Anybody with a Kia Optima or Sonata? - Fuel Economy, Hypermiling, EcoModding News and Forum

atikovi · 10-01-2019, 09:14 PM

Just wondering if there is a way to increase the level of HV battery charge on the gauge. I know light throttle and extended regen but cant seem to even get it 3/4 full. Any way to briefly shut off assist for example?

mpg_numbers_guy · 10-01-2019, 10:20 PM

Why do you want to increase the battery SOC? Typically most newer hybrids have a SOC goal they try to keep the battery charge at. For example, the Gen 2 Prius keeps the battery at around a 62% charge - any more and it uses the battery more, and any less it charges more. This is to help maximize the life of the battery and prevent early failures like were common on those early Honda hybrids we're both familiar with.

atikovi · 10-01-2019, 10:29 PM

I can get the battery gauge to full on my Insights pretty easily so there is more juice stored up when I need it. Want to see the same on the Optima, if for no other reason than a photo op.

mpg_numbers_guy · 10-01-2019, 10:38 PM

The Insight is a different animal compared to the more modern hybrids. Full SOC on the Insight isn't actual full charge. The Insight also allows such a wide variance in charge, from empty to full (20%-80% actual SOC IIRC) that the batteries fail sooner. Newer hybrids try to maintain a specific SOC, usually between 50% and 80%, for best battery life. Going down a steep hill and braking will get the battery SOC up higher, but it isn't great for battery longevity if done often. Remember that having a higher charge does not mean more efficient driving. Since we're talking about a regular hybrid versus a plug-in hybrid, all charge must ultimately come from burning gas.

S Keith · 10-02-2019, 02:18 AM

You don't want what you think you want. Apples and oranges with different SoC behavior by design.

G1 Insight = NiMH with a tendency to seek higher SoC with 10 voltage monitoring points. NiMH has some limited tendency to "balance" north of 70% SoC.

Optima/Sonata use pouch-type LiPo. They swell rapidly at higher SoC. Car holds them closer to 50% SoC in most cases and monitors each of the 72 cells. The battery BMS has limited battery balance capability but does so all the time.

atikovi · 10-02-2019, 08:14 AM

OK, I was expecting to be able to see the gauge at full even if the software fakes the actual state of charge. I know on some cars like Ford, the oil pressure gauge always reads the same, faking it, unless the pressure is critically low.

S Keith · 10-02-2019, 09:49 AM

Quote:

Originally Posted by atikovi

OK, I was expecting to be able to see the gauge at full even if the software fakes the actual state of charge. I know on some cars like Ford, the oil pressure gauge always reads the same, faking it, unless the pressure is critically low.

You were expecting a completely different technology to behave like one developed a decade prior. Their hybrid systems are completely different, and they have completely different battery chemistry.

Prius battery gauge almost always shows 6 blue bars of charge. You won't get the top 8th bar unless you're on a long downhill, or your battery is very weak and the usable capacity causes it to fill more rapidly than is normal.

Honda IMA is a slap-on low-tech hybrid system using D cells. It's unique in its construction, performance and behavior. Hondas behave like Hondas and most other cars behave differently, but similar to each other with the default SoC somewhere in the 50-60% range.