XC70: Electrical Best Replacement Battery

[GMcL]

Originally Posted by GMcL

I'm surprised to read some of the batteries going early.
I had an '05 MY S60 which still had the original battery in when I sold it at 9+ years. That got put on a trickle charge once/year between Christmas and New Year.

My current S60 has flashed up battery low warning a couple of times. I have a dashcam permanently live. It usually takes a week of not driving to trigger the message.

If I needed a replacement I'd go Volvo unless hideously overpriced then I'd look at Bosch/Varta.

Haha, Murphy's Law in action. Yesterday evening got the "Low Battery" warning message. Put the battery on a recondition charge yesterday evening. All looked good this morning, drove to work and got the Low Battery warning again. My car turned 4 years at the end of last month.

Time to put my money where my mouth is...

[Rooster]

How are you charging it,

If you put battery leads pos to pos, neg to neg on battery the Battery Monitoring System will be having a hissy fit

[GrantA]

Originally Posted by Rooster

How are you charging it,

If you put battery leads pos to pos, neg to neg on battery the Battery Monitoring System will be having a hissy fit

Why is that then?? How do you charge your battery?? I have done this frequently on my MY '09 XC70 without any "hissy fit".

Not saying it doesn't happen but just noticed your Volvo is an '04 XC90 perhaps the "hissy fit" on your "Battery Monitoring System" is something associated with the year of your car as it doesn't happen on mine and no-one else has mentioned that on this thread. I do however remember reading a Thread in this Section about low voltage from the battery giving all sorts of warnings. On mine, if I don't use the car for a few days in the winter, I get a headlight failure warning on starting up but VIDA Dice identifies the fault as a low battery voltage.

[Rooster]

Nope do it daily on new volvo's

Positive to Positive,

negative to body of car or engine, anything but battery negative post,

Good practice on every car actually especially when trying to jump start with jump leads,

The BMS system monitors battery voltage and charge state and drain and then the smart charge alternator charges accordingly, charging or jumping across battery will upset this process,

[GrantA]

Originally Posted by Rooster

Nope do it daily on new volvo's

Positive to Positive,

negative to body of car or engine, anything but battery negative post,

Good practice on every car actually especially when trying to jump start with jump leads,

The BMS system monitors battery voltage and charge state and drain and then the smart charge alternator charges accordingly, charging or jumping across battery will upset this process,

I fully agree when using jump leads positive to positive and negative to an earth on the car, engine or somewhere else that has a direct (earth) connection to the negative battery terminal. The reason for this of course is hydrogen gas which is given off from a lead-acid battery and any spark near the battery, from connecting to the negative terminal, could cause an explosion. BTW I would never connect the negative terminal to the car body as some body parts are insulated from the engine, chassis etc to prevent electrolytic corrosion from dissimilar metals and some body parts are not even metal.

Although it is also recommended that most battery chargers are connected the same way as already stated for jump leads IMO it is possible to connect the positive and negative terminals of the battery charger directly to the battery as the charger should be disconnected from the mains when the connection is made and therefore no sparking should occur. Only when the connections are established should the battery charger be switched on.

I don't understand the term "the smart charge alternator charges accordingly", are you talking about a "smart" (electronic) battery charger - could you please explain. In conjunction with that I cannot see why by connecting the negative terminal to the battery i.e. "charging or jumping across battery will upset this process" as the position you are choosing to connect the negative terminal to will have a direct link via earthing straps from engine, gearbox or whatever direct to the negative on the battery unless, on the latest Volvos, there is now some electronic device fitted between the negative terminal on the battery and the earth straps fitted to the engine, chassis or whatever else is earthed.

[tt82]

I have read in the owners manual for mine that they don't recommend connecting the negative lead, instead saying it should be attached to a suitable earthing point. (anybody want to suggest one?)

I've had a couple of low battery warnings and more recently the headlamp failure on startup. Charged it 2/3 times with the negative lead connected to the battery since I've had it!

[GrantA]

Originally Posted by tt82

I have read in the owners manual for mine that they don't recommend connecting the negative lead, instead saying it should be attached to a suitable earthing point. (anybody want to suggest one?)

I've had a couple of low battery warnings and more recently the headlamp failure on startup. Charged it 2/3 times with the negative lead connected to the battery since I've had it!

Hi tt82, As I said before in my last post (sounds final....) if you are charging the battery with a battery charger IMO it is safe to connect the positive and negative leads directly to the battery terminals. That is what I have done for the last 40 odd years and, as I have always done it in a well ventilated area (outside), I have never had a problem. If you wish to follow the guidance in the manual then you do need to find a "suitable earthing point".

On that point (sic) I have just had a good look around my engine and would suggest possibly one of the best and most accessible places would be the bolt on the top engine mount, next to the cooling water reservoir, that connects the centre rubber part of the engine mount directly onto the engine. That is about the only suitable place I can see where there is an exposed metal bolt connected directly to the engine that is easily accessible and that is where I would connect my jump leads if I ever had to jump start the car. I would avoid the bodywork (as I explained above) as well as the front shock absorber / suspension mounts, piping or tubing, anywhere near the fuel rail, the radiator(s) or the headlight retaining clips. There are other "bits" bolted directly onto the front of the engine, below the plastic engine cover, that could be used but there is always the danger of shorting something out or damaging a hose or pipe. Perhaps those who have jump started their Phase 3 car could let us know where they connect the negative jump lead to.

I understand the "headlight failure on startup" is a classic warning of a low battery voltage on our cars and, as I said before, I experience that in the cold weather when the glow plugs take their bit of voltage out of the battery before the engine turns over.

[rogerb]

Originally Posted by GrantA

I don't understand the term "the smart charge alternator charges accordingly", are you talking about a "smart" (electronic) battery charger - could you please explain. In conjunction with that I cannot see why by connecting the negative terminal to the battery i.e. "charging or jumping across battery will upset this process" as the position you are choosing to connect the negative terminal to will have a direct link via earthing straps from engine, gearbox or whatever direct to the negative on the battery unless, on the latest Volvos, there is now some electronic device fitted between the negative terminal on the battery and the earth straps fitted to the engine, chassis or whatever else is earthed.

A lot of the newer volvos DO have an electronic device , a current ,voltage and temp sensor unit built in to the negative battery terminal clamp. If it is fitted there will be a pair of small wires going to it , one to the positive terminal and one to the cars electronics.
This is used together with other information to control the altonator output voltage .
In fact in some conditions the car will run off the battery on purpose , down to a set % of charge and hold it there, and charge it more under braking. This is all to do with fuel saving.
There is pages of info about it onVARDIS , one problem is that it works the battery harder.
If you charge the battery directly it dose not not know how much power you have put in and gets confused. This will cause it to have to relearn the battery , if you have a completely flat battery or change it for a new one , volvo state that you are meant to reset the system . In fact you can now buy an after market electronic plug in tool for doing this , and also a lot of other makes.
It will sort it selfie out eventually normaly.
This is not just on stop/start cars.
Roger

[GrantA]

Thanks Roger, For me that sounds like one technology "step too far", it is bad enough driving round without a spare wheel with your heart in your mouth every time you go over a pothole praying that the side wall of your tyre doesn't get damaged. That happened to me in France just after I bought the car and of course in France they refused to just change one tyre on an axle and I ended up buying 2 new tyres.

Getting back to the "sensor unit built in to the negative battery terminal clamp", as the car gets older, or if it is only used for short journeys, or the battery works harder (as you said) there is a greater chance that the battery will need to be replaced sooner rather than later - and then you have the problem of the "system" having "to relearn the battery". It all sounds as though car manufacturers are designing cars more and more so that they can only be maintained by the main dealers. Of course, as you said, "after market tools" are or will become available to overcome any "reset" or fault code problems but my point is; is it really necessary to do this as there doesn't appear to be any advantage to the car owner other than some fuel saving? I would actually dispute the fuel saving argument unless the car engine is very small and, IMO, any fuel saving on a larger engine would be very marginal. It would be nice to know what the "fuel saving" claims are and what engine size they are based on.

For my next car that will be one thing I will be looking to avoid.

[Rooster]

Basically what roger said,

Its not just volvo that runs this system, nearly all new cars do,

It can be reset by disconnecting the little sensor on the negative battery terminal for 20 seconds but doesn't always work,

New car batteries are AGM bateries and are differant to older batteries,

AGM explained - http://en.wikipedia.org/wiki/VRLA_battery