Battery percentage

[MeeLee]

Can the average battery charge percentage be modified from 50% to 66%?

I live in pancake flat Florida, and my regen is at most off of a bridge going 50mph.

I'd much prefer to have more energy to coast on the motor, as at 45mph the engine fires up every minute or so...

 

Also, with batteries having 500 charge cycles, 

How long does the hybrid's battery last?

[Waldo]

Every time you regen and every time you run on electric power, you are wasting energy in the conversion.  It is more efficient for the engine to fire up every once in a while than to try to capture more regen energy.  The efficiency curve of the regen varies with battery state of charge, the more full the battery is, the less efficient the regen is.  That's why you don't want to be running around with a nearly full battery all the time.  Working in the middle of the battery's range also helps preserve it's life.  It will last longer than the rest of the car if you let it operate as it was designed from the factory.

[VonoreTn]

What kind of mpg are you getting?  What year FFH?  Nickle-metal hydride battery or lithium?  How many miles on it?  I agree with Waldo.  Mine is still running fine at 160K miles, going on 12 years old.

[MeeLee]

2019, i'm at 46.5MPG nowadays (bought it at 30k miles and added roughly 6k miles to it).

 

Pulse and glide is the key to good mpg. But pulse and glide requires the battery to be charged fuller. Regen barely fills <5% of the battery, if I had to put a number to it. And that's in a mostly start-stop scenario.

Increasing charge, should increase electric range, which I often could be cruising 3 to 5 minutes straight at 35-55mph over here, and could really use at least 2 more minutes of electric range.

[Waldo]

Pulse and glide has nothing to do with battery "fullness" or regen.  Pulse and glide is the idea of using the gas engine in it's most efficient mode - ie at it's peak BSFC points.  The whole point of a hybrid is to allow the gas engine to operate at it's peak BSFC point much more frequently, which essentially means the hybrid system is doing the pulse and glide for you.

 

Let's say you're cruising steadily at 40mph for 20 minutes.  You could run the gas engine for 2 minutes, let it fill the battery and then run on electric power for 8 minutes, then repeat once.  Or you could run the gas engine for 30 seconds, charge up some of the battery, then run on electric power for 4.5 minutes, then repeat 3 more times.  Theoretically both would use exactly the same amount of gas.  But actually since the energy used to charge the battery is not linear (charging when it's more full requires more energy), it's actually more efficient to do the 30 second / 4.5 minute scenario.  In fact it would probably be even more efficient to do 15 second/2.25 minute scenarios, but at some point the engine going on and off too frequently just annoys people.

[MeeLee]

No, it's more efficient to keep the battery charged longer. The engine doesn't run efficiently when start stopping frequently, because it cools down enough to lower efficiency.

It takes roughly 5 minutes at 70+ mph, before the engine is hot enough, and runs at optimal temperatures. That's with every engine BTW...

 

Pulse and glide is a proven procedure for extending range, and is entirely off topic (besides the point). Accelerate on the engine at ~3 (~3k rpm on the odd tach, which isn't really a tach), and glide using 0.6-1 on the ev mode (~6-10 HP for 40-45mph, or 1.2-1.5 for 50-55mph).

But if you had read my posts, the hybrid system does NOT do it all for you!

There are many times when the engine remains on, running for 0.9 to 1.4 (I presume k RPM) on the tach, and remains there (doesn't switch to ev mode). Usually when speed is low, and the pedal is held steady.

Other times it will switch between the two, but not efficiently. I accelerate, engine stays on charging too long cruising, red light and brake.

During the entire ride between stop lights, the car consumed 20-25 mpg.

Instead, the driver can manipulate it, and make it more effective. 

Accelerate, then manually turn off the engine by forcing on the ev mode for cruising.

[Waldo]

On 5/5/2021 at 1:56 PM, MeeLee said:

No, it's more efficient to keep the battery charged longer. The engine doesn't run efficiently when start stopping frequently, because it cools down enough to lower efficiency.

 

 

Where are you coming up with this?  You're suggesting that turning off the engine for longer periods of time will allow it to stay hotter?  Once the engine is up to temperature, it pretty much stays there.  That's what the thermostat is for.  Again, remember that the energy required to charge a battery is not linear.  It takes much more energy to charge the battery the last bit than it does to charge it in the middle bit.  That's why it's most efficient to operate the battery in the middle of it's range.

[MeeLee]

On 5/6/2021 at 4:14 PM, Waldo said:

 

Where are you coming up with this?  You're suggesting that turning off the engine for longer periods of time will allow it to stay hotter?  Once the engine is up to temperature, it pretty much stays there.  That's what the thermostat is for.  Again, remember that the energy required to charge a battery is not linear.  It takes much more energy to charge the battery the last bit than it does to charge it in the middle bit.  That's why it's most efficient to operate the battery in the middle of it's range.

No, it takes more energy to start stop the engine. So reducing this is automatically a better thing to do. (not to mention the engine wear is higher too).

Also, it is my understanding that the batteries aren't charged to 50%. 

Part of the pack is fully charged, and part is totally depleted, with only part being ~33-66% filled.

Third, it doesn't take more energy to charge a 80% battery to 90%, as it would a 10% battery to 20%.
The charging process runs more efficiently at high currents, but the latter percent (80-100%) of a battery charge works just as well through slow charging; which can easily happen on longer highway rides.