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battery use when accelerating

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Old 12-04-14, 06:30 PM
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gianttama
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Default battery use when accelerating

Newbie hybrid owner here, bought a used 13 rxh few months ago. I've been paying attention to the engine/battery diagram on the dash lately, I realized that when I accelerate from a stop, it doesn't really use battery power to help accelerating and give the instant kick in power.

It uses battery(battery only) when I'm really really light footed. Or if I switch to sport mode and really step on gas I'll feel the power. However, when I'm in eco/normal, I find acceleration uninspiring. I understand it is a heavy vehicle but I also thought it would use battery to help with accelerating and give me the instant power feeling.

I'm in Vancouver Canada and it's been cold these few days, not sure if it matters. Looking for your veteran input.

Thanks
Old 12-05-14, 10:29 AM
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Droid13
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It depends on a lot of things, so many variables are being considered at any moment. But just some of my own insights:
  • It is not a priority to use the battery as much as possible all the time. Doing so will shorten the battery life and reduce the ability of getting a vehicle lifetime of use.
  • If you floor it, you'll likely see the battery being used most of the time under full acceleration, if the battery charge is in good shape.
  • Outside temperature makes a big difference on how much battery is willing to be used. Mild summer days you can actually get away with a lot of electric acceleration and cruising if you have the patience. Really cold days, forget it, at least until the system is very well warmed up.
  • After starting, there is a short period of increased tendency to use the battery on acceleration. I think this is the system giving a bit of a break to the cold engine.
  • With moderate acceleration, it can go either way. It's a balance of when is it going to be most efficient to use that (up to) 50HP of battery charge vs what is it going to cost later to recharge it vs how efficiently the engine is operating right at the exact moment with speed and engine load. It might just as well decide it's the best time to recharge the battery vs using it. All that while trying not to over stress the battery with too much usage.

Regarding the "feel" of the acceleration... The RXh always feels like a gentle giant. It never lurches away from a stop and the early part of the gas pedal position is easy going (especially in ECO mode) and power comes later with more pedal travel. If you restricted this vehicle to only being able to push the pedal down 1/4 of the way, it would very often be slower than lesser cars with the same restriction. Change the restriction to 3/4 and it goes the other way easily.

Like it or not,
Smooth is what you got.
If you like to get jerked, and who doesn't once in a while,
Climb aboard a dragster, for a 1/4 mile.
Old 12-05-14, 01:57 PM
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RXSF
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the instant torque that is advertised as part of electric drivetrains is really muted by the weight of the vehicle and by the Atkinson cycle engine which reduces torque numbers in favor of mpg numbers. From a standstill and under normal driving behavior (not hypermiling), the battery will always be working together with the engine and only acts as a slight booster, nothing dramatic. The hybrid powertrain in the RX is really meant to maintain speed after using the engine to get to your desired speed.
Old 12-05-14, 02:56 PM
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gianttama
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Thank you both. Before i got the rxh, I often saw cab drivers launching off with their prius and I was like is that really a hybrid?

But now it makes sense, different vehicle and I didn't get the rxh for that purpose neither.
Old 12-05-14, 06:44 PM
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Andy, you gave an excellent analogy of the RX450h. I especially liked "so many variables are being considered at any moment" . I named him Watson because of all his 'Geeky' computer processing while rolling down the road.
Originally Posted by Droid13
It depends on a lot of things, so many variables are being considered at any moment. But just some of my own insights:
  • It is not a priority to use the battery as much as possible all the time. Doing so will shorten the battery life and reduce the ability of getting a vehicle lifetime of use.
  • If you floor it, you'll likely see the battery being used most of the time under full acceleration, if the battery charge is in good shape.
  • Outside temperature makes a big difference on how much battery is willing to be used. Mild summer days you can actually get away with a lot of electric acceleration and cruising if you have the patience. Really cold days, forget it, at least until the system is very well warmed up.
  • After starting, there is a short period of increased tendency to use the battery on acceleration. I think this is the system giving a bit of a break to the cold engine.
  • With moderate acceleration, it can go either way. It's a balance of when is it going to be most efficient to use that (up to) 50HP of battery charge vs what is it going to cost later to recharge it vs how efficiently the engine is operating right at the exact moment with speed and engine load. It might just as well decide it's the best time to recharge the battery vs using it. All that while trying not to over stress the battery with too much usage.

Regarding the "feel" of the acceleration... The RXh always feels like a gentle giant. It never lurches away from a stop and the early part of the gas pedal position is easy going (especially in ECO mode) and power comes later with more pedal travel. If you restricted this vehicle to only being able to push the pedal down 1/4 of the way, it would very often be slower than lesser cars with the same restriction. Change the restriction to 3/4 and it goes the other way easily.

Like it or not,
Smooth is what you got.
If you like to get jerked, and who doesn't once in a while,
Climb aboard a dragster, for a 1/4 mile.
Old 02-06-15, 02:35 PM
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COPAPILOT
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The battery as all batteries does not function well until the car interior warms up well or the battery warms up from charging. You will not only notice a difference in the way the battery/motors work when the weather warms but also a large increase in gas mileage. I was getting 32 mpg in August but only 27 mpg now. I also noticed that when I was driving thru the mountains and allowing the vehicle to drift down hills I was getting better mileage than on the level ground. You should notice that around Vancouver. The motor will kick in on the uphill runs drawing from the battery and then the motors will recharge the battery when you drift down the hills. I found that when approaching the bottom of the hill the best course is to start applying power to help you up the next hill without using a lot of gas. If you try to keep the power meter at or below "ECO" you will get the best mileage.
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