Battery care on a short tripper?

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Originally Posted by Quattro Pete
Originally Posted by gathermewool
That's too low. One and/or all of the following is/are true:

1. There's no way you charge every two weeks (or even monthly) if this is what you noted

I did not say that I charge it every two weeks. I asked if I should be charging every two weeks.


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2. You need to find the source of your excessive parasitic drain
There is no excessive parasitic drain, but sometimes I wonder if my alternator is doing a good job actually charging the battery when the car is running.

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3. You will need a new battery soon
No question about that. This battery is 5 and a half years old and likely on its last legs.

Look, all I'm asking is this: should I just accept this kind of battery life, or should I take some measures (such as frequent charging) that will result in my next battery lasting much longer? If it's not going to last much longer anyway, then what's the point?



I believe I answered your question, sir.
 
Hardwire a ring terminal charger connection with an SAE plug to some hot 12v underhood spot. I used the jumping connection to the mains wire under the hood on my 135i.

One of these:

[Linked Image]


You may need to extend the leads a bit to get a pigtail out from underhood. Easy to hide in a BMW grill...

Then you can just connect it up on a whim, anytime you think of it.

Would I run AGM? For a trunk mounted BMW battery? Yes...

But just get some charge in when you can.
 
11.6 volts is unsat under any conditions. You're lucky the battery isn't freezing. Act now!
 
Originally Posted by eljefino
11.6 volts is unsat under any conditions. You're lucky the battery isn't freezing. Act now!


I wish I knew what unsat means.

Mine has been down to 11.5 volts, but that when it's like 20 degrees out. Mine actually has a voltage display, it's in a hidden menu. It was like that 2 years ago. Today it was about 35 and it's at 12.0 volts. It was at 11.9 before I shut off the lights, the heated seats and the radio. My car starts giving out battery low warnings at 11 volts and starts to cut off various things like the radio etc.
 
Originally Posted by Wolf359
Originally Posted by eljefino
11.6 volts is unsat under any conditions. You're lucky the battery isn't freezing. Act now!


I wish I knew what unsat means.

Unsatisfactory, I'm guessing.

BTW, I checked running voltage this morning... 25F outside. With the engine running, voltage at the battery shows 14.15V, checked with a DMM. At the same time, car's computer (hidden menu) shows 13.6-13.7V. Not sure why the discrepancy.

DMM is not faulty - I checked with multiple ones.
 
Originally Posted by Quattro Pete
Originally Posted by Wolf359
Originally Posted by eljefino
11.6 volts is unsat under any conditions. You're lucky the battery isn't freezing. Act now!


I wish I knew what unsat means.

Unsatisfactory, I'm guessing.

BTW, I checked running voltage this morning... 25F outside. With the engine running, voltage at the battery shows 14.15V, checked with a DMM. At the same time, car's computer (hidden menu) shows 13.6-13.7V. Not sure why the discrepancy.

DMM is not faulty - I checked with multiple ones.


Interesting may just be your car or just the nature of the built in voltage meter. Mine sorta does the same thing, in the 13 range at idle but goes up to 14.3-14.5 on the highway. Today at 28 it was at 11.9-12 volts with the engine off with the built in voltage gauge.
 
I posted this in another thread, but I thought I'd update this thread as well:

Some results from a cheap battery tester after a drive:

[Linked Image]


[Linked Image]


[Linked Image]



Right now I put this battery on a charger. The charger shows it's at around 50% charged, yet the charger only pushes about 1.5A of current into it at 14.8V. This battery has had me perplexed for quite some time now. I can't figure out what is going on with it.
 
Quattro I think that battery has early stage sulfation and high internal resistance.
Charge it at ~14-14.5V for 8-12 hours, until charging current stops dropping.
Check electrolyte level, then charge for an hour at 16V.
Then see how it tests.
I have a couple automotive chargers, but I prefer an adjustable DC supply for full control.
 
Last edited:
Originally Posted by Quattro Pete
I posted this in another thread, but I thought I'd update this thread as well:

Some results from a cheap battery tester after a drive:

[Linked Image]


[Linked Image]


[Linked Image]



Right now I put this battery on a charger. The charger shows it's at around 50% charged, yet the charger only pushes about 1.5A of current into it at 14.8V. This battery has had me perplexed for quite some time now. I can't figure out what is going on with it.




Have you tried the Recovery feature on your NOCO?
 
Originally Posted by circuitsmith
Check electrolyte level,
This is a maintenance free battery with no way to get to the electrolyte, unfortunately.
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then charge for an hour at 16V.
Thanks. I don't own a manual charger to accomplish this.

As for this BA101 tester, I don't really trust it. The internal resistance that it reports seems suspiciously low. And when I used it to check the battery in my SRT, where the battery is practically new and I keep it topped off, it showed that it's only charged to about 75%. Doesn't seem right.
 
Originally Posted by Duffyjr
Have you tried the Recovery feature on your NOCO?
I have. It didn't seem to make any difference.
 
Dropping to only 10.29v cranking the engine, is this overnight cold or a warm restart?

What is the temperature of the battery?

If it is a cold battery and cold engine then 10.29v is pretty respectable, in my opinion.

I view every engine start as a load test, watching a dashboard mounted digital voltmeter during cranking, and have watched my 1000+ deep cycle 5+ year old group 27 northstar AGM battery voltage fall lower and lower during cranking. When new it would stay over 12v, yet now 5 years later and 1000+ deep cycles, I now see it drop to the mid 9's overnight cold and not quite fully charged in low 60 f ambients It does not sound like the starter is struggling in the slightest, and 2 months ago in sub 20f a 96% charged battery dropped to only 9.2v.

Maintenance free flooded batteries require higher charging voltages to reach a true full charge, especially if they have been inadvertently or intentionally cycled deeper than 80% state of charge, which many vehicle's voltage regulation today intentionally does.

If I were asked to insure this specific battery were absolutely top charged, I would discharge it at about 15 amp rate until voltage fell to about 11 under that load, then instantly put it on a charging source, limiting amps to under 25 intially, but then bringing it upto and then hold it at 15 volts on my Meanwell rsp-500-15 adjustable voltage power supply, and hold it there until amperage tapered to near Zero.

This assumes a battery around room temperature, A 40 degree maintenance free flooded battery I would bring closer to 15.5v.

These MF flooded batteries behave a bit differently than normal flooded starting batteries, when one can observe the voltage and amperage flowing into the battery at that voltage and compare it to regular or marine batteries of the same general size.

As far as these impedence based battery testers, I personally would not view its readings as set in stone accurate and reliable, but it would be nice to compare its readings as the battery ages, or a longer extended recharge has been performed and see what differences arise from earlier tests. The trend will be most telling, compared to a one time readout on an unknown health battery at an unknown state of charge. and as far as the stae fo charge reading, that is entirely based on the voltage when it was hooked up, and full charged resting voltages will vary from 12.6 to 13 depending on the specific battery.

Goto a parts store with a new same group size battery and see what your tester reads on those........ The comparison will be useful and help you decide.

As far as recharging, Few 'smart' chargers will actually be able to return a somewhat compromised battery to full charge, as they will not hold high voltages for long enough, and the maintenance free flooded batteries requiring higher voltages is generally unknown and most otherise awesome mechanica have very little idea what a lead acid battery really requires to reach a true full charge as anything over 30% charged is likely going to be able to start the motor, meaning any charger that can get it to 85% or better is 'good enough'

But if one were actually cycling a battery, even fairly shallowly, and all of a sudden no new batteries were available in some sort of mad max sceanrio, the battery retuned to a true 100% state of charge would last 2x as long as the battery only returned to 98% state of charge.

You can restart your 'smart' charger over and over but you will have to bleed off the surface charge until voltage falls below 12.6v, then quickly restart the charger and let it go. It should seek mid 14v range for a period of time before reverting back to the mid 13v range, at which point little to no further charging will occur. When it reverts to 13.7 or less and flashes the green light, repeat the process. use the AGM setting also, if one is available. Generally the AGM will hold the battery in the mid 14v range for longer than the regular battery setting, and float will be higher than regular, but this of course varies among different chargers

Multiple restarts are the only way I have gotten the specific gravity to max out on not so healthy batteries using so called 'smart' chargers, and this is an annoying procedure, which is why I acquired adn predominately use the Meanwell adjustable voltage power supply, as it has 40 amps available to hold any dang voltage I command, for as long as I command it to do so.. Overcharging is a possibility but I've not yet destroyed any battery by forgetting to reduce voltage in time or disconnect it when full has been reached.
 
Originally Posted by wrcsixeight
Dropping to only 10.29v cranking the engine, is this overnight cold or a warm restart?
Warm restart.

Quote
What is the temperature of the battery?
Around 30F.


When I tested the battery the night before, it showed 0% charge level:
[Linked Image]
 
11.9v seems way low. Were doors open, lights on when you hooked it up? Meaning Any load on the battery? What does voltage drop to when you put the headlights and high beams on?

I've no experience wih 30F sulfated maintenance free batteries, only those in the 65F+ range that were drained to dead by a electric fan, that I can recharge myself on my adjustable voltage power supply, and honestly I have not recorded minimum voltage during engine cranking on it.

If you can warm battery upto room temperature, then your 'smart' chargers voltage might be adequate to return it to its maximum remaining capacity after multiple restarts, but if it is still 30F then that voltage must be pushed way higher for any hope of dissolving some of that sulfation back into the electrolyte.

I'd still recommend putting your new device on a new battery of same size group to get something to compare readings to.
 
FYI, this is after I charged the battery for a whole day. My charger was already indicating 100%, but it was still topping it off some.

I turned the headlights on for 10 seconds prior to doing the test to get rid of surface charge/voltage.

[Linked Image]
 
You could not pay me to believe any smart chargers state of charge percentage.

I'd believe only an accurate Ammeter, with the battery held at absorption voltage of 14.7+ at 77F.

Since NO smart charger asks for the size of the battery in amp hours, and it does not have a battery temperature sensor,

It simply cannot know when a battery is fully charged. it is guessing. Hoping.

The green light indicating full charge is mocking anyone who believes it.
 
Originally Posted by wrcsixeight
You could not pay me to believe any smart chargers state of charge percentage.

I know, but 46%?

My point was this battery tester can't be believed either. Going to return it as it is fairly useless.
 
I think the only figure I would believe on such a device is the resitance and the voltage, all the other figures seem to be little better than WAG's.
 
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