light weight battery kills the alternator?

[NoHaveMSG]

Originally Posted by Yetti

Ok just checked with the current alternator and the battery is 13.3 volts with the car off (which seems kinda high). The car is not daily driven so it has been sitting since it got home from the AutoX yesterday and with the car running it is at 14.3 volts.

Was that shortly after running the car? It may have a bit of surface charge that will dissipate and level off to it's standard voltage.

[jflogerzi]

Originally Posted by Matt93SE

Just be sure whatever tender you use on it is compatible with the battery type. LiIon batteries can be charged by a standard charger, but you don't want to leave them on a standard tender long term. IIRC, AGM batteries don't like to be de-sulfated either, to be sure to look into the charger's compatibility with that battery type.. do it thru both battery mfr and charger mfr information, cause the charger people will say "it's compatible with everything".

Thanks! Its a harbor Freight but it does has a AGM charging mode.

[steverife]

I've got the Antigravity ATX20-RS in my car. Everything worked fine for the first 11 months or so. Then I was getting ready for an event about 6 weeks ago. I took the car down the road to get gas and the car wouldn't restart. Dead AF. Couldn't even unlock the doors with the fob. Bought a stock battery, put it in the car, drove to the event. Get there and mess around with a multimeter and eventually hit the battery with Eric1855's jump pack. Battery works fine. Put it back in the car. Car runs great in the event, no issues. I bought a jump pack off Amazon to carry around. I've ran 2 locals (250 mile round trip) and went to SCCA Solo Spring Nats (2k mile round trip) without issue.

My default answer is battery. These batteries can get weird on you.

[ZDan]

I got a Shorai LFX36L3-BS12 (4.8 lb) two years ago. I've put ~20k street miles and 20 or so track days on it. I have removed it for winter months but will likely keep it in next winter, supposedly good down to 0F or lower (they recommend putting the lights on for a few minutes at 0F to warm it up a bit prior to trying to start).

Anyway, no problems or weirdness at all, and it starts the car up with greater eagerness than the huge lead-acid battery.

[grumpysnapper]

Been running a 2.5 kg / 5.5lb lithium (Lithiumax) battery for about 2 years with no dramas at all yet with the alternator (touch wood!).

But we dont get super cold temps here, and the car is always on a lithium friendly trickle charger overnight.

[Yetti]

Originally Posted by NoHaveMSG

Was that shortly after running the car? It may have a bit of surface charge that will dissipate and level off to it's standard voltage.

I took the voltage at the battery before I started it so it had been sitting for a day. I checked the voltage again after running it briefly and it was the same 13.3 volts.

[NoHaveMSG]

Originally Posted by Yetti

I took the voltage at the battery before I started it so it had been sitting for a day. I checked the voltage again after running it briefly and it was the same 13.3 volts.

I'd consult the manufacture with what it should be at. Even a normal AGM should be around 12.6v so it is really not like it is crazy high.

I know with our 48v systems, seriesing 4 group 34 12v batteries nets around 51v, but the equivalent lifepo4 battery pack is around 53v.

[Yetti]

I checked another battery tender lithium iron battery and it was also at 13.3 volts (completely disconnected from a car and sitting on a workbench). My stock battery was 12.7 (disconnected from car). Now out of curiosity would someone else check there different brand lithium battery for what voltage it is at while car is off?

[ZDan]

Originally Posted by Yetti

I checked another battery tender lithium iron battery and it was also at 13.3 volts (completely disconnected from a car and sitting on a workbench). My stock battery was 12.7 (disconnected from car). Now out of curiosity would someone else check there different brand lithium battery for what voltage it is at while car is off?

Lithium batteries definitely have a higher "resting" voltage than lead-acid. 13.3v-13.5v is perfectly normal, while a lead-acid will be at 12.6v.

[geraldjust]

Yes lithium batteries actually have a higher resting voltage than your traditional lead acid batteries. The chemistry is just works that way. And from what I'm seeing is a mixed reports that for some people take last year's and for others they die within weeks. I'm guessing what is more important now that I'm reading into a lot of this is the actual BMS being used in these batteries. when it comes to these battery BMS is probably more important.

[Yetti]

For future reference for anyone else running down this issue.



Today on the way back from an AutoX the car cut out a couple more times so I plugged in the OBD reader and logged the voltage. The couple of times I caught the car cutting out the voltage was spiking high. I only had the graph set to a max of 16 voltages which it pegged out so I am not sure of what voltage it got to. Also the temperature of the battery (measured with an infrared thermometer) was ~120 F which seems normal for a car operating in 85 F ambient temp.

[Ultramaroon]

Originally Posted by Yetti

For future reference for anyone else running down this issue.



Today on the way back from an AutoX the car cut out a couple more times so I plugged in the OBD reader and logged the voltage. The couple of times I caught the car cutting out the voltage was spiking high. I only had the graph set to a max of 16 voltages which it pegged out so I am not sure of what voltage it got to. Also the temperature of the battery (measured with an infrared thermometer) was ~120 F which seems normal for a car operating in 85 F ambient temp.

Did it go back down like a real spike, or did it look like a shelf? How did the period of abnormal signal correspond to loss of power steering?


An abnormally high voltage means there is nothing wrong with the alternator. It is doing what it is being told to do. Now we compare the graph to what you feel.

[Yetti]

The short spike in voltage corresponds with the cut out of the engine and speedo going to zero, it is short period of time less than a full second.


I agree the alternator is not the cause I even went back to the original one as the new one was no better. At this point I am planning to just remove the battery and go back to the stock one and take the weight hit (I'm not competitive enough for it to matter anyway).