What’s going on.

[SeanC]

Sometimes the car starts fine and other times it really struggles even when the battery voltage is the same.
By struggling it just turns over slowly. You think you are only going to get half a dozen turns at most but it just keeps cranking and cranking until it finally starts. It sometimes drags the charge low enough for the android entertainment system to reboot.

In the screen shot the first time it started fine the second time it struggled. Battery connections are clean and tight.

Any ideas?

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[PeterJ]

Initially, simplest thing, I guess I would get the jumper leads out and hook up your LiPo backup battery to make sure you have proper battery function as far as current is concerned.

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Strange looking graph, not what would be expected for Voltage Vs Time when cranking an engine. I gather the "X" axis is time ?? units would be seconds??
Maybe explain the car actions in relation to the graph,have a careful look at how you are recording the data.

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Peter

[SeanC]

Initially, simplest thing, I guess I would get the jumper leads out and hook up your LiPo backup battery to make sure you have proper battery function as far as current is concerned.

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Strange looking graph, not what would be expected for Voltage Vs Time when cranking an engine. I gather the "X" axis is time ?? units would be seconds??
Maybe explain the car actions in relation to the graph,have a careful look at how you are recording the data.

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Peter[/QUOTE]That’s over a 24 hour period. So start and drive for half an hour. Stop for an hour and a half. Start and drive for about 15 minutes. Then stop.

[PeterJ]

Hi Sean, sorry my bad interpretation of what you were explaining. I would still try jumper leads or change to a known good battery as a easy quick check, how old is your battery?. After that, have another go at describing symptoms. Time the cranking cycle until start, does it happen hot / cold/ both. Is it becoming more frequent, any other things come up, perhaps error codes, unusual warning lights.

Peter

[SeanC]

Hi Sean, sorry my bad interpretation of what you were explaining. I would still try jumper leads or change to a known good battery as a easy quick check, how old is your battery?. After that, have another go at describing symptoms. Time the cranking cycle until start, does it happen hot / cold/ both. Is it becoming more frequent, any other things come up, perhaps error codes, unusual warning lights.

Peter
Battery (Odyssey PC1350) replaced Jan 2019. Definitely worse when cold. But doesn’t appear to be related to the battery voltage. 12.5 -12.6V should be plenty to start the vehicle. Struggled to start this afternoon. Hadn’t been driven for a couple of days. 4km drive to get fuel. Started fine after filling up. If the voltage gets pulled down far enough get a lot of faults due to losing power. The strange thing is how it will continue slowly turning over much longer than you would expect with a flat battery. Starter motor??

[Tombie]

I’d almost put money on the battery having problems.
I went with the PC1350, and 3 months later threw it back at the shop... went bad really quickly.

[SeanC]

I’d almost put money on the battery having problems.
I went with the PC1350, and 3 months later threw it back at the shop... went bad really quickly.

Hope that’s not the problem.

There is one fault that won’t clear.

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[DiscoJeffster]

Battery voltage is no indicator of health. It’s float voltage doesn’t correlate to the amperage it’s able to deliver. That said, that’s an interesting and related fault you have there. Maybe the failure of the battery saver relay has caused your battery to become really severely depleted/damaged? Dunno??

[Tombie]

From a while back on this forum... may help you in working through it.


https://www.aulro.com/afvb/l320-range-rover-sport/252653-help-washed-car-lots-faults-where-do-i-look.html

[PeterJ]

So I think back to square one, try to start the car tomorrow, if it's playing up stop, hook up a jump start battery ( following procedure in owners manual) and have another go, assess and do the next step. Batteries fail prematurely, even the best of them but it should have a warranty. Any autoelect should be able to test it for you.

Peter

[SeanC]

Battery voltage is no indicator of health. It’s float voltage doesn’t correlate to the amperage it’s able to deliver. That said, that’s an interesting and related fault you have there. Maybe the failure of the battery saver relay has caused your battery to become really severely depleted/damaged? Dunno??

I do have intermittent parasitic battery drain. Never been able to hunt it down. Maybe change the relay.

[SeanC]

Does anyone know if the Battery Saver Relay is one of the replaceable relays on the fuse panel behind the glove box? If so which one is it? On a number of Ford forums the relay has been a implicated as a cause for parasitic battery drain.

[DiscoJeffster]

I’m guessing you’re asking because you don’t have the wiring diagram? What model do you have?

[SeanC]

I’m guessing you’re asking because you don’t have the wiring diagram? What model do you have?
2008 TDV6 SE
The Haynes manual has fuses and fusible links but not relays. It has the relays in the circuit diagrams but not the position on the central junction box.

[DiscoJeffster]

Sorry don’t have D3 wiring but on the D4 2010 (which will be similar) it’s labeled as R11, Junction Box Central. Worth a look.

[Graeme]

R250 is battery saver relay and fuse 1P (10A) the fuse.

[Graeme]

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[SeanC]

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Thanks Graeme.

[SeanC]

So The battery saver relay is located inside the central junction box so it sounds like it can’t be changed.

[DiscoJeffster]

So The battery saver relay is located inside the central junction box so it sounds like it can’t be changed.

Just did a google and yep, bugger. Whole unit needs replacing!

[Graeme]

Remove the fuse overnight to see if it makes any difference. You could also measure the current draw across the fuse contacts after removing the fuse once the vehicle is in battery saver mode.