Proposed Traction Battery Simple Test/Database : Re-post

[uart]

I suggested this last week in the Prius II main forum but it passed without reply. Sorry to re-post this but I thought I'd try one more time before giving up. I realize this test might take an hour or so to plan and carry out so there may be a delay (until various people have the time available to do it) before any results roll in. But in principle is anyone else interested in some sort of test along the lines proposed. I think it could provide some really interesting data with regard to how the HV batteries are holding up with vehicle age and miles.


Direct re-post of previous thread :

I've noticed that people often ask questions here relating to the health of their traction battery and are sometimes concerned that it might be in less than perfect condition.

I was just wondering if anyone else would be interested in having a thread here dedicated to making a simple and hopefully somewhat "standard" test for comparing the performance of the traction battery in an unmodified Gen II Prius. I thought that if various people contributed their test results then it would form a kind of a database of typical battery capacity that would provide a useful reference.

Heres what I'd propose as a first draft for a standard traction battery test.

1. Choose a day when the weather is not too cold and record the temperature as part of the results.

2. Find a small and reasonably flat circuit of very quiet roads or a large carpark in which to do the test.

3. Drive the car for approx 15 minutes or so before the test at light load cruising speed on flat roads so that the ICE is powering the car and MG1 is lightly charging the battery. In this state I think the ICE just charges the battery to a preset level and holds it there (two bars from full). Don't deliberately regenerate down Mount Everest or anything to get all the bars up on the battery gauge just so you can "win". It's meant to be a standard test, not a dick contest.

4. Drive the test circuit in EV mode at a slow speed (I'm thinking say 12 to 15 mph but I'm open to suggestions here) until the battery gauge goes down to only 2 bars and the ICE kicks in. Record the total distance travelled in EV mode and the temperature and post results here (along with the year model of the car and the total miles on the odometer).

Is anybody interested in contributing to this? I haven't even done the test myself as yet because I thought we'd get agreement on the standard conditions of the test first and the willingness of at least a few people to participate (in their own time of course).

Let me know what you think of the idea.

[jpadc]

Well, I would be interested in reading the results. Not sure the method is standard enough to give good data, but worth a look...

The problem I have is that most of us Gen II North American users don't have an ev mode switch (unless we added a mod for it) so it would be hard to do the test as described.

[uart]

Originally Posted by jpadc

The problem I have is that most of us Gen II North American users don't have an ev mode switch...

Ok I see, that was an oversight on my part. Little wonder no one responded before. Yes I think the test is not going to reliable enough to get any meaningful results without being able to force it to run "EV" mode. Oh well it was just a thought.

BTW I'm in Australia and have only had the Prius for a few weeks. Since it's a 2004 model and has an "EV" switch I just assumed that everyone had them.

[tochatihu]

I have considered similar tests; possibly more consistent because of no human involvement.

Make the Prius "ready", with base electrical load (or with headlights on) measure timing of several engine on/engine off cycles.

At an adequate external temperature the cycles will be controlled by HV battery discharge rate. If all do this with the same Prius electrical load, the "engine offs" would be shorter in Prius with weak (rapidly discharging) HV batteries.

There are several variations on this theme - the problem has always seemed to be getting many people to perform consistent tests.

[ken1784]

Originally Posted by uart

I think the battery SOC indicator is too vague to judge the stable SOC level.
We'll need ScanGauge or other instruments to see the SOC in 0.5% unit.

Ken@Japan