That darned last 1/4 of a mile!

Nice going! Are you not worried driving around without the BMS? And what about the charger, does it protect against overload without the BMS?

 

I am a bit weary about using the EV mode; unless I anticipate a lot of stopping so the Enginer can recharge the stock pack. I've noticed that the Prius computer execute the recalibration code (draining the pack to 2 bar then let it charge back up) more often when I use the EV mode.

My concern is for the health of the stock pack, granted that 2-bar is still 40% SOC. My 2004 has 160kmile now; out of warranty

 

I did a 9 mile drive and 90% charge with CellLogs. I was surprised that the batteries started so low. Less than 50%. Be really careful. you do not know where the cells are at until you run them to the low limit and the high limit.

Thanks,
Dan Lander

 

The Prius checks the current flow going in and out of the HV pack and based on that estimates the SOC and that is shows as a certain amount of bars on the display.
On occasion, I don’t exactly know when, it makes a very accurate calculation of the SOC of the HV battery. That is what is called the ‘recalibration’. The actual SOC may be different to the estimates it made while driving.

Last summer I noticed the the SOC on the display was at only 4 bars while my Scangauge told me it was a 60.5%SOC. A few seconds later it suddenly jumped up to 6 bars for no apparent reason. It seems the Prius made a recalibration at that moment. This was in my standard Prius, no Enginer kit yet or other modifications.

Why the system works like this I don’t know, it doesn’t really make sense: if my Scangauge can show the real SOC why doesn’t the Prius do the same. And I also don’t know what the conditions are for making a recalibration.

 

Hi David,
I am sorry for not being clear.

The RealForce cells were less that 50% SOC when I recieved them. If anyone is running them without a balancer or some way to know the actual SOC then they are very much at risk of dammaging these new batteries.

Thanks,
Dan

 

Hi Adric,

The 52mph hack may work for you, but i believe you need a scangauge to clear the code before you can drive the car

Any chance you could do a video of your drive so we can see what kind of speed/terrain you're on?

 

The "recalculation" is just to reset the integration, which is numerically imperfect and can diverge. The key word is the SOC is an estimation.

I don't think the system knows the real SOC, just an educated guess. I believe the Scangauge just display the serial messages on the communication bus. The recalibration is called for when there is some sort of discrepancy among the monitors.

My concern is to minimize the range of the SOC for the health of the stock pack; though I think Toyota is already doing that by keeping between 40-80%. I just notice that the recalibration is more often when i push the EV mode