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Regen not charging battery

Regen not charging battery

Hey guys, i was wondering if anyone out there has experienced or knows what is going on with my scenario.

I have had my model x for 8 months. when i look at my trip meter every time i charge it, it never represents the amount of power i have in my pack. Lets go into a deep dive so that you can understand what i am talking about.

I have a Model X 75D. This means i have a 75 Kw pack. I charge it to 90% every time i drive. This means that i have approx 67 KW in my pack after I charge. I have tried many times and i get the same result.

Normal scenario, I drive 2 and from work every day, at a moderate 20 degree Celsius. I have every option enabled and on, included heat / cool, radio, etc... when I finished my pack my display reads that i have used 37 KW. I am in shock at this point to think that the accessories use up almost half of my power.

Scenario 2: I drive to and form work, with every accessory disabled. Put it in range mode, chill mode and make sure i am not wasting a single drop of power on anything such as AC/ heat, music, dashcam, sentry mode, or even online tracking. and the most i can squeeze out of the pack is 43 KW.

Now my regen braking works and works well, there is no doubt. When i go down some steep hills i see the reading for KW used rolls back as if it was recharging the battery, however my power meter never reverses and says i have more power it just keeps going down down down.

I am curious to know what other people use when they run out, how many KW does your car say you have used when you plug it in. If you are in the 60 KW range i will definitely take my car in to get fixed. I understand accessories take power so not all power will go to the motors. But i am not getting anywhere even close to the rated mileage, and i never expect to i just want to know where does all the power go.

Uncle Paul | 11 juin 2019

Where do I start:

Regen does indeed recharge your battery, but in normal useage if is only strong enough to reduce your current used. You will only get + miles if you regenerate down a long hill. Then extra miles will go into your range. Maybe start down the mountain with 40 miles of range, but end up with 45 miles at the bottom. For little hills you may not get enough juice to roll the meter backwards, and usually end up using that juice to get back up the next hill.

Your 75 KWh battery does not have all 75 available for your use. Some battery volts will not be usable at either the top or bottom of the pack. This is used to protect the life of your battery.

The math rately works out because owners do not have all the exact technical data to calculate. In addition there is some loss of juice, both when charging your car and also when it discharges. There is some loss due to the reality of using batteries, rather than just running your car off a very long extension cord :)

tesla.com | 12 juin 2019

I don't believe Uncle Paul has it correct. Regen always puts charge back into the battery. It doesn't show up on the range gauge because the regen periods are relatively short. I have seen times when I just ticked off a percent of my battery and then did a major regen and had it tick back up one percent. That just means that was the point where 49.99% got 0.01% added back onto the range so it showed 50% for a bit before it was run off again.

But I have never found anyone who could provide any real evidence that you can't use the full 75 kWh in your battery if you charge up to 100% and down to 0%. The reserve amounts in the battery are either in a battery that is software limited (actually a larger battery) or they are talking about the reserve amount they design in to prevent damage to the battery, but you will never be able to touch unless they specifically turn it on for events such as fleeing a hurricane or similar disaster.

If you really can only get 43 kWh of use out of a 75 kWh battery, I would ask the service center to look into it. Be sure you are also factoring in vampire drain. I usually only see about 3 miles a day (1%), but others can see up to 10 miles (3%) a day.

jjgunn | 13 juin 2019

Charge to 90% = ~67 kW

Use ~43 kW throughout the day.

Leaving you with ~24 kW or ~35% of your battery left.

Miles or KM's mean energy used whether it's electricity or gasoline.

Everything sounds right to me -- I have a question....

Did you track your gasoline car tank & usage this closely?

jeremy99s | 13 juin 2019

I have noticed this because my dash says KW/h used is 43kwh and my battery is empty, its like me driving a gas car that has 75 liters in the tank and after the engine drinking 43 liters the gas gauge says its empty (like there is a leak). I know everything from the computer, screens, AC, lights, etc... use power and those are not reflected in the gauge provided by tesla, as this gauge is what the motor used.

I have since tried a straight freeway, no traffic drive and i do get the milage the car is rated for but i cannot get the KW/h used higher than upper 40's

is the rest of the car really that inefficient that it requires that much power to use it? or is the calculation wrong that the dash shows?

beaver | 14 juin 2019

On my model 3 I have only measured 68-73 kWh usable discharge energy. The battery pack is supposed to be 78-80 kWh. The difference is due to battery reserve (protection) and discharge loss.