Battery testing questions Topic is solved

[abscate]

We are in the beautiful time of year when a weak battery magically works again, and lulls you into the confidence that it is fine, and you will get another year - only to whack you over the head next November with the text from SWMBO 'my car won't crank' just as they close the door on the plane to the 12 hour flight to TLV...

[WhatAmIDoing]

In terms of batteries, I have used mostly Interstate here (which is the OEM Volvo in Canada). I changed the battery out on our 2006 XC70 last fall as I did not know the age of the battery and we have had the car for 7 years and I have no record of a change before that that I can find. I previously swapped out a 9 year old battery from a 760 Turbo I had 15 years ago that had started to fail, and the same with a 1999 Audi A4 we had that had a 10 year old battery when it started to fail due to lack of maintenance by the dealer (it was almost dry although the checked off it had been inspected at every service).

But quality is the key. I removed and replaced the battery in my 03 4Runner as the dealer said it was weak. It is a Panasonic OE Toyota battery. A new battery from the dealer was $260 CDN, whereas a higher rated Interstate from local supplier was $160 CDN with a better warranty. Swapped the battery out and although it said it was 'maintenance free' all it has was stickers over the access holes on the top. I removed those and added distilled water (it was below min. mark) and charged with my smart charger. It charged fully. Took it to get the core refund and had it checked and they said the battery was still strong and good to go so it came back home.

Batteries these days are kind of a crap shoot. Some times you get a good one and it lasts years, and sometimes you barely get 2 years out of the same brand. I'm still using the World SourceOne battery that the PO bought used from a junkyard over 7 years go. Rated at 650CCA. Still cranks good every time. Not sure how old it is, as it wasn't stamped with a manufacture date, but if the copyright sticker is to be believed, it says 2006. My record setter though is the John Deere branded battery I bought 21 years ago. Finally stopped holding a charge and just couldn't turn the engine over, and Deere replaced it free as a courtesy service.

[scot850]

So over 2 weeks I have had both batteries charged and sat in the car for about 4-5 days each. Both batteries drained to about 12.5V very slowly so I am now convinced there is nothing wrong with the car or batteries.

Neil.

[misha]

Good news!

[scot850]

It is as the car has been provisionally sold to another Volvo enthusiast for his son to drive!

Neil.

[oragex]

Just chinning in, I haven't read the other comments, so sorry if I'm saying the same, but here's my recent experience on a similar issue.

I'd mention that my car is a 2003 so the alternator may charge in a different way the battery

Besides corrosion on the power cables or even cracked power (red) cables at the battery or alternator or engine bay fuse panel, it can be three things:

1. worn out battery (normal after 10 years or so)
2. parasitic drain causing the battery to discharge overnight and getting recharged while driving the car: after a few months of discharging-recharging even a new battery gets damaged and cannot be properly recharged again.
3. worn out brushes at the regulator, faulty regulator, or even alternator pulley (or other pulley on the serpentine belt) about to seize

If replacing the battery, always keep the old one as well. With the new battery and the engine running, read the voltage at the battery: it should read around 14.4V. If it's rather 14.0V or less, the alternator may not be charging properly (to make things a bit more complex, a good alternator may put low voltage such as 13.5V to a good battery when the battery is really fully charged, above 98%, see the link below). If the alternator works fine, the next morning before firing the engine, read the voltage at the battery: it should show around 12.6-12.7V. If it's rather 12.0-12.1V it means there is a parasitic drain (a short in one of the car modules or switches). Better to drive with the old battery until fixing the parasitic drain. To check for a parasitic drain a 10A multimeter is needed and there is a specific way to check this on our Volvo cars, I'll soon make a video about it.

It is normal for a battery to drop the voltage after shutting off the engine. With the engine on, the voltage at the battery will read as much as the alternator is pumping out. Right after shutting the engine off, the voltage at the battery will start dropping in less than 1 hour down to the actual charge of the battery (a new battery will stay at 12.7V)

This site has some information on these voltages https://www.batterystuff.com/kb/article ... asics.html

[abscate]

I’ve fired lots of battery test questions and it’s just lead faced?

What...is This capital of Assyria?

What ..is the flight velocity of an unladen swallow?

[scot850]

Well all will be answered, maybe in time......

Thanks for all the useful info, and thanks for the education to oragex. For a non-electrical guy that type of info is excellent, so thanks.

We can say this is closed.

Neil.