Correct me if I'm wrong... (new Gen1 owner)

Excellent!

BTW, here at the 'tags' if you want to put the table in a post, remove the " symbols used to defeat rendering:

• "["table=head"]" - signals beginning of a table with first line the column headers
• "|" or "," - these are field separators and yes, the "," is a pain in the ...
• 1st line is the headers
• following lines are the data with a field separator for each
  
• "["\table"]" - ends the table

	module id	Ahr @1C	resistance
1	1	3.5	0.02 mOhm
2	2	4.2	0.02 mOhm

BTW, I record the monthly Dashboard data in an excel spreadsheet and use the "concatenate" function to make the display tables. This gets the data in front of people rapidly without having to 'go to <someplace>' to read it.

Bob Wilson

​

 

+++ ROTFMALO

Bob Wilson

 

Mostly I'm loving your toys! Much nicer than mine.

I don't see a problem. The Toyota modules have six cells with a common space open at the top. This tends to keep the electrolyte 'level' constant across all cells. The KOH electrolyte is amazing stuff that 'climbs' walls . . . and eats organic material. I have no doubt 'the blob' is externally KOH.

Bob Wilson

 

Ordinarily, I would only discharge to 5.8 V and never tried to go lower. I did have self-discharged modules less than 5.8 V that recovered. Just I've never actively mapped that area.

Let me suggest using one of the older NHW11 modules as a test article. If it goes bad . . . well what is one more bad NHW11 module as there are so many.

Bob Wilson

 

Steve this is an awesome thread packed with useful information. You Honda guys are ahead of us Prius guys on battery theory. I have not had the time to respond so a lot of stuff is getting thrown together here.

The Gen I batteries are just a bit smaller. The terminal bolts do not line up if generations are mixed. I have seen it done with the bus bars just being bent. The Gen I batteries were beat to heck by the stronger Gen II modules. Gen II modules are a tight fit in a Gen I case. The case cover will contact the plastic terminal guards.

I just got one of these chargers. I have been using old Integy 16X7 Pros. They can discharge internally at up to 30 amps.

I use a rock tumbler with Dawn dish soap, Citric Acid, and stainless steel shot. Citric Acid can be found in the canning supplies in grocery stores. They come out nice and shiny in just a hour. If the bus bars sit for any length of time they tarnish and will need a quick brushing before assembly. I find a fine nylon rotary brush works well.

Do not let Kiwi know that high rate dischargers with logging exist. I think these will become the gold standard of chargers.

I think that all battery tests are comparative. The best you can do is be very consistent in your testing. Then your results will mean something. I have found IR very difficult to measure. It is just too dependent on timing. The automated measurement of your charger should at least be consistent.

That is the million dollar question. Please retest your two good Gen I modules in a month and let us know if they retained their capacity.

I have always discarded modules that self discharge below 7 volts. I might raise that threshold to 7.2 volts. I tested one module that had discharged to 6.74 volts. Sheet metal screws were inserted through the top of the module to contact the cell interconnects. Five of cells measured 1.2 volts and the sixth was at .74 volts. The low voltage cell also had minimal capacity. In the re-hydrating thread I cut the top off a Gen I module. Five of the cells had 6 Ahr capacity and the sixth was dead.

Currently I discharge modules at 20 amps to 5.4 volts. The next day I record the voltage they recover to, typically 7.3X to 7.4X volts. I let them sit at this low SOC until needed, at least a couple of weeks. Starting at a low SOC exaggerates the effects of self discharge. The modules either stay close to where they started or drop to 6.5 to 7.0 volts.

Gen II and Gen III do not fit well into a Gen I case Toyota would never smash modules into a case they were not desinged to fit.

If done honestly and not manipulated resting voltage is a good indicator of module health.

Bob, do you believe cycle charging, deep discharge, or any other tricks can improve the performance of modules?

I use an Electrophoresis power supply to grid charge a whole pack. At a 500 mAhr rate a pack will peak at 241 volts and then drop to 230 volts. The pack will start to heat only after the peak is reached. I let the modules sit overnight before discharge testing

I have tried deep discharges on a few modules. It does not seem to hurt or help.

Huh? I have cut modules apart and seen several that have blown there tops off. The electrolyte is a black goo the consistency of toothpaste. It is confined to the space between the plates. The open space at the top of the modules will evenly distribute oxygen and hydrogen gas. Bob, you have also seen the insides of modules. Why are we seeing this differently?

What I have found is that the Toyota batteries also fail by cell.

I think you will find just as many weak Toyota cells as Honda cells. The data logging of you chargers should show individual cells dropping off.

Let them sit for a month and retest to see if they retained their like new performance. The 7.24 volt module has a chance. I think the 6.74 volt module will return to its old ways.

Keep up the good work!

Brad

 

I have seen no evidence of this in my testing with the 989. My thinking is the cycle charging is more likely addressing cell imbalance in traditional, individual cells wired in series. So it gives the illusion of 'better' to RC hobbist. If the Honda packs are isolated cells, cycling to balance the pack makes sense.

Our NHW11 modules have a common passage way so the electrolyte should even out. It is only when the electrolyte is reaching too low of water content that the weakest cell (the most dry one) limits the module capacity. Add water, and cycling rebuilds that cell and thus the whole module.

My current thinking is the cell capacity is more of a surface, not a volume effect and driven by the:

Ni(OH){2} to/from NiO(OH) # charge and discharge effect​

When I disassembled my module, the 'charged' compound was a redish surface on the Ni electrode. The other was ordinary, metalic color:

• left terminal closest to non-functional pressure relief valve is redish
• right terminal is nickel colored

Now I'm going 'off the reservation.' I suspect the energy storage come from the OH+H to H{2}O exchange and the electrodes simply provide the physical storage of the OH and H reactants. I've just seen multiple modules reclaim slightly higher than 6.5 AHr capacity after adding water and cycling to reform the surfaces.

When I disassembled the module, I tried to cut above the electrodes, through the top:

Not shown, I dumped the parts in a 5 gal bucket of water as it self discharged. Once everything evened out, I was able to recover the smaller parts that were not 'chewed up' by the saw:

and

Half of the nickel electrodes are these perforated nickel plates embedded in the metal hydride paste with the plastic mesh separator from the other half of the nickel electrodes. I did not see how these electrodes were buss connected because my interest was in how to seal the water hydration holes.

SPECULATION: increasing the surface area of the nickel relative to the volume will increase NiMH capacity substantially. A nickel wire, 'cloth', using fine wire weave would maximize the surface area relative to the volume of nickel. The edges would be melted (this is a very high temperature metal!) to form the current buss.

Using a nickel wire 'cloth' would make NiMH energy and power density compatible with LiON but without the formation of non-reactive compounds of current generation LiON. Best of all, nothing is water reactive.

I would also look for high temperature separators including ceramic mesh or even asbesdos. What kills the cell is current concentrations that causes spot melting of the plastic mesh separator.

Finally, I would make the pressure relief valve do double-duty as a hydration port. Hydrogen gas is generated under pressure and will always find a way to 'escape.' We can slow it down but not stop it. The metal hydride is a hydrogen sponge but the case and terminals remain a hydrogen gas loss mechanism.

Bob Wilson

 

I have a no document grid charger I want to connect to my 2003 ( Sorry to hijack)
Gen 1 - Can someone take a picture of one that is connected OR inform me of which terminals it connects to in the casing.
Battery just sat too long and is good just very low and will not start the car. I would assume this is my best avenue to bring it back to life,
Any help would be appreciated.
Thanks

 

Contact me directly and I can help you out.
I have not heard of other Gen1 Prius chargers.

It would have to be higher voltage than a Gen 2 Prius charger.
Alternately you may need to split the pack when charging.

 

Whoa! Holy Poop Batman, that is some awesome initial readings.

Purty Please update us after 30+ days. Would love to see field use readings