Charging car battery?

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Jul 18, 2017
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This link may help . As far as I can see there is no need to re boot any of the ecu things.Note the main battery has to be turned on its side to facilitate removal. The auxiliary battery needs the post fastenings transferring. I’m inclined to think a good auto electrician could do this for you at home with either he or you supplying the batteries. He may surprise you and say you don’t need both changing🤔

Will you be videoing your efforts😁
Thanks. Yesterday morning after the car had been standing for 24 hours, both batteries were at about 12v. It has been confirmed that the original battery was a Bosch battery so it seems both batteries are over 6 years old?

If the seat is moved completely forward and then raised up, there is no issue changing the battery, but the aux battery needs to be removed. However National Tyres part of Halfords, told me that the seat needed to be removed and only a Jeep dealer could do that as cables needed to be disconnected.

At ETB around the corner the fitter did not even know where the battery was located or how to check it. I had to show him. The same fitter wanted to replace the AGM battery with a lead acid battery! This set off alarm bells whcih is another reason why I asked on here about battery chargiung or changing. Either way I now know a lot more about batteries than I did a week or so ago.
 
Nov 11, 2009
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Thanks. Yesterday morning after the car had been standing for 24 hours, both batteries were at about 12v. It has been confirmed that the original battery was a Bosch battery so it seems both batteries are over 6 years old?

If the seat is moved completely forward and then raised up, there is no issue changing the battery, but the aux battery needs to be removed. However National Tyres part of Halfords, told me that the seat needed to be removed and only a Jeep dealer could do that as cables needed to be disconnected.

At ETB around the corner the fitter did not even know where the battery was located or how to check it. I had to show him. The same fitter wanted to replace the AGM battery with a lead acid battery! This set off alarm bells whcih is another reason why I asked on here about battery chargiung or changing. Either way I now know a lot more about batteries than I did a week or so ago.
I had a E30 BMW 325M sport and couldn’t figure out where the battery was. Not under the bonnet, not under seats but tucked away in the boot for weight distribution.
 
Oct 19, 2023
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Given that both batteries are the same age and you're paying someone else to fit them I'd be tempted to have them change both. The additional work to change 2 vs change 1 will be negligible if they're done at the same time, but if they have to do them at different times the labour cost will likely double. If I couldn't do the work myself I'd bite the bullet and ask an independent auto electrician for a quote to supply and fit and take it from there. Granted one of the batteries may be OK at the moment, but at 6 years old it's likely to fail soon. Do both and you should have peace of mind for the next 5 or 6 years. The other advantage of this is that if they turn up with the wrong battery it's their problem. If they turn up and you've bought the wrong battery for them to fit it's your problem.
 
Jul 18, 2017
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I learnt a valuable lesson today. Never believe a fitter working at chain store! We had to go to the hospital this morning and on the way back stopped at an independent that had been mentioned on another forum.

They did all the checks and said both batteries were healthy! All this stress and worry about nothing all because of two different chain garages!

Guess where we will be going when the batteries really do need changing!
 
Nov 11, 2009
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I learnt a valuable lesson today. Never believe a fitter working at chain store! We had to go to the hospital this morning and on the way back stopped at an independent that had been mentioned on another forum.

They did all the checks and said both batteries were healthy! All this stress and worry about nothing all because of two different chain garages!

Guess where we will be going when the batteries really do need changing!
But how do you know which of the "chain stores fitters" is correct? I assume that since you don't see a need for changing the batteries now that the car is not doing odd things?
 
Jul 18, 2017
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But how do you know which of the "chain stores fitters" is correct? I assume that since you don't see a need for changing the batteries now that the car is not doing odd things?
Neither as both stated that the battery needed changing. Chatting with the Inde he said that the weird things probably occurred because the car was standing for 7 - 10 days before being used. We have used it a couple of times in the past week however there has never been an issue starting it, just the strange things happening. LOL! :D

If it wasn't for the helpful advice on here we would probably be more than £300 out of pocket! Again a big thanks to everyone. (y)
 

JTQ

May 7, 2005
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Still leaves the question, why were the two batteries at so low a state of charge, just at 12.0 & 12.1 volts?

You are not running it for long enough, your meter is duff, or the one that could really hurt, the charging system has a problem?
Plus, the indy possibly was not as competent as the other fitters?????

Best go for a really good run in it.
 
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Oct 19, 2023
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Good to hear. The 12v you measured sounds low though, what type/make of meter are you using and are you confident that it's accurate?
 
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Still leaves the question, why were the two batteries at so low a state of charge, just at 12.0 & 12.1 volts?

You are not running it for long enough, your meter is duff, or the one that could really hurt, the charging system has a problem?
Plus, the indy possibly was not as competent as the other fitters?????
Possibly because the vehicle had been sitting for about 10 days and alarm drained battery? Inde showed me the reading of 12.4v and also did the load test. Also last Friday I went to another fitter who said similar. Charging system reads 14.4v when the engine is running and that is supposed to be about right for the Jeep.

Just to add, we will be using the Jeep a lot more of the next week or so and will then see if there are any changes. It no longer does the strange and weird things.
 

JTQ

May 7, 2005
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Those values, which we were not I believe made aware of, really paints quite a different picture to the one we were struggling to help with. They read good news.

I would agree that seeing at least 14.4 volts maintained for a while is what would be expected, and possibly with odd peaks going into even into the 15 volt + region occasionally.
 
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Mar 14, 2005
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This link may help . As far as I can see there is no need to re boot any of the ecu things.Note the main battery has to be turned on its side to facilitate removal. The auxiliary battery needs the post fastenings transferring. I’m inclined to think a good auto electrician could do this for you at home with either he or you supplying the batteries. He may surprise you and say you don’t need both changing🤔

Will you be videoing your efforts😁
A useful video (for those with Jeep's) but I was quite concerned about the guy's carelessness regarding preventing the removed cables from accidentally making contact, and the use of a non insulated ratchet tool which came perilously close to shorting contacts at one point. The main batteries negative appeared to be touching the battery termial at another point.

Connections should be either held apart safely or the terminals covered to protect from accidental contacts.
 
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Sep 29, 2016
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I notice that there are a lot of references to Tayna for batteries.

I have bought from Tayna and will likely do so again in the future.

I also purchase items from Alpha Batteries, and I am very happy with them also.

It's worth looking at alternative suppliers for comparison on prices and warranties etc. it is sometimes surprising to note the significant differences there can be from one supplier to another.
 
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JTQ

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With both mentioned online battery vendors, it is worth the effort of a call to explore if as a member of either of our clubs or even a few other organisations, there is a bit of extra discounting to be had.

It could of course be just down to my well tuned, well practiced and refined phone call manner.;)
 
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JTQ

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However, it can also depend on how rudimentary the charger is, if particularly dumb then coupling it up and waiting might work, if a bit more intelligent it could struggle to see whether it ought even safely try.
Even relatively simple chargers might check if it is supposed to be a 12 or 6 volt battery.
 
Jul 18, 2017
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In response to my OP I have since found out that on the Jeep you can charge the battery while it is still connected. Makes a big difference when you use the correct terminology when using Google. LOL! :D
 

Sam Vimes

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By coincidence and my bad luck my car battery gave up on me yesterday. Of course a day when we needed it and it was extremely bad weather.

I'd had my suspicions for a while since the battery volts would sometimes drop to below 10 at startup. Overnight and first thing in the morning it would be just below 12V. Battery only 5 years old but like most things these days they don't last as long as they used to. Plus more stuff powered on constantly. Did the Stop/Start function make that much difference as its hardly ever used.

I always disconnect the a battery lead before charging the battery in the car. While some sources say you can leave it connected I think that may depend on the charger itself, so I take no chances.

A 30 minute charge got me going and we completed our shortish journey - there and back but not turning off the engine in between stops.

A new EFB battery is winging its way to us and hopefully will be here by Monday. You can get next day delivery but not if you live in the boonies :)
 

JTQ

May 7, 2005
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Battery only 5 years old but like most things these days they don't last as long as they used to.
"Most", ???, some though Sam do last way better than the "rose tinted days", when did you last do a decoke, regrind the valves, rebore or have a crankshaft journal regrind?
Modern batteries have a lot harder life and typically are a lot lighter than back then.
I remember few of us back when did not have a battery charger at home, today I suspect only those into our hobby and like, then not for our cars.
Understandably hurt by the inconvenience and cost of yesterday you are "down" a bit, so much kit is IMO pretty good today compared to decades back.
 
Jul 18, 2017
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By coincidence and my bad luck my car battery gave up on me yesterday. Of course a day when we needed it and it was extremely bad weather.

I'd had my suspicions for a while since the battery volts would sometimes drop to below 10 at startup. Overnight and first thing in the morning it would be just below 12V. Battery only 5 years old but like most things these days they don't last as long as they used to. Plus more stuff powered on constantly. Did the Stop/Start function make that much difference as its hardly ever used.

I always disconnect the a battery lead before charging the battery in the car. While some sources say you can leave it connected I think that may depend on the charger itself, so I take no chances.

A 30 minute charge got me going and we completed our shortish journey - there and back but not turning off the engine in between stops.

A new EFB battery is winging its way to us and hopefully will be here by Monday. You can get next day delivery but not if you live in the boonies :)
Now that we have been using the Jeep a lot more, the voltage is now showing above 12v. I have also be told that one can disconnect the negative on the battery to recharge the battery without needing to remove it from under the seat. Apparently the radio etc does not have coding as not need to make it theft proof.
 
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, so much kit is IMO pretty good today compared to decades back.
I have to agree. I remember the days of walking out to the car in the damp / snow and wondering how long it would take to start and whether or not it would need a squirt of easy start in the carb ...... Electronic ignition and fuel injection seemed to be the turning point for me in that respect.

Batteries, mine recently failed (or was on its way out) at 8.5 years old. My last car had one new battery in 15 years and 165,000 miles. The wife's car has had 2 in 16 years but it is a tiny 40ah battery.
 

Sam Vimes

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I agree todays cars are more reliable than my earlier ones but when they do go wrong its not easy doing diy repairs on anything other than the basic things. Mind you on my old Toyota even changing a headlight bulb meant a trip to the garage. But some consumables don't last as long..... Tires, brake pads and discs for example.

Of course when things do go wrong on todays cars they can be very expensive to fix. Which gives support to the old adage 'To err is human, but it takes a computer to really foul things up'

Caravans in my opinion have gone the other way. My earlier caravan had no problems I can recall and was built well. Successive vehicles - motorhome or caravan..... not so good.
 

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