Re: 2000 4.2d Patrol failing alternator
Posted: 12 Feb 2018 10:52
I disagree with the notion that 13.4 v or 13.6v is sufficient. The minimum charge rate should be 13.8 v else you are not putting enough power back to get the battery up to 100%. Even that is low, if you are running a second battery, like a deep cycle battery, the charge rate MUST be 14.4 volts to get them both up to an acceptable level. A standard Bosch regulator is set to 14v these days.
I would say it is the and brushes that have reached the end on their reach, also maybe the regulator, but I doubt it would be the regulator. If it is a Bosch alternator, it is a piece of old takkie to put in new brushes and voltage regulator. It is a single unit that is held in place with two Phillips screws.
To replace it, undo the two phillips screws and fit a new voltage regulator. They cost peanuts really. Even if it is not this, it is a cheap enough option to try. To replace the regulator, there is no need to disconnect the positive lead on the battery to prevent a short, or to pull the big spade connector (main battery wire) off the alternator.
On the any regulator, you should see the output voltage that the regulator is set to printed on the back of the regulator. I find that FLAG regulators for Bosch alternators are best if you run a dual battery system, these are set to 14.4 volts. The one in the pictures here is set to 14v exactly. If you cannot get a FLAG, get one that delivers at least 14v, but the higher, up to 14.4 max, the better. Over 14.4 v you will start boiling your battery water and it will evaporate quite fast.
Bench charge your old battery at home with a decent charger (6 - 10 amps) for 24 hrs, take a reading, it should read at least 12,6 to 12.8 volts. Then take a reading 24 hrs later, and if it has dropped to 12.4 volts it is still OKish, but not quite 100%. If it is above 12.4 your battery is still good. The problem is then with the charging system. If 12.4v or below, and you at this stage, charge it with an intelligent 7 or 8 step charger for 48 or more hours, you can still recover it.
If after the first 24 hrs of rest, it has dropped to around 10.6v, there is a dead cell and you can write it off. Just get a new battery if that is the case.
1 The VR on the Bosch Alternator 2 Undo the two screws 3 Pull it out like this 4 The actual regulator with the Voltage output printed on it 5 Putting it back
I would say it is the and brushes that have reached the end on their reach, also maybe the regulator, but I doubt it would be the regulator. If it is a Bosch alternator, it is a piece of old takkie to put in new brushes and voltage regulator. It is a single unit that is held in place with two Phillips screws.
To replace it, undo the two phillips screws and fit a new voltage regulator. They cost peanuts really. Even if it is not this, it is a cheap enough option to try. To replace the regulator, there is no need to disconnect the positive lead on the battery to prevent a short, or to pull the big spade connector (main battery wire) off the alternator.
On the any regulator, you should see the output voltage that the regulator is set to printed on the back of the regulator. I find that FLAG regulators for Bosch alternators are best if you run a dual battery system, these are set to 14.4 volts. The one in the pictures here is set to 14v exactly. If you cannot get a FLAG, get one that delivers at least 14v, but the higher, up to 14.4 max, the better. Over 14.4 v you will start boiling your battery water and it will evaporate quite fast.
Bench charge your old battery at home with a decent charger (6 - 10 amps) for 24 hrs, take a reading, it should read at least 12,6 to 12.8 volts. Then take a reading 24 hrs later, and if it has dropped to 12.4 volts it is still OKish, but not quite 100%. If it is above 12.4 your battery is still good. The problem is then with the charging system. If 12.4v or below, and you at this stage, charge it with an intelligent 7 or 8 step charger for 48 or more hours, you can still recover it.
If after the first 24 hrs of rest, it has dropped to around 10.6v, there is a dead cell and you can write it off. Just get a new battery if that is the case.
1 The VR on the Bosch Alternator 2 Undo the two screws 3 Pull it out like this 4 The actual regulator with the Voltage output printed on it 5 Putting it back