Sustainable Sustworks - Tools for Internet Travel
Inspired Tools for the Mac

TruePower Batteries
TruePower Battery Technology
Battery Memory Effect - What it is and what you can do about it

TruePower Laptop Battery Review


When I purchased my Apple PowerBook G4 12" about 30 months ago, I was surprised when the battery run time dropped by over 50% in just 15 months. The machine was under Apple Care so I called to inquire. Although 15 months sounded short, battery life is not covered. After paying $120 for a replacement battery, I've been on a quest to understand laptop battery life and how it might be extended.

The AppleCare specialist suggested not leaving the machine plugged in all the time. I also thought to myself perhaps the original battery was weaker than normal. When my brand new Apple replacement battery also lost 50% of its capacity in just 14 months, I realized something else was going on. The purpose of this page is to describe what I've learned about laptop batteries and battery life in the hope of creating a useful reference for myself and others. I welcome your comments to help keep this information up to date.

Killer Usage Pattern

My laptop is plugged in and turned on almost all of the time except for an hour or two most days when I run it off the battery. I let the machine sleep instead of shutting down so it's nearly always ready to go. The PBG4 is my primary development machine and normally attached to a 20" Cinima Display. It runs warm to hot much of the time.

Tips For Extending Li-Ion Battery Life

I've received many tips, some contradictory. Here they are:

  1. Do what you can to keep your battery cool. Excessive heat is bad for your battery. This is challenging in the 12" laptop form factor, but a cooling pad might be in order. Consider taking breaks, or otherwise reducing the load on your system.
  2. Re-calibrate your battery every month or so by fully charging, fully discharging, and then fully charging again.
  3. Recharge your battery before it reaches empty. I've been told deep discharging cycles are hard on Li-Ion batteries unlike some others which can develop a "memory effect" when not regularly discharged. Based on the re-calibrate your battery every month suggestion above, it would appear that "some" but not too much strenuous exercise is good for your battery.
  4. Don't keep your laptop plugged-in all the time. As the charge begins to fade, it will constantly begin recharging.
  5. Charge your new battery for 12 hours or more the first time it is plugged in and then allow it to discharge fully to maximize its capacity.

TruePower Experience

After my Apple replacement battery experience, I was ready to try an alternative. I ordered a "TruePower" replacement battery based on favorable reviews, longer warranty, and plausible technology description on the FastMac website. Here are some observations.

  1. The fit and finish matched my PBG4 well enough, but the outside of the case is actually a flexible molded plastic rather than aluminum as in Apple's replacement batterries.
  2. The 12" battery was advertised as 4400 mAh, but (a nice tool for monitoring your battery) shows the Battery Capacity as 4200 mAh out-of-the-box (Battery-Loadcycles: 0). [20-Jul-2006]
  3. After the initial calibration, CoconutBattery shows the Maximum (and Current) Battery Charge as 4492 mAh (more than the original capacity). [21-Jul-2006]

So far, it seems to be performing as expected. I'll comment more as I gain more experience with this battery.

[30-Jul-2006] No noticeable deterioration after the first week "100 % (4492 mAh)" after 5 load cycles (but I haven't tried recalibrating the battery yet). I added a Targus Traveler Coolpad which keeps the bottom of my laptop noticeably cooler ($10.73 + 7.98 shipping from Amazon). Very slick. The plastic outer skin of the battery remains close to room temperature which may be a slight advantage. My impression so far is that this battery is the real deal. If it lives up to its marketing claims, I'll be very pleased.

A few readers have asked for an update, so here it is.

The TruePower battery has worked well for me.  So well it hasn't been a significant issue.  Apple voluntarily recalled my previous battery and replaced it due to reports of bulging and overheating, so I have two batteries for the machine.  I also upgraded my primary development system to a MacBook in December of 2007.

The last measurements I did show the TruePower batter is aging, but at approximately half the rate of Apple's original battery.  Getting 2-3 years service from a heavily used laptop battery seems reasonable.

I've learned a bit more about batteries which I have described here:

Peter Sichel is founder and chief engineer of Sustainable Softworks, a software developer specializing in advanced Macintosh networking.

psichel "at" sustworks "dot" com

Last updated 10-Nov-2008.

Back to Interests and Opinions