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Discussion Starter · #1 ·
[Mod edit] Split from:
Project Insight - A real world 1,000 mile range EV?
http://www.insightcentral.net/forum/vie ... php?t=4554
[end edit]


Here is a page / Link to a source of "Primary Lithium SO2 Cells"
http://www.powerstream.com/LiPSO2.htm

I am wondering if such a battery would work in a replacement pack for the current insight - with it's needs for 144 Volts?
Also - if it worked in such a replacement - what would the likely Amp Hr capability be?

Also - this one for 18650 Litium Ion Types (Same Question):
http://www.all-battery.com/index.asp?Pa ... ProdID=555
Robert
 

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Hi wannab,

Yes the NiMH chemistry is becoming a bit dated. And there are newer batteries that yield a much better power to weight ratio. With many of the other NiMH problems being improved upon too.

As far as _could_ they work the simple answer is YES :!:

Since the Insight's MCM & BCM are only programmed for NiMH's, and batteries of a different chemistry require different "handling" a direct drop in replacement isn't possible. So in addition to the much greater cost (at a comperable cost / performance ratio to the NiMH's) different battery management is also needed.Then there's a different case for properly holding and cooling the batteries (small potatoes vs. the management issues).

There is an _implication_ that Honda has made late 02's and up and the replacement for the eariler Insight's MCM & BCM programmable. This will allow Honda to change the batteries and simply reflash the programming in the controllers. But as short lived as most cars are, as fast as technology is changing, and and until these improved batteries become _much_ cheaper I doubt we'll see such made available by Honda for the Insight. If and by the time the sweet spot is reached I'm afraid the Insight will be eclipsed be something better. Making such a modification a custom one done only by the few remaining dedicated Insight enthusiasts. :/

Kip you reading :?: :p

HTH! :)
 

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:lol: :lol: Here is how I understand it. Determining the level of charge on our existing batteries is tricky. As they are charged their voltage does not increase as a direct ratio to the charge, therefore the computer measures the current in and out of the battery with respect to time and assumes the charge based on programming. This technique will work for any type of battery. The key is, if you increase the capacity of the battery pack you have to decrease the sensitivity of the current sensor. There are numerous ways this can be done by changing turns ratios or resistance voltage dividers or reprogramming. If you change change the current monitoring sensitivity, the computer will give an accurate readout. The low voltage sense point will probably also have to be changed, the one that determines the voltage at which to do a recal. To make the setup ballanced, and safe from thermal run away, each manufacturer incorporates thermal sensors to determine if a battery is overheating. These would have to be incorporated into the control scheme as well. There is the issue of cooling which involves routing fresh air into the pack. Finally, there is the issue of mounting. This entails connectorization, space allotment and as Mike is determining, weight issues.

Once all of this has been done once, it really would not be that big a deal. ;)
 

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sounds like you are completely changing the battery sensor system....

besides... the BCM also counts the AMPS out , how will it liike it when more amps come out then went in??? ... the reason the Battery Booster on the Grid Charging thead doesn't run into this problem is that it just gives a no-load charge to the battery pack so the BCM can still use its normal in and out amp counting methods... and the power all still comes from the stock Pack... the booster pack is just used to recharge the stock pack without putting a load on the Engine....

I think Mike's Battery booster is about as good as we will get unless someone completely yanks the BCM and replaces it with something else.
 

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The NIMH cells in the Prius and the Insight are specially designed for high discharge rates. Look at the specs of the SO2 and the 18650 Lithium Ion
Only by paralleling cells can we get the 100A discharge necessary for full assist. The NIMH can do the 100A with a single cell.
Even the Lithium A123 cells that I was looking at, which are state of the art, can only do 60A for pulse mode.
The U1 Valence Li Poly batteries which are 45AH and can output 100A:
http://www.valence.com/ucharge.asp
would be my choice for the best batteries for a direct pack replacement with expanded capacity. Thats assuming that you can spend the $7800 for the 13 units that it would take.
The SOC measuring system is explained in this document:
http://99mpg.com/Data/downloads/related ... nation.jpg

The main down side to the boost system is the 15% energy loss in the converters. That energy would be better spent propelling the car.
As the size of the cells drops, and the number of cells increases, we will reach a point where hacking the battery pack directly will be the best way to go, and the booster system will meld into the BCM replacement that any cell type or capacity change would need.

I will be continuing to expand the scope of the boost charger, with active subpack balancing, independant SOC determination, thermal management, and a microprocessor on each sub system that communicates to a supervisory micro. This will eventually have all the functions of the stock BCM plus active pack balancing. At that point the stock BCM could be "fooled" into only being an interface to the car rather than an active battery monitor.The basis of a controller for what ever batterys we want to use as replacements for the stock cells. Any battery change will need a BCM interface, and if designed properly this booster system could be programmed for any type of chemistry.
The Vicor units really are a nice design from a control standpoint, and are designed to be part of a multi unit system. The converters can be turned of or on with a simple lv switch. They output an alarm and shut down if over temp over volts, under volts. The alarms can be tied together so one module in alarm will turn them all off.
The constant current system works well on a single unit, now I need to expand the control to all 10 converters. A lot of work with not much time to complete it.
 

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Ah Issues asside, one could still feasably replace the NiMH with Li Ion more easily if, instead of going for more power holding, the goal was simply less weight.

So you get the same amount of power stored, but reduce the 44Lbs pack's weight significantly.

Cheaper that way too. Sure it's not as fancy as a higher capacity pack, but if your pack goes bad and you have to replace it anyway, why not loose some weight in the proccess? :)
 

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Based on my test so far, more AH + PIMA = more MPG. So that needs to be figured in the equation. I have not found a lithium 6.5Ah cell that can do the 100A either. Some day soon. If the sub C size A123 lithium cells were "D", they would be up to the 100A output task, but the sub C is only 2.5AH
I still like the Valence U1's if the price were under $200 ea. They were $825 last year, now they are $600, but they do not expect them to drop more than another $25, until the volume goes way up.
Why is it that the battery I want always cost more than I can afford to pay.
 

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Quote from IamIan. " the reason the Battery Booster on the Grid Charging thread doesn't run into this problem is that it just gives a no-load charge to the battery pack".

Current flowing in or out of the pack must be monitored or the car will recal or worse cook the batteries. Bypassing the existing pack entirely and feeding the power exclusively to the motor control module could avoid this. (Likely Mike has considered this.) If however you wish to charge the existing pack, all current flow must be accounted for.

Note that the original question here was not about supplementing or paralleling the original pack, but rather replacing it with an improved pack that presumably would be lighter, cheaper, more durable, more readily available, more powerful, and/or more efficient.

Such technology is being developed but is not available yet. We will likely see it first on the next generation Prius. Toyota has the money and motivation to do it now that 7.5 percent of their vehicles sold here are hybrid. Eventually used packs of this new technology will become available. Patience!
 

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Discussion Starter · #10 ·
LiSO2 cells as linked = not Rechargeable!

james said:
Looks like somebody didn't read the data sheet on the LiSO2 cells. They're not rechargable. Gas is going to have to get REAL expensive to make them an option :)
So - James - your right there - now - if we can get buy that issue.....! Robert
 
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