Blackberry Playbook has just given up the ghost, or, at least, the battery has after completing 881 recharge cycles since new in 2012. 

 

It started playing-up 6 months ago, occasionally refusing to re-charge when it was only partially discharged. Over last weekend, it started refusing to re-charge unless the battery was less than 10% and a system reboot was performed.

 

Now today, its died completely.

 

I've ordered a replacement battery at the weekend, as the chassis and workings are still  in good order and, although perhaps slow by todays standards, its good enough for my needs i.e. just to collect the odd E-Mail and read the on-line news and weather and saves me having to power-up the desktop each time.

 

I'm wondering whether its possible to re-condition the LI PO battery by by-passing the charging control circuitry in the tablet, taking the back-off and attaching a suitably rated charger (4.2volt, 2amp) directly to the battery terminals ?  It would be interesting to see if 1,000 cycles could be achieved.

 

 

Nick

Edited 28 July, 201510 yr by Clunkclick

I would just give the original battery a decent burial.

I use LiPo batteries in my R/C models and they do lose capacity over their lifetime. They also need to be charged carefully to avoid any mishaps which can quite spectacular. Although the modern ones can be charged at a greater rate normally 1C (C being the capacity of the battery) is the fastest that they should be charged. The charge cycle starts at a constant current and then when the battery voltage reaches 4.2 volts it changes to a constant voltage and reduces the current gradually to top off the battery. 1000 cycles is not unheard of but the capacity is reduced. The playbook must have decided that the battery no longer has suitable capacity left and is refusing to charge it to reduce the risk of something going wrong.

I would ditch the original and go with a replacement - as you say for your needs the Playbook does what you want, and the complications around LiPo charging make it more risky.

 

I ditched my Playbook sometime ago after I realised that BB were no longer going to support plus we moved away from BB at work to Windows Phones so I went across to Windows tablet (Linx 10)

Liger1956

 

Would it be feasible to try and restore a dead phone/tablet LiPo using a  RC charger with selectable current i.e. remove battery completely from chassis ?

 

According to this source:-

 

http://batteryuniversity.com/

 

The decline in capacity is due to a build-up on cathode and anode.

 

I'm wondering whether that would be partially reversible , as with lead-acid.

 

Also wonder whether freezing the battery might assist, as apparently, LiPo seems to lose capacity with temperature increase - the reverse of lead/acid.

 

I shouldn't think there's any risk on re-installation due to the superior sensing circuitry on the PB, which closes the thing down unless supply is near perfect.

 

 

Nick

Edited 28 July, 201510 yr by Clunkclick

Nick - I still have the old Playbook hardcase and soft neoprene slip case if you want them?

Nick - I still have the old Playbook hardcase and soft neoprene slip case if you want them?

Already have 'em.

 

Looks like it wasn't the demise of the battery, after all, rather the two existing chargers I had (The cradle and the USB socket chargers). I knew the USB wasn't working properly because, the lightning bolt didn't show when its was plugged in and the cradle occasionally wouldn't charge even when the lightening bolt was showing, so I purchased one of BBs rapid chargers (Uses the magnetic attachment) at a knock down price and, lo and behold, it started to recharge the battery straight away ! Now t 91% and climbing.  The new charger and the cradle are rated the same 12v and 2A, so I must assume that the cradle charger has gone U/S.

 

The "Battery University" site quoted above states that the more you allow Li Pos to discharge and the lower the level of the discharge, the lower the number of re-charge cycles that you'll get before it goes U/S, so that if you're in the habit of allowing it to regularly discharge 100%, then you'll only get 500 cycles out of it, whereas if its only allowed to discharge 25% on a regular basis then they estimate that you'll get 2,000 -2,500 re-charge cycles - Mines been sitting in the cradle charger for the last 2years, so, happy days.

 

Give BB their due, they have been very cautious in the design of the charging circuitry and have allowed plenty of margins to prevent the battery being overcharged - they usually expand rapidily, go pop and burst into flames when this happens.

 

Nick

Edited 28 July, 201510 yr by Clunkclick

Liger1956

 

Would it be feasible to try and restore a dead phone/tablet LiPo using a  RC charger with selectable current i.e. remove battery completely from chassis ?

 

I am glad that you have found the cause of the problem. I have not heard of anybody rejuvenating a LiPo at all. If you discharge them below about 3 volt/cell then they do not like it and overcharging or excessive discharging can cause them to gas internally and swell like a balloon. Some of the smaller LiPo batteries now come with an inbuilt charger circuit to prevent over charging. I have some old 3 cell LiPo batteries that are not man enough now for use in my planes but I still keep them for bench testing purposes when I do not need to run the motor.

The PB did charge fully (100%) using the rapid charger, however, from that point on the Battery Guru software showed Battery Health @ 82% - it had previously been 84% for the last six, months and the charging cycle which was 881 is now reported as 883, despite only being recharged once in the interim.

 

I'm wondering how low can battery health get before the battery will either fail to re-charge at all, not charge fully or damage components when discharging due to low current ? And would the PB circuitry prevent damage by switching off ?

 

Also, on the basis of advice given in the various Crackberry forums, I again scrapped the connection pins on both the older cradle charger and the PB and cleaned them with a cotton bud soaked in isopropyl alcohol and that improved the cradle charging situation - now the cradle will charge on approximately 50% of the occasions when the PB is attached -I'd previously disassembled the cradle charger (Easy) and electrically tested input and output circuits for continuity and voltage and these seemed to be OK - the charger contains a small PCB in addition to the transformer.

 

USB charger seems to be OK too, as I later used it to re-charge my Blackberry Curve. What has failed is the micro USB port - it won't charge and it won't take data. You Tube videos show this a relatively easy replacement job using soldering (As long as you have got a Dremel to remove the anti-solder coating) and even Amazon are selling what they claim to be is a genuine replacement part. I don't think I won't chance that unless the cradle and rapid chargers cease to be effective.

 

There are a still number of problems still subsisting here, including a failing battery and intermittment connections caused by dirty and worn pins and manufacturing defect in the electrical plugs used in some plugs - the centre pin (Grounding) in my cradle charger is physically lower than the outer two pins. I even noticed that the trailing pin (Nearest the wire inlet) on the recently purchased rapid charger is lower than the two pins foward - both these attributes have been reported on in Crackberry forums as being (Fixable ) manufacturering faults confined to some production batches.

 

I am finding, sometimes, when I remove the rapid charger plug from the PB or remove the PB from the charging cradle, that Battery Guru continues to show that the PB being recharged, despite there being no electrical connection.   Whereas, the native blackberry software always shows the correct condition as regards plug removal i.e. Lightning bolt symbol always disappears when the electrical source is removed from the PB but sometimes reports the rapid charger as a DC source i.e. Plug symbol shows in place of the lightning symbol. What's causing that ? Bad battery voltage ?

 

Both the cradle and rapid chargers rarely will charge beyond 6 watts, and then only occasionally. Average charge rate is about 2.5 watts - though I understand that 9.5 watts are attainable. Is that failing battery and/or poor connections ? 

 

As an aside, and with reference to the aeromodelling front, is there a LiPo charger that can deliver a "Profiled" charge over time i.e. Like the CTek charger for "Restoring" lead-acid batteries ?

 

Nick