Folks, we're far off the mark here.

First of all, it is pointless to apply direct energy conversions to assert a direct FE contribution via the 12V sub-system. This is neither useful nor beneficial to the value of this thread. That is why I made it pretty clear that this mod does not feed the traction battery. The most anyone can say is that there is an "undetermined" inference on FE but unless you do your calculations right, you are just being subjective. That's all.

Now, the high school physics level calculations although an interesting recap for many, still do not represent anything even remotely close to the reality. The direct FE contribution is MUCH lower than what it was stated above. Even though each solar panel produces a maximum if 125mA at 17 Volts (which is something I did not disclose on purpose), the total contribution to FE would still would be significantly lower than 17 Kilo Joules. Why? Because there are way too many significant conversion and thermal losses in the system (upstream and downstream).
Now, when you consider that the flow of charge to the 12V battery actually comes from the traction battery (downstream), THEN you can BEGIN assessing the indirect impact on fuel economy. Good luck coming up with an approximation even remotely useful to anyone.

Personally this mod works for me because I have a slightly higher than normal power drain on my system on the account several permanently active systems in the car. If you are one of those folks who also drive no more than 10 mile trips and never have a properly charged 12volt system (especially in the cold winter months at -40F) then this MAY be for you. It should not be too hard to see that it is in my interest to supplement the power drain that would otherwise come from the IMA battery. In my case the 12V battery (and I suspect the same for some other folks) will ALWAYS take a charge... I categorically observe the phenomenon every single day. And if you have current flow, then it is taking a charge (or at the very least supplementing a existing loss).

How you use your IMA SoC is still up to you. I prefer to use less of it to keep my 12V system charged.


Cheers;

MSantos

 

That works out to roughly 2.83VPC, well above the gas generation threshold of a VRLA... Now admittedly while you're pulling current to power the other mods it's probably not an issue, but how does it react during the time it's just sitting out in the sun? Does the the internal resistance of the battery itself bring it down enough not to be a problem, or are you making a trade-off between VRLA service life and traction battery SOC?

 

Correct. The internal resistance of the battery in addition to the load imposed by the other devices on the system does bring the voltage down to its nominal range. As I indicated, it is rare for me to see more than 40mA flow from one panel - perhaps because now I keep my battery well topped. I observe the effective voltage level either through the scangauge II or through the multimeter and it has never reached 13V, it gets pretty close, but even with the second panel plugged in it does not reach 13V. So no, under these conditions I am not concerned about the life of the VRLA at all. If anything I now expect it to have a longer life.

Cheers;

MSantos

 

Do you need to unplug the solar panel when you are driving the car? I know some solar panel requires you to do that as driving with the panel attached will damage it.

 

Nope. This solar power contains protection circuitry so it won't be harmed... even if you invert the polarity by mistake.
Besides, the IMA charging voltage oscillates between 13.5 and 13.8 volts which is well within the solar panel's operational range.

Cheers;

MSantos

 

Hi msantos,

Did you investigate what could be the impact on the warranty of such devices ?

Pierre

 

Pierre:

I have it first hand from Honda Canada that these mods will not void the warranty as long as they follow roughly the following guidelines:

- The aftermarket device must be cleanly and professionally installed. Honda or its factory trained technicians may refuse to perform any work on the vehicle if they deem it unsafe or improper.
- The device must not interfere with any of the OEM systems and must be easily/effectively disabled or removed for proper servicing and warranty related work.
- The device must not render the vehicle (or its operation) unsafe.
- Last and not least, the device shall not be the cause of any mechanical or electrical failures. Honda empowers the dealerships to make the call on this one.
- The third party devices must protect the vehicle's electrical system with a suitable inline fuse and any other applicable means.

It is because of this that all my modifications can be easily removed/disabled if it ever becomes necessary. I already had my dealership look at my vehicle and at the exception of the direct TPMS sensors inside my tires (which they could not inspect) my car is compliant.
In other words, if you do a neat/clean/safe job then you should be OK.

Cheers;

MSantos

 

Frankly, I think it's a gimmick, and ultimately not very "green"

 

Seriously, would this "gimmick" be of greater benefit to some folks if I painted it "green" then? :

Cheers;

MSantos

 

There are definately benefits, esp if you are drawing extra current from your battery, i.e., cell phone charger, heated seats.

I am interested in doing this, but I have tinted windows and plan on using a sun visor as soon as the weather turns warmer.

It there a way to mount it in the front so it isn't blocked by a sunvisor? Seems dificult to perfect a sun-blocking and sun-harnessing setup.

And, thanks M for the great post.