Gen II Prius Individual Battery Module Replacement

you should take voltage records at lower SOC when blocks voltage approach 14V , that will make a better judgment about the health of your battery.

 

Don't confuse chargers with dischargers.

Yes, you can buy a cheaper light bulb discharger from HA, or make your own. If you see a picture of the HA lightbulb discharger, you will probably be able to make one quite easily.

Yes, just probably the parameters need to be customised for Prius use.

From the financial expense point-of-view, this is probably the cheapest. The trade off, is it is the most time consuming, you have to remove the pack and, at least partially, disassemble it. As you have stated you have the time, it seems like a win-win.

With Jeff at Hybrid Automotive bringing a Prius solution to the market, it probably just hasn't gained any traction. There should be posts about for the pre-HA era though.

 

If you have done an Insight charger you can do the same for a Prius charger, just up the voltage appropriately.

 

I did a discharge of my pack with the car in rev with the brake on. approx discharge 3amps., until the vehicles motor started.
approx 20 minutes.


then I let the car charge until the motor shut off


after discharge, .4 volt difference max pair to min pair.
after charge, .1 volt difference max pair to min pair.
Hope to get the car on the road in a couple of days.
Will be interested to see the pack balance after a few days of real life driving.

 

I see some talking about the Reaktor chargers.. as if it's like 4 bmax b6's due to higher discharge, charge rates but due to battery overheating and expanding, what is the maximum charges/discharge you guys recommend? I understand for discharge there is no limit so instead of the .7A you can use say 5 or 6, but isn't charge limited to 1 or 2? Seems pointless if there is higher specs that can't be used.

Still i'm new to this so what is the max we can use safely for charging and discharging a module?

 

The Prius modules can handle up to 100 amps (130 amps for 2006 or later) for a short time interval. You do have to watch out for overheating a module as they will buldgenand then become worthless. Always physically clamp the modules and provide cooling air flow.

JeffD

 

So if I used a Reaktor I could use 20 A charge and 20A discharge with no harm if clamped between to wood blocks and using a fan, then did 3 cycles? I am asking for the real maximum without damage to do the fastest module "balance" cycles..

 

No, in use the HV ECU limits the charge and discharge to the 40% to 80% SoC range, where it will see up to 100 A, so I would limit the charge in the 80%-110% to use 350 mA max for charging. I don't know what the safe limit would be for discharging 40% to 0% SoC. I would let heat be your guide, so get a good IR thermometer. Again, I don't know what the safe temp would be, but in use my HV battery is in the 32-36ºC (90-97ºF) range. Cooler would be better. This is only my opinion, and YMMV.

 

In my view, after using a hobbie charger and reading about others on the list, I don't am not convinced they are worth the time and expense.
***When doing any charging and discharging, always have a fan on and check temp with a temp probe(temp gun around 20.00)***
If you use either a home made or professionally built grid charger, you save time and the expense of many rc chargers.
I would discharge the pack before attaching the grid charger.
You may need to use a 12v auto light bulb to discharge each at the end to the same voltage.(I choose 6v under load)
This would bottom balance the pack.
Then attach the grid charger.
Monitor the voltages of the battery modules.
Any bad modules should show as a variation from the norm when charging.
After the pack is charged, let it sit for 24 hrs.
Check the voltages again. If any are out of the range of the norm, probably replace, or if you have a hobbie charger, try 3 cycles with it on the possible bad modules.
Connect a load to the pack and monitor the voltages under load.
Once again bad cells will show up with voltages outside the norm. replace or try the hobbie charger 3 times.
I believe this process will provide you with a balanced pack.

I guess it could be possible that using RC chargers may recondition the modules and provide more capacity and better gas mileage.
It would be nice to have data to confirm that before taking the time to do the conditioning.
It is also possible to say after you have a balanced pack, if you were to use a grid charger and a discharger, and performed 3 cycles, you would have more capacity and better gas mileage.
Once again, not sure if there is data to confirm that.

In my case, I appear to have balanced pack with 2 replaced modules and 2 cycles with a grid charger.

In all fairness to my view, I have only tested my pack in the driveway so far, after this process.
Hope to drive the car on the road soon.

 

Once another module goes bad, you have to start from square one all over again through this painful process. Its like fixing an endless money pit once it fails again. Better off with a brand new pack if you plan on driving another 10 years.

 

So I'm a bit confused.. doing the 3 cycles D>C 7250MAH cutoff, 3A charge (7200mah) and 1A discharge to 6V.. i noticed during the charge stage it's showing 8.77V which is super high no? Or is that fine?

Also at what point does the temperature start shooting up as the temps were pretty low with 3A charge.
One other thing Some say 2A is a safe charge amount while others use 5A within the pack with no issues... which is correct? My batteries are within the pack.. haven't taken them apart.


. Thanks!

 

on my grid charger, at .25 amps, the modules seemed to cap at about 8.5 volts.

 

update after 26km(16 miles) I was getting 6.5l/100km(36 mpg)
driving on mainly level roads The battery charged all the way up to full.
In the driveway I would only get charged to all blue bars, no green.
After a big uphill run, the battery came back down to all blue bars, lost the 2 green.
I suspect the battery was assisting with the hill climb.
After returning down the hill, I had all green again.
Fairly level home with a slight hill at the end.Finished run with one green bar.
Here is the snapshot when parked at the end of the run.

Should I be concerned with the temperature readings, or are they within a reasonable range?
I believe someone here had said the middle of the pack gets warmer.
I would presume T2 is in the middle of the pack.
The fan was only at a 2 , I could only hear a faint fan blowing noise.
I am impressed that my voltages are within .1 per bank now.

 

So I noticed that two of my modules are bad.. with one being 6.2V while the other 7.2V while the rest are all 7.5-7.7.. any tips on buying a good one from ebay? I see a few testers, test for capacity and voltage after doing a few cycles.. do I want to get them at 7.6+ or ones that are advertised at 7.7-7.8?
Toyota Prius 7.2V Nimh HV TESTED at 7.6V Battery Cells Cell 6.5ah 2004-2009 | eBay
TOYOTA PRIUS HYBRID BATTERY CELL NIMH MODULE 2004 2005 2006 2007 2008 2009 | eBay

Trying to choose between them..

 

If I were going the module replacement route, I would order modules from Hybrid Automotive. Based on their car & support for their other products, they should be a good choice

Replacement Toyota Prius Module - Hybrid Automotive

 

I would but the overall cost for just 2 modules is nearly 1.5-2x the top rates ebay module sellers. (tax and shipping adds up fast)

 

The modules are a new product for them. Perhaps @jeff652 could give you a deal. Picking them up may be an option too.
You do not know the quality of the module or seller from ebay.
Ideally the voltage would be close to your other modules and the same generation module. People here have recommended not mixing generations of modules in the same pack.

 

Standing voltage means little to nothing.If you want cheap, go with cheap. You will likely get what you pay for.
Realistically you will not notice much difference no matter what you buy since the equipment you use to test them is unlikely to be the same as what the seller is using.
If you pay $100 or less for 2 modules then that is a good deal.
And if $100 is too much to spend on repairing your car then you likely have the wrong car.
On the plus side, you will likely have to do this service on your car again in the future, so you will get good at it.

 

I agree with you.. which is why i'm asking the questions on here. To avoid getting back into my pack unnecessarily. Ideally what type of capacity AmpHours or voltage under load should I be looking for? As I said before the avg is around 7.7V under 1amp load. I'm not just going to blindly buy a module or two without knowing why a module is good or not. Just because someone can afford to pay more for the same thing (if I can find modules that have been tested/cycles/capacity checked in the same way), why would they?

 

I would like to thank everyone on this site for their help and guidance on my battery rebuild.
After a day of driving, the battery seems to be working well.
I have seen it push 124 amps for a short distance on acceration and close to 95 amps on regen.
I also connected my hymotion plugin addition and it seems to work well too, now that the stock battery is working properly.