Prius battery to power e-bike?

[gasfree]

Hi guys.

I am just curious if anyone has tried to take a prius battery apart and used the individual cells to make a battery pack to power an e-bike.
this what it looks like: http://www.cleangreencar.co.nz/page/prius-battery-pack

The reason I ask is cause i might be able to get one and am curious to see if i can get it to work. Only other thing I have to figure out if how to charge it.
Anyway I will keep my fingers crossed and hope I can get it.

 

[Jeremy Harris]

Old Prius cells should be fine for a battery pack. They aren't particularly light or small for their capacity, being NiMH and designed for a very high cycle life, but they should work well.

The only thing you have to take care with is disassembling the pack. It sits at around 270V when fully assembled, so care is needed when unbolting the cell connections. Once you have it apart then it's just a large stack of NiMH cells, like any other.

If you can get a pack at a good price, then it should be fine. The pack has an eight year, 100,000 mile warranty from Toyota, which is an indication of the quality of the cells (plus the way that the Prius manages cell charge/discharge cycling)

Jeremy

 

[Link]

You should have plenty extra, too, even if it was a junker in a crash. The thing is something like 270V 6Ah, so over 1600Whrs in the whole pack.

I wish we had a junkyard around here. :?

 

[gasfree]

Ok cool I will bring in my camera and take pictures of it. The guy who i talked to said its pretty safe to work with since he already disconnected it. I doubt I wi;; be using more than 60 - 80 volts so I will most likely part out the rest. I am only 2 weeks into the ebike scene but I am enjoying it thus far. Had I known about this 6 months earlier I would have also kept the other pack.

 

[Lessss]

Gasfree, all I can say is there will be high demand for the cells you are not using VERY HIGH demand.

 

[Link]

Hmm, not too many cells left over if you make a a 72V pack. Assuming it's a 1p string of 6Ah cells, then there are 225 cells. If you make a 72V 12Ah pack then you're using up 120 cells. Leaving only 115 extra, minus some bad cells.

Hmm, even 72V 6Ah would be a huge improvement to what I have now. Dibs. 8)

 

[docnjoj]

Those poor pampered cells are now going to learn what the word "abuse" really means!!!
otherDoc

 

[fitek]

I had a friend use a couple of Prius packs in his EV S10; he said they weren't very good EV batteries. They didn't have very high discharge rates. Ended up switching back to NiCads.

However, on a bike you don't need so much power and you have plenty of batteries, so you can just add some extra batteries

 

[Jeremy Harris]

The Prius batteries have a staggeringly high discharge rate, in fact one of the very highest rates I've seen for such low capacity cells.

At full chat, with both MGs driving, they deliver around 50kW from a battery that's rated at 273V, 6.5Ah. Ignoring the voltage doubler and motor controller losses, this equates to a minimum current delivered by the battery pack at full chat of around 183 amps. In practice, the pack delivers over 200 amps peak.

This means that the cells (which are all wired in series) can deliver over 30C, which is pretty impressive. I don't think we've got many other cell types that are able to deliver this sort of rate day in, day out, for years and many tens of thousands of shallow charge/discharge cycles.

Jeremy

 

[gasfree]

Sorry I haven't posted for the last couple of days. I was trying to figure out how to get the battery without getting into any trouble. I will have to wait for it to be paid by the warranty dept and from there I think it will be safe to be mine. I spoke with the tech that took it out and he said that it was a basic swap for the new one. The light came on for the battery and they just changed it. Reason's for it to be changed is a bad cell(s) or the bms is not functioning correctly. In either case I hope to be playing with it soon. I just have to figure out how to make a charger. I think i will be happy with a 60v setup. Just need some more range for the days when my knee flares up and I can't peddle as much.
Oh here is the pic I took while i had a camera.

 

[Link]

1620Whrs / 60V = 27Ah. Oo la la! 8)

 

[gasfree]

The guys at work were all pretty impressed when i brought my bike to work for the first time. They also thought I was nuts. But its all good I have to of them trying to build their own after they went on a test ride lol. One suggested I just plug the whole prius battery to the bike and carry it in a backpack. I am not really one to carry 100lbs on my back for 40kms to go to work.

 

[ngocthach1130]

you could search for a trailer. Some bolt on kid trailer could be rated for that weight

 

[diver]

Boy that would be nice for the etek three wheeler im building..lol

 

[dogman dan]

If the original pack is 270 volts i bet Link would love to stuff it in his backpack! Might need diamond brushes in the motor though! Seriously though, that could turn in to a helluva nice dirt bike pack at 100 pounds. Perhaps around 130 volts. See Ya!

 

[Link]

If the original pack is 270 volts i bet Link would love to stuff it in his backpack! Might need diamond brushes in the motor though!

30mph / 72V = 0.42mph/V

0.42 x 270V = 113.4mph

LOL

8)

 

[Patrick]

Umm, not quite 270 V. There are 28 batteries, each a nominal 7.2V, for 201 V. Normal voltages in a Prius are under 240 V, and can actually go down to about 170 V. Mind, the Prius very carefully controls SOC on this pack, and is designed to carry between 40 and 80% max range, with 50 and 70% more common. This is why the quote the lifetime they do; they're really only delivering about 500 Wh out of a 1.6 kWh pack. It's like Don Harmon claiming 5000 cycles - he's between 50 and 60 % SOC.

 

[Link]

Ah, I see. I did a Googling, and apparently the first generation Prius had 228 NiMH cells for a nominal of 273.6V. The later ones only had 168 cells for a 201.6V nominal pack.

Looks like I could only do 80mph with the newer packs, then.

 

[gasfree]

Yeah the pack is 277 volts if remember reading it correctly. I have it next to my locker just to make sure no one else takes it. The batteries might be lighter once I take it off the rack that its holding them together. I would love to plug the whole thing to my bike but I don't think I could handle the 300ft pounds of torque it does between 0 - 1000 rpm. =) If I have enough time I might take some cells apart tomorrow and play around with them. Hopefully I won't get in trouble or electrocuted.

 

[MitchJi]

Hi,

There is a thread here with some good information:
http://www.diyelectriccar.com/forums/showthread.php?p=40666#post40666

Pay particular attention to the following:

The cells can be useful, but need to be bolted together tightly, just as they are in the OEM pack, to avoid charge/discharge damage from expansion.

As Talonts pointed out the modules must be clamped together between end plates when charging or discharging. One of the modules from the bad pack was charged out of the pack and it swelled up and was ruined.

 

[Patrick]

Does anybody know anything more about this?

I'm working with a guy who does Prius conversions, and thinks he smoked an add-on pack (96 Toyota NiMh cells!). Some were swollen (a few). The pack was charged without temperature monitoring. The cells were bolted to Al angle, but not otherwise compressed as they are in the original Prius pack.

I've got a few for testing, as I want to quantify the damage done, if any. Any thoughts?

Thanks!

 

[Link]

Try the usual: Hook it up to a watt meter to a motor or some light bulbs and see how badly it sags. If you work out some sort of rudimentary LVC then you can leave it there and see how much capacity it has left, too.

You can charge it by alligator clipping it to your everyday AA/AAA/C/D battery charger. :wink:

 

[Patrick]

I'm sorry, I wasn't very clear. I'm building a PIC based automated test jig, with V, A, and T monitoring and cutoffs. And the batteries are 7.2 V nominal (i.e., 6 cells), 6.5 Ah. Aside from the voltage difference, NiMh have a unique charge profile, either dV/dt or dT/dt - they shouldn't be charged arbitrarily.

What I wanted to know was about the compression. I know this is recommended with ThunderSky lithium, but hadn't head about NiMh yet.

 

[fechter]

Cell pressure increases quickly at end of charge. Cylindrical cells will vent if it gets too high. This usually causes the vent to basically fail and allow the cell to dry out. It makes a cool hissing sound.

The prismatic cells apparently built up enough pressure to distort the case. This may or may not be a problem. See if there is any evidence of venting (white goop, crust, etc.). No venting is good.

 

[gasfree]

Well I took the battery apart and made a 60 volt pack. Unfortunately they weren't completely charged so it wasn't as impressive as I would of hoped for. I am gonna charge them tomorrow for a couple of hours and try it again and see if there is any difference. Compared to to my sla's it feel a little more sluggish at the begining but the top end is about the same about 50kph. I am thinking that is I build two packs and connect them in parallel I will get more amp's and therefore have the same kick as the sla's but with more distance. I took some pictures with my friends cell phone so I will post them up tomorrow. The battery are 11 inches long 4.5 inches tall and 5/8th of an inch thick. Each cell weighs about 1.5 pounds. My friend had his honda ruckus (with 49cc motor) in but he has more torque and more speed. For the most part I did ok keeping up with him in regular traffic but I lost sight of him after a 3 km straight away not to sure what happened. Overall I am quite happy with the sla just want to be a little lighter later on. Bike weighs in at about 80lbs and i am 212lbs so I can see why i need more torque hehehe. Well I post pictures later on tomorrow and give in another report with hopefully fully charged batteries.