Hello everyone:
After I purchased my new baby, I took some voltage readings . I used one of the cigarette lighter USB/voltage plug in's off ebay that shows voltage. The reading showed 12.3 motor off not on a charger and 13.7 running. I have read all the posts here and I am on the border line both ways. I have had it on my CTEK since I got it but left it off overnight for the readings. Do I need to get in the back next to battery and read it with a voltmeter or just go get another battery since this one is on the border line, I think? The carfax showed that a new battery was put on by the dealership in 2/20. I was told that I did not need a new battery by the dealership since it was only a year old. BUT I don't trust many dealerships. Any thoughts.

jdog

 

Yes you want to use a voltmeter at the battery in the morning and without using the ctek overnight as you stated. 12.6 volts is the minimum value. Now if you get 12.5 or 12.4, put it on a charger, not a ctek. Charge it and see if it holds. If it doesn't hold 12.6 volts, replace it. An alternative is to drive to an auto parts store and have them load test it. They can do it while the battery is in the car, but they should disconnect it first.

If you buy a new battery place the order one day ahead and have them charge it off the shelf. They will be happy to do that for you.


But I'll just say that's what I would do if it were mine but I'd also ask myself, am I having any issues as those readings off a lighter are probably a non issue.

 

I checked the voltage at the battery with a voltmeter showed 13.1. An hour later it showed 13.02 and the stupid cig lighter registered 12.3. So I wasted money on that stupid thing, so into the trash it goes. I will see what the voltage at the battery is tomorrow morning without the ctek. I thought the ctek was a battery charger. So do I need to buy a battery charger along with the ctek? I looked at the battery. It had all of the Jaguar stickers on it. But as I looked closer I noticed it said Interstate Battery made in Dallas Texas.

 

Ctek is a battery maintainer not a charger and takes at least 2 days of charging to bring battery up to cjharging levels . it is only 5amps . charge overnite using a 10 amp rated normal charger and i bet your battery will be good

 

A battery SHOULD last 6 years. On our beloved cars, which are mostly driven in the warm season, the battery should be tended by a CTEK in the Winter.

If you want to be on the safe side, change the battery every 5 years. Its cheap insurance. But it won´t substitute for a CTEK.

Hermann

 

Im running a change every 4 to 5 years. I don’t bother with a maintainer. Haven’t had any problems even when the car sits for months on end.
Cheers!

 

I checked the battery this morning with no overnight ctek. The voltage read 12.9. I started the car and checked the voltage and it read 13.58. Should it be charging around 14+ with the car running? I ordered a battery charger. I will charge it overnight with the battery charger when I get it and check it then. Is the alternator OK? Thanks everyone.

JDog

 

13.8 is good as it varies between 13 and 14 V. Also when they went to a BCM (battery control monitor) system after so many cycles the system goes into a regen battery mode where you will see it depletes the battery down to 12.5V and then starts the recharging cycle. It is explained in the maintenance manual under charging system.

 

^^^^^^
This. What JT wrote. You're good.

 

Thanks everyone!

 

1.Can you charge the battery with a battery charger still in the car without removing the battery cables from the battery? Or do you have to remove the battery from the car and charge it?

2.How can you tell if it is the alternator is bad or going bad?

 

I let batteries change every 5 - 6 years. 6 is deadline.

I had a CTEK cable set installed, so I do not look for the battery, but have a cable with the CTEK specific connection in the trunk. I just connect the CTEK to this connection, and the cable through the tailgate is protected by a hose, sliced sideways.

Whenever I think I will not drive for 3 or 4 weeks, I use the CTEK.

Hermann

 

If the car is running and you disconnect the negative battery terminal and the car dies, the alternator is bad. Kind of an iffy procedure though, as it may spike some electronics and blow them up.

 

1- yes you can charge it without removing the battery but you need to monitor it against overcharge. KABOOM! Unplug the boot lamp(s) and leave the boot open for ventilation. You should have good ventilation regardless of whether it's in the car or not. I prefer to charge mine on the bench for safety reasons cause I likes it when my car's not on fire. (KABOOM)

2 - easiest way to see if your generator is working is to use something like Torque Pro app on your phone. There are other apps as well but it will provide you with voltage output. There are several pinpoint tests you can do also. Download the workshop manual and follow them in section 414.0

If your generator is under performing, you'll most likely get a code or message "Battery not Charging". Codes would likely be
P163200 - Generator faults sensor/circuit - Charging system fault
B2A9016 - Battery low - Circuit voltage below threshold

and possibly B2A9116 - Battery - Circuit Voltage

 

Interesting thread.

I decided to test my battery and ended up being a little confused if I'm honest.

So I picked up the car on Wednesday and the previous owner had a trickle charger cable fitted to the battery and said he had it on charge recently.

Never one to take anyone's word on something one of the first things I did when I got home was to attach my Optimate 6 to the cable and let it do it's thing.

Seemed to charge OK for the first hour or so and then seemed to go into standby so I assume the battery was in tip top condition. The owner said he had it changed 18 months ago. I tried to take a pic of the top of the battery and I think it is a Jag one.

When I went to test it for voltage this morning I couldn't get a reading from the end of the trickle charging cable so decided to investigate further. Took off all the trim panels to reveal the battery and unbolted the charging cable to find that it had only been fitted with a 3A fuse ( my optimate cable has a 15A fuse ) which unsurprisingly had blown as my Optimate ramped up during the initial charge when I got the car. So I swapped out the el-cheapo cable and fitted my Optimate cable.

Enough of the preamble here's my confusion. Earlier in this post the comments were that if the battery tested less than 12.6V then it's time to change it.

Mine read 12.2V. I then tested my 1 month old Ford Puma Hybrid daily runner and it showed 12.18V so what's going on ?

I've also attached two pics of the Optimate charging. First one is after about 10 minutes then after about 45 minutes,

*** Update *** Did a quick voltage check after 1 1/2 hours on the optimate and it read 12.56V so looks like it's taking charge.

Any thoughts would be appreciated

Thanks

 

SteveX150 - Taking a charge yes. Holding a charge is the question. Once your maintainer has the battery fully charged, remove the maintainer and wait several hours. Overnight will do. Check the voltage then.

 

The way I see it, a battery could use a good kick-in-the-pants once in awhile... my F150 goes dead (under 12.2V) when I let it sit a couple weeks. Longer than that and I get the ole 2-10-40-200 Schumacher out and give the battery a good 40 amps. Sure, it only stays at 40 for a minute or so, then gradually the charge rate drops to what the battery wants to take.
Alternators are 150 amps easy, and diesel ones are upwards of 300 amps. With a regulator, you can't really overcharge a battery nowadays unless you have a crappy charger.

 

Last check my battery is now showing 13.1V, let's see if it keeps it

I've just ordered a decent 45amp charger as well

 

Random reading below 12.6 volts really means nothing. There are other factors which affect the reliability of the battery. As Sean said, holding a charge is key and being able to maintain constant voltage under load, such as operating the starter motor will tell you much about it or a sophisticated battery tester will as well.

 

Guys

Change the battery Before you get stranded......which could be life threatening in the summer.

https://www.jaguarforums.com/forum/x...07-xk8-247928/