Clarity PHEV battery capacity
- Thread starter ommatidia
- Start date
- Replies 7
- Views 10K
JustAnotherPoorDriver
Active Member
Capacity is 17 kWh, but only about 14 kWh is useable. They keep some percentage at the top and bottom to enhance battery life, and also to allow the range to stay the same as the battery ages and has reduced capacity.
The 47 miles electric range (average estimated) only uses the 14 kWh
The 47 miles electric range (average estimated) only uses the 14 kWh
Even less than that, probably more like 12 kWh because charging efficiency is about 85%.
MrFixit
Well-Known Member
Others have referred to "charging efficiency" too. To me, this is a moot point.
The car (as a black box) was given 14 kWh and it produces 47 miles nominally. I believe this is how it is evaluated from an EPA performance perspective.
You could either think of this as 14 kWh going into the battery with no "losses", or you could think of this as 12 kWh going into the battery and 2 kWh lost as heat... It doesn't really matter. In either case you expended 14 kWh to get 47 miles.
If you want to try and reverse-engineer how much Honda Engineering holds in reserve, then OK... these "losses" may matter to you. As the vehicle operator it doesn't matter.
It matters for drivers who are concerned about battery longevity. If the car uses only 12 kWh out of 17 kWh, that means Honda is conservative with battery management, so I wouldn't be to worried about charging to 100% or running the battery dry. This for me is much more important than driving energy efficiency.
MrFixit
Well-Known Member
@Agzand, We will likely never be able to infer enough technical detail about the battery management system to make intelligent operational adjustments to significantly influence longevity. There is ample evidence that Honda has buffering at both the top and the bottom. Longevity was undoubtedly one of their key design drivers since they don't want to lose their shirts with an 8 year warranty (across a very wide variety of user style / sophistication).
If you are able to infer enough technical detail to intelligently alter your operating style and improve the longevity beyond what the designers envisioned, you are a smarter man than I am !!
If you are able to infer enough technical detail to intelligently alter your operating style and improve the longevity beyond what the designers envisioned, you are a smarter man than I am !!
12 kWh is useful if you care about driving efficiency and it is also relatively fixed. The charging efficiency varies a lot depending on charging L1 vs L2, temperature, etc, and gives you an idea of cost to operate the vehicle. As stated, the wall kWh is what really matters and is used by EPA to give rating.
Typically PHEVs that run the engine at higher charge levels can't use the entire battery to prevent the engine running from damaging it. The i3 REx won't start engine even for maintenance until 75%, and other PHEVs top out around 85%. Battery only cars often charge to 95 or even 100%.
Cars should maybe go away from kWh measure as it is misleading, like thinking the Clarity has 17 kWh usable. Tesla is actually going away from this. If they do advertise it they should only advertise usable.
Typically PHEVs that run the engine at higher charge levels can't use the entire battery to prevent the engine running from damaging it. The i3 REx won't start engine even for maintenance until 75%, and other PHEVs top out around 85%. Battery only cars often charge to 95 or even 100%.
Cars should maybe go away from kWh measure as it is misleading, like thinking the Clarity has 17 kWh usable. Tesla is actually going away from this. If they do advertise it they should only advertise usable.
fotomoto
Active Member
I think the better word for this statement is "capacity"; 17kWh capacity of which 12kWh is used (usable). Kinda' like a gallon of milk isn't stored in a true gallon container. Gen 1 Volt has a 16kWh pack of which 10.5 was originally used. From an (somewhat) educated consumers point of view, I really like knowing both numbers. The typical joe may only care to know the usable figure; especially once (if?) kwh/mile calculations become more mainstream terminology.
Last edited: