Breaking down a Hybrid battery for use on my bike?

[Crash Machine]

I got this hybrid battery from a very good friend of mine that deals in used auto parts. It's a 2005-2006 Honda Civic hybrid. It had been totalled no visible damage to the battery..Through research I found it should be a 144 volt 6.5 Ah NiMh battery. Not sure yet what to do with it.
I took it apart last night(yee haw) and was impressed how well made it was. The cells are not tabbed as i had fear but have well made screw type terminals. They are in 6 cell strings, 20 of 'em. They are 1.2v 6.5 Ah cells I believe,they look like D sized cells. Total pack voltage was only 66 volts. Each 6 cell string only read 3.3v give or take for each string. Would that kill these cells?
I found my old 6v 1 amp sla charger and found the final voltage to be 8.20v. Doing the math each cells charged voltage should be 1.4 to 1.6v. So 8.4v to 9.6v final charged voltage for each string so 8.2v should be safe I assumed.
Armed with this knowledge I hooked them up to the charger last night and charged till I saw a string reach 8.15v.. About an hour and a half.
Woke up this morning and the voltage read 7.6v and holding. I then charged the same string again till it got to the final voltage of 8.2v. Another 45 minutes so 2hrs.15mins. That's where I am at this morning. Charging a second string now and I will see what the first string holds at.
6 of these srings should give me a 48v pack. So is it hard on NiMh to sit at such a low voltage or are they salvagable? Also there's alot of stuff I have no idea what it is.. I will post more as i find out.
This is great experience for me. I start college in the fall for electrical engineering. So even if it's kinda impractical for my uses I am still going to try to build a pack from these and will report my findings.

Btw this guy is gonna keep his eye out for these for me.

 

[Ykick]

I have 5+ year old NiMh F cells that sit around 0V most the time (self-discharge is rapid with NiMh) but come back to near original capacity after a couple balance cycles. Dunno jack about Honda NiMh cells but probably similar to Prius/Escape Hybrid stuff? I know there's a thread or two about those.

 

[fechter]

You can find a little information about that type of battery here:
http://endless-sphere.com/forums/viewtopic.php?f=7&t=11801
Sitting around dead for a long time doesn't really hurt them permanently. A conditioning cycle (full charge/full discharge) will usually restore capacity.

The real limitation is the capacity is only around 6.5Ahr. They are also quite heavy.
While you could possibly parallel strings, charging a parallel setup could be difficult.
As the cells reach full charge they begin to heat up and at the same time the terminal voltage will drop. The hotter they get, the lower the voltage. So with parallel strings, one string will tend to finish first, drop its voltage, and hog all the charging current from the other string. You can charge the strings separately then combine them in parallel during discharge, but this takes extra junk to make it work.

I still have a couple of weak sticks in my car. I've seen the sticks for sale on eBay for around $50ea. It may be of much more use to someone with a hybrid car.

 

[Crash Machine]

Ok after charging for 3 hours final voltage was 8.2v. I let these cells sit and they sill read 7.9v. So then I hooked up a 2 string in series for 12v and ran a trolling motor for 10 minutes. Seemed to handle the load pretty well. Does this mean these cells are ok?
I read that 1.6v is the charged voltage. So 9.6 per 6 cell string,then 6 of these 9.6v sticks in series should read 57.6v. So can I simply set my lithium charger to 57.6v and charge?
What I am going to do Sunday is configure these batteries to run a 12v trolling motor and see how they perform. My bike is down right now so this is the best way to test them, and go fishing. This will probably be what I use these for but I still will configure a pack to run my bike just for the fun of it. I can put it in my bob trailer for testing. More info as I gather it.

 

[amberwolf]

A proper NiMH charger needs to be able to read the heat of the cells, and preferably also the change in voltage, because as they reach full charge they *drop* in voltage (which is why you can't parallel-charge them safely). The chargers I have all typically charge them at 1.4V+ a cell, then they drop to ~1.2V-1.3V+ nominal at the end, and generate a lot of heat in the process.

You don't *have* to charge them that high, but they may not (probably won't?) provide expected capacity if you don't, and they may be out of balance because the normal charging method also balances them.

7.2V for 6 cells would be more like I'd expect for NiMH. 7.8V or so at most, if they are at 1.3V/cell full charge.

I expect your Li charger will probably work, but I have never tried that, so be aware it could cause problems either with charger or pack.

I did successfully use a Sorenson lab power supply to charge my packs before I got a "real" charger for them, and current-limited to only 250mA and max voltage of ~1.2V/cell, IIRC (been a while, but it should still be in my DayGlo Avenger thread). I had to limit current so that they would not potentially overcharge and die, or just cook at end of charge, as my Sorenson didn't ahve any method of detecting the temperature to cut off charge when they got hot, and I couldn't sit there and monitor charging the whole time.

 

[ambroseliao]

Hey Crash Machine,

Can you see who makes the individual cells? If it doesn't say on the cells, can you read the info printed on the individual cells?

Thanks,
Ambrose

 

[dogman dan]

I'd think a good RC lipo charger would be a safe way to charge em, including the temp sensor. Then put them in series strings, 1p, that the charger can handle. Parallel then series those strings to run, then seperate into individual 1p strings to charge. 18s strings would give aproximately 24v fully charged. You'd have enough cells for six of those. So 3p 36s to run them in a 48v pack with decent range. Call it 48v 24 ah.

Ugly, but free. The charger investment is a good one, handy for charging all kinds of stuff you may scavenge in the future.

 

[dogman dan]

Oops double posted

 

[ambroseliao]

Another solution is to find a good NiMH charger which should be easy on RC boards since NiMH cells are out of favor. I have an old Astroflight 112D chargee that I bought for dirt a while back that is great for old NiMH cells/packs.

Ambrose

 

[drunkencat129]

wow just serviced same pack for stevos insight lol thing took a week to ballence take each brick and put them threw 3 cyclec charg and disscharg the 10a charg 5a disscharge that will work them well and bring them back to life workes theas cells are good but get realy hot also there tabed oddly u need to carfuly cut the tabs because there caps that tab the middle first then tabe the under side to the side wall of the lower cell when u pull the shrink ull see what i mean

 

[amberwolf]

@dogman: I think you mean 1p strings for NiMH? Otherwise you're talking about charging single cells...it's gonna take a while.

 

[dogman dan]

Mixed up my p's and s's. Fixed now. I meant charging strings as long as the charger can handle, perhaps 18s 1p? You'd have to charge the strings one by one though.

 

[docnjoj]

+1 on the Astroflight Charger 112 D. Mine did 40 cells quite well back in the day. No thermal cutoff but a really fine charging algorythm that does not overcharge.
otherDoc

 

[liveforphysics]

If you want a useful ebike, honestly the best thing you could do is dump that pack in the ocean or sell the sticks on Ebay as unknown condition sticks for fools to buy.

NiMH is a nightmare to work with if each cell isn't all ready in the capacity that your pack needs, and nobody wants a 6.5Ah ebike.

 

[MitchJi]

Hi,

I got this hybrid battery from a very good friend of mine that deals in used auto parts. It's a 2005-2006 Honda Civic hybrid. It had been totalled no visible damage to the battery..Through research I found it should be a 144 volt 6.5 Ah NiMh battery. Not sure yet what to do with it.

This is great experience for me. I start college in the fall for electrical engineering. So even if it's kinda impractical for my uses I am still going to try to build a pack from these and will report my findings.

Btw this guy is gonna keep his eye out for these for me.

If you want a useful ebike, honestly the best thing you could do is dump that pack in the ocean or sell the sticks on Ebay as unknown condition sticks for fools to buy.

NiMH is a nightmare to work with if each cell isn't all ready in the capacity that your pack needs, and nobody wants a 6.5Ah ebike.

If your motivation is a fun project that's fine. But Luke is correct that they don't have much value for an Ebike pack. OTOH they have quite a bit of value as used Hybrid NiMh sticks.

The 6.5 Ah x 7.2 v nominal stick is ~47wh. About 1/21 of a kwh. A tested stick in good condition is worth $30 or $40 on Ebay.

Doc sells A123 (Dewalt) 18650 Cells 1.1ah 3.3v nominal for about $1.50 per cell. 47 /3.6 = 13 * $1.50 = < $20.

He sells Konion's for even less. And a A123 or Konion pack will be a great Ebike pack, rather than a marginal hard to maintain pack, will cost about half what a pack made out of the Hybrid sticks are worth, and be much smaller and lighter for the same power and energy and be IMO a better learning project.

And BTW Richard and I both have Hybrid packs with bad sticks if you want to sell them .

 

[Crash Machine]

Thanks guys I knew some of you had experience with these cells. Now I know the parameters. So I used the 6v 1 amp sla charger to slowly bring these 6s strings to 8.2 v. After resting overnight they all read about 7.8v and holding. Takes over three hours. Very impractical but I enjoy the process. They jump immediately to 8 v then slowly rise to 8.2v over the next three hours.
6 of these sticks in series only give a 46.5v battery. So charging with the lithium charger might be out. Maybe 7 sticks will be closer.
They seem to have a temp sensor underneath the shrink wrap or at least that's what I am assuming it is.
Don't know who makes 'em. I read somewhere that it was Panasonic. I'll send pics.

If you want a useful ebike, honestly the best thing you could do is dump that pack in the ocean or sell the sticks on Ebay as unknown condition sticks for fools to buy.

NiMH is a nightmare to work with if each cell isn't all ready in the capacity that your pack needs, and nobody wants a 6.5Ah ebike.

Ya I am beginning to see how these batteries might not be worth the trouble. I am really just trying to learn and enjoy the experience. And like dogman said. It may be ugly but it's free(well $50.00). Besides I've been laid up since the accident so this keeps me busy.
I might sell some of these sticks if anyone here is interested just pm me and we can work something out.

 

[Crash Machine]

Sorry can't get the pics to upload. I don't own a computer so it makes it hard to post pics.

 

[dogman dan]

Converting em into cash, then buying something better is a great idea if you are going to profit that way. Using them for other purposes has appeal too, like run a weedeater with em or a boombox. Something lower voltage than a bike.

 

[Crash Machine]

Converting em into cash, then buying something better is a great idea if you are going to profit that way. Using them for other purposes has appeal too, like run a weedeater with em or a boombox. Something lower voltage than a bike.

Used em to run a trolling motor today? Caught two nice bass.
Only used 6 of the cells. Should have been 12v 19.5Ah. They died almost immediately. Maybe they need to be run a few cycles? Maybe the sla charger doesn't bring the voltage up high enough?
So I think I am going to run 6 strings of these cells in series and charge them with the lithium charger. If I bring each cell to 1.6v x 36 cells that would be 57.6v. My charger is adjustable to this range and is 3.5 amps. Does this sound right?
I'm really just having fun with this battery,experimenting. I am still gonna try to at least run my bike a few times on them. Then maybe sell them, but its not about the money. Its knowledge.
This friend is going to try to find more hybrid/EV batteries.What cars should I tell this him to look for? Does anyone need anything off of a Honda Civic hybrid? Any other car? I will tell him to keep an eye out for it. Just let me know.

 

[amberwolf]

6 cells, or 6 strings? I assume 6 strings, because:

6 cells is only about 7.2V nominal, 6.5Ah.

12V requires 10 cells in series, and 19.5Ah would take 3 parallel strings.

6 strings would give you three parallel and two series, 2s3p, for about 14.4V nominal and 19.5Ah @100% DoD.


BTW, if you're not using diodes to hook the parallel strings together, then as soon as one string starts to run lower than another (becuase it's capacity or charge state is lower), it will begin sucking current from the others, and generating heat trying to recharge itself, isntead of letting that power be used by your motor.



Were your strings heating up near the end of charging? If not, they're not balancing, and so you don't know what state of charge each cell might be in, after having sat uncharged.

Before you can really determine if they are working, I suspect that you probably ought to read up on charging NiMH , becuase the "full" battery will *drop* in voltage and heat up, as they balance. Without balancing, you could have a nearly empty battery in there but all the rest nearly full, and end up reversing the empty one and have nasty things happen (or nothing, except the pack just run low unexpectedly).



There could just be a bad cell in there, too, in one or more strings. Only easy way to find them is to test the voltage across each cell in the string while under load, after running them all thru a few charge/discharge cycles with balancing in order to let them get closer to orignal condition.

 

[liveforphysics]

Charging these mofo's is not a game. They blow up like little grenades. They need to be balanced before you put them in series, and its impossible to balance them charged because voltage decreases near the top of chargeing, so the CV stage of a lithium charger or power supply is asking for problems. Likewise, when you parallel them to discharge, they go through CRAZY effects of trying to charge into eachother and do stupid things as they try to discharge.

If you're not using a 1p string that is at the capacity you need, its really not a chemistry to use. Charge in a place you don't mind exploding if you're not going to use a peak sensing NiMH charger.

This is not lithium. It is not friendly. It frankly freaks me out to work with it, so many ways to go wrong.

 

[amberwolf]

I'm really just having fun with this battery,experimenting. I am still gonna try to at least run my bike a few times on them. Then maybe sell them, but its not about the money. Its knowledge.

Personally, I don't see a problem with using them to run a bike, if you don't mind all the inconveniences of them; I used NiMH for quite a while on DGA and CB2, and will keep them around for other bikes as needed.

Buuut...you can't build them into a bike unless you also build ventilation and cooling in, because heat will be a problem both charging and discharging with these. And you have to build them either in high-voltage 1P strings, or use diodes of some type between the paralleled strings, or bad things can happen. So I don't have mine in battery boxes, but rather in open packs that air can flow freely thru. When I use them on DGA they're in an insulated cargo pod and that pod gets pretty warm inside, even on a cool day.

This friend is going to try to find more hybrid/EV batteries.What cars should I tell this him to look for? Does anyone need anything off of a Honda Civic hybrid? Any other car? I will tell him to keep an eye out for it. Just let me know.

[/quote]
The Prius, Honda, RAV4, and some others all use NiMH sticks like these, or possibly flat pack NiMH, so if you are after NiMH they are all sources for them.

There are some Lithium based cars around, too, and THOSE would be worth getting packs from if you could. Probably pretty rare just yet, though.


If I had a source for the NiMH sticks, and had enough of them to build HV packs with, I'd probably end up building a bike for them, or more likely a pusher trailer for cargo, with the NiMH running a booster motor. But they are heavy and so cost too much to ship, even if I could afford to buy the sticks themselves. Since you have a local source, though, you could easily do this yourself once you learn enough about the NiMH to use them safely.

 

[MitchJi]

Hi,

This friend is going to try to find more hybrid/EV batteries.What cars should I tell this him to look for? Does anyone need anything off of a Honda Civic hybrid? Any other car? I will tell him to keep an eye out for it. Just let me know.

Honda Civic's, first gen Insights (2000-2006) use the same sticks. I think the early Prius's use the same sticks (later Prius's for sure use Prismatic NiMH. My guess is that current Insights use the same sticks but that's just a guess (if anyone knows for sure please post). I'm not sure what the demand is for the other NiMN cells. I suspect it's relatively less because its Honda policy to make obscene profits on parts and they are not available anywhere else.

The following (RC Charger) seems like the way to condition and check these sticks:

I am now cycling the 20 removed subpacks with my robitronic charger Charge rate 6.5A, discharge rate 20A, 5 cycles per subpack. I shall record their capacity and IR etc...

 

[peterperkins]

There is absolutely no problem in charging these in a series string as long as you control the current and limit it to around 350ma for these ex hybrid cells. You can have 2 or 200 in series it doesnt matter and they will balance very nicely with a low current 300-350ma charge.

The cells which reach full first will simply burn off the extra charge as mild heating while the others catch up, it's incredibly simple. Reasonable ventilation is all that's required and a CC charger of the appropriate fully charged voltage around 1.5-6v per cell. The 48v LED Driver CC 350ma power supplies from meanwell make a great cheap charger for packs upto 36v. They just take time to charge at 350ma. You can put the CC supplies in series for a higher voltage pack. The meanwell 48V led chargers don't really care what the battery pack voltage is as long as it can reach the fully charged voltage. So you can use one charger for say a 24-36v pack the charger limits itself to 350ma.

You can charger quicker of course but that makes it more complicated so why bother :wink:

The cells are very powerful and rugged but tend to have a high self discharge rate so don't store the power well for long periods. Charge them and use them within a day or two and they will give great performance.

Cycling the sticks half a dozen times using a proper nimh charger like the robotronic overloader is a good idea before first use to rejuvenate them. That's what i do

If anyone wants any sticks in the UK i have hundreds I charge ~£15 for a stick of 6 cells.

 

[parabellum]

Not almost all modern RC chargers have NiMH charge/discharge mode? I just checked my Icarger and HK eco eight cheapo, they have NiMH mode. And something about Delta peak sensitivity written. Icarger3010b up to 25 cells and HK eco eight up to 27cells. (strange, was not expecting eco 8 outperforming Icarger in any way)