Changing bad module on hybrid battery without balancing? Please help!

Yes. You can always do shortcuts when repairing things.

You can simply remove the old one and put in some random replacement. Don't bother match the voltage or state of charge.

It will be fine... For a while.

The car will not be 100% reliable, but you will have saved some money and time in the short term

Then at a future date (days? weeks? months?) another module will fail.

Repeat the process again.

But at least you got to skip the balancing.

Feel free to call me if you have any questions.

 

just replace it with one that measures similar to the surrounding cells. the pain is removing and replacing the pack over and over.

 

A volt meter really isn't the best way to test the modules without a load inline...you are getting the "resting" voltage .. batteries will regenerate some voltage when sitting and might be bad under load. I use an old halogen fog light as a load when testing..

 

You do not have the equipment to do a balance charge. So you are going to skip that step.
Rearranging links in a rusted bicycle chain will not help fix the chain in anyway.
You can do it if it makes you feel better, but since you are skipping other steps, you may as well skip rearranging them as well.

Voltage reading with no load is somewhat meaningless.
Whatever module you get will be mismatched in other ways (State of Charge, Internal Resistance, Self Discharge)
There is no way anyone can match a module to make sure it is as equally crappy as your failing modules.
Especially since you can't quantify to the seller exactly the crappiness of your modules.

So skip it.
Buy a random module from anywhere. ebay, craiglist, junkyard, find one on the curb.
Try to get it close in voltage to whatever else is in your failing pack.

That's it.

You are not going to take the time, nor spend the money to do the entire process properly. Which is fine.
Don't bother trying to do half steps that by themselves will be meaningless, since alone, they will not get you to a more reliable pack.

 

What is your reasoning for putting in all that effort and not doing a proper job? In the whole scheme of things, $450 is not that much money compared with extending the life of your car. I assume you are considering this work to keep the car, not just sell it to somebody else to deal with.

Prolong™ Battery Reconditioning Package - Hybrid Automotive

 

Most people don't even bother getting protective equipment for working on hybrid batteries (less than $90!) that would save their life in case of a small mistake.

So if they take shortcuts in that area, trying to explain why they should buy a $450 charger/discharger sometimes is a exercise in futility.

I agree, spending $450 on a reconditioning system can be helpful for some failing packs. Especially when you start introducing mismatched modules into a pack.

The charger won't fix any shorted modules, but at least it will help mask the imbalance you get once you have to introduce, more and more random modules from various sources into your failing pack.

 

I understood that by discharging / recharging it would balance the modules.
Am I mistaken? If so, how do you balance the modules? A high level explanation will suffice here, thanks.

 

Basically fills all the modules to 100% (by overfilling the pretty full ones until the least filled ones catch up)

Eventually with time, since your modules in your failing pack have different capacities, internal reistance, and self discharge, they will get out of balance again.

So you put it back on the charger again to will it into submission. Stay balanced mismatched pack!

 

EDIT: I misunderstood. I thought you were asking how a charger/discharger system worked.

 

Reconditioning like that has proven to increase the battery pack life, correct?

 

Yes, this will let you use a pack that may have other faults like the ones I mention. (mismatched capacity, mismatched IR, mismatched self discharge)

You can continue to use it until eventually things get so bad that you finally give in and buy a replacement pack.

 

just try to find one close to the voltages of the surrounding cells. by your readings, 8+ is fine.

 

don't charge the modules outside the pack they can swell and you will never get them back together.
I balanced by modules by removing them all from the pack and lining up all the positive terminal's on one side and using a roll of solder to connect them all together (same on the negative side) let it sit overnight and all were showing near the same voltage in the morning, rebuilt the pack and have not had a problem, over a year now.

 

Ironically, what you propose does not actually balance them. But it is a good way to spend some free time if you are not busy.

 

it was suggested by a local hybrid shop where I get my modules, but as I said it worked for me..

 

Again, you can do it. It doesn't harm anything.
But you likely would have had the same result without doing it.