# Panasonic EV-95M, how to restore? Salvage value?



## rmay635703 (Oct 23, 2008)

Anyone willing to pickup a set of EV-95m's from the San Ynez Valley/ San Luis Obispo area in Cali?

I'm not sure how to ship the 12 I want to buy and who would be least expensive but have some questions before I even consider it.

These were "new" batteries that were fully charged and left sit. I know with NiCD that means you have to be able to discharge each cell ssslllooowwwly to almost flat and then charge vigorously, not sure how you fix large format NiMH like EV-95's.

I also have been looking for the charging curve, maintenance, charging solutions (for both 72v & 144v, not decided)

BMS solutions/cutoff ect.

And obviously I need to know the salvage value & where in wisconsin I could recycle them since some are likely inop.

I have been finding difficult to get decent info on the EV-95's besides the size, capacity, etc, rather generic info

Cheers
Ryan


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## TheSGC (Nov 15, 2007)

I have been told that the EV-95 batteries are extremely durable and can be revived by cycling the cell individually, or in small packs. We have a Solectria Geo at my college that was sitting for about 8 years with EV-95 batteries and they were all revived last summer using a bench power supply to charge them in pack of 12 volts, then anyone that was out got it's own individual charger.


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## EV-propulsion.com (Jun 1, 2009)

As far as shipping, www.freightcenter.com will give you an instant online free quote for many different shippers at somewhat reasonable prices. Unfortunately when you check the box for hazardous materials costs skyrocket......it may be cost prohibitive to use a shipper....
I have no affiliation with the above company, but have used them several times without a problem....
Mike
www.EV-propulsion.com


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## MN Driver (Sep 29, 2009)

I'm pretty sure they aren't hazardous. At least the dry cell cylindrical NiMh's I know for a fact are not and I think the Prius batteries can be shipped as well. Entire Honda Insight and Honda Civic Hybrid NiMh packs weighing nearly 100 pounds get shipped with UPS with no problem. Not sure about the flooded prismatics though, this guy deals with Prius packs and if I'm not mistaken those prismatics are filled with liquid. http://www.re-involt.com/About_Us.html You could call or send him an email and see what he thinks about shipping them. I'm pretty sure any standard shipper can do it, not sure what would be hazardous about it since the cylindricals are just fine, it would have to be due to the fluid involved, if the EV-95M's even have liquid in them.

I figure putting them all in a crate and sending them together freight might be your best bet for cost.


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## MN Driver (Sep 29, 2009)

I'm not sure how you will manage to charge the large format EV-95 cells, it is a constant current charge until negative delta voltage(when the voltage drops while providing the same current) or another method is when the cells temperature is rising 1-2 degrees per minute. Ideally you don't want them to get hotter than 45 degrees in standard charging as getting beyond 50 degrees can damage them. Since they are larger cells, you might want to charge at C/2 or C/3 to be safe on a temperature basis but you could go as low as C/10 which would take 16 hours of charging to ensure a full charge due to efficiency losses at low charge rates and to ensure they fully absorbed the charge. Cylindricals can be trickled at C/10 into overcharge for awhile but I wouldn't go for more than 16 hours and make sure they don't get too hot. C/20 and you could trickle them until their voltage becomes steady indicating the end of charge. The only issue with prismatics such as the Prius packs is that they buldge under overcharge as they can't handle it due to the pressure containment limitations of prismatic cells, not sure how the EV-95's hold up.

I'm not sure what you would use for end of charge termination detection though because most of what is out there for high performance NiMh chargers are for the RC community can only charge at 10amps tops(I personally have one that does 7amps but is limited to 150watts, so the higher the voltage, less power) and might miss the end of charge for a large format cell, although setting the mV delta peak detection to its lowest value might do the trick. I wonder if the MRC Superbrain 989 would be powerful enough to perform the cycling in at least a rudimentary way.

Bottom line, if you go about a crude way of charging them, don't let any one cell get above 45 degrees(which gives a margin of safety incase it is hotter internally than you can measure on the outside) and if you see any buldging, stop immediately.

For discharging, you shouldn't go below .9 volts per cell which is the standard measurement for a discharged NiMh, lower and you risk reverse polarity. If you have a way of charting the discharge, you will see individual 1.2v cells drop out if they are fully discharged which would indicate an inbalance and to stop charging and start another charging cycle, you might be able to cycle them back into balance, but sometimes you cannot and are left with an unusable module or a module that you wouldn't want to use below the voltage at which the lowest cell starts to drop out.

Common practice is to cycle them at the same charge and discharge rate until the capacity improves less than 5% from the previous cycle which is around 3-5 cycles for smaller format cells, not sure about these.

If they worked after cycling, what application are you going to use them for?
NiMhs are tolerant of abuse and it is possible that they may just as well come back, it seems that 0 volt cells seem to come back from the hybrid packs after an C/20 trickle for a long time followed by a number of cycles.
If you are going to recycle them, let me know, I'd like to have at least one just for the sake of having a keepsake of what the EV1's also had, or to see if I could revive one myself. I'd drive to Wisconsin myself to pick one up. I have no clue what they are worth, as far as salvage metal or components, probably nothing, but I could be wrong.


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## rmay635703 (Oct 23, 2008)

MN Driver said:


> I'm not sure how you will manage to charge the large format EV-95 cells.


I'm not either, thats why I am asking, as it stands they will be used in 2 strings of 72v charged SEPARATELY by my antique KW BC-20. I want to move to 144v but the charger is then a issue and my controller will have to be swapped. My D&D ES40b-9-r-w likely won't like 144v either though.


MN Driver said:


> it is a constant current charge until negative delta voltage(when the voltage drops while providing the same current) or another method is when the cells temperature is rising 1-2 degrees per minute. Ideally you don't want them to get hotter than 45 degrees in standard charging as getting beyond 50 degrees can damage them. Since they are larger cells, you might want to charge at C/2 or C/3 to be safe on a temperature basis but you could go as low as C/10 which would take 16 hours of charging to ensure a full charge due to efficiency losses at low charge rates and to ensure they fully absorbed the charge. Cylindricals can be trickled at C/10 into overcharge for awhile but I wouldn't go for more than 16 hours and make sure they don't get too hot. C/20 and you could trickle them until their voltage becomes steady indicating the end of charge. The only issue with prismatics such as the Prius packs is that they buldge under overcharge as they can't handle it due to the pressure containment limitations of prismatic cells, not sure how the EV-95's hold up.


EV-95s are supposed to be very tolerant of overcharge, so long as it is under controlled conditions, thats how they equalize, not sure what that means though. Also I'm told that trickle charging NiMH is very very bad under normal operation, again not sure why. Also these batteries once restored should be perfectly happy not being fully charged and likely except under heavy use I would avoid my charger being left to run amuck without a timer so they never achieve full charge except when I am around to watch. My main interest is in undervoltage protection, not sure what would be both least expensive and most effective.


MN Driver said:


> I'm not sure what you would use for end of charge termination detection though because most of what is out there for high performance NiMh chargers are for the RC community can only charge at 10amps tops(I personally have one that does 7amps but is limited to 150watts, so the higher the voltage, less power) and might miss the end of charge for a large format cell, although setting the mV delta peak detection to its lowest value might do the trick. I wonder if the MRC Superbrain 989 would be powerful enough to perform the cycling in at least a rudimentary way.
> 
> Bottom line, if you go about a crude way of charging them, don't let any one cell get above 45 degrees(which gives a margin of safety incase it is hotter internally than you can measure on the outside) and if you see any buldging, stop immediately.
> 
> ...


I doubt I can overheat the cells since I can't draw much over 10amps out of the outlet, which is likely a big problem since NiMH love being charged hard during bulk phase.

They are afterall from an EV so they will be in an EV, my ev thats the usage.

As for salvage metal, YES nickle is VERY VERY VERY valuable, in fact NiCD are required by the manufacturer (large ones anyway) to be sent back and you do get paid. Due to the nature and history of these batteries the salvage value is critical to whether or not I would be willing to purchase them. (too much risk if no possible salvage value) The individual I am buying from has 35, I plan on getting perhaps 14 of the beasties just as a safety net.

And shipping is very critical, I just paid $200 to ship 8 gel lead batteries 650lbs from Cali to wi, which is CHEAP, I do not want to send UPS and pay $800 or more for the set to be shipped.

Cheers
Ryan


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