Degraded battery capacity?

1221 Views 13 Replies 8 Participants Last post by EV Nerd, 18 d ago

02player02

Discussion Starter · 2 mo ago

Today, before I charged my 2018 Honda Clarity, the EV range on the car read 0.0 miles. I "fully" charged my battery with a chargepoint charger and 12.20 kWh was added before the charger said my car was fully charged. With the battery capacity being 17kWh, the amount charged seemed a bit odd. Are there settings that dictate how much you can charge the battery or does it charge to 100% or thereabouts every time? I'm wondering if there's a setting that I can toggle to get more of the battery charged. When I log into the HondaLink app, it says that it's charged 100% which is also weird considering it only charged 12.20 kWh. I just bought the car last month so I'm getting used to all of the quirks. Just wondering if this is another one. The engine noise when the battery runs out of juice was a quirk that definitely caught me by surprise. Thanks for the help.

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4sallypat

· #2 · 2 mo ago

With the 17kWh battery, you will never be able to tap into all of it.

Usually SOC buffer exists to prevent full charges and damage to the battery cells.

Don't know the exact usable number, but I vaguely remember 14kWh maximum for 100% SOC.

My home L2 charger puts out about 14kW but with 10% approximate losses (AC to DC conversion), 12kW sounds about right.

Also remember with low temps, the capacity is decreased.

Try checking the charge number in the summer - it should increase.

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02player02

Discussion Starter · #3 · 2 mo ago

4sallypat said:
With the 17kWh battery, you will never be able to tap into all of it.

Usually SOC buffer exists to prevent full charges and damage to the battery cells.

Don't know the exact usable number, but I vaguely remember 14kWh maximum for 100% SOC.

My home L2 charger puts out about 14kW but with 10% approximate losses (AC to DC conversion), 12kW sounds about right.

Also remember with low temps, the capacity is decreased.

Try checking the charge number in the summer - it should increase.

Thanks! I think once I swap out my tires, my range will increase too! I'm pleasantly surprised with the car so far. Pretty roomy including the trunk.

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hp79

· #4 · 2 mo ago

Last time I fully charged mine from empty (or 15% actual) was 13.1 kWh according to Juicebox Pro.
I have a 2019 with 32k miles on it. Battery cap shows 53.58 Ah. I do see it slowly getting lower only after a full discharge and full recharge. I was reading some posts and found a link to this GitHub. At first I thought really?! But then after reading and trying out the readout from a laptop, I was impressed with the nice report.

Some screen captures:

Font Number Screenshot Document Parallel

I'm tempted to try fully charging to 100% tonight and get one more reading using my laptop.

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4sallypat

· #5 · 2 mo ago

02player02 said:
Thanks! I think once I swap out my tires, my range will increase too! I'm pleasantly surprised with the car so far. Pretty roomy including the trunk.

Tires makes a huge difference in range.
If you want the maximum range, better to get the OEM Low Rolling Resistance (LRR) tires that originally came with the Clarity.

If you change to a non LRR like I did with mine - changed to run flat (RFT) the range took a 15% hit with more noise but better treadwear due to the heavy weight of the Clarity.
RFT has the security being able to drive up to 50 miles on zero air pressure - a feature I have always liked with all my vehicles.

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Overlook

· #6 · 2 mo ago

LRR tires also have longer stopping distance and less lateral traction for evasive lane change maneuvers.

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EV Nerd

· #7 · 2 mo ago

Overlook said:
LRR tires also have longer stopping distance and less lateral traction for evasive lane change maneuvers.

Don't I know it! The ~4" wide tires on our EV-1s cornered like a toboggan.

Went like a bat outta he|| in a straight line, though!

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shashinka

· #8 · 2 mo ago

Overlook said:
LRR tires also have longer stopping distance and less lateral traction for evasive lane change maneuvers.

No issues with my car driving for hours

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rogerdodger

· #9 · 1 mo ago

02player02 said:
Today, before I charged my 2018 Honda Clarity, the EV range on the car read 0.0 miles. I "fully" charged my battery with a chargepoint charger and 12.20 kWh was added before the charger said my car was fully charged. With the battery capacity being 17kWh, the amount charged seemed a bit odd. Are there settings that dictate how much you can charge the battery or does it charge to 100% or thereabouts every time? I'm wondering if there's a setting that I can toggle to get more of the battery charged. When I log into the HondaLink app, it says that it's charged 100% which is also weird considering it only charged 12.20 kWh. I just bought the car last month so I'm getting used to all of the quirks. Just wondering if this is another one. The engine noise when the battery runs out of juice was a quirk that definitely caught me by surprise. Thanks for the help.

I just got a chance to confirm your full charge data is reasonable, I got our 2021 Clarity down to 2 EV miles remaining and our 30a level 2 shows a full charge took 12.23Kwhr in just under 2 hours. Our battery is in good shape, just 13K miles on the car and we get 42 (winter) to 65 (summer) EV miles.

Audio equipment Gas Gadget Font Electric blue

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EV Nerd

· #10 · 1 mo ago

rogerdodger said:
I just got a chance to confirm your full charge data is reasonable, I got our 2021 Clarity down to 2 EV miles remaining and our 30a level 2 shows a full charge took 12.23Kwhr in just under 2 hours. Our battery is in good shape, just 13K miles on the car and we get 42 (winter) to 65 (summer) EV miles.

View attachment 1308

View attachment 1308

Recognize that the measurement reported is what the EVSE sent to the vehicle, and does not include conversion losses in the on-board vehicle charging circuitry. That figure likely isn't what actually went into the battery itself.

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bikematt

· #11 · 19 d ago

4sallypat said:
With the 17kWh battery, you will never be able to tap into all of it.

Usually SOC buffer exists to prevent full charges and damage to the battery cells.

Don't know the exact usable number, but I vaguely remember 14kWh maximum for 100% SOC.

My home L2 charger puts out about 14kW but with 10% approximate losses (AC to DC conversion), 12kW sounds about right.

Also remember with low temps, the capacity is decreased.

Try checking the charge number in the summer - it should increase.

The Clarity controls the Li battery charging, preventing over charging KW, etc . your house wiring needs to supply proper voltage and amperage to charge properly. When I lived in a 3 story condo with Garage under the building my extension cord slowed the charge rate quite a bit.

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EV Nerd

· #12 · 18 d ago

bikematt said:
The Clarity controls the Li battery charging, preventing over charging KW, etc . your house wiring needs to supply proper voltage and amperage to charge properly. When I lived in a 3 story condo with Garage under the building my extension cord slowed the charge rate quite a bit.

Which is why pretty much every L1 EVSE maker clearly states to not use one. I use one whenever I do an L1 charge, but it's a 12AWG version, to limit losses without sending me to the poor house. 12AWG extension cords are quite pricey. 12AWG is usually rated for 20A, or 16A for EV charging. (NEC 80% rule.)

Most regular duty extension cords are either 14AWG or ( shudder) 16AWG.

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bikematt

· #13 · 18 d ago

I was able to hook up a 100 foot extension cord for my Level 2 charger which improved it very much. I was getting about 220V +- The trick is to find 2 different sockets on different phases. The neutral is not used, a voltmeter is required. if you are not experienced consult an electrician! These voltages are dangerous and can be fatal! Do not take any chances if you are not experienced. Measure the voltage between two Hot lines. if is is 208-240V +- you have what is need for a level 2 charger. If you do this it is at your own risk.

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EV Nerd

· #14 · 18 d ago

bikematt said:
I was able to hook up a 100 foot extension cord for my Level 2 charger which improved it very much. I was getting about 220V +- The trick is to find 2 different sockets on different phases. The neutral is not used, a voltmeter is required. if you are not experienced consult an electrician! These voltages are dangerous and can be fatal! Do not take any chances if you are not experienced. Measure the voltage between two Hot lines. if is is 208-240V +- you have what is need for a level 2 charger. If you do this it is at your own risk.

Understand that this will not work if either of the two phases is individually protected by a GFCI outlet or breaker.

I had GFCIs upstream protecting each of the two circuits on the wall of my garage. I had to go back to the GFCI, and set it up to only protect the devices plugged into it directly. I then had to go to the j-boxes downstream, and install GFCIs into them individually...with the exception of the j-box serving the EVSE.

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