[Kgolf31]

Trying to look for the lightest battery possible.

Came across these. More CCA and AH rating than a Braille 15lb battery


http://www.batterytender.com/Batteri...t-Battery.html" rel="" target="_blank">http://<a href="http://www.batteryte...ttery.html</a>

Shorai has a similar battery. Both are around 4-5 lbs

Does anyone know if our car system will properly accept and charge a Lithium Battery? I know I'll have to do battery registration and remap it. I can do that with the BMWhat app.

So thoughts?

[Cloud9blue]

I wouldn't bother with things like this unless you are running a fully stripped car doing competition level events. Lithium batteries has different voltage profiles than lead acid batteries and are very suspectible to damages by overcharging or too quick of a charge rate, which will happen unless you rewrite the charging profile from the car. Not sure if that's even possible.

[Kgolf31]

I wouldn't bother with things like this unless you are running a fully stripped car doing competition level events. Lithium batteries has different voltage profiles than lead acid batteries and are very suspectible to damages by overcharging or too quick of a charge rate, which will happen unless you rewrite the charging profile from the car. Not sure if that's even possible.

I'm competing in National Level of events for SCCA Solo...so I'm preparing my car for STX. Lightweight batteries are on the list of things to do.

I can get a Braille 15lb for about $200, but if I can spend a bit more to shave 10 lbs, it is worth it IMO.

Car is at 2991 lbs, I would like to get it below 2900 with headers and a new exhaust plus battery

[Cloud9blue]

I see. I would get the Braille instead and use it during the track seasons and switch back to those huge OE battery during the winter. At 10lbs, it would be easier if you just go on a diet or drive naked

Personally, I won't feel safe using a lithium ion battery on a charging system that is built for lead acid. As I said, li-ion batteries charging and discharging characteristics are much different from either traditional (flood-type) and AGM lead acid batteries. Plus I know from two wheels, li-ion batteries have problem with cranking the starter when the temperature start to drop below freezing.

[Kgolf31]

I'm skinny as is to begin with

After looking at the regenerative braking system it details out using AGM batteries.

This car will be kept on a charger and only driven for competition events, so a 15lb battery should do.

[justpete]

Originally Posted by Kgolf31

Trying to look for the lightest battery possible.

Came across these. More CCA and AH rating than a Braille 15lb battery


http://www.batterytender.com/Batteri...t-Battery.html" rel="" target="_blank">http://<a href="http://www.batteryte...ttery.html</a>

Shorai has a similar battery. Both are around 4-5 lbs

Does anyone know if our car system will properly accept and charge a Lithium Battery? I know I'll have to do battery registration and remap it. I can do that with the BMWhat app.

So thoughts?

Voltphreaks makes the only "safe" lithium battery I've seen, fwiw. They're lithium iron phosphate type batteries so they won't burn to completion if a fire starts meaning a suppression system and/or extinguisher will put out a fire should one start for some reason. And they have internal cell balancing and low voltage disconnect, both of which are critical to battery life and safe operation. The standard AGM charge profile will work just fine so both the car's electrical system and a battery tender will have the right voltage and current output. But while they're ridiculously lightweight they're ridiculously expensive. The only safe choice though as far as I can tell though.

[Mavus]

Originally Posted by Kgolf31

Trying to look for the lightest battery possible.

Came across these. More CCA and AH rating than a Braille 15lb battery


http://www.batterytender.com/Batteri...t-Battery.html" rel="" target="_blank">http://<a href="http://www.batteryte...ttery.html</a>

Shorai has a similar battery. Both are around 4-5 lbs

Does anyone know if our car system will properly accept and charge a Lithium Battery? I know I'll have to do battery registration and remap it. I can do that with the BMWhat app.

So thoughts?

I have a Braile 6.6 lb Li battery. It was installed a year ago and so far so good.

[Cloud9blue]

Originally Posted by justpete

Voltphreaks makes the only "safe" lithium battery I've seen, fwiw. They're lithium iron phosphate type batteries so they won't burn to completion if a fire starts meaning a suppression system and/or extinguisher will put out a fire should one start for some reason. And they have internal cell balancing and low voltage disconnect, both of which are critical to battery life and safe operation. The standard AGM charge profile will work just fine so both the car's electrical system and a battery tender will have the right voltage and current output. But while they're ridiculously lightweight they're ridiculously expensive. The only safe choice though as far as I can tell though.

FYI, they (both OP's link, Shorai, and Voltphreaks) are all using lithium iron phosphate chemistry. I wouldn't be surprised that they source their cells from the same manufacturers. While fine tuning of the cell's chemistry is quite complex, but from a component level it doesn't take much to design and package the cells into a car battery (they are essentially a oversized laptop/cellphone battery), so anything more than $200-300 is way overpriced.

Also, li-ion battery cannot be trickle charged for extended time at constant voltage without suffer damages to the cells. Sure, they will work for a track car that is rarely driven, since the damage is done overtime, but it won't last long in a DD w/ charger system designed for AGM. So, make sure to get a li-ion battery compatible battery tender.

[justpete]

Originally Posted by Cloud9blue

FYI, they (both OP's link, Shorai, and Voltphreaks) are all using lithium iron phosphate chemistry. I wouldn't be surprised that they source their cells from the same manufacturers. While fine tuning of the cell's chemistry is quite complex, but from a component level it doesn't take much to design and package the cells into a car battery (they are essentially a oversized laptop/cellphone battery), so anything more than $200-300 is way overpriced.

Also, li-ion battery cannot be trickle charged for extended time at constant voltage without suffer damages to the cells. Sure, they will work for a track car that is rarely driven, since the damage is done overtime, but it won't last long in a DD w/ charger system designed for AGM. So, make sure to get a li-ion battery compatible battery tender.

Sure, all lithium car batteries are iron phosphate for safety since other anode structures will burn to completion. I design battery chargers and battery systems, among a lot of other circuits, as part of my job as a field application engineer and understand how critical lithium battery charging can be. Agreed that off-the-shelf lithium batteries shouldn't be left on a charger unless it's a dedicated lithium charger.

A couple of cells in series will self-equalize more or less with little impact on cycle life but by the time you get to four some sort of active cell balancing is needed to keep one cell from overvoltaging during charge. All it takes is the use of a single IC, no big deal really but necessary.

Most damage is done by deep discharge, thus the need for a low voltage disconnect. I don't know of any automotive lithium batteries with one other than Voltphreaks but I could easily be wrong about that.

And Voltphreaks' design is fully compatible with a daily driver's AGM charging system as well as lead acid tenders, no problems at all or so they claim. As expensive as they are I ain't trying them, a 21# Braille is good enough for me.

If the self-discharge and load discharge of a Voltphreaks battery drains it below the low voltage disconnect threshold you then have to physically reset the battery to get it reconnected to the electrical system. Supposed there would be enough charge left for a start if sized correctly according to their tech data anyway. And that's another part of the cost as well I think since this isn't all that simple really.

Agreed however that for a race car it's overkill if it's only a race car and a dedicated lithium tender is used when stored.

[edit] Forgot to mention these aren't the same as laptop or cell phone batteries, they have much much higher pulse current ratings, not even in the same class or build technology. High current lithium cells like these that are used in telecom backup systems, electric cars, etc. cost quite a bit more. And laptop batteries have some sophisticated circuitry in them for cell balancing, state of charge and health determination, communication with the charger, etc. which makes them a bit more expensive than they'd otherwise be.[/edit]

[Cloud9blue]

Well, I dont have a background in electrical engineering or what not. But I am doing a phd in battery materials, so I really hope that I actually know a few things about this kind of things lol. this thread is getting a bit too confusing, so i just want to reiterate my thoughts on this

- li-ion cells have lower charging voltage profile than lead acid. sure, you can match the overall voltage by connecting different number of cells in series, but you won't be able to cycle the battery correctly using the charge/discharge profile of lead acid

- charge rate for li-ion batteries matter much more than lead acid. for most chemistry/electrode configuration, the optimal charge rate is noticeably slower than typical lead acid. thus, charging a li-ion battery with current rating designed for lead acid will damage the cells.

- yes, laptop and cellphone batteries have noticeable smaller power output, due to the cell size and also due to the use of lithium cobalt oxide instead of iron phosphate. but cell packaging wise, they are nearly identical. trust me, once you get the chemistry part figured out, these things are quite cheap to make with the proper equipments (aside from those large prismatic cells made for larger scale applications such as electrical vehicle, backup energy source for servers and telecomm. and etc.)

- these electrode materials (whether it is iron phosphate used in the cathode or carbon black used in the anode side) are processed into a powder and then slurry coated to a current collector; without getting to technical, the power rating is determined by how fine of a powder is used (down to nanometers, that's why they can get quite expensive). you can design all the circuity you want for cell balancing, voltage cutoff, and etc., but if the cell chemistry isn't compatible with charge/discharge profile that is being applied, the cell won't live long. given the price of these things, and safety concerns, you are better off with switching a carbon fiber trunk instead.

[justpete]

Originally Posted by Cloud9blue

Well, I dont have a background in electrical engineering or what not. But I am doing a phd in battery materials, so I really hope that I actually know a few things about this kind of things lol. this thread is getting a bit too confusing, so i just want to reiterate my thoughts on this.

- li-ion cells have lower charging voltage profile than lead acid. sure, you can match the overall voltage by connecting different number of cells in series, but you won't be able to cycle the battery correctly using the charge/discharge profile of lead acid

- charge rate for li-ion batteries matter much more than lead acid. for most chemistry/electrode configuration, the optimal charge rate is noticeably slower than typical lead acid. thus, charging a li-ion battery with current rating designed for lead acid will damage the cells.

- yes, laptop and cellphone batteries have noticeable smaller power output, due to the cell size and also due to the use of lithium cobalt oxide instead of iron phosphate. but cell packaging wise, they are nearly identical.

- these electrode materials (whether it is iron phosphate used in the cathode or carbon black used in the anode side) are processed into a powder and then slurry coated to a current collector; without getting to technical, the power rating is determined by how fine of a powder is used (down to nanometers, that's why they can get quite expensive). you can design all the circuity you want for cell balancing, voltage cutoff, and etc., but if the cell chemistry isn't compatible with charge/discharge profile that is being applied, the cell won't live long. given the price of these things, and safety concerns, you are better off with switching a carbon fiber trunk instead.

Cool, this is pretty rare knowledge, thanks for sharing!

Agreed, you can't use a lead acid charge/discharge profile but I get the impression there's additional circuitry in the battery to accommodate this problem, maybe a shunt regulator although I've no idea how they'd cool it. But it's possible.

Also agreed. Again, I suspect there's a switchmode charger in the battery that manages the lithium cells independently of the AGM charge profile. This would be more efficient but managing dishcarge would be interesting. It can be done, I've done it with VRLA AGMs but it's tricky making a sync buck converter act as a boost converter when running backward as the control law has to be inverted. Could easily be something simpler though, hard to tell for sure except the cost tends to indicate there's some expensive circuitry in there. Could be more complicated with shunt bypass switching with FETs, too, on discharge at high current, hard to say. More than one way to skin a cat...

From what I've seen the cylindrical wound cobalt cells of laptop batteries don't resemble the monster (what appear to be) non-cylindrical wound iron phosphate lithium batteries used in telecom and some electrical vehicles. I'm assuming, and that's always a bad thing, the peak cranking amps indicates something other than wound cells for lower inductance, hard to say for sure.

Agreed that the cells won't last long if not charged properly, no argument there. It's likely though there's internal circuitry in the Voltphreaks battery that manipulates the applied voltage from the AGM charger into that required for the lithium cells, it isn't difficult but it is involved and difficult to make small and efficient and electrically quiet, not that it's all that but it's a possibility since they claim compatibility with existing automotive charging systems. I haven't seen this claim from anyone else anyway. At least the ridiculously high cost could reflect this. That or crazy lack of business sense...

Thanks for the clarification on how the materials are made and where they're located on the cell, that's a huge help!

[WatashiEd]

Sorry for bumping an old thread, bought an SSB LH20L-BS lithium battery (700CCA), the battery can start the car just fine, but the alternator doesn't seem to be charging the battery correctly since the original was the lead-acid battery in my car, does it mean if I just register the battery and code it to agm type the charging profile should work?

Also, I notice for INPA, even if registering in agm, there are different types Ah (amp hours) to choose from, would this option affect the charging profile too?

Originally Posted by justpete

Voltphreaks makes the only "safe" lithium battery I've seen, fwiw. They're lithium iron phosphate type batteries so they won't burn to completion if a fire starts meaning a suppression system and/or extinguisher will put out a fire should one start for some reason. And they have internal cell balancing and low voltage disconnect, both of which are critical to battery life and safe operation. The standard AGM charge profile will work just fine so both the car's electrical system and a battery tender will have the right voltage and current output. But while they're ridiculously lightweight they're ridiculously expensive. The only safe choice though as far as I can tell though.

Originally Posted by Smooth 330i

I have a Braile 6.6 lb Li battery. It was installed a year ago and so far so good.

[bNks334]

Originally Posted by WatashiEd

Sorry for bumping an old thread, bought an SSB LH20L-BS lithium battery (700CCA), the battery can start the car just fine, but the alternator doesn't seem to be charging the battery correctly since the original was the lead-acid battery in my car, does it mean if I just register the battery and code it to agm type the charging profile should work?

Also, I notice for INPA, even if registering in agm, there are different types Ah (amp hours) to choose from, would this option affect the charging profile too?

https://bmw.spool

street.com/threads/register-and-code-a-new-battery.1020/

Not sure what AH to recommend, but probably the lowest you can choose. See link above on how to code the battery. DEFINETLY change the coding from lead-acid to AGM at the very least.

[justpete]

Originally Posted by WatashiEd

Sorry for bumping an old thread, bought an SSB LH20L-BS lithium battery (700CCA), the battery can start the car just fine, but the alternator doesn't seem to be charging the battery correctly since the original was the lead-acid battery in my car, does it mean if I just register the battery and code it to agm type the charging profile should work?

Also, I notice for INPA, even if registering in agm, there are different types Ah (amp hours) to choose from, would this option affect the charging profile too?

Did you read the datasheet on this battery? Max charge current is 36A and max terminal voltage is 14.6V, are you sure you're staying within these limits? It's a fire hazard otherwise. And it'll total your car.

http://ssbpowersport.com.au/Products...6/Default.aspx

I don't see an Amp-hour rating so no idea how'd you ever get it to work.

[WatashiEd]

For charge current, basic car battery charger usually charges at 2amp per hour, so for 30amp, it will take 15 hours to be fully charged?

For terminal voltage, I think when off is 12.6v, idle would be ~13.5v, above idle would be higher since it is charging at somewhere around 14.2v-14.5v, so max terminal voltage at 14.6v seems to be ok?

Originally Posted by justpete

Did you read the datasheet on this battery? Max charge current is 36A and max terminal voltage is 14.6V, are you sure you're staying within these limits? It's a fire hazard otherwise. And it'll total your car.

http://ssbpowersport.com.au/Products...6/Default.aspx

I don't see an Amp-hour rating so no idea how'd you ever get it to work.

[justpete]

Originally Posted by WatashiEd

For charge current, basic car battery charger usually charges at 2amp per hour, so for 30amp, it will take 15 hours to be fully charged?

For terminal voltage, I think when off is 12.6v, idle would be ~13.5v, above idle would be higher since it is charging at somewhere around 14.2v-14.5v, so max terminal voltage at 14.6v seems to be ok?

A car battery charger isn't an alternator charging system so these numbers are irrelevant. You have to verify the car's charging system is within the maximum limits of the battery.

[WatashiEd]

Originally Posted by justpete

A car battery charger isn't an alternator charging system so these numbers are irrelevant. You have to verify the car's charging system is within the maximum limits of the battery.

I think our alternator is rated at 170-180 amps? But regardless of rating, a 180 amps alternator does not continuously produce 180 amps unless there is a sufficient current draw? (i.e. all stereo, a/c and other accessories added up drawing ~180 amps ish when the car is runnng)

Otherwise, if total current demand from the electrical accessories (including the battery) is only 20 amps, the alternator will only produce the necessary current (20 amps) to maintain the target voltage (which is determined by the alternator's internal voltage regulator)?

[Cloud9blue]

Unless it is a race car, changing the lead-acid battery to a Li-ion on the e9x is just a bad idea in general.

You can do all the coding you want, but you won't be able to edit the charge profile to one that is suitable to Li-ion since no factory e9x has ever been supplied with a li-ion battery.

You guys are better off using a small capacity AGM cell instead... Few lbs difference, is it really worth the trouble, extra cost, and potential safety hazard of a exploding battery???

[WatashiEd]

Originally Posted by Cloud9blue

Unless it is a race car, changing the lead-acid battery to a Li-ion on the e9x is just a bad idea in general.

You can do all the coding you want, but you won't be able to edit the charge profile to one that is suitable to Li-ion since no factory e9x has ever been supplied with a li-ion battery.

You guys are better off using a small capacity AGM cell instead... Few lbs difference, is it really worth the trouble, extra cost, and potential safety hazard of a exploding battery???

Originally Posted by justpete

A car battery charger isn't an alternator charging system so these numbers are irrelevant. You have to verify the car's charging system is within the maximum limits of the battery.

Confirmed the lithium battery doesn't work reliably, switched back to AGM after 2 days... =[