Got a prius, should be interesting to mess with....

[MetroMPG]

I can sympathize with the 12v battery woes. Even after I replaced mine, it seemed unusually easy to discharge it too far.



As for intentionally using the hybrid battery to propel the car, I avoided that like the plague. Too much charging inefficiency. The only case I could think of where it made sense to use battery power is if there was a significant regen event ahead to regenerate the spent power. Like a hill descent.


Get that EV mode/kill switch in there! You'll wonder why you waited so long.

[ps2fixer]

I've been busy with my business, sales are up like 2-3 times what I'm used to so not a whole lot of free time. Growing pains I guess you could say, it's all good stuff and it comes in waves, just the wave's haven't spaced far enough apart for me to catch up lol.

EV mode will be interesting to play with, couple areas I can see possible benefits

Cold start, I have 1/4 mile to drive 10-20mph, battery can easily handly it and it seems to not use the engine at all but it's there idling trying to warm up.

In cruise I should be able to switch to EV mode below the max threshold and run off the battery until it forces the engine back on. When the engine on charging it's showing around 45-50mpg, it's loading the engine more so I suspect it's pushing it into the better efficiency range for load and rpm so there might be a slight gain but testing would be needed. The other factor is the slight up hills I deal with kicks it out of EV mode, so of my understanding, using the EV mode button will allow me more pedal/electric output use so it should start/stop the engine less often. This is when I drive 40mph or less. I'm thinking larger tires for winter will be real interesting to compare things since I'd like to push the max speed for EV to around 45mph.

If you look at the chart for speed vs mpg, the range it can use EV mode the MPG jumps up quite a lot, so in steady speed driving, it's completely fine to be in EV mode as long as the recharge cycle of it is done at low speeds. Higher speeds it might eat up more fuel than it gave for a benefit. Cold vs warm engine is another factor, so lots of variables to play around with for different situations.

I want to poke around the 12v system a bit and see what draws the most power. It has an aftermarket radio that I basically always have off, so don't really need memory power for that. Clock is nice, and the main engine computer's memory. Anything else I'm not super worried about when the car is "off" and at my house.

Anyway, got a trip to go on, helping my dad get a Mill machine. Going to have access to a metal shop eventually =).

[Piotrsko]

You may want to search for the typical minimum battery draw. For example according to Ford, the typical draw on my F250 for "keep alive" is 100 to 250 ma. For me that is the target, so maybe every 9 months I consider either starting it or boosting the batteries

[MetroMPG]

Originally Posted by ps2fixer

I've been busy with my business, sales are up like 2-3 times what I'm used to so not a whole lot of free time. Growing pains I guess you could say, it's all good stuff and it comes in waves, just the wave's haven't spaced far enough apart for me to catch up lol.

Nice problem to have, I guess!


What's the business, if you don't mind saying? (I'm guessing related to your username?)

[ps2fixer]

Originally Posted by Piotrsko

You may want to search for the typical minimum battery draw. For example according to Ford, the typical draw on my F250 for "keep alive" is 100 to 250 ma. For me that is the target, so maybe every 9 months I consider either starting it or boosting the batteries

120ma is pretty low for car standards, but the thing is the battery is small in them compared to most other vehicles. The F250 battery is quite large, probably like an 80ah one, so 200ma draw would take around 17 days to draw the battery really low. If it's a diesel and has 2 batteries, you can double that figure. Generally it's best to start a vehicle that's sitting every 1-2 weeks or monthly for worst case. If the battery goes under around 12v there's physical damage happening to the battery that isn't reversible.

Originally Posted by MetroMPG

Nice problem to have, I guess!


What's the business, if you don't mind saying? (I'm guessing related to your username?)

https://www.facebook.com/groups/derbyws

That's my facebook group. I've only been in the market for around 7 months at this point, but derby season kicked up since it got warm out and haven't had too much of a break to do much of anything else. I'm sure it will die down since the orders come in waves. I also make atv parts and sell them on ebay, pig tails, adapters, small harnesses, etc.

I guess my business is about the exact opposite of what ecomodder is about lol.




I played around a little more with the car, nothing too specal, 8 mile trip night time and no traffic, went 35mph and tried to get it to cycle the gas/ev mode. It seemed to do really well but once the engine got warmed up fully it didn't want to turn the engine off any more. Maybe I wasn't in the "normal" mode yet since I didn't come to a complete stop for 5 secs. The mpg wasn't out of this world or anything for such a slow speed, got home with 55mpg on the scan gauge and state of charge slightly higher than what I started with. I also messed around with a little pulse and glide, 30mph to 40mph. It did well then right before my corner it refused to turn the engine off so it ran the whole distance to my house for the last 1/4 mile. If it ran off battery only it would probably have indicated closer to 60mpg but have a lower SOC for the hybrid than what it started with.

Too bad the hybrid battery didn't have enough capacity to get to the post office and back, about 10 miles. Around 50% or so of my trips or so could be done on pure electric if that was the case, then converting to a plug in hybrid might be worth it at that point and then the EV mode would make sense to eat up battery instead of fuel on the lest little bit before my house on longer trips.

[hayden55]

You should quit using EV mode and see if your mpg goes up. I noticed mine did when I stopped using EV mode. We aren't grid charging so that's not really how these cars work. EV mode is also very hard on the battery compared to png.

[ps2fixer]

Originally Posted by hayden55

You should quit using EV mode and see if your mpg goes up. I noticed mine did when I stopped using EV mode. We aren't grid charging so that's not really how these cars work. EV mode is also very hard on the battery compared to png.

I've been driving as little as possible with out using the battery, I noticed a jump up in mpg when using EV mode and SOC for the hybrid battery was about the same as when I left (within 1%).

Pulse and glide isn't always an option, the hybrid battery is a electronic way that's probably less efficient version of doing pulse and glide.

Toyota knew what they were doing on these batteries, I haven't done the research myself, but I've read that NiMh batteries kept in the range that Toyota does makes them last for just about forever. Something like 40-60% charge is ideal. Lowest I've had mine so far is 49% and highest has been around 65%. I mean most batteries last 10 years or less, this car is 16 years old, so I'd say the battery has served it's life well. Internal resistance might be higher, not sure, but the capacity seems alright.

This is the chart I've been referencing. Notice the huge bump up right at 41mph? That's the point where it can do the automatic electronic version of pulse and glide.

My numbers aren't nearly as high as those, but I'm not running in ideal conditions on flat ground with no wind either.

Basically some of the driving I do I can do 45mph and at times I can drop down to 40mph, so I'm experimenting with the EV mode stuff. I've done a few trips at steady speed 40mph and it doesn't seem like anything special until the engine warms up enough to kick off and it does a "pulse and glide" cycle and by the time the battery is charged back up, it brought up the average pretty well. I could coach it into keeping the engine on, but based on that chart, it would be lowing my average mpg. I'm pretty much just wanting to try to get longer glides since my typical trip the car is ready for a 2nd glide, but it's more hilly and it doesn't like to go back to ev mode. If I could get it to go a bit farther on battery, then charge up for say an extra mile, it would be about perfect for my trips.

The stage 4 or whatever state for "normal operation" requiring a full stop for 5 secs is kind of dumb, would be nice to be able to spoof that. I suspect that might be part of why the car acts a bit goofy, I have only one stop in each direction for the trips, and the first time it's too cold to be in normal mode, and the 2nd one it's all fields so I treat it more like a yield sign and roll through if it's clear.

I probably should setup a cam on the car screen and scangauge for one of these trips and see where I'm doing things wrong besides longer coasting (I brake about 25mph and typically do a little coast down regen at 35mph that's probably where I can improve) and the potential for pulse and glide or driving slower.

Not real long ago, I was in a rush and drove 55mph and was taking off more around 2300-2400 rpm and the overall trip ended up being around 50mpg for a longer trip. I didn't coast much and wasn't taking off as ideally I don't think. If I drove 45mph in the sections I could, I probably would have hit 55-57mpg. for the trip. I know coasting is better than regen, but it seems like overall it's a pretty small effect, that or the way I coast down and let off the gas fully at around 35mph to slow down faster is doing the same thing as effectively flying up to the corner and slamming the brakes on. I'm still learning the distances for coasting. I've actually been wanting to play around with that a little for testing, like "normal stop" vs coast a ways then slow down with gas pedal off completely, and regen only at the end with brakes. About the only way I can think of testing the different patterns of stopping like that is to coast from the same spot at the same speed. More I think about it, the more I think it doesn't matter too much when the braking happens as long as the friction brakes are used as little as possible. The starting point of the coast is probably the main factor.

[ps2fixer]

Quick update, I've been running around a lot more lately than normal. Anyway, messed around a tiny bit with coasting and it seems like costing to the stop sign and lightly hitting the brakes to make it regen gives the same energy back so if someone is behind me, I can coast for a ways and regen only when to the sign to be less annoying to others.

Too bad the gas pedal didn't have any regen, like you let off the pedal and it's coast mode. I'll have to pop up the TPS display and see if there's a consistent value that works.

I think it would be neat to mess around with the accelerator pedal signal a bit. It should be possible to make no touching the gas pedal at all be coast (no regen), and should be able to adjust the pedal to be more logarithmic like the blue line in the chart below. Say coast mode is at 5%, adjust the signal so 0% = 5%, say 40% is where the engine runs at the 2k rpm, make that more like 60% throttle and above 60% ramp up quickly from the 40% output to 100%. Basically it would give finer control over cruise locations for the pedal, but if I wanted to floor it, I could still. Just thinking out loud. Of course being able to control the throttle would also mean I could build my own cruise.

Anyway, I finally got around to swapping the tail light out, yay for all lights working now, no risk of a fix-it ticket.

[Drifter]

I suspect, but don't know, that regen efficiency will vary depending on regen rate and battery state of charge. I've read that this is the case for motor output so I assume it is the same in reverse...


As for throttle, on my gen 3 there is no 1 pedal position that coasts. Above ~10mph with the accelerator pedal off, the generator regens slightly to mimic an automatic transmission's drag. From ~5mph to 10mph, zero pedal coasts. Below around 5mph, zero pedal actually applies a little bit of power to creep forward (again like a normal automatic).

[ps2fixer]

For the little amount of throttle input to get it in to coast mode, I suspect wouldn't be much of a difference for the creep speed at basically stopped speeds. Assuming it's smart enough to stop the creep current when the brakes are applied harder, I don't think it would be too much of a down side. Would be less wiring involved which would be a lot nicer to hook up.

I guess the TPS is kind of a bad indication since the pedal isn't hooked to the engine directly. Not sure if there's a read out for the pedal input. I might have to pull my scope out again and record the voltage for coast. Over 41mph is a little hard to tell when it's costing since the on screen display still shows power flow. If I remember right, arrows pointing to the engine from battery is roughly the point that it's in coast mode. I guess it's using battery power to keep the engine spinning to keep the rpm's in check. I wonder what's different between that and neutral coasting.