Traction battery rebuild question

There are many instances of people not getting the safety disconnect plug on the battery properly clicked into place. Since you got it together before, perhaps this is not the case this time. You are doing fine so far, but clearly a detail has been overlooked. Somewhere a jumper loose? A wire misplaced?

You would be way ahead with this project if you had the mini VCI reader (or the one from Autoenginuity), and actually finding out what the DTCs being set are. Otherwise, no one will be able to say for sure what's up. When in a jam, more info! It's cheap and comes quickly (eBay).

 

It sounds like the batteries are not quite balanced. Did you connect it in parallel after balancing all 28 batteries? When I check my voltage after leaving it connected in parallel, every module was exactly 7.80 volts with the occasional variation of 7.81 volts. I would remove the pack and check the voltages again. If they are fairly close together ( .15 volts ) I would connect the pack in parallel. If it is farther apart run a single dsch<chg cycle to all of the batteries. Make sure they all come up to the appropriate charge.

Take some pictures and post your set up. It sounded like you may have had a loose connection with one of the battery modules. I know how frustrating this can be.

 

Torque Pro ($5) on an android pad or phone should do the job. Priidash (free) on a Linux or Windows machine is also a good choice for use with a good Bluetooth OBDII dongle.

JeffD

 

YY,

When you did the discharge, how did you measure the module voltage? You need to measure the voltage at the module terminals to eliminate the voltage drop in the discharge load wires. A recheck of module voltages after you finish (with no current draw) is also a good idea as each module has an internal series resistance and differences in series resistance can cause voltage imbalance under high load/charging currents in active use.

JeffD

 

The DC6 connection leads do have a voltage drop that can cause differences. I measure the module series resistance (read module voltage drop with a 1 amp discharge current) to determine that all 28 modules (Gen2) have comparable series resistances.

JeffD

 

Below is a picture of my parallel set up. The black wires represent the negative terminals. I connected all the negative on one side and ran a alligator clip to connect to a negative terminal on the other side. As long as all the negatives are making proper contact you should be solid.

The crazy wires you see going over the top was for the positive terminals. I took a single speaker wire and ran it back and forth over the top. I would strip the wire and loop it once around the positive terminal before running it to the next one. I used the nuts for all the terminals to keep the wire in place. You just have to make sure none of the positives make contact with the negative connections. Double check everything as you are placing the wiring. Wait a few hours and check the voltage of each of your modules. You will notice the voltage will start to equalize with all of the batteries. Mine took about 6 hours.



A difference of .2 volts was all it took to throw the triangle for my Prius after I put it back together the the first time around (had not balanced the modules then.) The modules must be balanced properly. I would not bother driving the car until you get the modules equalized.

 

To even out the voltages on each module you do need to remove all the bus bars.

Then connect all the positive terminals together and all the negative terminals together. Let the battery sit like this over night, this will equalize all the module voltages, the higher voltage modules effectively charge the lower.

A voltage difference of .2 volts or more on a pair of modules will throw a code.

John (Britprius)

 

In order to connect it it parallel you will need to remove the bus bar from both sides yes. Just pick up some simple speaker wire to make a harness for wiring parallel. Just remember, positive to positive, and negative to negative.

When charging/discharging, did you make sure to leave the top and bottom black compression bars installed and tight?

 

Folks, just replacing and charging/balancing modules will not make your pack work properly unless all modules have similar Internal Resistance and usable capacity. If you don't have have a good method of measuring IR, and measuring voltage UNDER LOAD you are probably wasting your time. Measuring voltage at rest doesn't really tell you too much. (think of the 12V battery on a normal car, it can register 11-12 volts with a voltmeter but is useless at starting the car...that is why good 12V battery testers put the battery under load)

YY4U has spent countless hours trying to "self rebuild" his pack. While I'm sure it has been a great learning experience, others should note that rebuilding a Prius is battery is not as simple as "buying slices on Ebay and bolting them into the battery enclosure".

If you are looking for a project, have a lot of spare time and patience, and want to learn new things, go ahead, Do it yourself. But remember, many DIY's install and remove the battery multiple times before getting it right. (aka "whack a mole") Be prepared to be without your Prius for many days (possibly weeks).

If you just want your car to work, buy a complete rebuilt battery from an experienced rebuilder with a good warranty.