Prius Batteries - How to make them work

Well it looks like a newer battery but the part number doesn't cross over in my system. Where did you get this from? Japan?
The new prius uses the same type of cells but are smaller from what I have read. The HV pack is part# G9510-47060. Should still contain 28 cells.
 
gasfree said:
Well it looks like a newer battery but the part number doesn't cross over in my system. Where did you get this from? Japan?
The new prius uses the same type of cells but are smaller from what I have read. The HV pack is part# G9510-47060. Should still contain 28 cells.
Click to expand...
Thanks! The battery is listed on ebay in Australia.
 
To stay on topic, here's how I make the Prius modules work for my 2 bikes, set up the same way:

At 6 cells/module, I have 7 modules in series for a 42s block (50.4V nominal for my 48V controller). Then, 2 of these blocks in parallel for a 42s2p. I discharge in parallel with no Schottkey's to join. At 40A draw max (controller limit), each Prius block only contributes 20A max. This way, I feel it yields more AH per block because it is not so demanding on either one. I should have at least 8AH realistic (13AH on paper) total, but I haven't tested the limit. My normal 10 mile round trip to town includes a very long steep hill at the end, and uses 5.1AH total. The set-up handles the steep hill, no problem, drawing 40A continuous if I ask. The voltage sag under load is minimal, example - 52V down to 50V, but recovering back up well.

Because these cells are so balanced (and came from the same original batt) I recharge in parallel. I use a Soneil 4808SRF, set at 57.5V CV clamp and 3.5A max flow. This equates to around 8.21V/module (or 1.369V/cell) max charge. I ran fiber optic outside the box from the amber/green LED on the Soneil so I can see the switch over from the CC to CV. When I hear the fan go off, the charge is complete.

Here are some pictures of my wife's bike: One battery block is in the black box and one is split 4 modules/3 modules each side of the basket, joined by 8GA wire.
View attachment 3
View attachment 2
View attachment 1
04.JPG

--Tom_D
 
I just bought 4 complete NHW10 batteries, from first gen Prius which was only sold in Japan.
One of them also has the 12v to 288V charger on it.

I'm struggling to find information about how to dismantle and recondition them, does anyone have a link?

There is an owners group: http://autos.groups.yahoo.com/group/Mk1_Prius/
but I don't know yet if there is useful info in there.
 
http://hiwaay.net/~bzwilson/prius/pri_batt.html
the home brew capacitive pressure sensor is pretty cool.
some potential there for a charge termination/protection switch when charging in parallel?

looking for 3 more 7.2V modules to complete a 72V pack.
pls let me know if u have a few ur willing to part with.

lesdit said:
Offhand does anyone have the specs for the Prius batteries, like max discharge rate10C=65A cont, 20C=130A pulse for 5s, and max recommended charge rate? 0.2C to 0.5C=1.3A to 3.25A recommended, 1C=6.5A max
Click to expand...
 

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Well, they are not quite ready for shipping yet...



I hope there are more good modules in there than I need.
 
Now I know why the first post here says you should not buy anything other than Gen 3 packs!

These Gen 1 packs are not prismatic cells, they are "D" cells, in strings of 6s, with some screw connector at the end.

The Vehicles they are from are the 1997-2000 Prius Mk1, sold only in Japan, but now being exported as used vehicles to some countries.

Still, I got them cheap, and I will probably find a good use for them.

The inner workings of the battery:

Maybe there is an interesting BMS in that "Computer" box on the left hand side!

Does anyone know how to best disassemble this type of battery?

EDIT: Changed to 6s. Each "Stick" has 6 cells, not 7.
 
Yowsa, fantastic to see so much interest in Prius cells after all this time! I've been way too busy to post for quite a while. If anyone is interested, I still have my original ones working without any problems. I also noticed a lot of whole Prius batteries on ebay for pretty cheap money, hope you guys are in Prius heaven. I see quite a bit of variance from my original charging recommendations and I'm surprised at the success folks have had over 8.35 / 8.4v - someone even charged to 8.6 and another till bulging! I think you guys are nuts but if you're not noticing problems you win. Drop the temp probe down one of the wells rather than on the side of the battery.

Tom, why just 8.2 volts on the charge?

March on!
 
powermed said:
Tom, why just 8.2 volts on the charge?
Click to expand...

I was breaking in a new pack at 8.34v/module and had a bad experience. :shock: :shock: :roll:

I figure that 8.2V is more like what Toyota does, not charging to the limit. I am purely guessing, but since I have ample AH, I just want to err on the side of safety. Plus, I am charging in parallel, so don't want to push it to the edge.

-- Tom
 
Thats why i think the toyota computer likes to do th 20-80% discharge/charge approach. It doesnt know how to fully charge it without plumping them up. I think charging them in parallel helps them equalize. They display similar characteristics as SLA when charging. When they are charged they will all have the same voltage and internal resistance If they ccame from a matched pack. If you try charging the modules in series and they have different voltages and resistances and arent matched they will plump. They didnt do this in parallel.
 
Tom, no doubt if you have the extra capacity and it's working for you, no reason to change. I've left 8.3v on overnight once by accident and there was no issue, the cells were drawing milliamps, but no heat/defomation/gassing. A while back I set my charge to 8.35v and charge them in series strings of 4 packs. I run my hub motor using 2 strings of 4 packs (about 60 odd volts after the charge settles. I run my midengine with single 4 pack string (30v'ish off the charge). I have not had a single issue despite daily use - but again, I don't drain them. My chargers for some time have been the vicor AC to 48v converters trimmed to the charge voltage. After my 10 mile ride, the packs usually draw about 5 amps to start and taper to .1 and reach charge voltage within about 2.5 hours, my typical timed charge.
 
powermed said:
Tom, no doubt if you have the extra capacity and it's working for you, no reason to change. I've left 8.3v on overnight once by accident and there was no issue, the cells were drawing milliamps, but no heat/defomation/gassing. A while back I set my charge to 8.35v and charge them in series strings of 4 packs. I run my hub motor using 2 strings of 4 packs (about 60 odd volts after the charge settles. I run my midengine with single 4 pack string (30v'ish off the charge). I have not had a single issue despite daily use - but again, I don't drain them. My chargers for some time have been the vicor AC to 48v converters trimmed to the charge voltage. After my 10 mile ride, the packs usually draw about 5 amps to start and taper to .1 and reach charge voltage within about 2.5 hours, my typical timed charge.
Click to expand...

Biil, I think the issue is measurement accuracy. If I had a more accurate meter I might go along with setting my charger at a 8.35v/module limit, but for now, its 8.2v for me. The Soneil charger is very consistant at holding the voltage at CV. The reason I suspect my meter is that when I look at my Watts Up right after charge, it reads .2-.3v higher that my el-cheapo radio shack vom meter. (In reality, we both are probably charging about the same.)

Again, I'm just trying to get these modules to last for years, and so far, I haven't found any battery that has what these have for performance. :mrgreen:

--Tom
 
Tom, my thoughts go something like...."run, don't walk" to get a good quality meter you can depend on. Here's a clamp meter for $80

I rely on clamp meters exclusively to measure current going to each cell of my single cell LiPO chargers, it's just incredibly easy, and in general.

http://cgi.ebay.com/Mastech-Auto-AC-DC-400-Amp-Clamp-Meter-Multimeter_W0QQitemZ190285153787QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2c4de105fb&_trksid=p3286.c0.m14&_trkparms=65%3A12%7C66%3A2%7C39%3A1%7C72%3A1205%7C293%3A1%7C294%3A50#ht_2721wt_1032
 
Here are some more photos of the older style, "D"-cell NHW10 Prius batteries and the BMS that comes with them. That is a nice BMS by the looks of it!
 
icecube57 said:
Oh sweet Jesus! Battery Porn! SHES NAKIE AND BEAUTIFUL.
Click to expand...
And performing, too!

So far the first 10 or so "Sticks" have tested as about 6.2Ah @ 6.5A to 5.4V cutoff level.

I charge them on a RT808D with 0.6A to 8400mAh. Slight warming at the end, about 4degC above ambient temperature.

I also bought a bench power supply, max 36V / 3A.

I can charge 4 sticks in series that way.
 
Does anyone have some capacity testing results? I have managed to buy 5 NHW20 modules and am unsure if they are OK or not.

I can only get about 4Ah ( at 6.5A) out of them.

Charging @0.6A causes swelling to start when they reach about 8.5V, so I stopped the charging when I noticed the swelling and the cells were probably not yet full.
The swelling disappeared by resting the cells for overnight.

CV charging to 8.3V lets the current gradually drop to 0.08A, maybe more if I wait longer, but the cells I have are either already damaged or they do not fill well that way.

Anyone with actual bench measurement results, please?
 
That seems to be the magical number around 4AH. I dont think its because of age. They seem to display the same behavior as SLA. Getting about 60-70% of capacity.
 
icecube57 said:
That seems to be the magical number around 4AH. I dont think its because of age. They seem to display the same behavior as SLA. Getting about 60-70% of capacity.
Click to expand...
I cannot believe that is all they can do. Many of these cells should be having near-new capacity when they are pulled from accident vehicles.
A charge range from 20% to 80% DOD leaves 60% usable without deleterious effects on the cells longevity.
That means 6.5Ah - 1.3Ah = 5.2Ah should be what can be sucked from the cell at 20% DOD if discharged to 0% DOD on a CBA2.
One should not drain it past the 80% DOD on a regular basis, though.

I believe that the NHW20 cells I bought are either damaged, or they need to be charged with compression.

And that is happening now. We shall know in a few hours how much charge I can get out of a NHW20 cell charged with a power supply set to 8.7V max and 3A max when the cells are compressed between wooden boards to limit swelling.

If the 8.7V do not result in cell warming, then I might try a higher CV charging setting.

The NHW10 cells I am testing have near-nominal capacity, barely different between 6.5A and 0.7A discharge rates. At 19A (maximum my CBA2 can do) I get a little bit less out of them.

I really doubt that Toyota / Panasonic reduced the quality of their third generation cells compared to the first generation!
 
I was right!

Here are the test results on a CBA2 for the same NHW20 cell (R1 for my own logging purposes):

RED curve: Charged on Lab power supply to 8.3V until current had dropped to 0.08A. Discharge started within minutes of charging end. No compression, no visible swelling of cells.

BLACK curve: Charged on the same power supply to 8.7V until current had dropped to 0.63A. Clamped between 19mm pine boards, temperature rise 6degC above ambient (measured with IR thermometer along the lower and upper plastic edge, temp much higher at lower end). The pine boards got visibly bent!

 
I know the nimh chemistry has a little bit of a surface charge. I tried to let my packs charge up to 8.7 they swelled and bloated a little bit but they didnt hold at 8.7 for long they quickly fell down to a nominal voltage.

Actually when I let them charge that high they were warm they got swollen and bloated when they werent compressed. You could hear the electrolyte bubbling in the cell 2-3 days after they were taken off the charger.

Atleast this chart proves that they can deliver the 1c capacity if we can figure out how to charge to about 8.75 to 8.8 volts under compression. Thats only 1.46v a cell which is high but not to high.

I still say they act like SLA. Put them on a 5-10c discharge. I think you would be back down to 4-5AH capacity.

If you can find the original toyota cell pack end cap compression plates and use 3 threaded rods and bolts you should be able to compress them properly and not worry about bloating.
 
icecube57 said:
..
...

I still say they act like SLA. Put them on a 5-10c discharge. I think you would be back down to 4-5AH capacity.

If you can find the original toyota cell pack end cap compression plates and use 3 threaded rods and bolts you should be able to compress them properly and not worry about bloating.
Click to expand...
This should do to simulate the original compression, I hope:


.

And this will allow me to test the cells under high current loads:




There is of course a Peukert effect, reducing the Ah which you can get out of the batteries if you draw high amp rates.

But at 6.5A = 1C I get the same capacity results as at 0.65A.

I should be able to test up to 150A with my new gizmo soon!
 
ohhhhh u are using the cylindrical cells. I see. Maybe gasfree can play nice and send you one or two of the prismatic to do a side by side comparison. Funny we might need to find the old Gen 1 packs instead of 2-3. Gen 1 seems promising.
 
icecube57 said:
ohhhhh u are using the cylindrical cells. I see. Maybe gasfree can play nice and send you one or two of the prismatic to do a side by side comparison. Funny we might need to find the old Gen 1 packs instead of 2-3. Gen 1 seems promising.
Click to expand...
I have 140 cylindrical 6s sticks and 5 NHW20 prismatic cells to play with.
 
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