Emira I4 ECU Flash Tuning is Now Possible (~510HP Turbo)

[lynchy73]

They will work just put on tender, but it won't work like standard battery that recharges when you drive, it will always be on the bare limit of having charge and cause some CEL eventually - but for a track car just keep it plugged in all fine. And yes any lithium since they are higher voltage and that is what causes issues.

The alternator does charge in short bursts (at high current) even when the lithium battery is at a relatively high SOC, but most of the time power to run the car is coming from the battery (at lower current levels), not the alternator. I’m keeping an eye on things to better understand what’s happening. It is quite strange how it behaves, it is not immediately obvious what’s going on or why. My battery is currently showing about 50% SOC after several drives, will continue to use it and see what happens at lower SOC. My battery is 60Ah, it’s at least as much or likely more capacity than the factory battery.

There are other types of cell that might be better suited to our cars that will better match how an AGM behaves. My company assembles battery packs, so I know lithium batteries well and we could build something ourselves.

Another possibility is that you might be able to change a setting via diagnostics, to change the voltage at which charging is initiated.

@Kaz Have you logged the voltage and current flows using the standard AGM battery? What is the capacity of the LFP battery you were running?

 

[lynchy73]

So basically any lithium battery will not work on the Emira correct?

Lithium Car starter batteries are almost always LFP type cells. That is not the only type of cell that could be used for this application.

It could be possible to change the alternator control logic so it is better suited to an LFP battery.

 

[Kaz]

The alternator does charge in short bursts (at high current) even when the lithium battery is at a relatively high SOC, but most of the time power to run the car is coming from the battery (at lower current levels), not the alternator. I’m keeping an eye on things to better understand what’s happening. It is quite strange how it behaves, it is not immediately obvious what’s going on or why. My battery is currently showing about 50% SOC after several drives, will continue to use it and see what happens at lower SOC. My battery is 60Ah, it’s at least as much or likely more capacity than the factory battery.

There are other types of cell that might be better suited to our cars that will better match how an AGM behaves. My company assembles battery packs, so I know lithium batteries well and we could build something ourselves.

Another possibility is that you might be able to change a setting via diagnostics, to change the voltage at which charging is initiated.

@Kaz Have you logged the voltage and current flows using the standard AGM battery? What is the capacity of the LFP battery you were running?

The alternator will do tiny bits of charge when you lift throttle (just momentarily) and under braking for a little bit. Every 4th, 5th? drive cycle the battery regardless of the state of charge will charge in all driving conditions. I have to look at my SOC and voltage logs but basically an AGM battery will drain to about 65% before the car decides to start charging via the alternator. This voltage trigger is hard to do with a lithium battery because it's just a higher voltage battery, I found even below 50% charge the alternator will not charge a lithium battery. You will see actual voltage while running the car will start to deterioriate to about 12.5V where it should be closer to 13.7-14V where the battery is charging. I had the 60Ah Antigravity with lots of reserve and I had to just plug it in all the time. Remember after a drive the I4 fans and pumps keep going for about 20 minutes and that further depletes your battery as well.
The behavior you are seeing is exactly what I and other are seeing with lithium, charges kind of once in a while, state of charge is about 50-60% max if you just drive the car around like normal. With my methanol pump and all the electronics in the car I just decided to not risk it and use a big capacity AGM battery.
If one day we can reprogram the car for lithium that would be great, but this is deep Mercedes efficiency code that is in all modern Mercedes cars. It's call Bluewave or something and saves a tiny tiny bit of fuel if the alternator is not engaging till the stock AGM battery gets down to about 65%. And again every 4th or 5th drive cycle the car will fully charge the battery no matter what.

 

[lynchy73]

The alternator will do tiny bits of charge when you lift throttle (just momentarily) and under braking for a little bit. Every 4th, 5th? drive cycle the battery regardless of the state of charge will charge in all driving conditions. I have to look at my SOC and voltage logs but basically an AGM battery will drain to about 65% before the car decides to start charging via the alternator. This voltage trigger is hard to do with a lithium battery because it's just a higher voltage battery, I found even below 50% charge the alternator will not charge a lithium battery. You will see actual voltage while running the car will start to deterioriate to about 12.5V where it should be closer to 13.7-14V where the battery is charging. I had the 60Ah Antigravity with lots of reserve and I had to just plug it in all the time. Remember after a drive the I4 fans and pumps keep going for about 20 minutes and that further depletes your battery as well.
The behavior you are seeing is exactly what I and other are seeing with lithium, charges kind of once in a while, state of charge is about 50-60% max if you just drive the car around like normal. With my methanol pump and all the electronics in the car I just decided to not risk it and use a big capacity AGM battery.
If one day we can reprogram the car for lithium that would be great, but this is deep Mercedes efficiency code that is in all modern Mercedes cars. It's call Bluewave or something and saves a tiny tiny bit of fuel if the alternator is not engaging till the stock AGM battery gets down to about 65%. And again every 4th or 5th drive cycle the car will fully charge the battery no matter what.

LFP is not the only cell type used in starter batteries. Sodium Ion offer some advantages and should have a voltage curve closer to an AGM, so it might play nicer. Not quite as light, but still much lighter than lead. Would be cool if it works.

For me, the LFP is certainly usable, as this is not my daily and in order to avoid battery issues with my AGM I was having to top it off with a charger anyway. I was getting lots of random errors occurring (no CEL) that seemed to be voltage related due to low battery voltage, but I never actually had an issue starting the car, ever…

 

[675430VME]

The alternator will do tiny bits of charge when you lift throttle (just momentarily) and under braking for a little bit. Every 4th, 5th? drive cycle the battery regardless of the state of charge will charge in all driving conditions. I have to look at my SOC and voltage logs but basically an AGM battery will drain to about 65% before the car decides to start charging via the alternator. This voltage trigger is hard to do with a lithium battery because it's just a higher voltage battery, I found even below 50% charge the alternator will not charge a lithium battery. You will see actual voltage while running the car will start to deterioriate to about 12.5V where it should be closer to 13.7-14V where the battery is charging. I had the 60Ah Antigravity with lots of reserve and I had to just plug it in all the time. Remember after a drive the I4 fans and pumps keep going for about 20 minutes and that further depletes your battery as well.
The behavior you are seeing is exactly what I and other are seeing with lithium, charges kind of once in a while, state of charge is about 50-60% max if you just drive the car around like normal. With my methanol pump and all the electronics in the car I just decided to not risk it and use a big capacity AGM battery.
If one day we can reprogram the car for lithium that would be great, but this is deep Mercedes efficiency code that is in all modern Mercedes cars. It's call Bluewave or something and saves a tiny tiny bit of fuel if the alternator is not engaging till the stock AGM battery gets down to about 65%. And again every 4th or 5th drive cycle the car will fully charge the battery no matter what.

Luckily I checked with you guys before I place an order. No wonder Ryan does not have one installed.