Battery Reconditioning Guidance

There all extremely old battery’s. How many battery’s have you seen last 15 years fail then you can do a couple of discharges and still work?

Its just temporary at best. Those that last the longest are the ones driven the most the battery’s stay energized. Leta rebuilt pack sit all the time it’s going to fail fastest.

 

The first sentence is a problem. You're charging the modules prior to letting them tell you where a problem is located. Let the modules help you. Always do a discharge first, so you can see how much energy (mah) remains in the module when it's in the 'as removed from the car' state. Even better if it's been removed for a while, as you can more easily see if a module has a high self discharge rate. It's very easy to see modules that have low capacity when you do a discharge first. For example....If you end up with 25 modules that discharge 3000-3400 mah, one that discharges 700 mah, 1 that discharges 1200 mah and 1 that discharges 1700 mah, you already know which ones are more likely going to be problems, and which ones are still pretty well balanced. Sometimes they will recover very well after being cycled, sometimes not. Sometimes you may want to just toss those three and replace them with ones that you know are good from previous testing.

If the first thing you do is charge them, you lose that data and can never get it back. Charging first can hide a lot of problems. Even after I cycle a pack, I let the modules sit for at least a month before using them, just to be sure there are no self discharge problems. My battery packs are bullet proof.

A 2 amp charge rate is NOT too aggressive. It's exactly what I use. I mount 28 modules on a Gen 2 base (mounted and clamped just like OEM) and have an OEM cooling fan and ductwork connected to the bottom plenum for air flow. I have a Prolong kit set up on the bench just to run the fan. I have (10) 4 channel charger/dischargers available, so I can do all 28 modules at the same time.

 

Even if the pack has been sitting for 18-24 months, still discharge first?

 

When I get an HV battery, I disassemble all the support systems from it and install the clamped modules onto my test base. I do not remove the modules from the OEM clamp. The very first step I perform is to record all serial numbers and current voltage of each module. Then I connect all the test cables to the terminals. All my chargers are setup to do discharge/charge cycles. I ALWAYS do a discharge first. I've had battery packs that sat on a salvage yard shelf for 6 years. Discharge first. Discharge setpoint is 5.8 volts and 1.5 amps. It may immediately trigger the 5.8 setpoint, no big deal. Then it waits 20 minutes and starts the charge portion of the cycle. All my equipment uses the same program. I have a routine and I stick with it. Every module gets the same setup.

 

Pretty sure mine are set to 20. Eliminates just about all false triggers.

 

Hi TMR-JWAP, Sounds good. Having a well thought out and standardized procedure, as well as sufficient equipment, seems like the way to the most likely success and avoidance of having to redo things.

Would you mind sharing what chargers and dischargers you use? And are they capable of outputting data to graph results? I'm trying to learn as much as I possibly can and minimize the time spent on trial and error. Thanks in advance.

Aloha. John

 

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Thanx Alf!! Aloha.John

 

Hello TMR-JWAP, thank you for sharing your wealth of knowledge. I have a 2014 Toyota Aqua (Prius C). It recently started throwing the hybrid battery error, each time I reset with Dr Prius app it runs normally for a week or so. But when I happen to have a prolonged EV event it's as if the ECU forgets to start ICE until battery SOC goes too low. Delta SOC and Delta V is never suspect until this even happens. Battery health is around 51% as per Hybrid assistant.
-Could this be a symptom of something that's not the HV battery?
-I just recently got a CQ3 4 channel charger and was wondering if it's possible to charge two modules per channel( the number of supported cells(15) got me thinking if I can speed up the process this way but have not seen anyone suggesting this procedure on the forum)?

Thank you in advance.

 

The charger can handle doing two series connected modules on each channel. It will save some time, but only on the charge side of the cycle. The charger will still be limited by it's 10 watt heat dissipation capacity on discharging. You could do this and use the capacity information to narrow down which module set(s) is weak and then do single modules if needed to determine the exact module that is weak.

 

Thank you for the reply, and for confirming that detail.