XC70 Battery Options

[BigGreenThing]

I too have an XC70 D3 FWD (MY2011)...with about 146k on the clock..and albeit not totally immaculate (odd stone chip/supermarket "ding" bit of surface rust underneath/ kid treats it as a climbing frame etc) , I have also sought the "preventative maintenance route", as the car is great and a "keeper" - as the comfort, practicality and MPG makes it worth keeping.

Anyhow - I had exact same issue on exact same car, as had user Tommyweaves (with exact same car): https://www.volvoforums.org.uk/showthread.php?t=325150

Best bit of advice I had was: "replace it - as when they start to degrade, you don't want to be caught out (in winter) when the battery does decide to die".

Mine started fine like yours - but for how long it would've continued to - who knows! I couldn't find anything in paperwork about the battery being replaced - so guesses it'd been in there a decade.

I went for a replacement direct from Volvo. cost was something like £8 more than Varta or similar...

[Tatsfield]

I'm not sure to what extent it applies to Volvos but on previous cars I found that starting the engine isn't actually the most difficult thing the battery has to do. The starter is just brute electrical force but running the pre start status checks (the warning lamps in the dash on and then off) requires accurate currents to be sent to the units to be tested and then the return current can be compared to see if it is within test range. If the battery is not putting out accurate currents, the return will not match the initiating current and the car will fail the status check. This can happen long before there is insufficient power left to turn the starter. When it does happen and the car refuses to start or throws up warnings, there is nothing you can do but change the battery.

On my XC70 there is a starting programme where the starter doesn't kick in until the ECU tells it that the engine is ready to start. When I first had the car I couldn't make out why it didn't "start on the button". The delay is mainly concerned with diesel glow plugs, so the old trick of turning on the ignition and waiting for the status checks to finish before turning the starter over to avoid taking heavy current out while the status checks are running, will not work. So if the car refuses to start, I think it is telling you to change the battery.

[al dm]

I had a look at the battery today and it is a Bosch S4 010 (80Ah, 740CCA). It looks almost like new. So the battery HAS clearly been replaced at some point, which is good.

It's dark now, but I will go and find the date code tomorrow to hopefully give an idea as to when it was replaced.

Anyway, while I was there, I unplugged the cable to the BMS (ignition on, but engine off) as per one of the videos I saw, waited about 20 seconds and then plugged it back in again.

Still getting the "Battery Low" warning in the driver's display and centre console, so that clearly didn't work. Back to the drawing board to find more YouTube videos.

All the voltages and currents look to be just peachy using Car Scanner and my OBDII scanner. BUT - the SoC (Battery State of Charge) readout shows 0%. So there's something wrong there as the battery is clearly charged and starts the car perfectly.

Oh well, I will have another fiddle with it tomorrow.

[scbamber]

You have a new-looking Bosch, the brand you like - Good.

You say you have a Noco battery charger, presumably with big enough charging power, at least 5 amps...so why not take the easiest course and just charge it and see what happens to the battery warning message?

No need whatever to remove the battery from the car or even disconnect it for a normal charge cycle at 14.5v (though Noco suggest you disconnect the battery for the Repair cycle as it uses a higher voltage of 16.5v and might affect the car's electrics). After any reconnection of the car's battery leads it resets the BMS automatically after a few hours eg overnight.

[al dm]

Originally Posted by scbamber

You have a new-looking Bosch, the brand you like - Good.

You say you have a Noco battery charger, presumably with big enough charging power, at least 5 amps...so why not take the easiest course and just charge it and see what happens to the battery warning message?

No need whatever to remove the battery from the car or even disconnect it for a normal charge cycle at 14.5v (though Noco suggest you disconnect the battery for the Repair cycle as it uses a higher voltage of 16.5v and might affect the car's electrics). After any reconnection of the car's battery leads it resets the BMS automatically after a few hours eg overnight.

That is such a good idea, that I have just done exactly that.

I disconnected both battery terminals, connected the Noco Genius 5 charger/maintainer and set it to the repair mode. I'll leave it a few hours and see where it goes. If it finishes the repair cycle and goes into Standby mode, I will just reconnect the terminals along with the BMS and leave it overnight.

If it hasn't finished repairing, I will just leave it going overnight anyway.

Either way, the BMS should get at least a few hours disconnected and the battery should be fully charged and repaired (if it even needs it) by the morning....

[Tannaton]

Originally Posted by al dm

That is such a good idea, that I have just done exactly that.

I disconnected both battery terminals, connected the Noco Genius 5 charger/maintainer and set it to the repair mode. I'll leave it a few hours and see where it goes. If it finishes the repair cycle and goes into Standby mode, I will just reconnect the terminals along with the BMS and leave it overnight.

If it hasn't finished repairing, I will just leave it going overnight anyway.

Either way, the BMS should get at least a few hours disconnected and the battery should be fully charged and repaired (if it even needs it) by the morning....

Sounds a plan, in those circumstances I usually run the program (RECOND on a CTEK) twice maybe. FYI it’s only necessary to disconnect one of the terminals.

[Tatsfield]

Originally Posted by Tannaton

Sounds a plan, in those circumstances I usually run the program (RECOND on a CTEK) twice maybe. FYI it’s only necessary to disconnect one of the terminals.

Do not connect to the - terminal while it is connected to the car. The procedure is either to connect to the + while connected to the car and to an earth point on the chassis or to disconnect both terminals before connecting to them. The - connector on the car has the linkage to the battery monitoring system and connecting chargers to it is not advised. My CTEK charger has a permanent connector fixed to the + terminal and to a suitable chassis earthing point and the charger just plugs into the connector.

[al dm]

Well, that seems to have sorted things out. The maintain/repair cycle had finished late last night, so I just pressed the button again and went to bed.

This morning, the larger is on standby, the battery is maintained and fully charged.

I reconnected the terminals and the State of Charge is reading 80%, which I read is the default reset state of the BMS. And now, the low battery warning isn't coming up any more, so all is good. And I have saved £120 on a new battery.

Now I just need to figure out how to reset the auto window function. I have done the clock ;-)

(Edited to add: Windows now reset. That was easy. With window closed, hold the window up button at first position for one second. Release. Hold at first position for one second. Auto close function reset. Done.

Happy now. Time for brunch and a Bloody Mary.)

[Tannaton]

Originally Posted by Tatsfield

Do not connect to the - terminal while it is connected to the car. The procedure is either to connect to the + while connected to the car and to an earth point on the chassis or to disconnect both terminals before connecting to them. The - connector on the car has the linkage to the battery monitoring system and connecting chargers to it is not advised. My CTEK charger has a permanent connector fixed to the + terminal and to a suitable chassis earthing point and the charger just plugs into the connector.

If either of the battery terminals are disconnected from the car - positive or negative - then the battery is disconnected period and it matters not where the charger clips are attached.