Voltage testing and questions

Hello,

I’m trying to do some battery testing/comparisons to see if it’s time to replace mine (I already know the answer is YES, but I thought I would post my findings for additional comments and/or suggestions).

The rides: 2007 328xi (115k on the odo) and 2008 X3 (77k on the odo). Both with original battery.

Test equipment: BAFX ODB Scan tool and Torque Pro for Android..

328xi:
Before starting, the voltage is reading roughly 11.2.. it dips as low as 9.0 during start up, then smoothes out once the alternator starts running around 12-13 volts.. (the starter definitely works a little harder to crank the engine when it’s cold or the very first start after sitting overnight).

X3:
Before starting, the voltage reads roughly 11.8. It too dips but only to about 10.2 during start up, then smoothes out once the alternator starts running to around 13+ volts. (Starter fires the car instantly every time)

I know these ODB scanners can be flaky, so I’m going to run my tests again with a real volt meter plugged into the lighter…

I’m no expert, but I assume I should be seeing a constant 12.4-12.8 with the car turned off and voltage closer to 15 when the car is running?

Looks like the 328i needs a new battery and the X3 should be good for at least another year.

328 defiantly x3 marginal
I would change both unless you want to get stuck .

Originally Posted by brewder

Test equipment: BAFX ODB Scan tool and Torque Pro for Android.

Deep-six that POS....purchase a reliable & capable tool.

Below 9.6 VDC during crank is an issue. Replace that battery.

Originally Posted by CALWATERBOY

Deep-six that POS....purchase a reliable & capable tool.

Do you get commission from them?

If any ELM 237 works then the data is going to be fine. The worst I've read is that some don't function in the high speed mode; mine does. Digital either works or does not work despite what manufactures of $100 hdmi cables may say. Glitches appear as glaring errors.

Originally Posted by MP3_E46

Do you get commission from them?

If any ELM 237 works then the data is going to be fine. The worst I've read is that some don't function in the high speed mode; mine does. Digital either works or does not work despite what manufactures of $100 hdmi cables may say. Glitches appear as glaring errors.

If you replace the battery, what is the registration procedure with BAFX's product?

Does it define BMW P Codes specifically?

Originally Posted by CALWATERBOY

If you replace the battery, what is the registration procedure with BAFX's product?

Does it define BMW P Codes specifically?

Of course the generic device won't do BMW coding. They pull generic codes which assist in many situations, work with any car and did we mention cost next to nothing

Most people will never need more. If they get a code than cannot be given meaning even after Googling then the $300 restricted BavTech or $700+ unrestricted BavTech are options. For me $300 for something that's both feature restricted and restricted to three VINs is too much. If it could do coding like turn off the seat belt gong I'd have bought one. It does not, so I am going the ncsexpert route as soon as the car is out of warranty. Thought about doing it asap but don't want to jeopardise the warranty.

Simply being able to watch how fast the coolant heats up on my dash mounted phone without wires to the OBD port is worth the $24.

http://www.amazon.com/gp/product/B005NLQAHS

coding setup cost 100 or less. It takes some time to set it
up but its not VIN restricted and you can do the battery resets and anything else
worth doing.

Originally Posted by MP3_E46

Of course the generic device won't do BMW coding. They pull generic codes which assist in many situations, work with any car and did we mention cost next to nothing

Most people will never need more. If they get a code than cannot be given meaning even after Googling then the $300 restricted BavTech or $700+ unrestricted BavTech are options. For me $300 for something that's both feature restricted and restricted to three VINs is too much. If it could do coding like turn off the seat belt gong I'd have bought one. It does not, so I am going the ncsexpert route as soon as the car is out of warranty. Thought about doing it asap but don't want to jeopardise the warranty.

Well, the diff I see between BT models is the number of VIN's it handles - capabilities are same both models.

Not intended as a low level programming tool. Still, for <$300, so what? You'll get commensurate value....maybe see what's happening you can't now vis-a-vis power issues.

Shadow & hidden codes totally useless until a problem comes along....then you must whip it, or pay the man his toll. Oof!

Originally Posted by ctuna

coding setup cost 100 or less. It takes some time to set it
up but its not VIN restricted and you can do the battery resets and anything else
worth doing.

The lower levels yield total control, but study, skill, & experience are needed to steer clear of issues. High fence for most.

BT offers what mechanics & shadetrees need at low price, I say a pretty good price.

EZ to deal with, the larger share o'benefit, IMHO.

Originally Posted by CALWATERBOY

Not intended as a low level programming tool. Still, for <$300, so what? You'll get commensurate value....maybe see what's happening you can't now vis-a-vis power issues.

Agree it's value for what it can do. I might get one for the mean time and re-sell when the car is out of warranty (will do the coding then).

My gut is saying raise a stink at the dealership and get them to figure this out now I've proved it's battery related, but I just want these final gremlins fixed and a reliable DD for Winter.

Originally Posted by ctuna

coding setup cost 100 or less. It takes some time to set it
up but its not VIN restricted and you can do the battery resets and anything else
worth doing.

Looks like more fun too

So my SA tells me that my model (2007 328xi) can have either a 640 or 720cca..... I thought that was interesting. Any thoughts on why my car might have "one or the other"?

Amp hours is one of the more important specs
And they don't have it printed on the battery or in the advertizements
for most battery manufacturers . You have to ask.

Originally Posted by brewder

So my SA tells me that my model (2007 328xi) can have either a 640 or 720cca..... I thought that was interesting. Any thoughts on why my car might have "one or the other"?

Cheapest supplier at that time?

Originally Posted by MP3_E46

Cheapest supplier at that time?

hmm... maybe.. He quoted me two different prices though "depending on which one is in my car"... I would prefer the higher cca's but I was a bit miffed why he didn't just quote ONLY that battery...

Originally Posted by brewder

hmm... maybe.. He quoted me two different prices though "depending on which one is in my car"... I would prefer the higher cca's but I was a bit miffed why he didn't just quote ONLY that battery...

Sorry, I mean at the factory. Supply Chain and all that - you can be sure when built, the car got whatever was least expensive to BMW and matched specs.

CCA won't make much difference. When registering the new battery you'll tell the car Ah and AGM or Lead Acid. Apparently AGM tend to last much longer for not much more up front cost.

Originally Posted by ctuna

Amp hours is one of the more important specs
And they don't have it printed on the battery or in the advertisements
for most battery manufacturers . You have to ask.

Generally they quote Reserve Capacity which can be converted to Ah.

Originally Posted by brewder

So my SA tells me that my model (2007 328xi) can have either a 640 or 720cca..... I thought that was interesting. Any thoughts on why my car might have "one or the other"?

Ask your SA if one is for the hardtop and the other for the convertible.

Originally Posted by CALWATERBOY

Deep-six that POS....purchase a reliable & capable tool.

Attachment 355224

FWIW.. I compared the output from the BAFX ODB reader against a true voltage meter... it was spot on.. the battery will be replaced on 1/31!

Originally Posted by brewder

FWIW.. I compared the output from the BAFX ODB reader against a true voltage meter... it was spot on.. the battery will be replaced on 1/31!

It's worth $24. Now how you going to register the new battery, or did you buy an identical BMW unit?

Memory's a funny thing, often sure when actually mistaken & hazy. Mine says: Even a new battery should be registered to reset software adapted to deal with the failing unit, to charging a new unit, a very diff profile.

'Course in my case, hazy might mean crazy.

DSX?

Originally Posted by CALWATERBOY

It's worth $24. Now how you going to register the new battery, or did you buy an identical BMW unit?

Memory's a funny thing, often sure when actually mistaken & hazy. Mine says: Even a new battery should be registered to reset software adapted to deal with the failing unit, to charging a new unit, a very diff profile.

'Course in my case, hazy might mean crazy.

DSX?

Since I don't own the BT tool, I have to bite the bullet and just let the dealer do it... They quoted me $417 for athe 640cca and $438 for the 720cca version.

Originally Posted by DSXMachina

Ask your SA if one is for the hardtop and the other for the convertible.

For a datapoint my E93 came with the 90Ah 720CCA battery

Originally Posted by brewder

Since I don't own the BT tool, I have to bite the bullet and just let the dealer do it... They quoted me $417 for athe 640cca and $438 for the 720cca version.

That's an insane markup considering many replace with a ~$100 battery from WalMart. Check out BMW Coding to DIY register the battery with a $100 cable; it looks pretty easy.

Originally Posted by CALWATERBOY

It's worth $24. Now how you going to register the new battery, or did you buy an identical BMW unit?

Memory's a funny thing, often sure when actually mistaken & hazy. Mine says: Even a new battery should be registered to reset software adapted to deal with the failing unit, to charging a new unit, a very diff profile.

'Course in my case, hazy might mean crazy.

DSX?

Yes. No. I don't know. BMW's policy is that their computer controlled alternators are throttled to precisely match the ability of the battery to take a charge, and the rate at which charging will optimize the life of the battery given demand (load) on the system. Registering the battery ensures that the best charging rates are established for the battery from the get go.
I've heard tales of non-registered batteries not lasting, and I've seen non registered batteries go forever. I'd register the battery to play it safe, but wouldn't lose a wink if I didn't.
Always glad to set the record straight.

Edit: Batteries are different now. Most BMW's have AGM construction, something new, and there are also two other types one of which is the traditional cell construction. I think the most important factor is the construction and that if an AGM type is replaced with an AGM type then your worries about not registering are less.

Originally Posted by DSXMachina

Batteries are different now. Most BMW's have AGM construction, something new, and there are also two other types one of which is the traditional cell construction. I think the most important factor is the construction and that if an AGM type is replaced with an AGM type then your worries about not registering are less.

Wikipedia Tech Note

A VRLA battery (valve-regulated lead–acid battery) more commonly known as a sealed battery is a lead–acid rechargeable battery. Because of their construction, VRLA batteries do not require regular addition of water to the cells, and vent less gas than flooded lead-acid batteries.[1] The reduced venting is an advantage since they can be used in confined or poorly ventilated spaces.[2] But sealing cells and preventing access to the electrolyte also has several considerable disadvantages as discussed below.

VRLA batteries are commonly further classified as:

Absorbed glass mat (AGM) battery
Gel battery ("gel cell")

An absorbed glass mat battery has the electrolyte absorbed in a fiber-glass mat separator. A gel cell has the electrolyte mixed with silica dust to form an immobilized gel.

While these batteries are often colloquially called sealed lead–acid batteries, they always include a safety pressure relief valve. As opposed to vented (also called flooded) batteries, a VRLA cannot spill its electrolyte if it is inverted. Because AGM VRLA batteries use much less electrolyte (battery acid) than traditional lead–acid batteries, they are sometimes called an "acid-starved" design.

The name "valve regulated" does not wholly describe the technology. These are really "recombinant" batteries, which means that the oxygen evolved at the positive plates will largely recombine with the hydrogen ready to evolve on the negative plates, creating water and preventing water loss.[1] The valve is a safety feature in case the rate of hydrogen evolution becomes dangerously high. In flooded cells, the gases escape before they can recombine, so water must be periodically added.