while i have the HV battery out of my gen1

bob, what is the lowest amp hour capacity you would deem "good to use" for a re-build?

 

I don't have a good number. It is more important that the modules be charge balanced and have similar Ahr capacity than anything else.

A strong module will have a flatter 'charge-discharge' curve than a weaker one. So if we had individual modules monitored, not the 19 pairs, the strong ones would stay closer to the nominal operating voltage and the weaker ones would go higher voltage on charge and lower voltage on discharge. By pairing the weak and strong modules, we're 'fooling' the battery management software into seeing the pairs work as if they are same Ahr capacity.

What happens is as the modules become weaker, they tend to run hotter with a slight increase in internal resistance. The electrolyte is 'drying out' by loss of H{2} and O{2}. This means a smaller and smaller area of the plastic separator carries more and more of the current flow. Eventually this smaller area gets hot enough to melt the plastic mesh separator and that shorts the cell . . . fails the module.

What we've done is 'battery emergency repair'. Consider it the same as using a can of 'quick fix' for a flat. You can now go far enough down the road to get the tire properly repaired but you are living on borrowed time. But you can 'baby' the traction battery to maximize the remaining life:

• Heat is the Enemy
  • Do not go up a hill so fast the traction battery is providing charge to drive the wheels. Back off the speed in a hill climb until just the engine is providing the climb power (i.e., look for a semi to follow up the hill.)
  • Drive with cruise control as this minimizes the human 'fretting' that can cause micro-charge and discharge cycles. Smooth is you friend.

Shop for a good traction battery rebuilder. In the East, I have used ReInVolt but there may be others closer of equal skill. Regardless of who, see if you can coordinate having the battery swap done over one of the three day weekends:

• Price and payment expected (add 10% safety factor)
• Check if they have a battery ready the week before (offer a deposit to hold it.)
• Understand their hours (call frequently including ' I just wanted to let you know I'm on the road . . .')
• Get a reasonable room; eat a nice dinner, and; let them know how to reach you if a problem shows up.

Each shop is going to be different so negotiate. I would have no problem if ReInVolt offers to change the transaxle oil and coolant fluids. Especially if they can also do the inverter coolant pump. Negotiate because you want to leave with your car in the best possible operating condition. Living with a marginal car is no fun.

Bob Wilson

 

bob, would you say my calculations here are correct?

here are 3 cycles worth of mili-amp hour readings i took on a 2005 module with my supermate dc6:

D1 2922
C1 4705

D2 4552
C2 4828

D3 4638
C3 7249

is it correct to say that the amp hour capacity for this module is 4.552 Ahr and that this would be a good working module? i know 6.500 is the ideal capacity for a perfect module.

Read more: http://priuschat.com/threads/while-i-have-the-hv-battery-out-of-my-gen1.130701/page-6#ixzz2e3t8UVwX
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It looks like you've got the "dc6" working correctly.

Bob Wilson

 

Put it in Utube and you can make a reference.

I only have experience with the MRC 989 and it works perfectly fine. I have no experience with the DC6.

GOOD LUCK!
Bob Wilson

 

Read the manual: http://www.modelrectifier.com/resources/BatteryChargers/RB977_manual.pdf

We do not know the current capacity so assume:

• 3000 mAhr (3.5 Ahr)
• 300 ma - 1/10 C safe charge
• get two boards and clamps to secure modules so they won't swell

You will use "A" channel because it also allows a discharge:

• voltage -> 0V set so it will use delta peak
• current -> 300 ma
• cells -> 6
• mV -> 5 mV (the manual suggests 30=6*5 mV)
• mAh -> 3500
• Min -> default

Let it run until it stops. If you the a thermometer, monitor the temperature. If it goes over 90F, watch it. If it reaches 100F, stop. It has reached peak charge some time earlier. Whatever charge it shows, assume that is an initial approximation.

Configure for a discharge to 6V limit. Whatever discharge is measured is the capacity. Put it aside and do the other one. Use the first module value + 20% as the estimated Ahr capacity on the charge and current.

Bob Wilson

 

Just pull one side to the module. You want the discharge Ahr as that is the metric of interest. According to the manual, it will report an error yet keep the values. But double check how to program the discharge to stop at a given voltage level.

Bob Wilson

 

Certainly look around but I am going to suggest an alternate.

Do you have a video system that can run in 'time lapse' mode? It may be possible to setup a 'time lapse' video mode that might monitor the output. With say a 15 or 30 second delay between shots, you might be able to make a video recording and play it back later with the time-stamps . . . just a thought.

The other alternative is to use higher currents. Double the current, half the time with some loss of accuracy. Still the 2,680 mAhr sounds about right.

Now if you are handy with microprocessors and single board computers, you might 'crack the case' and see if there might be a debug-interface. In theory, you might be able to get a debug-interface to the microprocessor for your computer and see if it responds. Then comes the fun part, trying to find a way to read out the Ahr.

Bob Wilson

 

I use the MRC 989. Although it claims up to 24-28(?) NiMH cells at once, my one attempt to do multiple Prius modules did not work out. It failed the MRC 989 but it was within the one year warranty. It took a month but they fixed it and since then, I only do one, six-cell module at a time.

It keeps the last eight charge and discharge values and puts the battery on whatever tickle charge you want.

The man-machine interface is 'modal' which means margin notes help. Also, the indicated charge limit of my unit continues for an additional 12% (very bad!) So now I take my desired charge limit * 88% and that is what I program in the unit. I hate that it does not indicate why the charge ended: dV/dt, charge limit, temp.

It supports multiple battery profiles so you can have one for Prius modules and another for other systems.

All-in-all, it seems a little pricey for an awkward man-machine interface. I would much rather have one with a serial interface that could be programmed from a laptop and record the data back into the laptop. I have to manually transcribe the numbers from the display.

Also attempts to use it as a dumb power supply . . . well it still decides to shutdown after some finite time that I can not control. Still, it meets my primary requirements . . .

Bob Wilson

 

I have a hack-tastical prius-aware scanner based on some ELM327 clone that is currently giving me this kind of output:

Code:

>
send: 01af
data read: 01af
48 6B 16 41 AF 7F 7F 7F 19 0F 02 <DATA ERROR
48 6B D5 41 AF 06 51 01 D0 

It's based on djs/obdii from github, but I can't for the life of me figure out how to talk *just* to the battery ECU.

I also saw some other comment about how heat is the natural enemy of a Gen1 prius battery, and I can definitely confirm that. My donor battery pack was perfectly happy last night when it was cool, but is rather unhappy in the heat today. (I'm hoping I can manually balance recharge the two cells right in the middle that have a lower voltage than all the others)