For those M4's that do a lot of sitting …

[John dillinger]

anyone put a battery tender on ? and if so, can you pls tell me which ?

[to_riffic]

Got this and it's awesome.

http://www.amazon.com/gp/product/B00...ilpage_o01_s00

[kitw]

I like CTEK chargers and bought this:
http://www.amazon.com/CTEK-56-926-LI...y+charger+ctek

[aboulfad]

Originally Posted by John dillinger

anyone put a battery tender on ? and if so, can you pls tell me which ?

are you looking for a charger for our LiFePO4 batteries ? i think that's the only one i've seen on this forum: http://www.amazon.com/CTEK-56-926-LI.../dp/B00EUF6UM8

[kylecronin]

Why would you buy an M4 and let it sit? Such a waste of a great car.

[Marckymarc305]

Originally Posted by kylecronin

Why would you buy an M4 and let it sit? Such a waste of a great car.

I work offshore and mine seats three weeks parked. Then I spend two weeks at home to drive it.
Bmw dealer said its not good for the car but I won't let anyone drive it for me.
After three weeks, it starts right away

[shortseller]

Originally Posted by Marckymarc305

I work offshore and mine seats three weeks parked. Then I spend two weeks at home to drive it.
Bmw dealer said its not good for the car but I won't let anyone drive it for me.
After three weeks, it starts right away

Pretty sure up to a month and you're good based on my experience, but if never hurts to hook up a charge device especially if it's much more than that and even more so if your up for the winter and just plan to start it up now and then and not able to drive a good distance to help self charge.

[Fast4d]

I have shorai LiFePO4 batteries on my bikes. they can sit 3 months and start with zero issues.

that's one of the benefits of LiFePO4.

I don't think you can use any battery charger. it has to output over a certain Voltage or get a specific one for LiFePO4

[RocketBoots]

Originally Posted by kitw

I like CTEK chargers and bought this:
http://www.amazon.com/CTEK-56-926-LI...y+charger+ctek

I have this as well; works great. It charged my car and credit card

[aclockwrk]

I have the CTEK lithium as well, it's a very good charger. Cheapest place is Amazon to get it.

[AustinY 2208]

Using CTEK lithium for almost a year, it's a very good charger.

[AZAtom]

We have run 10 CTEK chargers rotating throughout our inventory (including multiple BMWs) for several years and never had any issues with the cars starting. At one point, one of the tenders went bad and we returned it to CTEK. It was promptly replaced under warranty with no questions asked. Great products!

[whatheheck]

I use this NOCO model and it works great. It charges all types of batteries including Lithium Ion.

Note that the M4 battery voltage will drop so low after sitting for 2 months not hooked to a charger that the battery will no longer hold a full charge and most likely will need to be replaced.

http://www.amazon.com/NOCO-G3500-Ult...s=noco+charger

Dan

[John dillinger]

Originally Posted by whatheheck

I use this NOCO model and it works great. It charges all types of batteries including Lithium Ion.

Note that the M4 battery voltage will drop so low after sitting for 2 months not hooked to a charger that the battery will no longer hold a full charge and most likely will need to be replaced.

http://www.amazon.com/NOCO-G3500-Ult...s=noco+charger

Dan

thanks dan

[whatheheck]

You're welcome.

When the M4 is delivered from the factory it has a maintenance checklist for the dealership to do. (I have a copy)

One of the checklist states (If I remember correctly) is to charge the battery after 6 weeks of sitting undriven.

My car sat on the dealership uncharged for over 6 weeks and when I took it for a test drive there was a warning message on the display "battery low, charge ASAP" or something like that.

The dealer said the car will charge the battery when I drive it.
Make a long story short I bought the car, drove it for 4 hours home and the low battery light did not go out.

I hooked up the battery to a battery charger when I got home and the battery will no longer take a full charge so I contacted the dealer and they replaced the battery and registered the new battery.

(Lithium Ion) Battery replacement cost for parts and labor = $1,800.00. Ouch! Lucky I did not have to pay for it.

So I encourage everyone to hook up their battery to a battery tender if you wont be driving it for over a month as replacement costs is not cheap if you are at fault. This info is also covered in the owners manual.

Hope that helps.

Dan

Originally Posted by John dillinger

thanks dan

[whatheheck]

Also, take note that proper charging of Lithium Ion battery is supposed to be low and slow so be patient.

[Jockey]

Time for me to buy one, poor car is going to sit not driven for 7 months.

My last BMW did fine sitting for 6 months with a battery tender, hopefully this one reacts the same way.

[TheFlyingMouse]

Originally Posted by whatheheck

Also, take note that proper charging of Lithium Ion battery is supposed to be low and slow so be patient.

You're also supposed to keep them cold and at 50% charge when stored for extended periods to maximize the life of the battery. Not sure if BMW's internal charging system already takes care of this. I would guess not, since sometimes you really need that full charge.

Anyone know of a tender that will do this for you?

[Donger Kim]

I thought it was as simple as disconnect the battery and let it sit... Unfortunately my job requires me to be out of the country for 75% of the year (at the minimum) so my brand new car will unfortunately be doing lots of sitting :/

[WinterScene]

Originally Posted by whatheheck

(Lithium Ion) Battery replacement cost for parts and labor = $1,800.00. Ouch! Lucky I did not have to pay for it.

I'm genuinely confused (or ignorant) as to why the battery replacement cost would be $1,800.
getbmwparts shows that the battery MSRP is $326.47. If they replaced every single battery part including clamps I could only come up with $1,200 per this diagram:
http://www.getbmwparts.com/parts/201...agramCallOut=1

Did they give you a breakdown of the costs as I'm not looking forward to shelling out that kind of money in a few years...The $326.47 seems reasonable though.

[04cobra]

Does the ctek tender get hooked up to an extension cord and then a wall outlet? I heard some people just plug it into the cigarette lighter, but that makes no sense to me.

Just wanting to confirm

[04cobra]

I just bought one as well