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Daimler 2.5 V8 Battery/Dynamo issues

AlanD
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Daimler 2.5 V8 Battery/Dynamo issues

Post by AlanD » Mon Sep 23, 2019 3:09 pm

I am new to this forum and am hoping that someone can assist with a problem I am having with a flat battery on my Daimler. The battery itself is probably about 4 years old but I have re-charged it successfully with a battery charger after it went flat twice in the past month or so. The problem seems to be that the dynamo is not charging the battery properly. I ran a check with a voltmeter and with the car idling the battery is not being re-charged, in fact it is discharging. With the throttle down the reading is still barely above 12.5 v which would suggest a problem with the dynamo? (may be the original one?) or could it possibly be a problem with the current voltage regulator?
Do you think I need a new dynamo? If so, I have found one online for £125 (including instructions for polarising for my positive earth car). If I take the car to a garage for fitting how many hours do you think the job should take?

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John-B
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Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by John-B » Mon Sep 23, 2019 3:21 pm

I can't give you any technical advice other than to say that dynamos never charge when idling, but 12.5v does seem to be a bit low when above idle speed.

My main advice would be to measure a replacement dynamo. I bought a reconditioned dynamo that was supposed to be correct for my Dart and found that it was longer so the rear fixing clashed with the steel bracket which I had to saw off. I suppose that the dynamo and bracket I had must have been non-standard.

Borrow a battery and check how it gets charged before buying a new dynamo.

Flinty
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Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by Flinty » Mon Sep 23, 2019 3:59 pm

Alan.
My dynamo when I had one needed about 2000 RPM before it showed a charge on the ammeter, so I would rev your car to 2000 RPM and take a voltage reading.
If it is still only 12,5 Volts then disconnect the Dynamo and connect both the terminals together i,e, Dynamo wire and field wire and take another voltage reading from these two wires to earth. this should be well above 13.5 volts if not then the Dynamo is faulty, Probable brushes need replacing, If voltage is higher then it will be the regulator.
To change a Dynamo takes 1/2 an hour.

Steve.

classiclife
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Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by classiclife » Mon Sep 23, 2019 5:19 pm

Hello Alan,

Indeed, good advice by the other contributors.

Before you go splashing out on a new dynamo, I would have the old one overhauled; the original Lucas units are so much better than anything about now.

There's not a lot that goes wrong with them, normally just wear. If you think it is the original unit then without doubt the brushes need replacing and a general clean inside. Again, Lucas regulators hold their own and very rarely play-up; I'd certainly focus on the dynamo.

You can change brushes easy enough and a simple job. If you are not happy doing that, then a decent auto electrician will have the job done from start to finish including dynamo in and out within an hour and that's taking time out to have a brew !!

You have not indicated where you are, but if in the UK I can give you some excellent auto-electricians to call.

Regards.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Area Representative.

Southern Classics Society Events Co-ordinator.
www.southernclassics.org.uk

AlanD
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Joined: Sat Sep 21, 2019 1:24 pm
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Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by AlanD » Mon Sep 23, 2019 6:50 pm

Three brilliant responses on the same day I posted the query! - thanks guys :D

classiclife
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Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by classiclife » Mon Sep 23, 2019 8:18 pm

No charge, excuse the pun !! :lol:
1968 Daimler V8-250 Saloon
DLOC East Sussex Area Representative.

Southern Classics Society Events Co-ordinator.
www.southernclassics.org.uk

AlanD
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Joined: Sat Sep 21, 2019 1:24 pm
Location: unknown

Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by AlanD » Mon Dec 02, 2019 4:29 pm

It seems like my battery has finally given up the ghost (stuck on a charging rate of 10 amps for the past 5 hours). Can anyone suggest a good new battery bearing in mind that I don't use the car much for 7-8 months of the year, just 2hr spins every month.

classiclife
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Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by classiclife » Mon Dec 02, 2019 6:01 pm

Hello Alan,

Regardless of the battery quality / type, it is important to ensure you keep it trickle charged during your nigh-on dormant 7 month period.

A battery does not take kindly to self draining and it becomes useless pretty soon.

You can get decent trickle charge units for not a lot of money and the battery can be left in situ.

As to battery preference, that is down to pocket money - but I tend to go for Bosch sealed, of which most modern batteries are these days.

Every owner has their favourite and in your case I would certainly go for at least 4yrs warranty.

Worth surfing the usual outlets to secure best price.

Regards.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Area Representative.

Southern Classics Society Events Co-ordinator.
www.southernclassics.org.uk

Ian Slade
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Location: Akrotiri Cyprus

Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by Ian Slade » Mon Dec 02, 2019 6:33 pm

Regarding batteries, except for types most batteries are the same, the difference in price depends on the length of the warranty, the longer the warranty the higher the cost, the extra cost is the bet of that manufacturer against failure, so with similar batteries the one with the less cost over say 4 years is the better battery, your bet as to whether you by the cheap one with one year or pay the manufacturer to take risk. I would purchase a small cheap intelligent battery charger that you can leave connected when the car is not in use, the Aldi or Lidl versions are about £15 and are eminently suitable.
Owner since the 70's, Genghis is slightly to my left.

ShandyandLady
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Joined: Thu Nov 10, 2016 5:26 pm
Location: Swansea

Re: Daimler 2.5 V8 Battery/Dynamo issues

Post by ShandyandLady » Mon Dec 02, 2019 10:55 pm

I have used a simple solar panel to trickle charge the battery for the past three years with great success.

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