I4 Battery/Alternator Charging Behavior...batteries shutting off, dying, car not starting, etc.

[Kaz]

Since early 2025, so a little over a year. It was one of the first mods I made to the car after hearing about the stock battery issues.

To be fair, the car has only been lightly driven (~2500 miles total). Closest to getting stranded was when I took a zoom call in the car with the engine off and it locked me out when I went for a coffee. The antigravity jump start seemed to fix that though.

Is there any damage from frequently jump starting with anti gravity that I should know about? Does that power reserve run out at all or is that charged alongside the car?

I think it's just the minimal residual charge it will always keep to turn the motor - I don't think anything is necessarily "wrong" with what's happening it's just sketchy lol (!) I've got too many accessories that need power in my car to deal with a low voltage state - sub, amps, methanol pump, dashcam, radar, digital rearview mirror, etc. Like was said before I'd love the charging logic to get updated to get the antigravity happy and fully charged up...I think it would be worth it at that point. For now just running a lighter AGM from Braille with lots of reserve because of all the stuff running on my car. And even then the car doesn't top off the AGM often lol.

 

[Lotus F1]

So here are the solutions I have come up with with this issue. I have a solid state lithium battery. I also have a supercapacitor connected to it that assist and guarantees super strong starts, recharges in seconds and minimizes the load on your battery everytime and never needs to be charged when connected to the battery.

Now in a pinch if you ever want to force the cars alternator to charge the battery simply pull the 2 wire plug on the negative terminal. The alternator will go into a default mode bypassing the logic and forcing a charge to the battery. You will get possibly a light on the dash but it will not affect how the car runs. You could run it like this way all the time as well but just keep in mind at least once a week put your lithium battery on a charger so that proper cell balancing can take place as it will not with the cars charging logic. It doesn't reach a high enough voltage to force the battery BMS system to balance the cells

 

[lynchy73]

So here are the solutions I have come up with with this issue. I have a solid state lithium battery. I also have a supercapacitor connected to it that assist and guarantees super strong starts, recharges in seconds and minimizes the load on your battery everytime and never needs to be charged when connected to the battery.

Now in a pinch if you ever want to force the cars alternator to charge the battery simply pull the 2 wire plug on the negative terminal. The alternator will go into a default mode bypassing the logic and forcing a charge to the battery. You will get possibly a light on the dash but it will not affect how the car runs. You could run it like this way all the time as well but just keep in mind at least once a week put your lithium battery on a charger so that proper cell balancing can take place as it will not with the cars charging logic. It doesn't reach a high enough voltage to force the battery BMS system to balance the cells View attachment 83478

That “Solid State Buttery“ is just a name/BS. It’s almost certainly LFP. Semi solid batteries are available, but their nominal voltage isn’t suitable for a 12V starter battery (typically 3.6Vnominal).

I’ve been using a Sodium Ion battery in my I4 for months. It charges fine, it charges strongly as soon as the car starts and quickly gets up to 100%. It works as the voltage curve is pretty much identical to AGM. LFP voltage curve is quite different and doesn’t play nicely with the alternator algorithm in our cars.

 

[Lotus F1]

That “Solid State Buttery“ is just a name/BS. It’s almost certainly LFP. Semi solid batteries are available, but their nominal voltage isn’t suitable for a 12V starter battery (typically 3.6Vnominal).

I’ve been using a Sodium Ion battery in my I4 for months. It charges fine, it charges strongly as soon as the car starts and quickly gets up to 100%. It works as the voltage curve is pretty much identical to AGM. LFP voltage curve is quite different and doesn’t play nicely with the alternator algorithm in our cars.

Oh wow ok. I'll look into getting a sodium ion battery... The battery I have is definitely a solid state battery but the bigger issue is the charging profile as discussed. If the sodium ion has the same compatible voltage profile then that would be a better more convenient solution.... Thanks

 

[lynchy73]

For info, sodium ion seems to have various nominal voltages, depending upon the precise chemistry. The higher power versions are typically lower nominal voltage from what I’ve seen, and that’s the sort that are best suited to a 12V starter battery.

Capacity is a bit less than LFP (35Ah for my H6), but it’s enough, so long as you don’t leave it parked too long. Best to get something with an app, so you can check how it’s doing.

 

[Lotus F1]

I'm going to keep my supercapacitor connected. It gives me app info and guarantees a high voltage start evertime (not just when low) and pretty much leaves the battery alone for starts. Thanks for the heads up! $215!

 

[Lotus F1]

New sodium battery it's only about 12 lbs. And reportedly has the same profile as a AGM battery. Seems like a win-win. Let's see how it goes

 

[Lotus F1]

6640 a.m. I'm using the supercapacitor to guarantee an easy start seems like cheap insurance for a guaranteed start every time

 

[BeagleButler]

This thread is great. I got linked to it from another forum member when my car developed issues 4 hours after delivery. Anyway, I see that AntiGravity is in the process of developing their own sodium ion batteries. Hopefully they will be available soon for real-world testing.

Benefits of Sodium-Ion Batteries

Antigravity Sodium-Ion Starter Batteries offer many benefits over lead/acid: longer life, built-in Jump Starting, Bluetooth monitoring, lighter weight, more.

antigravitybatteries.com

 

[Livert]

Anyone know if the charging logic is different for the emira 420 as they have lithium batteries? I'm hoping a simple software upgrade can fix our issues.

 

[Milk242]

I recently replaced my battery with a ohmmu sodium ion h6 battery. Seems to work fine. I added an ancel bm200 to track charging. I’m no battery expert so if someone wants to see the ancel bm200 data, let me know.

 

[lynchy73]

I recently replaced my battery with a ohmmu sodium ion h6 battery. Seems to work fine. I added an ancel bm200 to track charging. I’m no battery expert so if someone wants to see the ancel bm200 data, let me know.

I’d be interested to have a look at the data, either DM me or share it here.

 

[Milk242]

I don't drive much

I’d be interested to have a look at the data, either DM me or share it here.

 

[lynchy73]

I don't drive much

Both sets of data were with the sodium ion battery? A bit hard to know what’s going on, without knowing what you were doing at the time. First thoughts are that the data doesn’t look great. What would be useful to see is how the voltage changes on a partially discharged battery, once you startup and drive for maybe 30mins or so. Your data doesn’t seem to show what I’d hope to see, which is the battery going from say 30 or 50%, then quite quickly get to 100% or close to it, then stay in that ballpark whilst driving, then drain a little after parking as the fans will drain the battery a bit.

 

[lynchy73]

I only checked the data on my phone, didn’t see the data to the right for each day. Will take a look on my computer when I get a chance. All data is for the sodium ion battery, or there is data for another battery type in there too?

 

[Milk242]

All data is for the sodium ion. My factory battery is totally dead so replaced it with this.

 

[Milk242]

All data is for the sodium ion. My factory battery is totally dead so replaced it with this.

Yea let me know how I should drive to test this thing. So far even after a week of sitting and between short drives it seems to start up fine

 

[lynchy73]

Yea let me know how I should drive to test this thing. So far even after a week of sitting and between short drives it seems to start up fine

You haven’t been using a trickle charger, right? The main thing is just to be able to use it normally, short drives and leaving it parked up for like a week or more.

Will have a look at the data on my PC later. Been a busy few days.

However, honestly I’d be more comfortable if whatever battery folks are installing has Bluetooth and data so you can see what’s going on properly.

 

[Milk242]

Yea no trickle charger, just installed and connected the ancel bm200 to the terminal so I can monitor battery health via Bluetooth while I drive. Wanted to see if sodium ion actually works fine.

Battery does seem to start charging when it’s under 30% according to the ancel app.

I normally only drive my car on the weekends so it mostly just sits for the 5-6 days and if I do use it during the weekday it’s usually a short 1-2 mile drive.

 

[Lotus F1]

Yea no trickle charger, just installed and connected the ancel bm200 to the terminal so I can monitor battery health via Bluetooth while I drive. Wanted to see if sodium ion actually works fine.

Battery does seem to start charging when it’s under 30% according to the ancel app.

I normally only drive my car on the weekends so it mostly just sits for the 5-6 days and if I do use it during the weekday it’s usually a short 1-2 mile drive.

Did you put in the Sodium Ion battery voltage profile in the BM200. You have to do that or the reading will not be correct. From what I see you did not do that.