Been reading about replacing cells, just wondering if I have the gist of it down

Well, you said you think. Y not invest in a tech stream based scanner, and try to read for codes, and watch the live data of the blocks. That would give you an idea, what you need to do next.

Its not just buying some few modules and slamming them in there. Its got procedures you follow.

 

Welcome.

First, if you're going to play "whack-a-mole" with the modules, you need to know which ones are bad. As @Dxta said, you need something to read the codes so you can find out. Techstream is best, but there are other alternatives using OBDII wireless scanners and smartphones with Torque Pro or Engine Link. All three are a little involved, but will save you a few years of guesswork. You can search for the hundreds of threads here about all those topics.

Second, replacing individual modules just kicks the can down the road a short distance and then you're doing it again since all the others are just as old. If you recondition the battery with Hybrid Automotive's Prolong grid charging system, that will greatly improve the quality of the repair, and it's just good preventative maintenance on older batteries.

Third, a new hybrid battery is the best option or at least a near-new one from a totaled car. We have a member here, @2k1Toaster, who offers an alternative to the Toyota battery that's getting good reviews as well.

 

Best choice for DIY for Gen 2 & 3 HV battery is new cells from 2K1Toaster. NewPriusBatteries

How will you do this? As in, what test will show you good or bad modules? A simple load and discharge test?

Again, how will you do this? This sounds easy when you say it out loud, but is very difficult in practice. It is the key process in successfully rebuilding a battery, though.

Nope. Balancing is charging all the cells in a module so that all cells charge up to the same level and discharge to the same level. If the cells are still essentially viable this will work to a large degree. But when, even only, one cell charges/discharges at a different rate to the others is when the module starts to become a problem. Whether you use an RC charger to charge a single module, or a grid charger to charge a whole battery of modules, all cells are charged in serial. I don't know I have come across anyone charging in parallel.

 

Charging them all in parallel would be a huge undertaking. You'd have to unwire everything, rewire in parallel, charge, and then rewire them for use. And that's after taking apart the car and battery. Just connect the prolong grid charger without even taking anything apart or even exposing the battery once the cable is initially installed, and go do something else for a while.

 

Short answer: The modules will not likely all discharge at the same rate. New cells are more closely matched for less work.

 

but your theories are conflicting. I completely agree that you cannot simply add cells with an unknown state of charge into a battery and expect them to function properly. And in the exact same theory you cannot perform a battery level charge/discharge using that prolong grid charging system and expect the weak cells to be reconditioned, if anything a deep discharge/cycling will shorten the life of the battery if the cells are in various states of health. You simply can't get around this issue (it seems like prolong means to address it via marketing) the cells must be individually balanced and charged.

 

The Prolong charger relies on valid theory & experience, not marketing (except from satisfied customers)!

I know your mind is made up, but here are the facts. Battery Reconditioning - Hybrid Automotive

 

Not a theory, it's experience, and not just mine. That's how it works and it works very well. Yes, it does degrade the cells very slightly every time you use it, so you shouldn't use it unless you need it. But just driving the car degrades the battery, too and so does not driving it. But since the Prolong only puts electrons into the battery at a third of an amp and it runs the cooling fan full speed, there is very little stress on the battery. When running, the car draws around 100 amps from the battery and pumps a whole bunch back in when braking. I don't recall how much. But a couple grid charges a year won't cause appreciable damage. It's just that there's no sense in balancing an already balanced battery.

It won't fix a bad cell, but it will balance them all if they are all functional. If you have a bad cell, get one that's as close a match as you can, install it, and do a grid charge per the Prolong instructions. You'll still have a bunch of old cells waiting to go bad, but you'll have a better battery than what many rebuilders sell by not grid charging them.

 

And if you discharge & recharge following the Prolong instructions, experience says the battery pack performance increases for several months or more.
@Raytheeagle and others need to share their experiences.

 

And @srellim234, @edthefox5, and a bunch more!

 

Go Jerry!!!

 

Don’t just cheer
Share your experiences too!

 

I have in depth. But I did the discharge procedure completely wrong and still got stellar results so don’t listen to me man lol....

 

Not in this skeptical thread. Have a link to share then?

 

I have used it successfully on a Gen3 and share this with a member here who has a Gen2 .

I have loaned the Prolong equipment to another member here who rebuilt his battery (2 bad modules) and has worked well for him .

Works well for us.

 

so this grid charger, how is it connected to the battery? Via a single connection at the battery level? Or does it contain 28 leads that attach to each cell directly and have an intelligent feature to charge/discharge each cell individually? You cannot bend physics if your charger only has the capacity to connect at the battery level, then you have no mechanism to prevent overcharging cells with high voltage (besides let them degrade by bleeding off that energy as heat) or risk damaging cells with low voltage or even bringing them to negative voltage as you discharge your healthy cells.

 

Connects to the battery side of the main relay. Charger hard limited to .337 charging current. Takes a nice long slow time to charge entire battery up so no heat. Fan is driven with outboard circuit to max speed to protect battery from any heat. It works.

 

it technically is not a huge undertaking, and is the only way to properly balance cells. We have been doing this for a long time with NiMh cells in the RC industry. all you need is an intelligent charger with enough leads. You physically disconnect the bus bars and attach the leads. The intelligent charger cycles each cell through a predetermined charge/discharge cycle which restores that cell's capacity.