New Product Idea: >$400 PiHEV charger kit - feedback wanted

But in those cold temperatures engine runs just to get itself and catalytic converter warm so benefit of charging the hybrid battery is very small when it’s cold outside.

Actually you do get a better fuel economy in cold temperatures if you park Prius (when sitting for hours) with 2…4 bars of hybrid battery. Then you get good fuel economy in the end of the trip by using mostly battery power. And at the beginning of next trip it still gets bad fuel economy but instead of wasting fuel just to warm up it charges the hybrid battery.

 

A block heater would be more useful than a charger in cold weather, I'd say, at least based on my Gen 4 experience (not having either a block heater or a charger).

 

I'm not too sure, there's the initial stage of warm up that would drain the HV battery if you set off, but after that there's a second stage when the engine tone or strain is much lighter. I can enter EV mode or drive in a way that coaxes the engine to charge the battery. If I don't start moving by then and start getting some distance, I've normally see a +5mpg decrease.

But what bugs me is that the engine is constantly getting cold and stays on a light load, after I presume the cat has warmed up after that first part. As much as possible I drive with the pulse & glide technique. Gliding and slowing to a stop almost always has the engine on. I think it might be the recent 5W-30 oil it had that the mechanic stubbornly insisted in using (as the manual says) instead of 0W-20.

I'm been trying to use the EV button every time I start to coast down - until the engine becomes too cold again.

@bhtooefr A block heather wouldn't do for me, apparently cables across the path is illegal. Even if I did, I wouldn't trust any of the nosy neighbors around to leave it be.

 

Well, in that case, this product wouldn't help you either, unless it was plugged into a gasoline-powered generator... which would defeat the point, would it not?

 

Maybe, it's concern I would take.

But from just one experience I had, I have seen how it behaved at full 8 bars right after start up - after getting 7 bars on the way home, then a quick force charge. After sitting over the night, I didn't wait for the warm up and it pulled up hills with over 35 mpg on the instant-mpg-reader and reflected under 50 mpg for the first 5 minute interval. Normally, like today, the first 5 minutes is well below the 25 mpg thresh hold, something like 17 mpg. ... This is an '07, if I should've mentioned that before.