MikeT's C5r 1.6 hdi Estate

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Zelandeth
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Re: MikeT's C5r 1.6 hdi Estate

Post by Zelandeth »

Assuming engine running so looking at a battery voltage around 13.5V and a standard 55W H7 lamp, that's a ground impedance of around 0.03 ohms... that's fine I'd say.

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Re: MikeT's C5r 1.6 hdi Estate

Post by MikeT »

Zelandeth wrote:
28 Oct 2017, 17:06
Assuming engine running so looking at a battery voltage around 13.5V and a standard 55W H7 lamp, that's a ground impedance of around 0.03 ohms... that's fine I'd say.


Actually, no. Engine off and battery was 12.5v. Yes, 55WH7.

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Zelandeth
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Re: MikeT's C5r 1.6 hdi Estate

Post by Zelandeth »

It's not going to shift things by more than one or two least significant digits really, still sounds like your ground there is okay.

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Re: MikeT's C5r 1.6 hdi Estate

Post by MikeT »

I also have a concern my battery might be getting past it's best. Can a discharged battery put such a demand on the alternator causing a high enough spike to kill a headlight bulb? It doesn't sound a likely theory but thought I'd ask as this latest blow-out was after the car had been sitting for a few days and I have auto-lighting, meaning they were switched on before I had buckled up.

Today, I tested the voltage after a long drive and while still running I got 14.3v which I thought was a little high considering the distance (~20miles) and no lights on or other accesory lloads. After engine off it dropped to 12.5v which again I thought was lower than it should be after such a long drive.

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Re: MikeT's C5r 1.6 hdi Estate

Post by GiveMeABreak »

14.3V is normal for when the car is running.

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Re: MikeT's C5r 1.6 hdi Estate

Post by myglaren »

MikeT wrote:
29 Oct 2017, 13:58
I also have a concern my battery might be getting past it's best. Can a discharged battery put such a demand on the alternator causing a high enough spike to kill a headlight bulb? It doesn't sound a likely theory but thought I'd ask as this latest blow-out was after the car had been sitting for a few days and I have auto-lighting, meaning they were switched on before I had buckled up.

Today, I tested the voltage after a long drive and while still running I got 14.3v which I thought was a little high considering the distance (~20miles) and no lights on or other accesory lloads. After engine off it dropped to 12.5v which again I thought was lower than it should be after such a long drive.


Mine is exactly the same Mike - I have a permanently connected digital voltmeter in the car (USB plug with voltage and temperature).

I recently took out the battery and used the spare fro a couple of days - which was sub-optimal but still worked OK.

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Re: MikeT's C5r 1.6 hdi Estate

Post by MikeT »

I realise the readings are within acceptable limits, that's not what I was asking though.
Steve, what's your voltage before starting, following an overnight rest?

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Re: MikeT's C5r 1.6 hdi Estate

Post by myglaren »

Usually 12.3. I'll check in the morning as the car hasn't moved since yesterday morning. Been in and out of it quite a number of times in the interim though, retrieving tools for work at daughter's house (just over the road).

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Re: MikeT's C5r 1.6 hdi Estate

Post by MikeT »

myglaren wrote:
29 Oct 2017, 20:41
Usually 12.3. I'll check in the morning as the car hasn't moved since yesterday morning. Been in and out of it quite a number of times in the interim though, retrieving tools for work at daughter's house (just over the road).


Thanks Steve, I'd apprecaite that reading in the morning.
I'm struggling to find any more than 12.1v from overnight and with todays reading of only 12.5v straight after 20-odd miles of charging, I think my suspicion is justified.

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CitroJim
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Re: MikeT's C5r 1.6 hdi Estate

Post by CitroJim »

I suspect your battery is soon destined to be recycled Mike :(

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Re: MikeT's C5r 1.6 hdi Estate

Post by MikeT »

My thoughts too, Jim. The car starts easily enough and it may last through the cold season but I won't bet on it. :lol:
When I bought this car and went through the service history, I noted it had a new battery 2014 but voltage checks back then told me it hadn't been maintained very well.
Now to determine what the correct Ah and CCA specs should be for my car.

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Re: MikeT's C5r 1.6 hdi Estate

Post by myglaren »

Sorry Mike - car was frozen over this morning and by the time I had located a scraper and cleared the windows I had completely forgotten to check the voltage.
Will do it in the morning - going to write myself a reminder and keep it with the keys.

Most mornings I don't get the chance to do this as my son uses the car at night - night worker - he comes in at about 07:15 and I leave at 07:20 normally.

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Re: MikeT's C5r 1.6 hdi Estate

Post by MikeT »

No worries Steve, I don't mean to put on you. I think what with all the electrical drain just from waking up these cars, especially the suspension pump draw, it's good to get some baseline comparisons.

I went out to my car today and only got 12.03v this time! However, with key out and doors closed, the voltage recovered. I accidentally set off the pump again and saw voltage plummet to low 11's but again, it recovered over time and presumably after everything went back to sleep I eventually saw a high of !2.39v. That's still poor but not as bad as first assumed.

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Re: MikeT's C5r 1.6 hdi Estate

Post by myglaren »

If you have the means and opportunity it would be advisable to put your battery on a trickle charge for 48 hours.
Did my - fairly recent - battery a power of good.
As I do mainly short trips it really doesn't get charged properly.

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Zelandeth
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Re: MikeT's C5r 1.6 hdi Estate

Post by Zelandeth »

A fair few of the more modern electronic chargers have a battery conditioning mode, if yours has this, may well be worth a shot.