Regenerative Braking in Hybrid and Electric Vehicles Explained

[@greensoup0407]

I just got a new Toyota Prius. There are so many new features compared to my old gas car. Regenerative braking was one of the features that was really interesting but I had no clue how it worked. Thank you for explaining how it works in an easy to understand way!

[@kbcoggin]

I have watched a few videos on this topic, NONE of them are worth the time. Your explanation was clear and easy to follow! Fascinating! Thank you so much for takin the time to make this video.

[@AutoScholarwithMrB]

Thanks for watching Kenneth!

[@ray_c_yuen]

When I bought my hybrid Camry, I asked my dealer salesman how regenerative braking worked and when was I using actual brake pads. He couldn't answer me properly and just said the brakes last forever. I now realise that the motor generators can only provide so much braking (showing maximum charging on guage) then it's actual brakes pads rubbing against rotors after that. I drive as smoothly as possible and make sure my charging needle stays below maximum. That way my brakes will last forever. Even in a normal ICE car, my brakes last a long time. Thanks for the technical explanation. 60 to 70% is more than i expected to regenerate.

[@elsaarmstrong-zp6ng]

At last regenerative braking explained in accurate manner! Some of the others I listened to talks of dynamo feeding into the batteries!

[@Torch315]

Maybe you've done this already, but I'd like to see an explainer on planetary gear systems and how they enable hybrids and drive regenerative brakes. Thanks!

[@mayurmhaske545]

Very well explained by giving a practical example. Thank you for the easy and perfect explanation..!!

[@AutoScholarwithMrB]

Thanks for watching!

[@johanvandermerwe4620]

the best video I've seen Thanks

[@TimmyMaharaj-n1c]

Thanks so much ,i understand hybrids alot beter now

[@seshachary5580]

very educative. Thank you Regards

[@maheshkp3558]

I watched you hybrid system videos and it helped me a lot going good.can you please do how hybrid cars ac system works,how the power transition in both battery mode and IC mode

[@AB-C2]

Thank you very much ❤

[@riceburner4747]

Great video! 👍

[@AutoScholarwithMrB]

Thanks as always, Rice!

[@guilhermepiresdasilva4264]

I have a problem with my Prius, but there is no warning on the dashboard, when I press the brake it is not regenerating, the CHG bar does not fill when I press the brake, it could be a lack of calibration of the valves, the brake servo has already been changed, because the original was the problem in 3rd gen what should I do

[@AutoScholarwithMrB]

Definitely check the ABS module for any codes. I would also do a linear valve calibration with a good scan tool.

[@alanburns2898]

The current Honda system does allow for electric motor assisted braking while the battery is full. Not exactly sure where this energy is sent/dissipated.

[@JR_3251_]

How do I change my regenerative braking pads?

[@foxlies0106]

Depends..?😁

[@mohammedsuboh1420]

Good work ❤️

[@AutoScholarwithMrB]

Thanks for watching Mohammed!

[@prabaltiwari4603]

Thank you so much for explaining it so well!!! I was wondering if there’s any chance of harvesting the inertia energy when you accelerate or break?

[@linodhesandu001]

Then sir, which Motor Generator is used to recharge the battery in regenerative braking ? MG 1 is generator, and MG 2 is motor that drives the car in EV mode ?

[@kennethwinter5665]

Can we discuss the difference in the Regen processes in the prius and tesla?

[@tomswan3805]

Thank you!

[@AutoScholarwithMrB]

Hey thanks for watching!

[@rngod2121]

I have a 2023 Toyota Corolla hybrid that had a registered average MPGs of 50 and I get 63. My neighbors just bought a Toyota Tundra hybrid and we're getting 11.3 miles per gallon, until they let me get in the vehicle and show them how to drive a hybrid. On the trip home, after resetting everything, I showed them how to accelerate gently and break gently as if there's an egg in between your foot and the pedal. The result is it more than doubled the MPGs from 11.3 to 23.1. My only frustration is that this type of technology has been around for decades in the train, locomotive, industry. Why did it take so long for the automakers to be dragged, kicking and screaming, into the modern world?

[@dark_side_cookies]

I think it's lots of different reasons. The more unfortunate outcome was how they started building up the hybrid fleets, and then suddenly stopped when Tesla showed up and proved how effective an electric car could be. Cheaper gas didn't help either. Then lots of companies scrambled to play catch up and immediately make electric cars into this mainstream, money printing machine, without considering how impractical this is for 90% of US drivers currently. I live in well a developed suburb of Chicago, and I know of exactly *one* electric charging station within 10 miles. Granted, there are a lot of homes in the area, so homeowners would be mostly fine. But there are also a fair number of apartments, whose drivers would not be able to charge at home. When you factor in the stupidly high cost of most EVs and PHEVs, it erodes most savings over getting pure gas or HEV. Now that expensive electric cars have failed to gain traction (shock!), lots of these manufacturers are going back to reliable hybrid tech. And I think it makes sense. It's true HEVs are a stopgap technology, but it's the perfect bridge for when EVs are ready for mainstream. In the meantime it's less reliance on dirty fuel, and being able to manufacture way more HEVs for the same amount of elements (batteries, etc) as a single EV. Not only that, consumers in my area obviously prefer them. Big trucks, SUVs, and even sedans sit on the lots while hybrids are just flying out left and right.

[@marblox9300]

Gen 3 Prius 2013 here. Coasting shows small regeneration but using the brake pedal shows more regeneration.??? How does harder pedal braking cause more regeneration.???

[@hatchali6765]

brakes aren’t pads and discs, it’s using more resistance on the motor to charge (mg2)

[@marblox9300]

@@hatchali6765 So on the Prius - mild braking doesn't actually engage the pads to the rotor.???

[@hatchali6765]

@@marblox9300 nope, see the energy meter, until you fully reach the left, the hydraulic brakes don’t engage and it’s all regen braking

[@marblox9300]

@@hatchali6765 So are you saying my previous comment is correct.???

[@tedesilambert9971]

One question I have is when applying stronger brake input, I understand that the greater drag produces and captures greater recharge, but how do the generators apply greater drag to the axles based on brake input exactly?

[@domenicsandri5836]

Is it possible to install a regen braking system on a car that was not made for it?

[@pabloso8403]

What type of maintenance is needed to know for hybrids

[@cs_fl5048]

I understand the conversion...induction motors, bridge rectifiers, etc. That part I understand. But I'm wondering if the energy goes back into the battery or into a supercapacitor between the controller and the batter....

[@psolsrud]

I know someone who uses the B mode for slowing down with the assumption that it charges better instead of using the brake pedal. What say you?

[@AlexV-pf3io]

Looking for answer - can’t find it. Why during Regen voltage of a battery reach red zone - over 260-270 V at nominal 201.6 V (harder I brake higher voltage). Why voltage regulator is not limiting the voltage (like in regular alternator system)?

[@Codelyoko281]

Hello mr B, in another video "How the Prius Hybrid Drivetrain Works (Explained)" when you explain which one is MG 1 and MG 2 is reverse, so which one is which, i am now confused ( at the 2:40 mark of the video ) which video is right or wrong? not trying to be picky but i love learning this stuff and rather not be confused. thank you!!

[@AutoScholarwithMrB]

MG1 is the one closest to the engine and MG2 is larger and further away.

[@larrymendoza2570]

Thank you! Brilliant insights! My question is this: I’m super familiar with the Ford hybrid/ PHeV implementation, which uses two electric motors! Their explanations seemed to say that the 2nd smaller motors was for dedicated Regen. Seems inefficient and I didn’t understand why… here you stated that the second smaller electric motor serves as the alternator/ starter (I now get that!) (Q1) Is this also true in the Ford implementation? (2) I just purchased that 2017 Ford Focus EV, all electric. Does the FFE use two electric motors like Ford hybrid solution? Or does it only use one? Thanks!!!

[@bachir1559]

Great video , can you recommend any hybrid cars to purchase ?

[@AutoScholarwithMrB]

Most of my experience is with the Toyota Prius and the Honda Insight. I would not have any issue owning either. Thanks for watching!

[@davenone7312]

I bought the 2023 Hyundai Santa Fe Hybrid and absolutely love that car! You would too!

[@sollows1]

Whats the output votage of the motors?

[@MJ-kd2em]

Coasting down a hill when a battery is full it's still going to use regenerative breaking but with engine braking too. You going to see your engine rev up to 3000 rpm which will consume the energy regeneration as battery is full

[@bornWinnipeg]

best cars ever

[@AutoScholarwithMrB]

I like mine a lot.

[@Dogpool]

At 8:30 I don’t think this is right. Unless there is some wacky brand new system, the Prius has always had a mechanical brake connection. Meaning the hydraulics will work and stop the car even if the brakes are off. The solenoids in the abs module can close off to prevent that flow. If this was not the case in the event of a stall or something , there would be no brakes at all.

[@azlansharom7011]

How does the system regulate the amount of regenerative braking applied as the driver presses the brake pedal more and more? Is it varying the resistance within the circuit, or something? Thanks.

[@AutoScholarwithMrB]

In most hybrids the pedal pressure is input to the control module by either a pressure sensor on the stroke simulator or a pedal position sensor. This is then communicated to the battery control module to decide if the battery needs charged or not. If there is room in the battery for charge, regeneration will occur. If the battery is full, the conventional brake system will be used. Regenerative power is controlled through a field, much like how alternators are regulated. Higher field equals more drag on the drive wheels and consequently more power to the battery being generated. Hope this helps, my friend, and thanks for watching!

[@azlansharom7011]

Lovely! Thank you for taking the time to explain. 👍🏽

[@michaelhodge9902]

When the rotor is move by a prime mover the induction motor could also act like a generator but you have to make shure the rmf speed is always less than rotor speed this causes way more voltage to be generated which induce a reverse current 270dgree behind the magnetizing current.

[@plolochufu]

Does anyone have info on the details regarding the 2019 prius prime? Im wondering what arr the parameters for whenever ev mode automatically changes to ice whenever on a slope and at what degree that slope must be. Does the car detect the slope or just the increase in torque?

[@wavyzeex]

how does it slow down, while the brakes are off & the battery is being charged. does it have enough magnetic resistance to slow down the momentum of the vehicle. or is there a brake in the motor.

[@AutoScholarwithMrB]

It does use engine braking strategies as well.

[@wavyzeex]

@@AutoScholarwithMrB what about a full blown EV vehicle not a hybrid. Does it still use a type of resistance in the motor to slow the vehicle

[@AutoScholarwithMrB]

@@wavyzeex electric motors on EVs work the same way. Also regen will most likely always be active because there is always room in the battery. The hydraulic brakes still work at low speeds and situations where regen isn’t applying enough drag.

[@harry7384]

thanks! One question : can the regeneration make the vehicule come to a complete stop? (if not : why?) (I do not understand the one pedal process to stop the vehicule...)

[@AutoScholarwithMrB]

When the car reaches a lower speed, the conventional brakes will take over for a more precise control. Hope this helps and thanks for watching!

[@NathanYiangsupapaanontr]

Thanks for the video! I have one question. When the battery is full and the vehicle is coasting downhill in B gear, MG1 spins up the engine to dissipate energy. Does it mean that the vehicle is still using regenerative braking from MG2? (i.e. The engine is just spun by MG1 to dissipate energy but the engine itself is not the one that's actually slowing down the vehicle.)

[@coachmarc2002]

Is the system you explained on this video the same for a 2008 Mercury mariner hybrid?

[@AutoScholarwithMrB]

No, they only use one electric motor.

[@coachmarc2002]

@@AutoScholarwithMrB Oh Okay.. but as far as light use of the brake pedal acting to recharge the battery the system is similar I believe. There is a needle that points toward charge while breaking and assist when the car starts moving up to around 20 mph before the gas engine starts up.

[@AutoScholarwithMrB]

@@coachmarc2002 correct, it regens and stores that power for when it is needed later in the drive cycle

[@gym_bob]

Does the plug in one (prime) also use regenerative braking?

[@AutoScholarwithMrB]

Sure does.

[@jeffjo8732]

If you start at the bottom of a hill with 100% SoC, when you get to the top of the hill about 30% of that will be have been lost in various places (heat in the drive train, tires, and road; atmospheric drag), and 70% will be in kinetic and potential energy of the car. You only recover from that level. Accepting your 60% to 70% efficiency for regen braking, the battery will be at 42% to 49% SoC at the bottom of the hill. I don't necessarily believe that efficiency; I have a 2015 study of PHEVs where the best (Accord PHEV) almost reached 60%, and three others (Prius, Fusion, C-Max) are between 45% and 50%, so the SoC would be between 32% and 40%. And as a point of reference, due the 30% loss I assumed going up the hill, this will get you about a quarter of the way back up. This is the fallacy of regen braking. It does not let you gain SoC, since you need more from the battery to "undo" the braking.you just lose less in the cycle.

[@JWM5773]

100000 Miles for brake pads . That's impressive!

[@AlexV-pf3io]

Brakes on my Yaris(non-hybrid) still ok for another 100K - never changed. Brake soft…

[@yusuflbs7535]

When vehicle in high speed and use Regenerative Brake, is the ABS system active to prevent slip ?

[@AutoScholarwithMrB]

No, at least not on the Toyota systems. They will turn off regen and only use the friction brakes.

[@lao1634]

Can you exsplain how the battery recharges by coasting? Also can a battery with low cells recharge its self, by coasting more? My 2014 prius c only got 123,000 miles on it & my check hybrid engine pull over in safe place immediately light came on My son cleared the computer I took to Toyota dealer they said My cells were low I'm bummed becouse I was under impression these cars run up to 200,000 mi Dose the way you drive effect this

[@LakshayGrover]

Does the battery charge during a downhill roll (not applying brakes at all)?

[@AutoScholarwithMrB]

Yes it will charge while coasting if there is room for charge in the battery. Thanks for watching!

[@TheTruthSeeker756]

@@AutoScholarwithMrBwhen you’re coasting is there a lot more drag than when coasting with an ICE car because it’s like you’re putting your brakes on?

[@awaiskhan889]

V nice

[@AutoScholarwithMrB]

Thanks for watching!

[@arunfz]

nice

[@TheTruthSeeker756]

So the majority of electric vehicles have regenerative braking?

[@AutoScholarwithMrB]

I cant think of one that doesn’t.

[@TheTruthSeeker756]

@@AutoScholarwithMrB Thanks! Great video and new subscriber!

[@AutoScholarwithMrB]

@@TheTruthSeeker756 thanks a lot! We will be adding more content on EVs and hybrids soon.

[@jeremyfields571]

Front tire wear also.

[@andreoviking]

I have a question, so on a bmw X3 there is regeneration meter, when you let the car coast, the charge meter raises a bit, however the harder I brake the more it raises! So if I when I brake hard the actual brake pads actuate, how is it regenerating more?

[@foxlies0106]

I think(!) e.g., try on a long say 3-5% downhill If you slowly increase brake pedal pressure, (if battery is not nearly full), regen power (maybe torque but i think power) up to a threshold (max regen power i think) then car (toyota) “sees” you want more braking power and brings in (maybe engine braking) the friction (hydraulic) brakes, then i guess at high pedal pressure the hydraulic brakes really crank down (regen is cut out i think he said idnk why). im still trying to determine what max regen power is dont want to blast esp smaller hybrid battery (say 1.5KWH?) with too high a power/current (more than like “20C”rate like 30KW?). E.g i think say If Prius on highway kinetic &rotational energy at vo=30m/s highway ~0.5*(M+mrot)*v^2=~1500kg*(30m/s)^2=700 kJ, approx. will also have drags on order of? F_Aero drag ~-200N, Froll resist&friction~-Mg*(frr0+fdrvtn)~ -200N? so car “drags~ -400N at that vo 30 m/s. my numbers prob off anyway if prius batt not near full, say you come off accelerator start slowing (on level ground w no wind!) (Faero+Froll+Ffric)/(M+mrot)~-400N/1500kg~ -0.3m/s2 tangible but not much.. and then bring in fairly soon full regen power max say it is Prmax=~-30KW_elec means wheel torque at vo=30m/s, of Frmax(v)=Prmax/vo =-1000N/(drive_effic)~ -1100N (?) mechanical atat (Faero+Froll+Fdrvtn+Prmax/(vo))/(M+mrot)~ (-400N-1100N)/1500kg)~~ -1m/s2 or -0.1g. not much. But as Prius slows the max regen Torque increases, which i think i can feel; at max regen on dial, my RAV4 hybrid slows, and speed v decreases, my regen pulls “harder and “harder” imho, puts more force on me & car, as quotient Frmax(v)=Prmax/v increases i think. Still getting data. Feedback appreciated. sorry to go on & on. BR.

[@djtruth8425]

You need a rectifier to go from ac to dc; not an inverter.

[@foxlies0106]

Yes that is correct ., What is cool is that the inverter can do pretty good job of rectifying; in fact i think often more efficiently but costlier than diode rectifier.. the (3-phase “full-bridge”) inverter like in EVs or Prius rectify the AC motor regen output , by how its control proceesor time its switching ( using FETs or IGBT transistors, as you know,).. Im winging it here but sort of: the motor in regen mag fields creates high AC sinewave voltages in its (stator) windings (phases), as you know and inverter switching is timed ( in their phase and sometimes also with a small slip freq offset for say induction motors) so the switches only conduct then only when a phase-to-phase voltages exceeds, by a margin, the inverter’s “DC link” voltage (i.e. in basic systems, that is ~ battery voltage, or thru a dc-dc converter) So controller and inverter uses timing to act as rectifier to push current (power) from motor windings back into inverter DC link and then (via perhaps dc-dc ckt and batt mgmt sys) back into battery. Controller of course monitors and limits regen for SoC, and for OC, OV, OT). I hope this helps some sorry if too much basic idea is there but im rusty so pls check me. but in general full bridge inverters can do nice job rectifying if o/c designed well; maybe even if input is not just sinusoidal, but harmonics and junk, which is also cool.. BR.

[@angelamartim8337]

4:03

[@stargazer7644]

60-70 percent efficient? Not even close on a Prius Prime. When I climb a particular grade, I’ll use over ten miles of charge climbing to the top. When I coast down with regen I get only two miles back.

[@foxlies0106]

I was thinking aero drag and roll resistance and any stops likely robbing you, too. If 10 miles of charge is 2.5KWh_elec, thats about 2.3KWh mechanical; if u climb at say 20m/s im numbers rough Fdrag~ -60N, Froll*+ Ffric~ -180N, so every km you drive (if say at 20m/s) they steal ~240kJ, and car uses~say Pload=1kW forr loads like pumps&fans &hvac for that km50s=50kJ so ITHINK🙄 you lose on order of 300kJ /km. (i used roll resist but during climb tractive slip is happening idnk how to calc so fudging here using Froll🙄) Unfortunately i dont know steepness of hill, or initial speed at bottom vs final speed at top ill assume KE1=KEo: say 4%grade.. Etract_mech/(Fdrag+Froll+Ffric +Pload/v + Mg(-1*4%)) +(KEo-KE1)=~distance driven to climb~ or approx -2.3kWh/(-290kJ/km + 13kN*-4%) ~ distance driven in climb ~ -2.3*3.6MJ/-800kJ~10km~6.6miles@4%? how am idoing..anywhere close long steep climb 4% avg@20m/s =45mph? w my guesses of params which prob stink, itd be about 400m ascent for 10km climb@4% thats a big hill.. Anyway, if you roll back down my guessed hill and params at same~ steady speed, (battery not near full no wind) Fgrade(-4%)=~+650N, and Fdrag&Froll&Ffric take their lb of flesh ~-290N, or ~0.8kWhleaving available Fregen~360N. Pregen~ -7.2KW which i think below regen Pmax, so okay. For 10km descent mech regen power ~ 3.6MJ =1KWH_mech the regen system absorbed mechanically. I THINK this measly 1KWH mechanical, work that regen actually did is the energy to compare to what you get into battery as kwh_elec, then especially the fraction back out as useful mechanical energy So a certain amount gets to battery as electrical, people say like 70%-80%, then prob 85% of that gets back to wheel when driving.. Also note during descent, that i guessed at 10km, the cars Pload (motors fans, drive sys hvac) pullong on batt of course i gueesd swag Pload=1kW so Pload*(10km/(20m/s))~500kJ~0.13kWh? so that hurts only maybe “see” 0.87KWH elec in batt at end of descent? anyway my numbers seem bad bummer => you pprob get 3 miles out of 870Wh not 2 miles My point is just that The regen system only gets a small portion of the total energy, thanks to drag, rolling resistance and friction in the drive system, and then the car sips some of the battery power away. .. my numbers were too rough I think but maybe if you measure the length of the climb in the distance and your speed, and check the numbers on the losses, it might be a way to get a good number for your actual regen efficiency from mechanical in to mechanical out, hope this was useful and not too rambling. BR

[@stargazer7644]

@@foxlies0106All those things you mentioned are also in effect when you're NOT in regen, and they don't use 80% of your battery then. The Prime just puts very little back into the battery during regen. And we're not talking about any stops, and the climate control system is off. I'm talking about driving up vs down on the same long grade on the highway. When you're at a steady speed on a flat road your discharge rate tells you the sum total of all those losses.

[@foxlies0106]

Errata: A. first made mistake above: i said 0.87KWH might show up in battery as final result Error sorry. B. secondly, tractive slip loss is important i glossed over. sorry. A. the 0.87kWh calc wrong. ironic i neglected much of the crucial loss that we want to know! i skipped the from “regen_in effic” from how well motor&inverter&BMS convert regen wheel mech energy into the battery electrical energy [kwh_elec] that shows up on dashboard; if that efficiency is 80%,(say) that 1KWh of regen mech input energy would convert to 800Wh_batt that arrived into battery; and then subtract the energy removed by loads from battery ; i SWAG guessed Ploads~-1kW, and Eloads~ -1KW*10km/(20m/s))=500kJ_elec ~0.13kWh_elec. so batt might show a net of ~ 670Wh_elec, in my swag example, from the -2.5KWh_batt invested, due to all the different losses. => And that was me assuming drive output effic of 2.3KWh_mech/2.5KWh_batt_elec=~90%, and that regen_in_effcy assumed80%, which means im testing a regen round-trip efficiency (RTE_regen) hypothesis of 90%*80%=72%. which seems optimistic To get to the point, sorry: even at really good seeming 72% regen RTE, if my numbers are roughly good, so many losses like drag, etc, remove energy from system and battery, the numbers look lousy, like getting only 670Wh_batt back from the 2.5KWh_batt it can be recovered by the regen, the regen can look worse than it is. Unfortunately what I didn’t provide you is a useful way to figure out these parameters, but I think if i maysuggest, what im going to try 1) get good parameter value estimates (ignore my swag guesses sorry )re: a) mass M of Prius primeprime+driver+gas+payload; b) mrot mass-equivalent at wheelsof the rotational inertia of wheels&drivetrain; hubs shafts, transmission motor rotors. unfortunately, probably varies as driving varies and ICE, M1, M2 “clutched in and out via planetaries? c) big issue imho eqns for the longitudinal tractive slip loss from tractive driven tires on ascent, and loss from braking tractive slip all braking wheels on descent) {idnk this yet sorry i assume ~proportional to tractive force torque or power applied by motor and/ or brakes, (or even drag)at tire patch and car weight fraction supported by driven tires, and depends also i think on the tire type, pressure, contact pressure, treadwear, tire temperature, road surface&temp {aint this fun fun fun!} d) frr~0.012 parameter for tire hysrpteretic rolling resistance of undriven nonbraking e) lesscrucial Ffric friction (constant force/torque)losses in drivetrain from bearings, gears, etc f) viscuous kosses in drivetrain get estimates people provide, lke his video, to compare.) usually assumed constant but has increase with speed c) Cd*Afrontal*air_density d) hill length, grade and elevation e) ascent&descent speeds. 2) record temperature, SoC, speeds, locations for map data. distance grade of climbs& descents at different ~steady speeds if at all possible ayk. Dash cams can really help. GPS OBD2 im in process. Elevation data hard often to get accurately, imho☹. GPS often large errors; GPS-inu_barometer prob best (Hunter research Theodolite phone app my current focus.,) a) record drive modes used, D probably best to use throughout but idnk for sure. Using N say on descent ayk often disengages regen? b), Use slower drive speed is better for inital calcs, if safe, to lower eg the typically large uncertainties in aero drag eg in Cd*Af*ρ, and wind; b)lower speeds less energy but lower drag, ohmic and other energy &viscous losses.. c) better of course ii know if tires fully inflated and same each time, d) tires and battery pre-warmed to ~same. e) A/C&heater off, and other loads minimal, f) check battery has plenty of “room”; note battery temp & SoC at start and end of ascent, and same start&end of descent.. f) ayk test with no wind if possible, and best precipitation nor say a very wet or hot or rough-surfaced road; g) if possible do runs same day or two, same ar condition and ~payload h) or i may try adding say 100kg and repeating test.~.2.5%more energy from batt on ascent on 8% more Frr loss, but i think we’d see 20% more regen energy back in on descent, for my swag example. thus i think good param/result check to do that, assuming if slip loss is linear with weight! 3) Compare the runs check param estimates.(how best to do that? um .notsure?.tbd?🙄🧐☹) a) for variation/checkascend partway not full, record that; or b) take data using different hill w different slope.. 4) as you know, Wind esp, temperature and HVAC of course vary results. hope this is useful not pedantic.BR work in prog🙏