Tuesday, June 30, 2009

Repairing the battery computer

The good news is that the battery computer can be repaired. We reconditioned a hybrid battery for Auto Electrical Solutions Ltd in Palmerston North It had a faulty computer. The tortoise would come on when the battery indicator showed half or 3/4 charge. This is a sure indicator that one of the diode sensors is faulty.
Because the battery is now fixed, it is now possible to check the diodes in the computer and change the faulty ones. This is what AES did and all error codes also went away.
This is good news as it completes the process of repairing and reconditioning the series 1 hybrid battery.

Wednesday, June 10, 2009

How to tell if your prius battery computer is faulty

The prius series 1 battery computer has 40 diodes and capacitors in an array. If one of these diode or capicators fail the computer is faulty.
If you see the tortoise icon when the battery charge level is in the green, your battery computer is faulty. You will have to get another computer. Driving with this computer will overcharge the battery and destroy it completely. I mean completely that is most of the cells will be destroyed until you can't drive it at all.
You can't even replace the battery with a new one!!! The computer have to be replaced.
It may be possible to carefully drive the vehicle but you must not let the overcharge 100% charge indicator show for too long and you must back off when you see the yellow charge indicator. It is difficult to drive within these parameters.

Tuesday, June 2, 2009

How to recondition your prius hybrid battery - Series 1

This post is to help those who wants to recondition their Series 1 Prius battery themselves. Do note that the series 1 Prius ( 1997 - 2000 ) refers to the model that uses the Nimh D cells. These were never imported into the United States. Those in the US will refer to the Series 2 ( 2000 - 2003 ) using the parametric Nimh cell module as the Series 1. ( Confused ? )


Caution : The Series 1 Prius battery pack consist of 240 Nimh D cells in series. Up to 360 volts could be exposed. Wear protective gloves when working with this battery at all times.

The first step is to remove the battery pack from the vehicle. You can refer to our website for more detail information. HERE

When we first started reconditioning this battery in 2007 we did what most people would do that is to check the condition of each tube with a volt meter and replace the weakest tubes with better ones. This process though logical is extremely frustrating. The problem is that each tube consist of 6 D cells in series and measuring the voltage of the whole tube does not accurately reflect on the condition of the tube. To more accurately check this remove the plastic wrapper and test the voltage of each D cell separately.

Whenever you try to determine the status of a cell by it's voltage you have to know the state of charge before you start your measurement. Using a suitable Nimh charger give the tube a full charge before you start your measurement.

To accurately determine the capacity of each tube discharge the tube with a know resistor and measure the amps used. If you get 5 amps and above the tube will be suitable for use in the pack.

When you get all 40 tubes, assemble the battery pack and with luck you have reconditioned your own battery pack successfully and your car will be roaring back to life again.