24hrs of charging from "dead"- only 91%

[Calbrit]

I have a spare Mako which I have used a few times but had placed back in it's box for a few months. Having read the numerous postings and suggested solutions for battery problems, I charged the unit continuously (without having switched it on) for 24 hours to ensure 100% charge.

I unplugged the Mako then switched it on only to find a battery reading of only 91%.

Any ideas on why it should not have charged to 100%?

[MikeMcC]

Possibly the batteries became depleted while the machine was not being used and it isn't registering correctly now. Try running them down again, then perform a "hard" reset and give them another full charge.

[ncarbonara]

Mike

This is worrying. I just bought a brand new Mako and, after it had been fully charged to be tested, I decided to let it lose all its power and sleep in the drawer until my present Revo dies and I need to switch to a new machine. Perhaps should I keep it alive by charging it periodically? But this solution presents the risk of tiring the battery for nothing and when I shall finally decide to use this Mako, its battery will already be old.

What is the solution, Doktor?

Nicole

[MikeMcC]

Nicole,

I am not an expert in battery technology but it seems that generally NiMH batteries require a long charge the first time they are used, to "condition" them, and then they should subsequently charge fairly quickly.

Unlike NiCd batteries though, NiMH don't like to be fully discharged and I suspect this is the reason some users have problems when they have been left for long periods - the machine doesn't switch on and it can be difficult to charge the batteries again.

This happens for two reasons. Firstly, the Psion continues to draw current from the batteries to retain the data in RAM (much more than earlier Series 3 machines) and, secondly, NiMH batteries left unused lose their charge even if not connected to anything.

I would therefore suggest that, if the batteries have been charged up following the correct initial charging process, they should ideally be kept charged and not allowed to discharge to the level that becomes a problem.

[doogald]

I'm not an expert either, but it sounds as if the battery charging sensor is confused and registering an inapropriate charge level.

You can try a few things:

1. Ignore the 91% and use ot for a several hours, bringing the charge down to what is registered at 50% or so. Then try recharging, this time with the unit powered on. See if it goes to 100%.

2. Let it discharge all the way (turn off any power off options) and then, after it will not power on anymore, do a hard reset and let it charge up with the unit turned on. Again, see if the charge level goes to 100%.

I had several times where my Mako would say that it had a greater charge then it ended up having - it would say 21% and then suddenly not power on. Doing a full charge cycle seemed to bring things back in order, though.

[ncarbonara]

Mike

>> the Psion continues to draw current from the batteries to retain the data <<

The only data in this Psion are System. Otherwise it is completely empty. Doesn't leaving it completely discharged equal the way the machines are before they are sold to the public?

Nicole

[netBookBabe]

Nicole

Check out the following link for some excellent advice and information about Revo battery maintenance:

http://www.millican.info/Home/RevoBats.htm

This is written by Kevin Millican, the author of ChaDis, the Revo battery monitoring program. You will find a link within the above article for downloading the program if you wish to try it. It is freeware.

Hope that helps
Julie

[ncarbonara]

Thanks, Julie. I deduct that I can leave it the way it is (completely discharged) in the drawer.

Nicole

[ohsix]

I deduct that I can leave it the way it is (completely discharged) in the drawer.

I'll see what happens, too. Because of all the battery problems, I've gone back to using my 5ive until it bites the dust. Meanwhile, I've put my Mako in the drawer. Once my 5ive has gone to the great 5ive in the sky, I'll drag out the Mako and *try* to do a correct charge.

[ncarbonara]

>> I've gone back to using my 5ive <<

I would not like to go back to my 5mx, because it is too big and heavy. I have been using a Revo + for a bit more than a year without any battery problem (but it had a hinge problem).

Nicole

[MikeMcC]

Originally posted by ncarbonara
The only data in this Psion are System. Otherwise it is completely empty. Doesn't leaving it completely discharged equal the way the machines are before they are sold to the public?

Nicole I have to admit that I am getting a little "out of my depth" here with battery technology. I just had the impression that NiMH batteries having had their initial full charge liked to be kept "topped up" rather than being left to lose their charge again. However, others will have more knowledge about the long term effects than I do :)

[ncarbonara]

>> NiMH batteries having had their initial full charge liked to be kept "topped up" rather than being left to lose their charge again. <<

Well you are probably right but now it is too late for me to charge it again because I have left it discharge completely so the damage is done anyway. I shall leave it the way it is and see how it reacts when I need to use it.

Nicole

[Calbrit]

Julie, my first MAKO had all the known battery problems and I went through Kevin's instructions to the letter (several times) and it did not sort the problem out. I also installed ChaDis but it didn't really help me resolve the problems. I managed to return the machine to SPARCO in the USA where I bought it in exchange for another unit. This one gave me no problems (but I have now given it for my daughter to use - dow!) hence me resurrecting the other MAKO. I hope that this MAKO is not going to cause problems as my first did but who knows. I read somewhere (probably Revoworld) that a number of people who had "left their's in a drawer for weeks to totally discharge had better luck next time round with battery management. We'll see!

Adios all.

[djl]

Originally posted by MikeMcC
Possibly the batteries became depleted while the machine was not being used and it isn't registering correctly now. Try running them down again, then perform a "hard" reset and give them another full charge.

Ugh! It will take awhile to become accustomed to this interface. Surely allowing the Revo battery to be _fully_ depleted must have the identical effect as a hard reset, because there will be zero information about battery status in the machine's memory?

djl

[MikeMcC]

Surely allowing the Revo battery to be _fully_ depleted must have the identical effect as a hard reset, because there will be zero information about battery status in the machine's memory? Dennis,

Yes it would, but how would you fully deplete the batteries? At a certain point the machine switches off with insufficient power to run and the remaining battery power is used to retain data until they can be recharged. As I understand it, it is at this point that the hard reset has to be performed and a full charge given so that the charging setup is recalibrated. Problem is that restoring from backup can also restore wrong battery info, though I have no idea where this is stored.

[djl]

<< how would you fully deplete the batteries?>>

Mike

I understood the proposition to be that the machine had been left unused long enough to fully deplete the batteries (i.e. a month or longer), and subsequently did not report a full charge even after overnight on the dock. My (narrow) point is merely that I would not expect a hard reset to alter anything under these conditions because the machine would seem to be in the same state after a month in the drawer as it would be after a hard reset (unless we think there are capacitors which are flushed by a reset.)

In the interest of empirical research I retrieved a well used Revo (8MB) which had been in the drawer since it started making a rattling sound (loose interior piece). Following the initial overnight recharge it reported only an 88% charge. Removed and replaced on dock, red light stayed on for only a few seconds, still reported 88%. Removed and replaced on dock again, red light stayed on for quite awhile, reported charge slowly increased to 100%, left on dock overnight until trickle charging stopped. Removed from dock, disabled auto-off, it's now been "on" for more than ten hours, shows 44% remaining. I conclude the battery "really" did fully recharge.

As chance would have it, yesterday I received a new battery for a digital camera. Battery care instructions note "When charging the battery for the first time your [device] may indicate that charging is complete after just 10 or 15 minutes. This is a normal occurrence with rechargeable batteries. Simply remove the batteries from the charging mechanism and repeat the charging procedure."

dennis

[ohsix]

Mike wrote: < Problem is that restoring from backup can also restore wrong battery info, though I have no idea where this is stored.>

So whenever I get back to using my Mako (if ever) maybe the best thing would be, after a *proper* charge (whatever that is), to not do a retore, but rather go through the process of installing apps, then copy my files from the PC backup folder. A prophylactic method? :p

[Calbrit]

"Problem is that restoring from backup can also restore wrong battery info, though I have no idea where this is stored"

I think we may have one of the main issues here. On my previous Mako (before I returned it for a replacement) I did all manner of battery discharging, hard resets (including Kevin Millican's proceedures to the letter) and restoring of files to no avail. Maybe the ongoing problem was being "inherited" every time I restored my files.

Who knows?!

[MikeMcC]

Originally posted by ohsix
So whenever I get back to using my Mako (if ever) maybe the best thing would be, after a *proper* charge (whatever that is), to not do a retore, but rather go through the process of installing apps, then copy my files from the PC backup folder. A prophylactic method? :p Yes, that would seem to be the safest method, unless anyone can identify a file with battery details in.

[MikeMcC]

Dennis,

My (narrow) point is merely that I would not expect a hard reset to alter anything under these conditions because the machine would seem to be in the same state after a month in the drawer as it would be after a hard reset (unless we think there are capacitors which are flushed by a reset.) Yes, that seems fair comment :)

[ncarbonara]

Originally posted by MikeMcC
Problem is that restoring from backup can also restore wrong battery info, though I have no idea where this is stored.

This assumption seems to me a bit hazardous. If I change machine and restore unto a new machine the content backed up from an old machine, the battery info would pass from one machine to the other?!!!

Nicole

[Calbrit]

Has anyone asked Psion whether the battery settings remain in the memory?

[MikeMcC]

Originally posted by Calbrit
Has anyone asked Psion whether the battery settings remain in the memory? In another thread (dead battery again?) I posted about this question:
This was discussed in the Psion newsgroups and, although I don't remember for sure, it may have been suggested by a senior member of Psion Customer Support who was participating in the groups at the time.

[MikeMcC]

This was posted by Clive Evans (while he was still with Psion) in the newgroups and may be of interest. It is actually in relation to possible problems when using ChaDis with a Revo:

--------<quote>-------------
I don't have time to really get into this discussion right now, but
the whole issue of overcharging, and what ChaDis does to make people think that their machine is overcharging is something that needs to be addressed.

There is a gas gauge in the charging mechanism which is far more
accurate at determining the charge level within the batteries than the guess made by the OS on the basis of the voltage across the cells. This is used to control the charging mechanism (after it has been initially calibrated by the first long charge). It is carefully
designed to prevent the batteries from being overcharged.

During charging, the OS makes it's best guess as to the charge level of the batteries, and generally this is pretty darn accurate, even given the difficulty of doing this by indirect measurement, however this isn't always the case. It will occasionally believe that the batteries have reached 100% charge when they haven't, and at this point ChaDis does its' damage (I like the program by the way, but it can cause problems). The overcharging alarm sounds and the user panics and removes the machine from charge - the machine now displays 100% charge when in fact it's less so, and the calibration of the software is slightly out of step. Repeat this often enough, and it's possible to be barely actually charging your batteries, and strangely enough they don't last very long ...

This is pretty rare, by the way, but it can happen.

Anyway, in terms of charging advice, to get the best life out of your batteries, recharge them regularly, 'topping up' the charge, not running them all the way down too often. Try to avoid interrupting charging during the fast charge part of the cycle. This isn't essential, but it's a good practice to get into.

Clive
--
Clive Evans
a personal comment from a Psion Digital employee
--------<end quote>-------------

[ncarbonara]

Mike

Thanks for this.

Nicole

[makoman50]

if nicad or nimh batteries for that matter are left for a while with only partial charge in them it can damage the total capacity and lifetime. if u left the batteries discharging very slowly (leaving the mako off) the batteries may have lost some of thier capacity therefore offsetting the total percent. what i would do is send it back to psion (for 150 pounds) and they will change the batteries (make sure u back it up first, as all data is lost). psion recommends a battery change every 3 odd years. you could try replacing them yourself with 2 AAA size nimh batteries or give chasinrecordings a jingle.
see what works
makoman