downhill charging, overcharging?

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laele

New member
Joined
Apr 22, 2023
Messages
4
Location
Maui
loving my new-to-me Leaf, 2015 S model, 87K, second owner, first owner (local) took delivery 2/17/2015, 9 of 12 bars, full charge at home using L1 shows 60 miles on GOM; and the crucial info is: we live at ~1500 ft altitude on the mountain; we drive 8 miles down that hill, smooth curves and straightaways to roughly sea level to get to "town"

so the question I have: left home showing 60 on GOM, did not note % charge on startup, but all three lights on dash were lit; lost 1 on GOM driving to downhill highway, driving ECO mode down it for necessary speed reduction since I dislike using brakes for that, in plain D speed rapidly builds over 65 when speed limit there varies between 45 and 55; but in ECO mode was rapidly charging, at bottom of hill showed 71 on GOM and 95% on battery charge -- so .... did i overcharge the battery?? should I limit how much I charge before leaving to drive that direction? we have solar panels on roof so $ to charge is not the problem but don't want to degrade battery any further than it already is; awkward to keep between 80 and 20% given that I have to drive back UP those 1500 feet in 8 miles, and usually shows little power back in our driveway

also it's Maui which mean temps in 70s and 80s (cooler at altitude), and unfortunately car is BLACK; keeping EVSE in insulated bag off ground because we get lots of mist, drizzle, and rain

happy to get any advice on any subject, prowling the site as often as I can, reading the manual which is tedious

thanks, Candy (greatgrandmother not stripper)
 
A Leaf is a heavy car so being able to use the regen on the way down the hill will be a big plus IMHO. So, the first thing I'd do is cycle through the dash options and set the display to % of charge. Then drive for a while and see how much charge is gained going down the hill and how much it takes to go back up.

Regen is limited by the car so if the battery is at 100% you will have no regen. Also, as the battery ages the regen is reduced but that's a secondary effect compared to the % charge.

The amount of available regen is shown on the dash on the left 4 green 'bubbles'. When all 4 bubbles are double, you have max regen available. At 100% charge all the bubbles will be single wall and that means no regen is available.

Once you know how much power you generate on the way down, try to charge to about that value below 100% so you will reach full charge at the bottom of the hill. I'd also get Plugshare on your phone and try to find local charging stations. It's always nice to know where you can charge if the need arises.

Enjoy your Leaf!
 
very lucky here, L2 free charging stations at Target, Home Depot, and UH Maui which are at, or close to, where I need to go in town (Kahului), local driving is mostly 4 to 8 miles away at relatively same altitude, before I found the % charge indicator I normally got home with the same amount on GOM as I started with, or a mile or two more, we have small hills and canyons on the quiescent volcano where we live
 
Don't worry, you can't overcharge the battery past 100%. While leaving the battery at 100% isn't recommended for long intervals (days, weeks) if you're looking to maximize longevity, it really isn't much of a problem for a short period. And since you'd soon be draining down from 100% once you reach the bottom, I wouldn't worry about it. The only thing to keep in mind, as already noted, regen will diminish at high state of charge, dropping to nothing when the battery is full. So be prepared for additional braking if/when that happens.
 
braking when necessary not a problem for me, my car on the mainland (east of Olympia) is a stick-shift, cruise control, Yaris (dealer was shocked that I wanted those options on a leftover year end car), used to drive a Subaru when employed as a ski instructor driving up the pass before plows were out in the morning LOL; so I am OK with driving in neutral though I hear it's not good practice in a '15
 
There's obviously nothing wrong with coasting down a hill and using the brakes, and 1500 ft in 8 miles doesn't sound all that steep but one of the beautiful things about an EV is its efficiency in recovering kinetic energy. I'd much rather charge my battery and save my brake pads while going down a hill than ride the brakes but that isn't always possible. But when possible, it's much preferable IMO.
 
Sounds like you have an almost perfect situation! It's like an MC Escher! :D
Use regen down the hill to town, then charge for free at your destination and use that charge to drive back up home! If you're only going to those destinations, I don't even think I would bother charging it at home.

You've probably also figured out that the regen is reduced the closer to a full battery you get. So you're wasting that free gravity charging if you're charging the battery at home over 70 or 80%.
 
If you have not already found it, try B-mode (with or without ECO) for more regeneration going downhill. B-mode is engaged by pulling the shifter puck twice (first time gets Drive and second time gets B). Personally, I use B-mode without ECO all the time because I like the increased "engine" braking and I don't care for the accelerator pedal response of ECO.
 
One caveat to the above endorsements of downhill Regen: if the battery is already Hot (six temp bars or more) when you leave the house, then I suggest you avoid "cooking" it further with heavy regen. Hawaii is one of those places with 'sneaky degradation' because of the warm nights.
 
One caveat to the above endorsements of downhill Regen: if the battery is already Hot (six temp bars or more) when you leave the house, then I suggest you avoid "cooking" it further with heavy regen. Hawaii is one of those places with 'sneaky degradation' because of the warm nights.
warm nights - well not really in the winter which is when we drive our Leaf -- need two blankets on the bed, night-time temps in the low 60s F -- recall we are at ~1500 ft altitude, part way up Haleakala volcano; rest of the year in a closed garage, concrete block construction and the floor is always cool underfoot, even in the rare summers when we have stayed here for unusual reasons -- but will be sure to watch battery temps, hadn't been taking that under consideration though had watched out for home charging -- electricity rates here lowest during the DAYTIME due to solar roof chargers, Maui Electric doesn't have to burn diesel then -- higher rates after dark -- so we usually wait to plug in until after car has cooled down, parked under shade when possible
 
warm nights - well not really in the winter which is when we drive our Leaf -- need two blankets on the bed, night-time temps in the low 60s F -- recall we are at ~1500 ft altitude, part way up Haleakala volcano; rest of the year in a closed garage, concrete block construction and the floor is always cool underfoot, even in the rare summers when we have stayed here for unusual reasons -- but will be sure to watch battery temps, hadn't been taking that under consideration though had watched out for home charging -- electricity rates here lowest during the DAYTIME due to solar roof chargers, Maui Electric doesn't have to burn diesel then -- higher rates after dark -- so we usually wait to plug in until after car has cooled down, parked under shade when possible
So in February where you live it’s like Minnesota September. Wow. I don’t put extra blankets on my bed. I insulated my whole house. There’s a 3 foot thick blanket made of shredded newspapers in my attic.
 
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very lucky here, L2 free charging stations at Target, Home Depot, and UH Maui which are at, or close to, where I need to go in town (Kahului), local driving is mostly 4 to 8 miles away at relatively same altitude, before I found the % charge indicator I normally got home with the same amount on GOM as I started with, or a mile or two more, we have small hills and canyons on the quiescent volcano where we live
Wow. Free lv2. That won’t last. Too expensive.someone is going to figure out they can charge a power wall there, go, charge their power wall all the way up, dump it into the grid. And pocket the difference. Go every day and it’s a whole other income.
 
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