trickle charging how long?

[Ron07x5]

Motordavid did not say I put charger on for two weeks, just 10 to 18 hours. Our use of x5 will be low miles often on level ground. I would like to know if we may deeply discharge the battery this way or not.

So my plan is to manually charge at 1 then 2 and 3 month intervals. If manual charging time increases in like linear pattern then I will know we can face deeply discharging the battery.

I know once a battery has less than 50 percent charge the voltage it provides drops. If lower voltages cause systems to get flaky then I want to avoid that..

Seems nobody really knows what the algorithm of battery charging is so I am left to discover in part by this experimental manual charging.

[motordavid]

Originally Posted by Ron07x5

Motordavid did not say I put charger on for two weeks, just 10 to 18 hours. Our use of x5 will be low miles often on level ground. I would like to know if we may deeply discharge the battery this way or not.

I meant, why wait to 'recharge' for two weeks? Unless it's not convenient, or you are running some kind of test. The low miles/rolling around town may or may not provide for keeping batt charged; in my experience with our cars, it does not. Or maybe it is OK, but hooking up our BT regularly is easy stuff, for 'prevention'.

So my plan is to manually charge at 1 then 2 and 3 month intervals. If manual charging time increases in like linear pattern then I will know we can face deeply discharging the battery.

Batts should go a month or more, and some surely do...my old 'company car' used to sit in airport parking lot(s) for 2 weeks straight, and I never trickle charges those car(s). That was then, this is now, with very different levels of electronics on cars, and maybe different/increased loads and charging req's.

I know once a battery has less than 50 percent charge the voltage it provides drops. If lower voltages cause systems to get flaky then I want to avoid that..

Seems nobody really knows what the algorithm of battery charging is so I am left to discover in part by this experimental manual charging.

Not exactly an EE or Batt xpert here; it is purely anecdotal, but my battery charging regime has worked on my Scoots for 30 yrs, and on our cars for 20 years. Good luck in your test regime, and curious to read an update.
BR, mD

[Ron07x5]

It will be interesting if I discover x5 would become more and more discharged. There.is no question the alternator can charge the question when and if the computer software has the alternator charge. I believe.the software.design seems to minimize alternator use.to then improve epa gas mileage. But this is problematic if the x5 is used lightly?
We shall find out!

[josiahg52]

My 2011 X5 35d sat for 16 days with the doors locked and alarm armed and it started right up first time. Zero hesitation or drama. I have not looked to see how old the battery is but I got my X5 in November. My driving routine consists of several one to two mile trips a several times a week and a 50 mile trip once every six or seven days. These longer trips are key, I think.

Incidentally, if you want the best battery maintainer, get a BatteryMINDer. I have several and keep them connected to my cars while they are not being operated regularly, i.e., greater than six months, over the winter, etc. I also use them on my spare batteries or other "bad" batteries that other people have given me over the years.

Between my recovery procedures and strict maintenance routine, I have recovered many of these "bad" batteries to greater than 95% reserve capacity. My oldest battery is over ten years old and recently tested over 120% of it's reserve capacity.

It's a hobby and a profession.

[London Lad]

Originally Posted by Ron07x5

It will be interesting if I discover x5 would become more and more discharged. There.is no question the alternator can charge the question when and if the computer software has the alternator charge. I believe.the software.design seems to minimize alternator use.to then improve epa gas mileage. But this is problematic if the x5 is used lightly?
We shall find out!

The system will only disengage the alternator under acceleration if the battery charge level is relatively high in the first place, if its low it will charge all the time. This cut off point is, IMHO, set to low and if the battery is older, or conditions arduous such as low temperatures, short runs or high demand, the battery can become discharged.

I used to find in the winter, running my remote diesel cabin heater could render the car unable to start, even though the heater is supposed to cut out if it detects low battery voltage or low fuel.

If I could I would code this function off as I think it's value to economy is pretty much zero and it's there just so BMW can claim to use wasted breaking energy. I have not been able to discover how to code it off or recalibrate it.

My solution has been to fit a 110ah battery and recode the car to suit. This has solved my problems and I now don't need to use a mains charger at all.

I stress this has worked for me in my particular usage patterns and may not be the answer for others.

[e30cabrio]

What tender charger is recommended for an AGM battery in a 4.4 e53?

[e30cabrio]

Thoughts?
NPower Automatic Battery Charger/Maintainer — 2/8/12 Amp Charge Rate, 12 Volt Batteries | Battery Chargers| Northern Tool + Equipment

[josiahg52]

Originally Posted by e30cabrio

What tender charger is recommended for an AGM battery in a 4.4 e53?

What type of AGM battery do you have in your E53 X5?

Originally Posted by e30cabrio

Thoughts?
NPower Automatic Battery Charger/Maintainer — 2/8/12 Amp Charge Rate, 12 Volt Batteries | Battery Chargers| Northern Tool + Equipment

That charger is good for recovering batteries that are severely discharged but not for continuous use.

[e30cabrio]

This from Autozone:
Duralast Platinum/Battery Price: $174.99
Core $15.00

• Part Number: H8-AGM
• Warranty: 3 YR
• Notes: *** 900 Cold cranking amps (1000 cranking amps)***. 160 / 95 reserve minutes. Warranty consists of 3 years free replacement. STOP!: Use a memory saver (located in the store GOTTChA kit) to prevent the need to reset vehicle systems. Battery is vented to outside of vehicle. Battery located in rear under spare tire.

[BMWOO7]

In the summer months, the X5 doesn't get driven as much as we drive our 650. With that said, it was about two-three weeks since my wife drove it into the office and back home (about 40 miles round trip).

I have the BMW trickle charger and had it on for about 1.5 days before it started to flash the Green LED & the Red LED, it then took about another 1/2 day for it to go Full Green LED and stay there.

This I have found is about average for the X5 as my 2011 was the same as my 2013 is.

As well, in the winter time when the 650 is in storage, I might take it out if we have a nice clean day (no road salt etc...) for a quick drive (maybe once a month at most) and it has always remained in a state where it will always start and no issues.

The only difference in my case anyway is that when the 650 is in storage it is locked, and the X5 is unlocked (I don't know if this makes any difference or not). I sometimes think that they use less power (draw) when they are locked.

Given all that I've also recently heard that BMW has started recommending replacing the battery at certain service intervals as they are just 'hard' on the battery.

The only battery issues I've ever had were with my 2011 335i Convertible. After about two years the battery would not hold a charge and BMW replaced it under warranty.