d2 charging voltage

**Redback** · 12th February 2015, 06:33 AM

Here's what should happen;

When you start the car, the voltage should be around the 14.0 to 14.3(from memory of my old D2)then after about 30mins of driving it will settle to 13.4 to 13.7, but usually 13.6 is where it's most constant, when you test the main battery, the auxillary batteries should be the same.

If you test the main battery and your voltage isn't going past 13.2 with the motor running, then I would say it's the alternator, or at least alternator related, have it checked, most auto elecs will do it for free.

Baz.

**shack** · 12th February 2015, 07:51 AM

I bought the kit yesterday to replace the brushes and reg, from memory i think it would take most people a bit longer than 3 mins too remove the alt

anyway , I'll post back with my results once it arrives and I get it installed

**Mundy** · 16th February 2015, 06:26 PM

Deja vu all over again. I raised the question by OP some about a year ago.

My D2a does the same. Cold alternator outputs 14.6V, hot 13.6V. At the risk of starting an argument (again), I solved my second battery charging issue with a Ctek dc to dc charger. Has other advantages but lets not start.

**shack** · 17th February 2015, 08:46 AM

I have been seriously thinking about that as well, just didn't know they existed !
,I've looked on here but not found any info, anyway the last couple days been pretty cool in the morning, 18 today for instance ,and its charging like a champion, find it very frustrating

mundy could you please link too your post about it ?

found it

**Eevo** · 17th February 2015, 08:58 AM

dont waste your time with a dc to dc charger
plenty of info on this forum why they are a waste of time (literally) and money.

**shack** · 17th February 2015, 01:56 PM

The only thing that would make me get one would be if I cant get the charging voltage up on the car, it may be putting out plenty of amps but if it never gets above 12.8 or 12.9 volts it will take forever to charge a battery,as i said before, its ok when cold,but when hot it's useless

**Eevo** · 17th February 2015, 02:27 PM

13.6volts will still charge.
if its below 13.6 when hot, something is wrong

**Fluids** · 17th February 2015, 06:39 PM

Mine was always 14.2 to 14.6v regardless. Then one day it started doing what the OP has outlined. It can be mid 14s from a cold start but it eventually bounces between 13.13 and 13.94 by the Evo2. Makes charging the camper batteries a bit dubious.

I bought a new Denso alternator and they are specd as a 14v alternator (fixed, no temp compensation). It's specd for charging the original fitted D2 battery which is a calcium battery and needs the higher charging voltage.

My research leads me to believe that if your alternator is producing sub 14v then the reg/rectifier is failing.

Once I fit the new Denso alternator I'll be able to compare ....

Sent from my iPhone using two tin cans and a length of twine

**Mundy** · 17th February 2015, 10:24 PM

I replaced my alternator with another original. The first one was stuffed by ingress of dirty water and grease. After change, same performance.

I don't disagree that if you have a highly discharged second battery then the initial charge will be quicker with the alternator even at 13.6V as my dc to dc charger limits charge current to 20amps but the alternator is not limited to that. However, once it gets past the initial charge, the dc charger increases the charging voltage to up to 14.6V to maintain the 20amp charge till the battery is fully charged which the alternator won't do at 13.6V (not for a long time anyway). For my type of usage (travelling and camping) I found it difficult to get the second battery to a full charge between camp spots. The ctek charger also has an efficient solar panel input which works for me and a battery maintenance function which should keep the battery in better shape longer.

I know there's a lot of differing opinion on this. I can only relay what I have found to work for me.

**shack** · 23rd February 2015, 08:26 PM

So the new parts arrived,
went over to the workshop tonight too fit them, the ambient temp is only about 24 degrees and the thing is charging like a champ.

With the fridge running the optimas are sitting at 13.2 - 13.6 volts with the engine running, this has me concerned that there is nothing wrong with the alt, just that its not very efficient when hot, looks like a lot of work to do on the off chance it might help.

Has anyone else had this issue and fitted a new reg and brushes and seen any improvement?

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