Battery tender for agm battery via jump posts advised?

[upallnight]

I use a solar charger to keep the battery maintained. Sometimes I don't drive the X for months and with the solar charger maintaining the battery I never ran into a situation with a dead battery. I plug it into the power connector plug under the glove box. That circuit is live all the time.

[andrewwynn]

Good place where do you put the panel?

[upallnight]

Originally Posted by andrewwynn

Good place where do you put the panel?

On top of the dash.

[andrewwynn]

Hey Don: "dibs" on your X5 when you want to part with it. :-)


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[omodos]

Well appraciate all the responses....I opted for a standard lead acid battery, the agm and this both had the same warranty period despite the agm being 2x the price! ....as for my starter being the issue, guy swapping battery said he was sure my starter is not the issue, wpoll kindly posted me an audio file of the starting "noise" of his x5 3.0d and it sounds quicker, starter spins faster(despite him starting it in at 6c) here it is 26c and got a new battery and the starting still sounds slower compared to wpolls but improved compared to 5 year old battery that was in there..so a tad confusded


I have to hijack someone with an identical x5 and see listen to theirs start...driving me nuts this...

[andrewwynn]

"slower sounding start" with a new battery and recent killed battery almost always is the starter. "The guy" unless he measured the current draw is speaking out of is butt. I've seen at least four cases on xoutpost in the past year of a worn out starter drawing more current than design by a LOT. The symptoms are: cranks a little slower than usual, hard starts when cold especially, battery gets low easily causing some odd need for a jump start.
I think the diesel draws about 250A normally. I've been working on a system to measure the starter current by measuring the voltage from the cigarette lighter to the B+ I just need to know the scale. I did the measurement once just as proof of concept and of worked great.

[omodos]

@andrewyynn...hmmm have my suspicions...battery was a bit weak and had signs of leaking at top end of case despite it being a bosch...wot i plan to do is see how new battery fares over the next few weeks , if i get the same issue i.e after 1 week of my school run driving where battery needs charging with ctek i know its the starter sapping amps(although doing max 7miles per day cant be good or sufficient to keep battery topped eventhough alt is good and i have no patasitic draw)
As for battery guys testing he went on about the voltage drop and was adamant it was not the starter...but you are right doesnt make much sense to tell me the voltage drop on starting , when wot i needed to know was amp draw. Wot i really wish i could do is to take out starter....some say is easyish from below others have gone at it from the top and is a pain....one last port of call is another mechanic i know see if he has exeperience of other 3.0d x5 and how quick it kicks into life....thanks again for the feedback

[andrewwynn]

I plan to get the reference measurement of voltage drop during start which will make is very easy to measure your starter current draw. My wife will go a week driving less then a mile twice a day with no problem of the battery getting low. Not diesel but when temp not low you should not need to use a battery tender to get a reliable start. You need to determine your start current so you won't kill a brand new battery

[omodos]

Yup temps are crazy here still...IF you can get a base value will be great...think will just about be able to hook up voltmeter to jump posts in engine bay or use the unlocked obc to show me voltage before and during start-up and we can get any idea of starter draw from this eh? Anyhow very interesting you are good with yours considering low miles you cover.....

[wpoll]

Originally Posted by omodos

Yup temps are crazy here still...IF you can get a base value will be great...think will just about be able to hook up voltmeter to jump posts in engine bay or use the unlocked obc to show me voltage before and during start-up and we can get any idea of starter draw from this eh? Anyhow very interesting you are good with yours considering low miles you cover.....

The unlocked OBC UBAT: reading won't be much use during the start - it's too unstable to read an accurate value. Even a DVM on the jump posts isn't much use; this is one of the times a real analogue meter with a
needle is best.

I still have that 392Amps draw figure in the back of my mind and can't help but think that this is all going to end with a new starter motor and a happy omodos.

BTW, if I short run my 3.0d for a week (2x 10km per day) the battery is starting to show signs of depletion. I'd say I'm loosing maybe 3-4% of the charge each day I run it like this. A single decent run (2--30kms) brings it back up. Or a night on the maint. charge.