i3 REx with HoldCharge Coded

BMW i3 Forum

Help Support BMW i3 Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

r3zon8

New member
Joined
Sep 17, 2015
Messages
2
Can an i3 which has been coded to enable HoldCharge be driven completely without charging?
 
Technically yes, but every time you deactivate HSOC (for example shutting off the car), when you re-engage it, you can only re-engage it at the level of charge that its currently at. You'd probably lose a couple of percentage points each time this happened, and would eventually reach the point where you are at the nominal 6% level. At that point, you'd be restricted to only the power output of the REx (34 hp). People who have done extended trips on the REx seem to want to use it only to get to a place where they can successfully charge, not to just drive on gas.

So, while you could do this, the bigger question is why?
 
Jeffj said:
Technically yes, but every time you deactivate HSOC (for example shutting off the car), when you re-engage it, you can only re-engage it at the level of charge that its currently at. You'd probably lose a couple of percentage points each time this happened, and would eventually reach the point where you are at the nominal 6% level. At that point, you'd be restricted to only the power output of the REx (34 hp). People who have done extended trips on the REx seem to want to use it only to get to a place where they can successfully charge, not to just drive on gas.

So, while you could do this, the bigger question is why?

Not true, most of those who do a lot of RExing and post here seem to use it like a ICE car with a tiny tank. FrancisJeffries who was the first to describe the long range techniques posts here sometimes and he seems to use his as an EV most of the time but it also serves him for long drives too. I have taken a 1000mile trip in mine and I didn't even try to find a charge, just brought along a few gallons in a can to fill up between gas stations on the roadside.
Just keep the car turned on and exit through the passenger door when refueling if you want to keep a high SOC set point. That way the car never gets shut off and thus never loses the initial set point.
 
Was not implying that you couldn't or shouldn't do long range driving - its obviously possible to do so and many have (including me). Was just trying to respond to OP when asked if the car could be driven without charging. I interpreted that to mean indefinitely, which seems silly to me. Taking it on a long-range trip is certainly possible, as many have done. But the intent I was posting is that once the long range-trip is done (e.g. 300 miles, 500 miles, whatever), plug it in to get a charge again.
 
As I understand it, except if the car is almost entirely discharged, the percentage of charge you have when you select 'Hold' is the maximum amount you are going to get...IOW, the car won't charge above that value unless there's some unusual circumstances (like, say, you're going down a long grade and regen does it). So, depending on where you engage it, and if you stop and turn things off, you likely could run into problems. The i3 only runs on electricity, unlike say the i8 or the Chevy Volt, where they both have a significantly larger ICE, and can deal with things, including recharging the batteries. On the i3, it has essentially enough power to move you along on the level and maintaining your charge or recouping a bit if you exceeded the maximum it could provide previously for say climbing a hill or passing someone at speed. The dynamics of the thing mean that your top speed is limited if you really want to maintain things with the REx...34Hp, less conversion losses, doesn't make for a very big propulsion unit. Given that the size of the tank and the REx's fuel efficiency, at interstate cruising speeds, you'll be stopping about once every hour to keep the tank topped off. Yes, it can be done. No, it's not all that convenient. The choice is yours. The MPG isn't fantastic when using the REx compared to some other things. I'm currently renting a Toyota Camry with the small 4-cylinder engine, and I'm getting mid-30mpg out of the thing, and over 400-miles range. It's lots larger than the i3, and much more convenient as in several stretches, there were NO service stations within the i3's EV range...it would have taken use of all of the EV and most of the REx range between service stations along my chosen route, and then, I'd be stuck at a low SOC, and never get back unless I could plug in (none of those along the way, either!). To get from point A to point B, I could have gone another route, but I was sticking to the scenic route on purpose...I wanted to see the scenes!
 
Back
Top