Hold charge function

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Tim

Member
Joined
Oct 25, 2014
Messages
6
I'm enjoying my new i3 but am baffled when using the hold charge function it seems to still use the battery slightly. Is this correct or should I plan a trip to the dealer?

Regards Tim
 
How do you know the battery is being used?

What sort of terrain, what speed?

And where are you in the world?
 
Tim said:
I'm enjoying my new i3 but am baffled when using the hold charge function it seems to still use the battery slightly. Is this correct or should I plan a trip to the dealer?

Regards Tim
Click to expand...

If your I3 is stock - when the battery gets down to 6% the generator fires up and it will not charge the battery over 6.5% - its only a "get to your destination" mode in which the generator powers the car for speeds up to 60-70 mph depending on aux usage and terrain.

There is a "fix" available which allows you to start the engine at any battery level below 75% thus allowing you to travel and maintain a higher level of reserve battery.

Your computer display allows you to check the SOC state of charge in the menus.
 
Idleup said:
Tim said:
I'm enjoying my new i3 but am baffled when using the hold charge function it seems to still use the battery slightly. Is this correct or should I plan a trip to the dealer?

Regards Tim
Click to expand...

If your I3 is stock - when the battery gets down to 6% the generator fires up and it will not charge the battery over 6.5% - its only a "get to your destination" mode in which the generator powers the car for speeds up to 60-70 mph depending on aux usage and terrain.

There is a "fix" available which allows you to start the engine at any battery level below 75% thus allowing you to travel and maintain a higher level of reserve battery.

Your computer display allows you to check the SOC state of charge in the menus.
Click to expand...

Actually that is not really true, there is no BMW sponsored fix for cars sold in the USA. There are work arounds such as hacking your car to enable use of the Rex implementation like you can in the UK. Also there is a company that will sell you a flash drive to enable it yourself by just plugging it into the USB port on your car.
 
I have the mod on my I3 I can start the engine at will anytime I'm below 75% SOC. I wouldn't have the I3 any other way!


Mike
 
Tim - as I expect you know, the answer in part depends on where you are owing to the way the REX engages. That is why it is useful to have your location on your profile.

In UK I find that the ‘hold charge’ does pretty much what it says, if I engage it manually or when it starts automatically at 6.5%. However, if I’m driving over a few hills it drops below the original threshold but rises again on the flats or downhill. For example, yesterday the REX engaged automatically as the SOC dropped to 6.5%. I was driving from home up a series of fairly long hills at about 30 mph (only probably about 800 ft) and the SOC dropped to 4.5%. By the time I was back home the SOC was back to 6.5%. I see a similar effect if I drive at more than about 65 mph when the SOC drops but again regains when I drop the speed.
 
For the US cars - that 6.5% charging thing is a total waste and only there for BMW to brag on total electric miles - it makes no sense to deplete the battery to that level since with 2-4 people in the car and attempting to climb a hill or pass a car results in an unsafe situation.
 
Idleup said:
For the US cars - that 6.5% charging thing is a total waste and only there for BMW to brag on total electric miles - it makes no sense to deplete the battery to that level since with 2-4 people in the car and attempting to climb a hill or pass a car results in an unsafe situation.
Click to expand...
That's not really the case. It's to do with US CARB legislation for the BEVx class of vehicle which are allowed to claim to be a full EV despite having a gas powered range extender.

But I agree it sucks and the legislation should be changes to allow people to use it when they need it. Say on intercity trips where they know there's no way they can reach the journey end without using gas, so best to use the REX out of the city where it causes less pollution - well - I mean the pollution has less of an effect on people.
 
Idleup said:
For the US cars - that 6.5% charging thing is a total waste and only there for BMW to brag on total electric miles - it makes no sense to deplete the battery to that level since with 2-4 people in the car and attempting to climb a hill or pass a car results in an unsafe situation.
Click to expand...
Yes, yes, we know. Its be talked to death on here. However, your comment does not really add much to the conversation. :twisted:
 
Well I think everyone's comments are important wither you agree with them or not.

Don't get me wrong - I love my I3 even in stock configuration, I just made it better by installing the DVDinMotion mod - now I can start the engine at will and save my battery for when I feel I want to use it instead of some computer routine.

The part that bothered me the most is there is no facility for you to test start the engine. What if you're out in the middle of nowhere with your kids & wife in the car at night and your motoring along heading home and the battery gets down to nothing and for some reason the engine doesn't start! With a Range Extender menu in the car, I can test the motor any time I like. In addition, if I experience a engine fault, I can motor safely off an expressway or to a place were I'm safe!
 
I dont disagree with your comment, it was just that it has been said many times before.

You can ‘test start’ the REX - there is a recent thread on here that gives a link to the required document - here is one of them http://www.mybmwi3.com/forum/viewtopic.php?f=13&t=2075
 
Yeah sure - You and I know the routine of pumping the throttle and opening the hatch but how many poor saps driving I3's know about that - possible none!
 
Tim, that behaviour is quite normal. When the Rex fires up, the remaining charge in the battery is used as a "buffer" so it's quite normal for the level of charge to fluctuate.
 
Thinking about getting the Hold Charge Function. (not found on DVDinmotion site).
We rarely use our REX feature (due to the wife's reluctance to drain the car down to only a couple of miles remaining). But before Christmas, dressed formally, heading to special event, we thought we could find a place to recharge. Instead (with only 20 miles remaining) the "REX Maintenance cycle" came on and failed - displaying a take me immediately to the dealer message. After powering off / On to clear - thinking hopefully this is a glitch - i3 did the same in a few miles. I wanted to continue on to event (which we had waited for 2 months to attend) - instead my wife said please no - we have get it to the dealer 20+ miles away.
Bottomline: We never made it the event, just rolled into the dealer on dashes for several miles - vehicle kept by dealer for 4-5 days. They said they had to "swap out" the spark plugs.
All-in-all the wife has little faith that the REX will be available when we need it - on a vehicle with less than 3k miles and only charging at 70%.
So - looking at the dvdinmotion.com website, no where do I see the Hold Battery State Fix, or mention anywhere or battery charge state for i3 - only sales of playing your DVD player while driving
 
LivingBetterThurEV said:
Thinking about getting the Hold Charge Function. (not found on DVDinmotion site).
We rarely use our REX feature (due to the wife's reluctance to drain the car down to only a couple of miles remaining). But before Christmas, dressed formally, heading to special event, we thought we could find a place to recharge. Instead (with only 20 miles remaining) the "REX Maintenance cycle" came on and failed - displaying a take me immediately to the dealer message. After powering off / On to clear - thinking hopefully this is a glitch - i3 did the same in a few miles. I wanted to continue on to event (which we had waited for 2 months to attend) - instead my wife said please no - we have get it to the dealer 20+ miles away.
Bottomline: We never made it the event, just rolled into the dealer on dashes for several miles - vehicle kept by dealer for 4-5 days. They said they had to "swap out" the spark plugs.
All-in-all the wife has little faith that the REX will be available when we need it - on a vehicle with less than 3k miles and only charging at 70%.
So - looking at the dvdinmotion.com website, no where do I see the Hold Battery State Fix, or mention anywhere or battery charge state for i3 - only sales of playing your DVD player while driving
Click to expand...

My exact thoughts - and the reason I went for the fix!!
 

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