how often to run the gas motor

[khasenauer]

i am a proud new owner of an i3rex and i was wondering how often does everyone run the gas engine to keep it fit? i can not seem to find the information and the dealer said to run it at least once every other week. this seems excessive and somewhat defeats the benefits of charging it up from my solar panels at home. i had not used it in the first month after i purchased the car and a warning light came on stating it needed a diagnostic check. the service person told me to ignore that but, to run the gas at least halfway through the tank and refill it before going back to electrical charging.

 

[SSi3]

The REx will run it's own 'maintenance mode' every 6 (or 8?) weeks without you having to do anything.

 

[Jeffj]

But maintenance mode will only run if you are below 75% charge, so if you are getting warnings about maintenance mode that don't go away, that's probably the reason.

 

[jadnashuanh]

FWIW, the REx in maintenance mode will run for about (I think) 10-minutes...so, since it is generating electricity during that time, the computer won't let it run until there's enough 'room' in the batteries to accept it. They set that threshold at <=75% SOC.

 

[fdl1409]

The maintainance run starts automatically after 50 days without use. Runs for 10 minutes then. Last time it startet at 77% SOC, a little earlier than expected. Those 10 minutes are more than needed in my view, so if 50 days are coming close you can stop the maintainance run by starting the REx manually for some 2 minutes. Last time I forgot, so I got the full 10 minutes.

Had my REx since may 2014, still have not filled up the tank with 3.2 liters remaining after 19.600km.

Frank
Hoping to buy a REx-less i3 with 200+ miles range in the next 3 years.

 

[busaman]

well i have had my Rex 9 months now and only used the Rex once in 6000 miles and it has never run on its own or any indication that it needs to.???

 

[fdl1409]

Strange, it should run every 50 days. Never heard of anyone without.

Frank

 

[mindmachine]

Actually I remember when mine ran the maintenance cycle it ran for 12 minutes. And it will alert you that it is going to run. As for stopping it from running the full time it wants to run I think is a bad idea as you want it to warm up once it starts to get rid of moisture in the system. I am sure that is why they designed it to run on it's own if not used otherwise.

 

[justanotherdrunk]

only used the rex 3 times

once with the trunk open to test the maintenance mode just for fun

and twice to purposely run the batteries down to experience the rex driveability


hindsight is 20/20 and looking back now ...

i would have bought the BEV since ive never come close to actually needing the rex


:shock:

 

[jadnashuanh]

only used the rex 3 times

once with the trunk open to test the maintenance mode just for fun

and twice to purposely run the batteries down to experience the rex driveability


hindsight is 20/20 and looking back now ...

i would have bought the BEV since ive never come close to actually needing the rex

Over the years leading up to the i3 release, that was the finding of those that had the EV's BMW had out for testing...the vast majority of people would not need a REx, but they offer it to overcome the anxiety about running out of energy and getting stuck. Personally, I'm in the same boat, I figured with how I wanted to use my i3, I had no need to spend the money for a REx. If I'm going to be driving longer than the BEV, my other car is more comfortable and can carry more. Now, it doesn't get used all that often, and in reality, I could probably sell it and rent a car when needed for long trips, but it's paid for, and doesn't really cost all that much to keep around for when it is needed.

 

[imolazhp]

Congrats on your i3!

Up until my car got updated to the July, 2015 software update I manually ran my coded REx once per week to keep the CEL's away. Since getting the update I have not seen another CEL but have only gone about 15 days between running the REx so far. If your REx is coded and only ethanol fuel is available in your area you might try to use a tank of fuel every 90 days or so. It is my understanding that ethanol fuel only has a shelf life of about 90 days. Even though I have found a local station that sells pure gas I still plan to try to use a tank about every 3 months just to be on the safe side. I hope/plan to keep my car after lease-end, so whatever small steps I can do now to prolong its life later, hopefully will give me more trouble-free driving. I last filled up on 8/14 and I'm at about 2/3 tank so I'm about on schedule.

Off topic, a co-worked came into work yesterday "Did you see gas is down to $1.90?" Me: "Nope, its $0.00 for me, I don't use it." Coworker: Puzzled look, didn't know how to respond.

lol

 

[alohart]

It is my understanding that ethanol fuel only has a shelf life of about 90 days.

I don't know about that, but ethanol does absorb water from the air which could cause problems in a fuel tank that's open to the air. However, the i3 REx's fuel tank is pressurized and not open to the air, so I'm pretty confident that BMW's default maintenance mode would be sufficient to prevent fuel problems.

However, I have a BEV and don't understand why so many REx owners experience check engine lights (moisture somewhere, I've read), so I don't know whether forcing the REx engine to run more often than maintenance mode would reduce the frequency of these check engine lights.