Whenever I'm PnG'ing in a hybrid (prius v) at low-ish speeds, like 30mph or less, I've noticed that the Traction battery charge tends to drop with each cycle. I can't find anyone mention this in other posts or forums, so I'm not entirely sure if what I'm experiencing is normal or not. On a good glide to a light, I don't regen much, so the SoC keeps getting lower. Sometimes I make it to my destination or highway by the end of it so it doesn't matter, but other times the light might be red for so long that the engine starts up for recharge, and I'd rather avoid that. So, 1) I wanted to check if this is a fairly normal experience, or I'm actually using too much electrics somewhere in the pulse or glide. 2) Should I be doing anything to try to keep the charge up before reaching the light? My two options are just regen braking harder like I'd think Toyota's engineers were expecting the average person to be doing, or keeping the engine on longer. Of course I could also just let the engine recharge while waiting, though I'm not sure if that's more efficient than charging while moving. Haven't gotten a chance to check what RPM and load the engine is on while idling yet, will be doing that as soon as I get stuck at another long light. (Hold brake + gas to increase load???)
If I recall correctly, and I sometimes do, my 2015 Prius would occasionally lose some charge , even though I was careful to not lean on the battery during a glide. When that happened , I would make sure I run the engine more often. Or use more brakes , which means more gas , which goes against my nature. The Elantra can go pretty far on the battery, but the same thing applies. Whatever you take out needs to be replaced.
Thanks for letting me know it's not a unique case. Yeah I'm looking to figure out what the engine is doing during stationary recharge to make a rough guess on whether it's in a more efficient state than running the engine more during movement, since I figure brake regen energy still ultimately comes from gas anyways.
If anyone is curious, the engine recharge state is about 1200 RPM, and about 65% load, which is pretty similar to the warm-up stage. Strangely, pressing down the gas drops to 1100 RPM and 70% load, probably not worth doing. It's not hard to beat 65% load while moving, I'd think. The slightly more baffling engine state is if the engine is recharging while coasting, it seems to sit at 1K, 30% load. You'd think it would either crank up the load to be similar to warm-up or cut the fuel.
On a related note, does anyone know if there's an engine state that charges the battery faster, or are we at the mercy of whatever the ECU feels like at the moment?
Might be worth adding/monitoring what happens to your instantaneous MPG (and therefore average) when the recharging occurs while coasting vs sitting. Gut says lower load while coasting is still better than high load while sitting still. Unless the battery is in bad shape, I'd let the engineered design take care of itself. All of the above without data.
I agree, though there's not much choice in the matter if the car wants to recharge. If the light is red, then you have to charge while stationary. I ask because I've seen many posts about pulse and glide over the years, about using 0 electricity overall, and being a bit baffled when my own attempts has the battery dropping lower and lower until it just turns on the engine. Ironically it feels like just keeping the engine on longer at lower power keeps the charge up for when I can't move very fast, which feels a bit like using a hybrid wrong? There's less energy lost from restarting the engine constantly I guess. The inst MPG at least looks ok at 35 mph steady, and backing off on the throttle as much as i can without the electrics kicking in.
The red light scenario does pose a problem. Thoughts going through my mind. - If the engine fired up just before reaching the red light, the engine should shut down fairly quickly. - If the engine starts after reaching the red light, I would wonder why. There was some regen getting to the stop, and mainly 12V power drain from brake lights. HVAC off I presume. If the 12V battery is weak, then the HV battery would be used to recharge it. That would drain the small HV battery more quickly. How's the 12V battery state of health? A weak 12V battery would thus cause more engine starts in general to recharge the HV battery. The traffic lights I have encountered have not been that long. If I just miss a light and have a full cycle of waiting to do, it's never more than a minute or so. I suspect this is atypical elsewhere. It's been a long time since I've driven a straight hybrid and I have never been in an older one, so my ability to draw on my own experiences is very limited.
I'm pretty sure it's not the 12V draining the traction battery, though admittedly it is quite old now. During regular steady state cruising, the MPG is still about as good as initially bought. To clarify, it's just that the traction battery doesn't seem to charge very quickly at 30-40 mph, and the glide portion uses more electricity than the pulse portion. Also, the section of road I have the most trouble with is essentially two, 6-way intersections, so missing the light results in a painfully slow cycle, which gets even worse if the traffic backed up. Since I'm trying to avoid unnecessary regen, I'm lifting early and not regening much if at all until below 20 mph, which doesn't result in much electricity stored. I have figured out an alternate route that has a bit more if shorter lights to avoid it now.
To me , "glide" means you are using NO POWER. You have a gauge that shows whether you are drawing power from the battery or adding to it. A "proper" glide should not be using any power. I know it was tempting to try to extend a glide in my Prius with battery, but that will reduce state of charge very quickly. I hope this helps.
That's fair, I've often been using about 1 tick of EV since I've heard a little bit of use is better than a little bit of regen, and also Ken from Japan's notes from other prius drivers. I will try backing off more to see if the battery charge gets better in any case.
