HV Battery Voltage Level, Dash LCD Indicator?

I do not remember seeing it that high even with a forced charge:

• hold the brake hard
• hold the accelerator to floor
• engine will stop when battery is fully charged

Warning: charging NiMH batteries is exothermic. Force charging can 'heat pump' the traction battery up 7-9 C over ambient.

In some of the threads in Prius Technical Stuff around 2005-6, there was a report that externally charging the traction battery would not 'register' with the battery ECU. But trying to charge from the power line connecting the battery and inverter would 'throw a code.' But then how does the battery ECU know the SOC when the car first starts.

As a suggestion, charge the car to whatever level you feel comfortable and then restart the car. The battery ECU should go through a power-on, restart and use whatever voltage it finds as the initial SOC . . . just a thought.

Bob Wilson

 

Usually, the Classic SOC gauge will either show 75%, which is what your picture is showing, or else 50%. If it shows any other reading that may be a sign that the traction battery is having a problem.

When the original battery on my 2001 died, the gauge moved up and down from totally full (including the +/-) down to totally empty.

<Of course, totally full on the gauge actually means ~80% charge while totally empty actually means ~40% charge.>

 

This evening I did a forced charge:


Bob Wilson

 

This morning the display showed full and the Graham miniscanner reported 77% SOC and 298V DC. What this suggests is SOC is not voltage driven after sitting over night but rather 'columb counting.' This matches some of the earlier reports in 'Prius Technical Stuff.'

Do you have a scangauge, Auto Enginuity or something to read out what the battery ECU reports as the SOC?

A second test, I'll try tonight, is to force charge to a high value and then Saturday morning, disconnect the 12 V battery. This may force the battery ECU to recalibrate the SOC instead of just using the last stored value.

Bob Wilson

 

Just thought I'd add my 2 cents here.. I did on one occasion see the full mark (into the + - area) but that was when the Prius was just a standard prius.. Ironically, after adding the Enginer kit, I never saw it higher than the 75% mark, even though I could drive for miles and miles on EV. So I'm not sure what magic has to happen for the computer to show a full battery, but I don't think it happens very often.

 

Our 03' prius always says 75%, maybe once in a blue moon it would go down to 50% but that was going up very long hills. Please remember that force charging the battery will cause heat to buildup in the cells, and that's the enemy especially with practically an original battery pack! Now with your additional batteries in parallel it will just stay at 75% under much heavier loads ie; going up a 50 mile hill , etc... I wouldn't try to force it to be 100%. That's just too high for gen1, but consider that the display has huge histeresis and like Patrick said above 100% is really 80+% actual, but it could get too high and damage the cells. Monitor soc with a scanguageII it works good for this full time, and I hardly even look at that screen anymore. just my 2c and good luck.