For general interest :
Price of those cells varied from $12.150 to little over $ 23.00
Those are the same cells used in the Toyota Prius , first generation
| Digi-Key Part Number P019T-ND | |
| Price Break | |
| Unit Price | Extended Price |
| 1 | 23.83000 |
| 10 | 21.44300 |
| 100 | 19.06000 |
| 500 | 14.29500 |
| 1,500 | 12.67490 |
| 4,800 | 12.15075 |
Specification , I have been getting constantly , go to :
http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_NiMH_HHR650D.pdf
CAN ANYONE SUGGEST ANYTHING COMPAREABLE IN PRICE , SIZE EVEN DIFFERENT CHEMISTRIES ? ? ?
I have been looking for a 36-volt, 30 AH battery pack that can produce at least 30 amps continues output. According to the specification sheet linked above I would need a minimum of 5 batteries in parallel to reach 32.5 amp continuous output as these batteries are rated for 6.5 amps (1C) per cell. To get a 36-volts, 30 AH pack I would need 150 cells. The price break chart would indicate a price of $19.06 per cell. The total price for these cells not configured in a pack would be $2859.00 then you would have to wire them at an additional cost, a little higher than I want to pay. I have already found the batteries I wanted on ebay, as a completed battery pack (no wiring cost or time). Note the higher max current capability, 40 Amps verse 32.5 Amps. I just bought a Lithium Ion Pack, 36-volts, 30 AH and 40 Amps max current capability for $760.00 including shipping cost, a savings of $2099.00. I think the "D" HHR650D batteries are toooooo expensive.
One other piece of information, weight. At 6 Ounces per cell a pack as described would weight 56.25 Pounds (25.5 Kilograms) minus the wires and any kind of casing where the pack I purchased weighs in at 22 pounds (10 Kilograms) with wires and case.
Grandpa Chas S.
You are correct in your math .However I do not feel that the two packs are compareable in performance and if you are looking for cost effective wh/hr only the HHR650D do fall short , when peak power is thrown in , that is a different story .
Not knowing what cell you are talking about , I am fairly certain that they will not allow you to take anywhere the peak power that HHr650D , as I say numerous time ,have discharged the cell at 300 AMPS down to 100% ( one cell only ) lasted close to one minute .Would like to know the performance of your pack with a 300 amps load .
For the $2859.00 you would end up with a 36 volts 32.5 A/H with the capability of delivering about a 1,000 Amps ( 5 cells in parallel time 300 A )that is 36,000WH peak power.Of course the interconnection resistance will limit the peak power somewhat .
Toyota prius started with that cell and although the newer cell have been repackaged for better thermal consideration in a rectangle shape , they are essentially the same cell. Their new pack also has a much higher voltage.
I did not heard Toyota dropping them and embracing any Lithuim Ion pack any time soon .
They have forgotten more about batteries usage , performance cost effectiveness than we will ever learn .
I tried very hard to stay on top of their Engineering direction
At the time all my effort are focused on a BMS that will accept any chemistries and size cell , have giving up on trying to matched cell or chemistries to produce high power pack , ( large quantity of cells )
Finally accepted the fact that batteries regardless of chemistries are like people , they have their good days and bad days ( as far as accepting charge and giving it back out )even twin sibbling are different , though they started out as twin .Have seem cells matched withing .1% in capacity that when assembled into a pack diverge in capacity after a relatively few cycles , the reason being the thermal difference of the cells in the pack.
Maybe placing them inside a oil bath may eliminate the difference, TOyota has spend as much on the thermal as their BMS design . Regards
HEAT & LOSS & INEFFICIENCY RELATED DIRECTLY to IMPEDANCE
As far as I know nothing in the spec mentions supporting a 300A peak for those cells. Can you really count on that behavior. For the money and for Chas's needs why not go with Saft? You'd get better density. Two banks of F cells would cover his needs. Although charging would be annoying.
Saft F VH F 15Ah cell, 4 mOhm , 50 continuoue 180 peak. 28.50
Saft D VH D 9500 9.5 Ah, 4 mOh, 50 continuous, 150 peak, 18.75
Source: www.batterystore.com
The safts are still too rich for me however. I've been looking a Tenergy Ultra High F size 14Ahm cells. They can be had as low as 11.32 ea on ebay. They claim 40A continuous and 60A peak. I'm a noob though, and I don't understand how they come by those numbers given what I see in their spec.
Heh. Have you seen this PDF of the new Saft li-ion 6Ah 100C batts? That's 100C continuous, BTW. 250C for 100msec.
2 s Pulse 1,100 A
100 ms Pulse 1,600 A
O_o
Their specific energy is pretty low, though. Just over 60whrs kg.
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Incredible ! ! I stand corrected , never came across those Saft Lithium cells .
It seem that Lithium are more then able to deliver peak power .
Unable to find a impedance number for those cell , am I missing something ? or my eyesight falling me ?
Read the spec sheets , it appear that they will only sell batteries system not individual cell .( column on the left hand side of sheet .Would love to see the price on their system .Regards
HEAT & LOSS & INEFFICIENCY RELATED DIRECTLY to IMPEDANCE
I couldn't find any impedance numbers either, but I'd speculate that it would be somewhere around a very impressive 1-2mΩ (my calculations came up with 1.2mΩ based on A123's 2.3Ah/10mΩ figure).
The thought of shorting out even one cell scares me. 3.6V / 0.0012Ω = 3000A x 3.6V = 10.8kW from a single cell! O_o
And, yeah, they don't sell individual cells, unfortunately. Apparently, Saft caters mostly to NASA, though the Tidal Force bikes used to use their NiMH cells.
I'd like to see the price per Whr just for the LULZ. :P
The author of this post isn't responsible for any injury, disability or dismemberment, death, financial loss, illness, addiction, hereditary disease, or any other undesirable consequence or general misfortune resulting from use of the "information" contai
You are correct and very close . I calculated the impedance to be 1.7 mho , derived this from examining their discharge curve .
The voltage difference at 6 A (1 C)and 240 A (40C)is shown to be .4 volt . Therefore the DC resistance is .4 volt divided by 240 A = .0017 ohm . A very impressive number indeed ,as is the low impedance of the MAXELL Gold Cap . Fortunately this 5 KW ( peak power is divided among the cell and the external load) power burst would only last a very short time less than 1 sec.In the case of HHR650D I have been getting the 300 Amp for almost a 1 minute across a short ( time varies from 30 to 45 sec depending on the cell temperature and the short impedance which varied greatly depending on temperature )
I would not be surprised if those Saft cell went for upward in the $100 region / cell ( since the cell has close to 20W/H of energy a $5.00 W/H is not unrealistic figure for this exotic cell ).
Can only image the difficulty in connecting to them ( ideally the connection should be 10% of the cell impedance )
From past experience with energy power pack , have found that measuring the internal impedance of a completed pack when fully charged ( inter-cell connection,all cells series and wire )
with a HP4328A give a good indication of peak current available from it ,Take the pack voltage and divided by twice the measured impedance (peak power occur when the source and load impedance are matched).
That is why impedance or resistance measurement is so important , it provide a real max power ,which is what we need to get ourself moving whether it is a scooter or car.
HEAT & LOSS & INEFFICIENCY RELATED DIRECTLY to IMPEDANCE
Hello Grandpa Chas
I want to apologies for the somewhat hard response to your comments , additionally I stand corrected about the peak power capability of the lithium cells . Was unaware of the Saft VL 6 A - Very high power cell ,suppose that I am unable to keep with all the new stuff , falling behind in my senior age .
My whole life have focused on efficiency ,transfer , creation or conversion of power with batteries , converter etc
the reason for my obsession with impedance and resistance measurement .
Forgot that the whole world is content to use batteries without trying to extract 100% in efficiency .
As the saying goes , if you are a hammer , everything look like a nail .
Took a look at your web site ,very interesting and impressed with your assortment of toys and interest .
Again accept my apologies for assuming that your priority regarding batteries must be peak power.
By the way where you able to get a impedance figure on your purchased lithium cell , pack.
I have several HP4328A milliohmmeter,if you do not have one and care to borrow one for a short time,be glad to sent it to you,just pick up the round trip shipping cost.
Using the HP4328A will give you a real feel for all the loss , connector,wire, batteries connection solder versus welding , it open a whole new world , let me know if you are interested .
Regards
Andre
HEAT & LOSS & INEFFICIENCY RELATED DIRECTLY to IMPEDANCE
Andre,
No problem, I just figured you disagreed and that's OK because we will never agree with everyone about everything. However I must say there is one very important item we do agree on. The impedance of a cell is a very good indication of the battery's capabilities. I however would not try shorting a cell to see how it reacts, I don't like loud noises. LOL
I do not know the impedance of my cells and because they are rated to work with my application I will not need your generous offer of the milliohmmeter, but I do Thank You for the offer.
I have yet to try them on my bike as I have no good BMS at this time, still waiting for it as it is on order, well at least the parts.
I'll let you all know, in another post, how they work.
Grandpa Chas S.