disable battery regeneration

I am unclear what you are attempting. Regeneration happens when braking, if you do not hit the brakes, no regen.

You can easily defeat any charging of the HV Battery by shifting to Neutral.

 

I can't speak to Gen 3, but on Gen 2, there is a bit of regen (no more than 19 amps or so, as I posted before at Best way to brake / decelerate? | Page 2 | PriusChat) if not using the brakes and going above say 35 mph. But yeah, there should be no regen if shifting to neutral.

 

In my understanding, OP means change the target SOC (60%) to 30%.
I think lower than 40% SOC is not good for the battery, but I have no idea to do that.

Ken@Japan

 

On Gen 2, via ScanGauge, even when climbing steep hills at highway speeds, I recall it's rare that SoC (as indicated by SG) drops below 40%.

 

Shifting to neutral while going uphill is probably a losing strategy. Trying to outguess the firmware generally results in lower mileage.

 

About the only thing you can do is, if you're going uphill at 45 mph or less, coast briefly to let the engine shut off, then use a light touch on the gas pedal, keeping the HSI below the halfway point, to use some electric power with the engine off. If you're at 25 mph or less, you can use EV mode - in general, keep it out of the PWR range and it'll stay in EV. At normal highway speeds, you can't do anything.

In either case, don't try it before you are within spitting distance of the top - otherwise, the car will work extra-hard to recharge the battery while you continue to drive uphill. Any time the engine is running, it'll generally work its way towards a 60% SoC, since that provides a good balance between having power available for EV and having capacity available for regen.

Of course, doing this won't buy you much more economy, and it might cause some extra wear on your battery. But there's really no way to get what you want.

Now with the plug-in, you can effectively do exactly this - drive uphill in EV or HV modes, draining electricity as you go. Eventually it'll stabilize with about as much remaining energy as the liftback has at 60% SoC (so maybe 1/15th or so the total capacity), since that's where the computer wants to be for HV mode. And then you can regen the whole way down the mountain, getting more EV range back.

 

Hi macman408

This is just to confirm what you say.

I made a graph with more than 19,000 ELM327 readings of of Hybrid Batt Amps Vs Batt SoC while the ICE is injecting fuel. They are taken on my actual driving, 50% of them are urban and 50% are slow highway. That is reason that the most common points are about 52% SoC.

The red line of the graph (average curve) tells that the target SoC is 60% as you said. At 60% SoC, the average charging current of the battery while the ICE is injecting fuel is zero.


Big hugs from Frank

 

there is no posibility of soc spoofing in prius 2010. in prius 2G, there is a Battery ecu, that sends to hv ecu the soc, and you can spoof thas message via canbus. But in prius 3G, there is no battery ecu, there is a smart battery ecu that sends temps and volts of hv battery to hv ecu (via serial data link, no canbus), and is the hv ecu that calculates soc. So in prius 2G there are posibility of change target soc, but not on 3G prius...

 

Buy a PIP, then you can do this.

 

I'd have thought the best you could do would be to keep it just in the power zone. The car may want to provide some assist from the battery so it should, if anything, lower the SoC.

Also, make sure you're not in power mode since that causes the car to raise the target SoC.

 

Yes, you would save some on gas, but increase wear and tear on the battery by forcing deep cycling.

Incidentally, I personally get the best MPG when I use batteries the least.

 

If its a small ascent, just use EV, that = 100 mpg + On the down hill portion go back to HV and recharge battery. Save the battery for these type of situations.

 

This won't work for OP. The long mountainous ascents in that area are on roads with minimum legal highway speeds greater than the non-PIP's maximum EV speed. And the climbs exceed not only the EV battery capacity, but even the PIP's capacity as well.

 

Sorry, I have PIP on the brain.