Alternator upgrade

[940volvoman]

I thank you for your patience,Ash and Dave.It got rather technical for me,so I really appreciate your help.

[Laird Scooby]

Originally Posted by aardvarkash10

HTG, sometimes I don't know where I get the patience.

Dave - look after this will you - its dark-all-around o'clock over here and I've had a full day of dealing with Tongans pumped on beating the Aussies at rugby league and South Africans pumped on beating some poor ungrateful sods at the gentleman's form of the game.

I'm sure you can see where I'm trying to steer Shaun on this.

Cheers

I'll have a go Ash, it's where i've been trying to steer all the way through the thread but i get your drift.

[940volvoman]

The car has been standing, unused for 48 hours,and I just started it. So it has had time to discharge and drain anything it is going to drain.

I just started the car and it is charging at its maximum,which is 14.5volts.....(tested by to voltage across the battery terminals)with a DMM

So at least that part is ok. The battery was fitted a couple of years ago when the alternator was providing much less voltage,as confirmed by my aftermarket analogue gauge in car.

Therefore I am assuming that the battery was f###ed before the regulator was replaced.So a new battery would no doubt help?

[Laird Scooby]

Originally Posted by 940volvoman

The car has been standing, unused for 48 hours,and I just started it. So it has had time to discharge and drain anything it is going to drain.

I just started the car and it is charging at its maximum,which is 14.5volts.....(tested by to voltage across the battery terminals)with a DMM

So at least that part is ok. The battery was fitted a couple of years ago when the alternator was providing much less voltage,as confirmed by my aftermarket analogue gauge in car.

Therefore I am assuming that the battery was f###ed before the regulator was replaced.So a new battery would no doubt help?

Almost certainly - on both counts! Save you looking for the ebay link again :

https://www.ebay.co.uk/itm/HB096-Lea...v/192434766703

A normal, lead-acid, 70Ah battery that will fit in the battery box, give you improved reserve and starting and be able to make use of the 100A your alternator is (or should be capable of) giving.

[940volvoman]

I'll get that one,thanks Dave,But with the knowledge of my voltage wouldn't it sustain the silver ones?Or is that a whole new can of worms??

[Laird Scooby]

Originally Posted by 940volvoman

I'll get that one,thanks Dave,But with the knowledge of my voltage wouldn't it sustain the silver ones?Or is that a whole new can of worms??

No, definitely not! The silver-calcium ones need 14.7V just to start charging, they do not charge on 14.5V!

Look :



Brand new calcium battery, brand new alternator - wouldn't charge properly, kept going flat over a period of about a week. Added the voltage boost diode cunningly disguised in that plug fitted in the wire there to boost the voltage to 14.7-15.1V - no problem since!

I should add the battery wasn't labeled so i didn't even know it was a calcium battery, it had been sold as a normal lead-acid battery but without labels.


I've also had this with another member of the forum who was sold a calcium battery and couldn't work out why it kept going flat so he bought a new alternator from the same place. Eventually with my guidance, he took the battery back and explained to them the alternator wouldn't charge it because it wasn't designed to - they admitted they shouldn't have sold him the calcium battery and refunded and then he bought a normal lead-acid battery.
Since then he's had no further troubles except when he hasn't been able to use the car for an extended period.

[940volvoman]

I've probably fallen foul of this rule on my van,too,although I haven't experienced the same discharge problems.I will check it and see...

[TonyS9]

14.5V at the battery is a good result, but you didn't mention is you followed any of my loading suggestions (with high beam), or measuring the alternator voltage.

If the battery is well charged with no lights you might get a good result. Also if your alternator has a stupidly high voltage it may cause other issues.

This will be a more sensitive and definitive test. Volt drop to the battery depends on total current comming from the alternator and the resistance in the cables and connectors.

[940volvoman]

Thanks,TonyS9.
The battery wasn't fully charged,ie by an external charger,and hasn't been on a long journey since September.Back in the summer I added new cables from the alternator direct to the battery+terminal,an additional ground at the alternator to the body and an additional ground from the battery to the car body.So I'm hoping that there is little resistance between alternator and battery.I tested the voltage at the battery with airconditioning fan on full and low beam on.

[940volvoman]

So tell me,then,if my alternator is producing 14.5 volts and a a silver calcium battery needs 14.7 before it starts charging what happens to the 14.5 volts receives?