between the cells. Being as the battery is completely sealed in the robot.. it shouldn't mess with the thermistor readings.. as well the thermistor is taped right against one of the cells.

rckclmbr

12-28-2007, 09:25 PM

My battery had been charging for about 3 hours but then the charger began flashing red. I removed the battery and it was very hot to the touch. My concern is: when this occurs, what does the charger do? Does it stop charging until the battery cools down, or does it continue causing it to get hotter and hotter?

It worries me because what happens if you put the battery in the charger and leave the room or leave the house or a bit or let it charge overnight while you sleep? When it overheats, what is to prevent it from catching fire?

Is this battery safe to trust in the charger?

kchamster

12-28-2007, 09:41 PM

thats what i have been wondering and when my parents figured that out they wouldnt let me charge it while i was at school or not at the house anymore.....

Siren

12-28-2007, 09:44 PM

I left the battery in all night the other night, like I will do tonight. In the morning the light was green and the battery was cool to the touch. I guess when the battery is fully charged, it keeps the green light on, but stops attempting to charge the battery, giving it time to cool

Sounds like your battery got bumped at some point. Maybe if you have a pet or maybe someone in your house accidentally bumped the charger and made it blink and keep it hot. I know when I bumped the charger once, it started blinking.

Ypan

12-29-2007, 04:05 AM

Probably what happened was the thermistor circuit caught the fact your battery was getting too hot, and stopped charging. That's why it began flashing red. Sometimes chargers(peak detection chargers in general) won't detect the peak, and keep on feeding the battery until meltdown, one reason why there is a temp sensor here. One thing I do with my packs on my R/C chargers is keep track of the time when it is charging, so I know they won't be overcharged, and Never like it always says in the manuals, never charge a battery unattended, I don't mean pull up a chair and baby sit the battery, just keep track of the time a check on it often:cool:

Palidore

12-29-2007, 07:42 PM

Watch the following video for battery info:
http://www.youtube.com/watch?v=Xr707SYr9zs

Or check out the companion guide for battery info as well as general guidelines and info for Pleo:
http://pleoworld.com/downloads/PLEO_CompanionGuide_FULL_110707.pdf

But to sum it up, if the light begins flashing red, it's either not plugged in correctly, or in your case, overheating.
When it does that, it should continue blinking and stop charging until the battery cools down enough, at which point it will resume charging.

From my own experience, it seems that if I charge a battery directly after playing with Pleo or vice versa, it usually ends up overheating disallowing charging/play.

rckclmbr

12-29-2007, 07:52 PM

Yeah, I've read all the info re: battery issues - it's just overheating and I suppose my main concern was how the charger behaved when the battery had overheated. I'm finding that when I charge the battery starting with it being completely cool, it charges for around 2 or 2.5 hours, then overheats ... so then I take it out of the charger until it is completely cool again. Usually after that, it will finish charging.

Thanks for all of the responses - I just wanted to be sure that the charger wouldn't continue to charge when the battery overheats! Loving my Pleo, but still trying to find a good name for him. :)

Lappyexpert

12-31-2007, 02:05 PM

thats happened to me, when it does happen the charger starts flashing and stops charging the battery, it won't start again when the battery cools down, you have to take the battery out, leave it to cool and put it back in.

ZED

01-08-2008, 04:58 PM

using a better charger would help greatly in that regard. my charger has never overheated anything.. discharges quickly... slows charging when heat goes up.. etc..

InNM

01-08-2008, 06:19 PM

Your batteries should get warm (easy to hold) and the light should go green at the end of the charge. If you are getting hot batteries with red flashing light more than once then you have a problem with either the battery or charger. If Pleo moves slow and runs a short time much shorter than it use to), then it is the battery pack. Otherwise you have a defective charger.

Battery packs can get a shorted cell but the voltage will be low so it will not work well. If it is the charger, don't continue to use it, get it replaced. Of course, make sure you are charging is a well vented area and not close to a heat source first.

rckclmbr

01-08-2008, 07:06 PM

PleoWorldHostSauri

01-08-2008, 07:50 PM

rckclmbr I have escalated your problem up to some people that can help. :)

rckclmbr

01-08-2008, 07:52 PM

rckclmbr I have escalated your problem up to some people that can help. :)

Thanks, Sauri! I know I'm not the only one experiencing these same overheating issues.

PleoWorldHostCami

01-09-2008, 03:11 PM

Thanks, Sauri! I know I'm not the only one experiencing these same overheating issues.

Hi rckclimbr,

Thanks for the question, and I aplogize that our answers so far have not been helpful. It makes perfect sense that you want to make sure that the charger won't keep charging an overheated battery.

Here's the answer:

The charger does not continue charging the battery when the battery overheats. The blinking red light is an indicator that the battery is not currently charging. The charger will wait until the battey is cool again before resuming charging. As this point the steady red light will come back. So you don't need to take the battery out of the charger when it is blinking in the middle of the charge cycle.

I hope that answers your question, but if not please let us know. :D

rckclmbr

01-09-2008, 03:37 PM

Thanks, Cami, that's what I've been doing -- just frustrating when it requires taking the battery out several times just to achieve the full charge.

PleoWorldHostCami

01-09-2008, 03:58 PM

Thanks, Cami, that's what I've been doing -- just frustrating when it requires taking the battery out several times just to achieve the full charge.

You are most welcome rckclmbr. But you shouldn't have to be taking the battery out. Once the battery cools the charger will start charging again and should change to a solid red light to finish charging.

rckclmbr

01-09-2008, 04:02 PM

You are most welcome rckclmbr. But you shouldn't have to be taking the battery out. Once the battery cools the charger will start charging again and should change to a solid red light to finish charging.

Yeah, regardless of whether it overheats or not, the light turns green too quickly (apparently a common problem) so I have to pull the battery out and put it back in several times to get an actual full charge.

I know others have this issue as well.

PleoWorldHostCami

01-09-2008, 04:07 PM

Yeah, regardless of whether it overheats or not, the light turns green too quickly (apparently a common problem) so I have to pull the battery out and put it back in several times to get an actual full charge.

I know others have this issue as well.

How quickly is the light turning green? In one of your earlier posts you mentioned that it would charge for 2 - 2.5 hours before overheating. How long does it charge after that?

rckclmbr

01-09-2008, 05:17 PM

How quickly is the light turning green? In one of your earlier posts you mentioned that it would charge for 2 - 2.5 hours before overheating. How long does it charge after that?

The 2-2.5 hours was early on, but the last many charges it has charged for an hour, then turns to green, so I have to take it out and put it back in several times for at least another hour or so to try to get in a full two-three hour charge.

It's more confusing to explain than you'd think! ;)

PleoWorldHostCami

01-09-2008, 05:42 PM

The 2-2.5 hours was early on, but the last many charges it has charged for an hour, then turns to green, so I have to take it out and put it back in several times for at least another hour or so to try to get in a full two-three hour charge.

It's more confusing to explain than you'd think! ;)

Ahhhh now I get it...so you had two different problems. I will escalate this new information and see what we can find out. :D

rckclmbr

01-09-2008, 05:46 PM

Ahhhh now I get it...so you had two different problems. I will escalate this new information and see what we can find out. :D

hahah, yes, my battery is devolving .... ;) first it was the overheating problem, but that has given way to the premature green light issue.

thanks so much for checking into this!

InNM

01-10-2008, 02:45 PM

Do you have any idea if it is the battery or charger? If you have a volt meter, the battery is a little over 8V fully charged. Does it run Pleo ok?

rckclmbr

01-10-2008, 03:32 PM

Do you have any idea if it is the battery or charger? If you have a volt meter, the battery is a little over 8V fully charged. Does it run Pleo ok?

I don't know whether it is the battery or the charger, but I spoke with a very nice man at UGOBE today (he called me) and we're going to exchange my battery and charger for a new one which hopefully won't have these issues.

Pleo is backed by some impressive customer service, and I appreciate that very, very much!

InNM

01-11-2008, 11:21 AM

rckclmbr

01-11-2008, 11:41 AM

My posts have not been staying on the forums.
did you determine if the problem is the battery or charger? The battery is a little over 8V fully charged if you have a voltmeter. This would tell you if you have a shorted cell. If they are warm and Pleo does not run but a few minutes or not at all then that would indicate the batteries also. Ont thing to try is unplug the charger, wait a minute and plug back in. This may cause a reset if something is locked up in the control circuit.
If none of this helps, then the charger should be replaced.

I can see your previous post in this thread just fine, so I think they're staying. :) In any case, I spoke with Kurt at Ugobe yesterday and he is sending me a replacement battery and charger so that I can send my original set back in for them to check out. I'll be sure to post when I get the new set - hopefully to say the new one behaves normally!

denodan

02-01-2008, 12:42 PM

Well your battery will also get hot in Pleo, so think this after around 45 mins or so slows him down or makes him sleep. My pleo is always walking for around 45 mins, or very active, so heats up the battery causing Pleo to sleep.

To make him fully awake hold him upside down, he will scream. Then will be fully active again.

I think I will leave him this time to see if after a sleep he moves on his own again.

I know after playing with him, the battery is hot, like when you charge it, but mine takes 3 hours to fully charge, and no flashing red, but you can hold it and would not say the battery is warm. it's quite hot, but not enough to burn you.

I would not put the battery back into pleo until well cooled because when the battery is used it also heats up, do by putting an allready hot battery in Pleo would cause him to sleep or slow even more.

I accually get close to around 2 hours out of a battery. A lot longer then the 1 hour as suggested is the life of a charge.