Repair ViewSonic V150 BATTERY

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I bought a ViewSonic V150 airpanel Smart Display on ebay a while ago, and its battery was never very good. Now it won't hold a charge at all. This isn't surprising since the device was discontinued years ago. I see that a "new" battery is currently $129, and I've seen repairs for $79 (at BatteryRefill).

As a remote display, it is a nice laptop replacement for around the house, and repairs are too expensive, so I'm fixing the battery myself. Warning: I must mention that this is my attempt, and an account of my own experiences. I ended up encountering many warnings about Li-Ion batteries and their potential for fires and explosions. You may follow my instructions completely at your own risk, but you will need the skill (not just confidence) to do it safely and successfully.

The battery cartridge appears to be glued tightly all the way around, and the rubber feet have nothing useful hidden below them.




Carefully twisting this battery compartment cracked the seal on the connector's side. At this point, I can see that there is a groove that goes all the way around the compartment that holds it all tight, and is only glued together.

Some additional prying from the center, to crack open the entire connector side.

The with some gentle, but firm prying, the end came apart. Again, just glue holding it together.

As I claimed victory against the glue, I let the comparement open with the labels side down. A small circuit board, and 4 crudely taped batteries are exposed. Interesting that the space beside the batteries is clearly contoured to handle another row of batteries. The extra batteries must have been an idea, or buy-up option that you could have paid for.







A quick search on the internet for this ICR18650-20 Li-Ion Rechargeable Battery by Samsung reveals all.

Samsung Site for ICR18650-20 battery.

ICR18650-20 Li-Ion Rechargeable Battery

Nominal Capacity            2,000mAh
Nominal Voltage             3.7V
Dimension                   D 18.25mm, H 65.0mm
Charge Method               Constant Current
                  Constant Voltage (4.2V)
Max. Charge Current         1CmA (2,000mA)
Max. Discharge Current      2CmA (4,000mA)
Discharge Temperature       -20°C ~ +60°C
Weight (approx.)            44g
Energy Density              448Wh/I, 172Wh/kg
Charging Time               Standard : 3hrs.
                  Rapid : 2.5hrs.

I could order the same exact battery, or improve the battery with either the 2,200mAh or 2,400mAh alternatives.
See
http://www.samsungsdi.com/contents/en/product/battery/type01_ICR18650_20.html
http://www.samsungsdi.com/contents/en/product/battery/type01_ICR18650_22.html
http://www.samsungsdi.com/contents/en/product/battery/type01_ICR18650_24.html


I looked around at all the options, 2000mAh - 3600mAh, with slightly varying specs. Sometimes the built in safety protection circuits made the size slightly longer than 65mm tall. It looks like any additional length will cause problem with the already tight fit. I suspect that there are lots of options that will work, but I tried to go for close compatibility and safety. More capacity means more longer charging, higher density, and more potential instability. Closer specs to the original should mean the better the existing circuitry will treat the new batteries. I also want a good price without buying cut-rate or used merchandise.

I found an inexpensive battery that had a close match to the original Samsung 18650, except in a 2200mAh. It even had similar charge and discharge current numbers, which sometimes was the only obvious difference from the original battery. I decided to get pre-wired tabs since I'm not supposed to soldier directly to the battery. The company also had "reasonable" feedback on ResellerRatings.com.

I ordered:

Li-Ion 18650 Cylindrical Cell 18650 3.6V 2200mAh Cell (LC-18650H2-tab)

4 x $5.80 (includes $.25 for Pre-Wired Tabs) + shipping = $30.18

Here at BatterySpace

I NOTED THE ORIENTATION (DIRECTION) OF ALL THE BATTERIES. If I put a battery back in the wrong orientation and tried to charge it, the battery would probably catch fire or explode. The negative/positive ends must be lined up properly !!!

I removed the batteries by clipping the ribbon "tabs," then noted the orientation of all the batteries to install the new batteries exactly the same way as the old batteries. I removed all the tape from the tops and bottoms very carefully. Be most careful by the two small wires next to the blue one. Save the brown single sided tape if possible! Throw away all the double sided tape.

I soldered the SAME wires to the battery tabs the SAME way the old batteries were attached. I was careful to only solder to the tabs (and quickly) to be sure no heat bothered the fire hazard explosive batteries (as all the warnings told me).

I left the two dangling wires beside the blue wire. I'm convinced that they are thermo devices to help the circuitry ensure that the batteries aren't getting too hot during charging. These temperature sensors must attach the same way they were afterward.

I secured the batteries to the plastic compartment with double sided tape. I used "Glass-Tac Acrylic Double-Face Tape" from Home Depot. I also had to secure the batteries AFTER I soldered them in place. It would have been MUCH better for me to put tape in the plastic chamber, add the batteries, positioning the tabs for soldering, then solder them in. I was left trying to lift the connected batteries enough to put double sticky tape below, which was rather difficult.

When I secured the batteries, I made sure the blue wire's connection was reasonably far from the two temperature sensing wires, because I would then need to carefully secure those two with their own tape.

I put tape over the two wire temp sensors to secure them tightly against the batteries just as they were before. If I had saved any of the brown single sided tape from above, I could have reused it here. I ended up using the same double sided tape for this. I wanted to use heat resistant tape as was there before.






I resisted the temptation to use the typical black electrical tape. That stuff tends to get gooey over time and slide around. It certainly wouldn't work for anything that needed to be tightly taped. I did put the little paper dividers back under the solder points to protect the battery from contact and put a little bit of electrical tape on top of the paper to thicken the divider.

After reassembling the pack, I found that the battery pack would attach to the console without the battery pack top plastic attached. I attached the power supply and charged the unit out in the garage for 1.5 hours keeping it carefully covered (in case of explosion), and touched the batteries every few minutes to test for overheating. The unit charged perfectly, without the batteries warming up at all.

I will probably NOT glue/secure the battery pack shell together since when assembled and jammed into the console, it locks and stays together perfectly. If anyone other than myself were to use the unit, I would immediately consider gluing it back together. I will be carefully charging this unit for some time to come, and feeling for battery heat.

I spent less than $40, and consider the project a success!

If you want to further hack the unit, try this (I'm not going to)
PanelPet's Smart Display Panel page