DIY Laptop Battery Rebuild

by Kevin O'Brien

A day will come when your notebook's rechargeable battery will no longer charge and instead serve better as a paper weight. As you use your battery more often, the battery loses more and more capacity until it finally won’t accept a charge and goes flat. Replacing a battery is easy, but the new battery price could be so steep that it costs more than the notebook is worth. Buying a refurbished battery can drive the price down even lower, but what if you are super cheap? Well, we are going to cover this last option, which means tearing apart your old battery and fixing it yourself.

Dell E1705 Battery Specs:

• Voltage: 11.1v
• Capacity: 53WHR
• Original Cells: Sony SF US18650BR
• Replacement Cell Specs: LG 1650 mAh li-ion Battery w/ tabs

Teardown Process

Breaking the battery apart was probably the single most painful moment of this entire article. I had no documentation to work with, the plastic halves of the battery were glued together, and all I had was a mini snipper. I first started by peeling off the top sticker exposing the open framework with cells in view. After this I took my little snippers to the plastic, and cut away piece by incredibly small piece till the entire top was removed. I had black plastic bits flying everywhere; I think even into someone’s can of soda. The end result was a brutalized battery case that looks 100 percent safe for future use.

Once all of the excess plastic was removed, I could get to the cells I would be replacing. All of these were glued in place, so prying them out with a screwdriver was the only option. As I slowly lifted each group form the plastic case without shorting any circuits, I took my clippers to the metal bridges to fully disconnect the batteries. During this time I also made special note of the wire leads off the charging circuit and where they connected for future use.

Finding the Correct Replacement Cells

Who would have thought finding something as simple as US18650BR batteries would be so hard? It actually took two of us about 30 minutes to find a site that sold equivalent batteries. We narrowed in on MegaBatteries.com, as we found it mentioned on some odd website as a place to find batteries. Now the standard name for the battery size we were looking for was 1650, and we picked one at random since they had quite a few options to choose ... and I was too lazy to run the math on the correct cell capacity. With the cell selection locked in I ordered the batteries, and sat patiently until they would arrive.

Build Day

Once the new batteries arrived at the office, I got to work on prepping the batteries for installation. I verified battery orientation from the pictures of the old assembly, and started to solder together pairs of cells. I used some old wire to bridge together each group on the positive and negative side, and hooked the first battery group to the red power lead. Next step was soldering together the second group, attaching it back of the first group, and soldering both charging leads in place. Last was the third group soldered to the back of the second, and attaching the black lead to the rear of the battery group. The final result doesn’t instill much confidence of a non-firey demise, but it was finished. To add a layer of safety I placed some packing tape over the exposed battery groups, and mashed the "rebuilt" battery into the bottom of the notebook. To the surprise of all those around me, the battery did not ignite into a ball of flames, and actually started charging.

Performance

The Dell E1705 laptop was not the pinnacle of mobile performance from the start, but with the old battery it was difficult to get more than 25 minutes of life before the notebook shutoff. Anything above that value with the rebuilt battery would be a mild success, so I crossed my fingers and hoped that an hour of smoke inhalation (soldering) wasn’t wasted. The results of the rebuilt battery ended up being roughly 47 minutes of battery life, and a Dell battery warning saying the battery had reached the end of its useful life. While the cells were fresh, the batteries charging circuit hard already reached the point of no return. No matter what we could do, it would never reach the charge levels of its prior brand new state.

Conclusion

With the labor involved in rebuilding the battery, and the $53 spent on parts, the DIY rebuilt Dell battery never got anywhere near the performance of a new battery. Although it was a fun process the money could have been better spent on a professionally refurbished battery or a brand new OEM battery from Dell.com. Even if the rebuilt battery did achieve results similar to those of a brand new module, I don’t think anyone in our office would have trusted that notebook to charge unwatched for any significant period of time. With brand new batteries exploding left and right, do you really trust something you rebuilt yourself?

Pros

• Tons of soldering smoke that freaked out coworkers
• People don’t mess with you after they see this in your hand

Cons

• Bringing this through airport security creates a stressful and unhappy situation