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1995-2002 Range Rover P38A
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Discussion Starter · #1 ·
I have fitted the Hankook Calcium battery and the P38 4.6 Petrol Range Rover has a Bosch alternator (see pic attached). The fully new charged battery had a voltage of 14.6V. With engine idling output is 14.42V ( dropping to 13.8V after a few minutes) and @2000 rpm it is almost steady 14.42V. When some load is switched on it falls as low as 13.8Volts.
With these voltages I feel the battery will never get fully charged (14.6volts) and eventually fully discharge and fail.
1. What can be done so the battery remains healthy for many years? Is the alternator faulty or inadequate?
2. Can a voltage regulator like Regulator MOBILETRON VR-VW010 be fitted to the alternator or any other voltage regulator with higher output?
Any help will be appreciated.
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Discussion Starter · #4 ·
The battery should have a nominal voltage of 12V.
This means that it will be about 12.8V fully charged.
Charging voltage is regulated by the alternator and should be around the 13,7 to 14,4V i think.

If you measured your new battery at 14,6V then I would suggest either a faulty meter, a faulty battery or an error of measurement.
MF31-1000 12V battery has 6 cells like any other. Each cell is 2.1 volts so 12.6 V for the battery.
When the MF31-1000 battery was delivered it checked out as 14.59 V or rounded to 14.8 V, as the the supplier BatteryMegastore said it would be.
So no faulty battery or multi-meter.
If the battery is 11.99-12.06 volts it is only 25% charged. It will be 75% charged at 12.45-12.54 volts.
 

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Discussion Starter · #8 ·
As above, if anything the battery is at fault and not the alternator. A 6 cell battery should never have >13V at rest.
Sincere apology.
In my #1 post I did write the new supplied battery had a voltage of 14.6. It was meant to be 12.6 volts.
Thank you all for trying to help me. I no longer have concern if the battery will be healthy or not- it will be.
However I have moved on to find what is causing BATTERY DRAIN.
Since I have your attention I would like to put it here and share what I have found and perplexing (Moderator, if you feel it should be posted as a new subject somewhere else please say so).
I tested by removing fuses and nothing showed up. I removed the red cable form the battery + to the fuse box and drain came to zero. So when I remove the fuses one by one, why does it not show any drop?
Thankful for any help.
 

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Discussion Starter · #10 ·
How much drain have you got? Is the BeCM sleeping or being kept awake by something else? Don't forget that the BeCM will be drawing just under 1A while it is awake, but will sleep if all doors are closed and nothing else is switched on to wake it after 2 minutes. Easy enough to check at this time of year. Sit in the car in the dark, close the doors (no need to lock them) and look at the red LED next to the gear lever, it will be glowing very dimly. but after 2 minutes it will go out signifying that the BeCM is now sleeping. If it doesn't sleep, something else is keeping it awake. BeCM is fed via Maxi fuses 1, 4 and 5. These fuses are fed directly off the main input cable. Then there are also fuses 25, 27 to 35 and 38 to 44, which are all connected to the main power input. So, when you say you have removed fuses, have you removed all of the permanently powered ones?
1. I will sit in and observe dim light as you say.
2. I pulled all the Maxi fuses one by one. Pulled the normal fuses one by one. Nothing showed up.
3. Today I found the drain was 0.04 Amps. When I opened my electric remote garage door it shot up to 0.5 Amps but it settled down to 0.04 Amp after 2 minutes. When I finished it was reading 0.03 to 0.04 Amps. That is still above 25 milliamps as I believe it is acceptable for the P38s.
I will monitor tomorrow with the results.
 

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Discussion Starter · #13 ·
The remote for the garage door is obviously operating on 433 MHz (which most low power momentarily operated diveces do in Europe), so that will be triggering the BeCM to wait for a valid unlock or lock code from the fob receiver. Difference between the recommended 25mA and 30-40mA is negligible, it would still take about 4 months to fully discharge an MF31-1000. Additional draw may be down to an aftermarket stereo or any other permanently powered extras.

If you are in an area with high levels of RF, or lots of remote operated devices, they can keep waking the BeCM up. You can spend a fortune on a Gen 3 receiver, wait until Marty has more of his RF Filter boxes back in stock (see Range Rover P38 Parts Shop) or, in the meantime, disconnect the antenna (blue) wire from the receiver. This means you will need to be closer to the car to use the remote but will greatly lessen the affect of other nearby devices.
I don't believe the Fob receiver is getting activating in the night.
I am now concerned about alternator.
On 22/11 the battery was 12.03v. I ran the engine for 30min and battery went up to 12.76V.
On 23/11 battery 12.5v. Used DFC150N AA Charger & maintainer for 4 hours and voltage became 13.05V.
On 24/11 battery 12.5v. Drove to Hospital 22 miles and battery 12.9v.
Today 25/11 battery 12.53v. Drove a short trip 5 miles and battery went up to 13.05v.
Should the battery voltage go above 12.6 volts?
Will this damage it? Is the alternator faulty?
 

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Discussion Starter · #16 ·
Good to hear the battery is fine, thanks for the feedback! ;-)

As for the drain, it could be small short inside the fusebox, before the fuses. But I agree the readings you get are well within tolerance, so not really something to worry about. You could remove ALL the fuses and check again. If there is still a drain, it can only be a short.
As an aside, are you using a clamp meter or an inline one? A clamp can easily pick up other magnetic field so is less accurate at very low current levels. It is of course the easiest way and allows you to quickly determine which cable has current (fusebox or starter/alternator).
I will look into the fuse box short.
So my
Now I have a new problem.
Radio needed the code setting so I did (side issue-the CD changer magazine will not eject).
Now the drain is 1.02A. So back to investigation.
Will keep all posted.
Seems ok to me. +1 on you will probably never get the drain down below 0.04A or 40mA. Where did you find the 25mA target ?
Just picked up from Forums & Fb but not entirely sure where from.
Calcium batteries can withstand a higher charging voltage than older non-Calcium enriched lead acid batteries. Hence a very early P38 will have an alternator that is regulated to around 13.8V maximum to prevent the battery being boiled dry. With the introduction of Calcium enriched batteries, which can accept a higher charging voltage, the alternators were changed for ones with the higher voltage regulator, around 14.4V. The figures you are measuring sound perfectly OK.

Do you actually have a battery drain problem, finding the battery flat after the car has been left standing, or are you just concerned about the 40mA drain which you feel is excessive?
Now that I am increasing my knowledge from the Forum, I am not feeling too pessimistic.
I have mentioned elsewhere about my CD changer problem so I will concentrate on that.
I have not had a huge drain overnight with this new MF3-1000 (FOC) as previous one got sldes bulging cause the transport Red bung was not removed by the garage). However I would like to pursue and minimise battery drain. I intend to purchase NOCO GENIUS5 charger/maintainer. Any feed back on this will be appreciated.
 

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Discussion Starter · #17 ·
Calcium batteries can withstand a higher charging voltage than older non-Calcium enriched lead acid batteries. Hence a very early P38 will have an alternator that is regulated to around 13.8V maximum to prevent the battery being boiled dry. With the introduction of Calcium enriched batteries, which can accept a higher charging voltage, the alternators were changed for ones with the higher voltage regulator, around 14.4V. The figures you are measuring sound perfectly OK.

Do you actually have a battery drain problem, finding the battery flat after the car has been left standing, or are you just concerned about the 40mA drain which you feel is excessive?
I should have asked in my previous reply to you. Does my 2000 Reg petrol Auto 4.6 P38 has alternator setting of 14.4volts?
 

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Discussion Starter · #21 ·
See the FAQ sticky at the top of this forum. Owning a P38 and not having RAVE is a bit like having a mobile phone but living in an area with no service.

I posted the BeCM SID in your previous thread......
1.Thank you for your wise message.
I still do not know how to find RAVE.
Please help.
2. PS: I am still working on battery drain. Yesterday I did not check the battery voltage but turned the key and it started first time.
 

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Discussion Starter · #23 ·
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