Alternator overcharging?

[john b.]

I have an Isuzu 35hp engine with 2 70amp Prestolite(lucas A127 look-alikes), they are independant of each other one charging the starter battery and the other one charges a domestic bank of 3 110 amp batteries.What I am concerned about is the domestic alternator over the 1st ten minutes of running creeps up and stabilises at 14.7volts. I have changed the regulator but as made no difference, is there anything else in the alternator that could cause this problem? It never used to go above 14.4volts so am worried my batteries could be damaged.

Thanks John b.

[smileypete]

I have an Isuzu 35hp engine with 2 70amp Prestolite(lucas A127 look-alikes), they are independant of each other one charging the starter battery and the other one charges a domestic bank of 3 110 amp batteries.What I am concerned about is the domestic alternator over the 1st ten minutes of running creeps up and stabilises at 14.7volts. I have changed the regulator but as made no difference, is there anything else in the alternator that could cause this problem? It never used to go above 14.4volts so am worried my batteries could be damaged.

What sort of batts are they, 'open' ones or sealed/maintenance free, and what sort of charge current are you getting at 14.7V?

 

Might also be worth double checking your voltmeter with another, just in case.

 

cheers,

Pete.

Edited May 7, 2012 by smileypete

[blodger]

You would not by any chance have solar panels connected at the same time would you?

[by'eck]

14.7 volts sounds fine for most batteries apart from the twitchiest gel types. Your lucky to have alternator(s) producing such a voltage which will certainly help keeping sulphation to a minimum.

 

In any case are you measuring the 14.7 volts at the alternator or battery terminals?

[Burgiesburnin]

I have an Isuzu 35hp engine with 2 70amp Prestolite(lucas A127 look-alikes), they are independant of each other one charging the starter battery and the other one charges a domestic bank of 3 110 amp batteries.What I am concerned about is the domestic alternator over the 1st ten minutes of running creeps up and stabilises at 14.7volts. I have changed the regulator but as made no difference, is there anything else in the alternator that could cause this problem? It never used to go above 14.4volts so am worried my batteries could be damaged.

Thanks John b.

 

 

14.7 sounds a bit too high for me. Are the batteries getting hot?

Are the sides of the battery casings bowing on the longer sides?

 

If the answer is no to both of the above then check your gauge and change it anyway. Alternatively run a high pulling appliance and see if it straight line discharges or if it's erratic.

If erratic then definitely change you gauge.

[john b.]

Thanks for replies normal open wet cell batteries in use but haven't measured the current yet. I have an Adverc ECM fitted and also double checked taking readings at the Alternator B+ terminal and the battery terminals with a multi meter all register 14.7v. I haven't travelled to far while this potential problem exists so don't know whether batteries will get warm (don't like the idea of potentially damaging them).

John b.

[cereal tiller]

Thanks for replies normal open wet cell batteries in use but haven't measured the current yet. I have an Adverc ECM fitted and also double checked taking readings at the Alternator B+ terminal and the battery terminals with a multi meter all register 14.7v. I haven't travelled to far while this potential problem exists so don't know whether batteries will get warm (don't like the idea of potentially damaging them).

John b.

Aha,you have an ADVERC?

 

the adverc controller will hold the batteries a a high voltage,up to 14.8 for ten minutes,then shut down,then repeat the elevated voltage 3 more times.

 

this cycle will occur each time the engine is started.

[john b.]

Aha,you have an ADVERC?

 

the adverc controller will hold the batteries a a high voltage,up to 14.8 for ten minutes,then shut down,then repeat the elevated voltage 3 more times.

 

this cycle will occur each time the engine is started.

Hi,

I'm afraid not, I didn't mention the Adverc Alternator controller because I've unplugged it, the ECM is just the monitor.It started reading a higher voltage after I had replaced the regulator so bought another one but just the same.It was an easy job just 3 bolts, Could I have upset anything else?

John b

[blodger]

Hi,

I'm afraid not, I didn't mention the Adverc Alternator controller because I've unplugged it, the ECM is just the monitor.It started reading a higher voltage after I had replaced the regulator so bought another one but just the same.It was an easy job just 3 bolts, Could I have upset anything else?

John b

SmileyPete asked some time ago what the charging amps were at the 14.7. If it is very small because the batts are fully charged, say <9 amps then as someone else has ventured you have a good charging voltage. If with time the voltage is rising above the 14.7 and/or high charging current is still present I would then be worried.