How to test HV battery state of health on your Gen 2 (answer)

If I can get to 400K with this pack (using the HA kit), I will be very happy. As it is, I am not sure it's worth spending $3K+ on a battery at this time. I bought this car for $3.4K and it is in almost perfect condition. A new pack was not in the budget, but I did read about the reconditioned packs (I know, not a great option) and reconditioning systems, all for under $1K, which I did budget for. So this is the path I am taking. Also, I am in Massachusetts and so far I have not found a reasonable source of new Toyota packs. My local dealer quoted me something idiotic, which sounded more like "we really don't want your business", or numerically $3.5K for the pack and 8 hours installation charge at $100/hour. So total of $4.3K, which is way more than I paid for the car. If they expect me to jump on that, they are not based in reality. I know there are sources out there where I can get a new pack for closer to $2.5K, but I am not sure how shipping the pack and core back and forth will effect my cost. So in short, since my car is currently getting great mileage and seems to be well taken care of and driven only by one owner since new who was really into extracting economy from it, I think I am probably a good candidate for the HA system. I have had no battery related codes at all and the car drives great with good mpgs.

Thank you for your advice.

 

The AC does not use the 12V battery. It is loading down the HV traction battery.

 

If I were you, I'd take the same step you're taking now.
I think its part of HV maintenance

 

I understand that, but I also understand that the traction battery charges the 12V battery via DC-DC converter. So if you are constantly pulling a load from a 12V battery the system should kick in and provide the charge to 12V battery to compensate for the load. This is why I asked the question. If someone knows how the system handles loads on the 12V battery with respect to the traction battery, the test can be made much easier by loading the 12V battery. I know you can pull close to 100A from that 12V battery, which is around 1400 watts. That should be enough to sicharge the traction battery if it's trying to replenish the 12V battery at approximately the same rate as it is being used. A simple hair dryer can easily pull 1000 watts (with an inverter connected to the 12V battery) making the whole test more repeatable and simple.

Also in case the A/C does not pull the proper amount of current (like in cold weather), the load can be increased by loading the 12V battery.

Anyway, it was just a thought outside the box.

 

So I can confirm you can add a load to the HV battery pack with running items off 12 V. This is obvious since the rear defrost, fan blower motor, and other accessories like the lights are on the 12 V system. In another thread I saw that there is a certain limit the converter can do that chargers the 12V battery, so you can't put a 3,000 watt inverter on it but from what one thread said a 800 watt inverter might be big enough to pull the max current off the 12 V system. The other thread was someone preparing for the Hurricane season in Florida and got a 3,000 watt inverter but someone said it could blow the system that charges the 12 V battery. But maybe for those in colder climates or winter season could pull some load using a 120V inverter on the battery. I have a 200 watt? (I can't remember) and I will see if I can get a 16 amp draw for a test here in Idaho. I recently did a re-condition on my battery pack (101,000 miles 2009) where I discharged it 3 times and fully charged it back up each time, and I think I see a difference, but I haven't had time to analyze my torque log files. I do collect data from each drive for the last 2 years and I could probably tell the improvement after looking over my logs.

I'll post what I see on if I can drain it here for a test like described in the first posts.

 

this thread should be stickified. as short tempered as the o/p was, he was a great mind.

 

Great thread. Greatly appreciate all the posts and helpful comments. Is there a method or tool to test battery state of health on a battery out of the car?

 

Just charge up the battery pack fully and then connect it to load. Then you can measure the voltages of individual modules. From that (and the current, and time) you can calculate the internal resistance for every module and capacity of lowest module (and capacity of the entire pack).

 

That sounds like the Prolong conditioning system

 

What voltage is fully charged and how much of a load would you use, in light bulbs? Thank you.

 

Here is the user guide for the Prolong light bulb discharger. They also have a more automated unit now.

Prolong Simple Discharger User Guide - Hybrid Automotive

 

Thanks for your outstanding Technical knowledge. What are all the acronyms? for example SoC etc. At least once if it is explained the first time it is mentioned would help. The attachments are not opening, it is giving an error, how would I open up the attachments?

 

PriusChat Glossary | PriusChat

 

Unfortunately the attachments have been deleted. They were Excel graphs of the Techstream data that the poster made to interpret the data. Unfortunately the poster is no longer active here.

 

I didn't read every single reply but many and I never saw anyone mention that the SOC range Toyota says is fine is 40-70%, with a real range of 20-80%. So if you're around 40-60 and there's no problems, I wouldn't mess with anything unless it's something you're just really into.

 

Another old thread...

Basically, the idea is to force charge the battery to the max SoC, and then discharge until ICE will kick in. With the data of SoC, Current Draw, Time, Max and Min block you can conduct an approximate SoH of a batttery, right?

It does look a lot like a Hybrid Assistant app because you can estimate capacity by discharging to the lowest SoC with the current of 10-15 amps.

 

Correct. The life expectancy test in the Dr Prius app does it all for you and gives you a percentage of capacity left. The higher the percentage, the higher the SoH.

 

You're right, Dr Prius app indeed has that option. Although it doesn't tell you the estimate capacity for each modules. I suppose none of this apps will tell you the left capacity unless you take apart the battery and use RC chargers, but even this option is still not the best. 30k$ lab grade equipment will)