12V A123 LiFePO4 w/ BMS car battery replacement?

[mvly]

So far, I cannot find any 12V replacement battery for my car.

Do anyone know of where I can get them?

Here is the research I have done on it so far:

Required chemistry: LiFePo4 (4s = 12.8V nominal and 14.4V max. This is perfect for replacement of 12V Lead Acid. My car alternator would charge these to 14.4V which is same as Lead Acid)
Required cells: A123 26650 cells. These have high discharge rate required for starting my car. Typical CCA ~= 650. These cells handle up to 70A continuous or 120 burst for 10s discharge so having 10 is parallel should be more than enough. Having 7 or 8 in parallel would probably be more accurate.
BMS required! LiFePo4 requires BMS.

The problem is I cannot find a BMS that does 600Amps! So the next best thing is to have something that balances the cells ALL the time.

Is it possible to have the cells hooked up normally directly to the cables but a balancer attached to it so when the car do charge it, the balancer will balance the cells by bleeding the excess all the time? Yes I will have to drive the car once in a while to make sure the cells are not fully depleted and such by the attached balancer. My only concern is if there is a hardy enough balancer that can handle heat, physical shock, and longevity of the car. i.e. it will be hooked up once and never need to be replace until the car itself is dead.

Is what I am dream a pipe dream or is there currently a NON-chinese solution to what I have stated above available. If it's a available, can I get it?

I know falconEv has these LiFe packs:
http://www.falconev.com/batteries.html

But it is only suppose to be used in marine, boat usage which means the current is much much less than the 650A CCA.

 

[dogman dan]

Where are you?

 

[mvly]

Where are you?

Southern California, USA

 

[dogman dan]

These are in Canada

http://endless-sphere.com/forums/viewtopic.php?f=31&t=40426

Two, 18 ah or so, to start a car?

 

[mvly]

These are in Canada

http://endless-sphere.com/forums/viewtopic.php?f=31&t=40426

Two, 18 ah or so, to start a car?

This also need a balancer. The problem is not getting the A123 cells, but CAN it run on a balancer indefinitely? And CAN the balancer last the life of the vehicles (>10 years). The A123 cells will probably last at least that long.

 

[dogman dan]

I had a long talk with Tommy on the phone the other day. He's using a discharger (balancer?) to keep the alternator from overcharging the cells. But talk to him about how good it's working for his other customers.

The thing I thought was nice about his packs, was that they have a balance plug. That allows a variety of plug and play devices to be added for balancing and monitoring.

Seems like there are race car batteries out there, but I don't have a source handy, nor do I know if they are A123 cells.

 

[wedge]

Forget about trying to balance the cells while the car is running. Car batteries don't really go through charge/discharge cycles. The battery partially discharges at startup then is float charged while the engine is running. The battery may be required to supplement the alternator for short periods when accessories turn on etc. otherwise the battery pretty much just sits there getting float charged. Unless it is a newish car in which case the engine management system may turn off the alternator under heavy acceleration and at other times.

Alternators charge at between 13.8V (flooded lead acid/AGM) and 14.8V (calcium) depending on the type of battery the manufacturer installed in the car. Obviously 14.8 is a bit high so check yours if you haven't already. This float charging deal is like the constant voltage part of a normal charge cycle, current will drop off to nothing as the battery comes up to 13.8V or whatever.

A balance connector is handy for periodic checking/balancing when the engine is not running.

 

[agniusm]

Alternators charge at between 13.8V (flooded lead acid/AGM) and 14.8V (calcium) depending on the type of battery the manufacturer installed in the car. Obviously 14.8 is a bit high so check yours if you haven't already. This float charging deal is like the constant voltage part of a normal charge cycle, current will drop off to nothing as the battery comes up to 13.8V or whatever.

A balance connector is handy for periodic checking/balancing when the engine is not running.

I dont know if the charge voltage depends on battery, its alternator! Usually its 14.4V Lead acid battery - 6 cells at 2.37-2.40V per cell giving 14.4 fully charged.
Your described situation on float charge or CV state is wrong. It depends how you drive. if you sit in traffic for few hours sure, in my situation with lots of starts and stops it goes down but then balances out on the longer runs. My 20AH A123 pack is in use daily for almost a year and whole last winter when the temps go down to -20C. In the first 6 months voltage difference was within .02V without balancing and it floats at 3.45V. Real SOC is unknown.
I had to take it to repair once and boys ran my battery down, when one cell got to 1.7V. Since then that cell drifts by as much as .3V (real SOC is unknown) which is significant.

 

[999zip999]

mvly I gave you an A123 20ah cell so all you need is three more. I would just use the SLA and use your car once a week. I did have problem as I don't use my car much now. And it had a problem till I charged it up to 14 volts. I know I let it sit to much.
But don't think Lifepo4 is an answer for the problem of a car starter battery. I will buy a small float charger later. As I don't like taking out the car battery to charge or pulling on the psu and the 1420 to charge it in the driveway. Just don't want it to walk away.
So Agniusm you don't have a lvc ? How about a cheap alarm. That will teach the auto shop.

 

[wedge]

I dont know if the charge voltage depends on battery, its alternator!

The voltage output of the alternator is designed to suit the original lead acid chemistry that was in the car.

 

[mvly]

mvly I gave you an A123 20ah cell so all you need is three more. I would just use the SLA and use your car once a week. I did have problem as I don't use my car much now. And it had a problem till I charged it up to 14 volts. I know I let it sit to much.
But don't think Lifepo4 is an answer for the problem of a car starter battery. I will buy a small float charger later. As I don't like taking out the car battery to charge or pulling on the psu and the 1420 to charge it in the driveway. Just don't want it to walk away.
So Agniusm you don't have a lvc ? How about a cheap alarm. That will teach the auto shop.

What you gave me is the prismatic cell which I doubt can source 600A for starting a car. Yeah I'll talk to tommy L to see how it works for his customer. I think as of now the only route is the balancer attached because I hate to balance charge it one a month or so. But them the balancer so suck some energy so I would need to drive it at least once a month to charge the battery over what the balancer used.

Humm this is a tough problem and it does not seem like anyone has a solution yet.

BTW. Low voltage cut off of lead acid is 9V? If so this Means the alternated can let the battery drain to 2.25V before charging it.

This might also be a problem.

 

[arkmundi]

So far, I cannot find any 12V replacement battery for my car.

Do anyone know of where I can get them?

You can buy them from: http://www.buya123batteries.com/category_s/1820.htm

 

[999zip999]

We also need to know what car and engine you have. More info. A moster truck or an old VW 1200 40hp. ?
That cell was an old less than perfect high I.R. cell A123 20ah I thoght you would do a high discharge test or something to play with not for use in anything not even a head light.

 

[AlSpong]

EV Power in Australia sell lifepo4 battery packs manufactured as car batteries , I think they have one tested as a daily driver over a few years now .

 

[RedLine19K]

http://www.ebay.com/itm/RCE-12V-Lithium-Ion-A123-LiFePO4-16-1Ah-YTX20L-BS-GTX20-BS-lightweight-racing-/220917790894?pt=Motorcycles_Parts_Accessories&hash=item336fb9f8ae

these guys were licensed by A123. only $1100 for a 16ah battery. No idea why these never went mainstream

Of course, A123 developed their own battery, the only problem being it you can't buy it.
http://www.a123systems.com/lithium-starter-battery.htm

btw, the 7ah battery linked earlier isn't suitable for high power.

 

[gogo]

There are many vendors for lithium motorcycle starter batteries now. I'd guess the battery tender batteries are using cells without a discharge limiting circuit.

http://batterytender.com/includes/languages/english/resources/BT_Lithium_Battery_Manual.pdf
CHARGING:

• 
  a) Do not use a desulphation or pulse charger, doing so will damage the battery and void the warranty. Their standard charger has one or both of these?
  b) Standard lead-acid chargers may be used, as long as they do not exceed 14.8Volts during charging.
  c) Maximum charge rate is 10Amps. This suggests that there may be some sort of limiting and/or balance circuit for charging.
  d) It is strongly recommended the use of a lithium specific charger such as the units in the Battery Tender® Lithium Charger series.
  e) Do not allow the lithium battery to discharge below 8Volts as this will damage the battery and void the warranty.
  f) Do not charge the battery in temperatures below -10oC (14oF).

480 CCA starter battery:
http://batterytender.com/products/batteries/lithium-iron-phosphate-battery-lifepo4-la-eq-26-35.html

Their Lithium charger 1.25A:
http://batterytender.com/products/motorcycle/battery-tenderr-plus-lithium.html

 

[wb9k]

The A123 starter batteries are definitely real. We build more of those than anything in Livonia today and that will continue to be the case until starter battery volumes make cell costs practical for HV for everyone. McLaren, and now Daimler are starter battery customers and many others are in the wings. Available starter batteries are a hot commodity around the office, and I love my McLarens. The Daimler are also nice, but not as hobbyist-friendly. You may well see A123 take over the starter battery and "aux battery" application field in the next few years. Turns out EXT is real after all, and the results yielded in CCA are astonishing. I've been quiet about this angle here, but A123 is now officially releasing this info in a press release and series of media interviews over the next few weeks. I believe the WSJ has already published the first interview with Jason Forcier. I'll post a link in another thread later on.

As to using Li ion for an aftermarket solution, there are several issues that--for the DIYer--need to be addressed one car at a time. Making a battery you can just drop in and and forget about can range from relatively simple to something more involved. Making something at scale that just anyone can drop into any car is not a simple task. The electronics in these starter batteries are quite advanced. In OEM applications, the battery talks on the vehicles CAN bus (or LIN, as the case may be) to communicate a host of information. Key among them is information that tells a smart alternator where to set its voltage depending on the batteries SOC and vehicles auxilary load at the time. Yes, even the starter batteries talk now. But, how to DIY this?

First thing to determine, IMO, is what is the unloaded, open circuit voltage of the alternator at full tilt . You MUST assume that the pack can be subjected to this voltage for extended periods of time. If the alternator maxes out <14.8V (14.4 is ideal), you can be confident that calendar life will not be significantly at risk if there is a balance system in place that will insure nobody gets overcharged because of a lagging cell. (Continuous balancing is an absolute necessity in a civilian vehicle.) If the alternator maxes out higher than than 14.8V, you'll need to add some provision to cut off charging completely above 14.8 (measured at the battery terminals). If you don't limit voltage above 14.8V, you risk shortening the the life of the batteries significantly by causing Li to plate onto the cathodes, in turn leading to capacity loss AND impedance growth. Above 15 Volts or so, the risk turns to vented cells and the possibility of fire.

You can run at engine bay temperatures with these cells, but it would be preferable to get the battery out of the engine compartment if possible. They should last significantly longer at cooler temperatures. Those are the major points in my mind.....hope that's helpful.

 

[Punx0r]

Above 15 Volts or so, the risk turns to vented cells and the possibility of fire.

I'm not sure about the latest cars, but a reasonably common failure in the alternator in older cars is regulator failure. People usually find 17-18V being pumped into the battery (and boiling it) at idle. I can only guess how high the voltage might be at higher engine speeds.

This doesn't seem to end in disaster with lead acid batteries, just a ruined battery and a stench of rotten eggs. If there's a realistic risk of fire with lifepo4 cells though, I'd ask if A123 have implemented something to protect the battery incase of a rare, but significant over-voltage?

Another possibility is people jump-starting, or using a boost charger at 24V on a 12V system...

 

[wb9k]

All current flowing in and out of an A123 starter battery goes through a bank of FETs that can be shut off by the internal BMS to protect from overcharge, overdischarge, and overheating. So, yes, they are supremely safe against catastrophic events--safer than LA, IMO. Short the battery out and the FETs become a fuse. This, of course, destroys the battery, but better the battery than your face.

 

[gogo]

I'm not sure about the latest cars, but a reasonably common failure in the alternator in older cars is regulator failure. People usually find 17-18V being pumped into the battery (and boiling it) at idle. I can only guess how high the voltage might be at higher engine speeds.

Truth. I had one go out on my 96 Roadmaster and saw 19V on a low rev and immediately turned the car off in horror.

BTW, the Battery Tender batteries I linked to in an earlier post seem kind of light in weight for their CCA and AH ratings.

 

[wb9k]

16V from the alternator open circuit is not uncommon in cars that are working just fine. Anyone contemplating using a Li starter battery has to be keenly aware of the max possible charge voltage and have a plan for automatic disconnection of the battery from the alternator should cell voltage ever go too high.

 

[SHARKBITEATTACK]

This brand had a couple motorcycle batteries on display at my local battery plus store http://shoraipower.com/

I also saw one that they used on the television show horsepower TV. I don't recall the name though

 

[dmwahl]

Maybe I missed it earlier in the thread, but why do you want to replace your lead car battery? Weight savings?

 

[wb9k]

Maybe I missed it earlier in the thread, but why do you want to replace your lead car battery? Weight savings?

Weight savings and longer life would be the advantage for an aftermarket user. Some race car guys like Li SBs for the weight. For the daily driver, the benefits are less meaningful.

In next-generation OEM's, start-stop functionality is the big driver. The SB needs to be able to turn the car over on a more regular basis, needs to run all aux loads while the ICE is off, and the battery also needs to be able to efficiently accept large spikes of current from regenerative braking systems. LA, even the good AGM stuff, isn't up to the job--at least not over it's old life expectancy.

 

[dmwahl]

I understand the general reasons why lithium may be advantageous, I was more curious why the OP wanted it. I've done the math and I can buy a lead starter battery warranted up to 6 years for $70 at Farm and Fleet, makes spending several times as much on a not-quite-mature technology seem less appealing even despite the long life and weight savings. Not suggesting it's a bad idea, but in general I don't think lithium batteries are yet a better option than lead for starter batteries unless there are other factors. I plan on putting one in my boat to run accessories when the motor is turned off, but I still wouldn't use it for the starter for various reasons.