[2021 Insight Jim]

New 2021 Silver Touring here that will never win a high MPG mark. I live at the top a hill. I have two choices - a long more gradual climb or a short steep grind. Long = 11 miles Short = less than 5 miles. Rough graphs attached. Am I better off going the long way or the short way? I will probably always go the short way down but will never make up for the climb I plan to make a circuit both ways and compare my MPG for the trip but you guys are a lot smarter than I am so I am seeking advice/opinions..

 

[insightfully]

New 2021 Silver Touring here that will never win a high MPG mark. I live at the top a hill. I have two choices - a long more gradual climb or a short steep grind. Long = 11 miles Short = less than 5 miles. Rough graphs attached. Am I better off going the long way or the short way? I will probably always go the short way down but will never make up for the climb I plan to make a circuit both ways and compare my MPG for the trip but you guys are a lot smarter than I am so I am seeking advice/opinions..

Welcome to the forum. For an apples-to-apples comparison of the circuit trials, try to start at the same HV battery level and outdoor temperature conditions. Neither climb scenario looks great, as both exceed mpg support even max HV battery level can provide.

My guess (?) is that your short drive will yield the better result. The short drive looks to have a steady incline and even some minor 'rolling downhill' periods. The long drive has even more rolling terrain but is offset by some super-steep (almost vertical?) periods of climb.

I have a hill in my daily drive, but it's a shorter distance (~3 miles) and less steep (500 ft). Some of the different things I've tried and compared on different drives: 1) pre-building HV charge with Sport mode, 2) Sport vs Eco mode for the climb, 3) slow/steady vs fast/get-the-hill-over-with speed for the climb. For my conditions, pre-building charge with Sport mode and tackling the hill in Eco mode at moderate speed have delivered the best mpg I can muster for the climb (45 mpg).

My worst result was fast speed and Sport mode to climb the hill (25 mpg). The engine drone was reduced, but the throttle was so responsive and consumed gas (to charge battery and power the wheels) in a way that didn't balance/offset the net output. This might be better/different for you, as your hill travel is over longer distance. Colder weather/temps would also hurt my uphill mpg results further, as it seems to affect the HV battery charge/discharge cycle.

I try to maximize building charge on the downslope to offset the uphill hurt (e.g. consume HV battery before hill crests, max regen on downslope, go easy on the throttle after hill ends to keep car in EV mode). My best ever was 92.6 mpg from the downslope to my destination - with help from early-summer temps, well-timed coasting/acceleration, and ~5 miles of EV distance after the hill. More typically, I aim for 65+ mpg on the downslope to offset the 45 mpg hurt for the climb, and net 50-60 mpg overall for the same drive across the seasons.

 

[CmpeGeek]

I'm basing this off of your charts where the most important values are the average slope over the distance traveled. Your long chart claims an average slope of 5.9% while your short chart claims an average slope of 8%. If I'm to assume those are accurate, the physics works out to you expending almost twice the energy on the longer route because the angle between the two slopes really isn't that far apart.

The math favors the shorter route all things being equal...but in reality, they aren't, because the energy used going uphill is not going to be equal to the energy regained going downhill and since both routes have some varying degree of inclines it makes it harder to calculate. As Insightfully just stated, the short route seems to favor fewer changes in incline anyway (on top of the math).

Your best bet is to just favor one route for a month check your average MPG, then try the other route for a month check that MPG, and see what's better. And if you really want to be thorough, do one month where you go up one way and down the other and vice versa. Hopefully, any additional driving you do that's not on these routes won't affect the results too much. Experimentation and time will be the ultimate teacher.

 

[Jet'ro]

I'm not knowledgeable enough yet to provide any useful information, but I'd like to know how you got elevation maps for your route. Is that Google Earth?

 

[insightfully]

I'm not knowledgeable enough yet to provide any useful information, but I'd like to know how you got elevation maps for your route. Is that Google Earth?

It looks like it might have come from Google Earth Pro, as the colors and axis labels match image @pasei shared in Terrain Mapping for Best MPG Route thread. I use plain old online Google Maps, which is more basic/directional but does the job.

 

[Jet'ro]

I agree with the points made by insightfully and CmpeGeek. I'll be looking forward to your results.

It looks like it might have come from Google Earth Pro, as the colors and axis labels match image @pasei shared in Terrain Mapping for Best MPG Route thread. I use plain old online Google Maps, which is more basic/directional but does the job.

You're right, looks like a match. I've tried Google Maps, but I could only get elevation for the route if I used cycling or walking. Of course, that is a problem for highway use, but I could estimate it to some degree using side access roads and what not. I'll give Earth a try.

 

[insightfully]

You're right, looks like a match. I've tried Google Maps, but I could only get elevation for the route if I used cycling or walking. Of course, that is a problem for highway use, but I could estimate it to some degree using side access roads and what not. I'll give Earth a try.

I like to click/drag the cycling or walking path on Google Maps toward the intended driving route (like highway path). It kind of forces Google Maps to recalculate what I want to see.

 

[2021 Insight Jim]

I'm not knowledgeable enough yet to provide any useful information, but I'd like to know how you got elevation maps for your route. Is that Google Earth?

Google earth pro. It is free. You make a path and edit it to show the graph

 

[Moviemike]

I have a hill in my daily drive, but it's a shorter distance (~3 miles) and less steep (500 ft). Some of the different things I've tried and compared on different drives: 1) pre-building HV charge with Sport mode, 2) Sport vs Eco mode for the climb, 3) slow/steady vs fast/get-the-hill-over-with speed for the climb. For my conditions, pre-building charge with Sport mode and tackling the hill in Eco mode at moderate speed have delivered the best mpg I can muster for the climb (45 mpg).

I really appreciate your detailed testing / comparisons !! Thank you
Your best mpg technique works best in my conditions as well !!!

 

[pasei]

In this scenario here, you should only care about the amount of gas spent for each route, i.e. distance/mpg. The ultimate goal here is to spent the least gas possible, so looking at MPG only can be deceitful.

Good call from @insightfully on making sure you start with the same battery level. I personally read the battery on my OBD reader whenever I do a test because you can have significant variation within a displayed bar on the dashboard. At least enough for a 5/10mi trip.

My guess here: short drive uses less gas.

 

[2021 Insight Jim]

UPDATE: The non-scientific results are in. As time permits I plan to test other modes but this was done in "normal" mode.
1) Long trip was 24 miles, average speed was 34 mph, temp was 52°, engine was cold = 55.3 mpg from top of hill to town and back.
2) Short trip was 8.8 miles, average speed was 31 mph, temp was 44°, engine was cold = 40.5 mpg from top of hill to town and back.
SUMMARY: Short trip uses less gas.

 

[pasei]

UPDATE: The non-scientific results are in. As time permits I plan to test other modes but this was done in "normal" mode.
1) Long trip was 24 miles, average speed was 34 mph, temp was 52°, engine was cold = 55.3 mpg from top of hill to town and back.
2) Short trip was 8.8 miles, average speed was 31 mph, temp was 44°, engine was cold = 40.5 mpg from top of hill to town and back.
SUMMARY: Short trip uses less gas.

Are you sure you didn't forget to multiply by 2 the distance of the short trip? If you did forget to multiply, then both trip actually use the same amount of gas

 

[Moviemike]

Are you sure you didn't forget to multiply by 2 the distance of the short trip? If you did forget to multiply, then both trip actually use the same amount of gas

The long trip is slightly more that x2 the short trip. But much more importantly, the short trip was done at a lower temperature. If the temperatures were closer to equal, the short trip would likely use less gas.

Also the short trip has a nice downgrade near the end. Suggesting the possibility of a careful battery charge / discharge effort leading to a stronger battery at start of a trip following the short route. Thus a slightly better mpg in the following days' driving. This gas saving wouldn't show up in the test reported, but would be present in a tankful to tankful mpg comparison.

 

[2021 Insight Jim]

Thx for the observations. I figure I would need more savings to justify twice the miles. Granted this is only a small amount of the miles I drive. I am sure if the temp had been warmer results would have been different but I can't pick and choose that. Would like to try it again in rain but we are entering our dry season.

 

[Moviemike]

Thx for the observations. I figure I would need more savings to justify twice the miles. Granted this is only a small amount of the miles I drive. I am sure if the temp had been warmer results would have been different but I can't pick and choose that. Would like to try it again in rain but we are entering our dry season.

Yes I agree the short route uses less gas. !!