Charging tapering down to 1kw

[rmd]

This week I purchased an 18 touring with 109k through a small dealership. The engine light came on the first day of ownership on the several hundred mile drive back home. I've yet to address that but in the mean time I'm experiencing a charging issue that could be related and looking for any similar experience. I've only used free level 2's on chargepoint/plugshare networks but in the several I've tried charges will start at 4-6kw and taper down to 1.5-1.6kw within 20-30 min. Looking for any ideas before taking this in as I've only learned after buying that this is maybe more finicky to work on and assumed the universal "honda reliability" applied across all models as I have no real knowhow under the hood.

 

[MrFixit]

This week I purchased an 18 touring with 109k through a small dealership. The engine light came on the first day of ownership on the several hundred mile drive back home. I've yet to address that but in the mean time I'm experiencing a charging issue that could be related and looking for any similar experience. I've only used free level 2's on chargepoint/plugshare networks but in the several I've tried charges will start at 4-6kw and taper down to 1.5-1.6kw within 20-30 min. Looking for any ideas before taking this in as I've only learned after buying that this is maybe more finicky to work on and assumed the universal "honda reliability" applied across all models as I have no real knowhow under the hood.

@rmd - Welcome to the forum !!

The "Normal" charging behavior of the Clarity tapers the rate down during the final 10-15 minutes as the battery reaches a 100% charge. I believe this is because during this time, it is doing some sort of cell balancing. So here is what a 'normal' full charge looks like:




The red curve is the input power (kW) and the blue curve is the cumulative energy (kWh). With a fully capable Level 2 charger, the Clarity charges at about 30 Amps (7.2 kW) at a constant rate up until it reaches near-full capacity when the tapering begins.

The amount of energy that the battery will take changes somewhat over time because of expected degradation. The rated capacity of the battery is 17 kWh, but the Honda Engineers held some of that capacity in reserve in order to prolong battery life so that much was never available for use. In my experience, when new, my usable capacity was around 14.5 kwh (bought car new in 2018). It is now more like 12.x kWh.

If you are technically inclined, it is possible to query the battery capacity from the vehicle computer - Details Here.

 

[Landshark]

There was a TSB issued for a software update for 2018’s to address a problem with using public L2 EVSE’s. The reported problems were that the car would not start charging or would stop charging before the charge was complete. This does not sound like the experience reported above, however, I’d recommend checking to see if the car has the updated software.

If the car is charging in the expected amount of time, ie, 2.5 hours for a full charge on L2, 12 hours on L1, or any partial charge that seems to be adhering to that schedule, then charging is probably functioning properly and it may not be a productive use of time to focus on what the car is doing every half hour.

We have had reports of charging problems which resulted in a dash display showing “Plug-in-Hybrid System” warnings. A Check Engine Light could be any number of things. You’d need to know the Code to even begin tracking down the exact problem or to determine if it is related to the alleged charging issue. Speculating is a favorite pastime on this forum. It rarely yields meaningful results. Get the Code for the CEL and use that information to determine a course of action.

 

[VickyECallahan]

There was a TSB issued for a software update for 2018’s to address a problem with using public L2 EVSE’s. The reported problems were that the car would not start charging or would stop charging before the charge was complete. This does not sound like the experience reported above, however, I’d recommend checking to see if the car has the updated software.

If the car is charging in the expected amount of time, ie, 2.5 hours for a full charge on L2, 12 hours on L1, or any partial charge that seems to be adhering to that schedule, then charging is probably functioning properly and it may not be a productive use of time to focus on what the car is doing every half hour.

We have had reports of charging problems which resulted in a dash display showing “Plug-in-Hybrid System” warnings. A Check Engine Light could be any number of things. You’d need to know the Code to even begin tracking down the exact problem or to determine if it is related to the alleged charging issue. Speculating is a favorite pastime on this forum. It rarely yields meaningful results. Get the Code for the CEL and use that information to determine a course of action.
Congrats on the purchase—sorry to hear it’s starting off rough. That charging behavior definitely seems off, especially with the CEL on. Could be related to the onboard charger or battery management system. Some Clarity owners have reported similar tapering with aging HV batteries or charging module faults. Might be worth checking codes with a scanner before heading to the shop! I was stressing about my personal statement, but Academized’s buy personal statement online service eased my worries. Their writers crafted a compelling statement that helped me stand out. Visit https://academized.com/buy-personal-statement-online for expert help with your personal statement. They know exactly how to write statements that make a lasting impression.

Thank you, you saved my day.