Hi Guys
I searched the forums but couldn't find anything relating to experiencing low alternator voltage during hot weather.
The background is that I had trouble with my fridge over Christmas/New Year. After a couple of days I got the voltage drop light & it wouldn't run properly. I discovered the second battery (deep cycle charged via Redarc isolator) wasn't charging properly.
In order to keep any eye on what was going on I fitted two voltmeters in the cabin with an LED off the isolator so I know when it was connecting the batteries (or not!). I also got one of the voltage boosting diodes.
Generally the alternator outputs enough to trigger the isolator to join the batteries although I think the output is a bit low. Often around 13.6-13.8V with a hot engine during 'normal' weather.
Over the last patch of hot weather, ie 35-39DegC, I found that the voltage would drop considerably. Down to 12.5-12.9 when running around town. This is with the extra 0.5V voltage boost. This is too low to kick the isolator into joining the batteries & was undoubtedly the cause of my fridge woes - just not getting enough voltage to trigger the isolator keep the second battery properly charged.
I've read lots about the low charging voltage of the Prado alternators but don't know if my issue is consistent with what to expect or whether my alternator is crook.
I spoke to two auto-sparkies today, one said I may need a new alternator (something like $700!), the other didn't have much of an idea & said he'd need to run some tests to find out what's going on.
Is there anything I can do to maintain a higher voltage during hot weather?
Is it likely that my alternator is crook & will a new one fix the problem?
All ideas & assistance appreciated.
Cheers
Craig
I searched the forums but couldn't find anything relating to experiencing low alternator voltage during hot weather.
The background is that I had trouble with my fridge over Christmas/New Year. After a couple of days I got the voltage drop light & it wouldn't run properly. I discovered the second battery (deep cycle charged via Redarc isolator) wasn't charging properly.
In order to keep any eye on what was going on I fitted two voltmeters in the cabin with an LED off the isolator so I know when it was connecting the batteries (or not!). I also got one of the voltage boosting diodes.
Generally the alternator outputs enough to trigger the isolator to join the batteries although I think the output is a bit low. Often around 13.6-13.8V with a hot engine during 'normal' weather.
Over the last patch of hot weather, ie 35-39DegC, I found that the voltage would drop considerably. Down to 12.5-12.9 when running around town. This is with the extra 0.5V voltage boost. This is too low to kick the isolator into joining the batteries & was undoubtedly the cause of my fridge woes - just not getting enough voltage to trigger the isolator keep the second battery properly charged.
I've read lots about the low charging voltage of the Prado alternators but don't know if my issue is consistent with what to expect or whether my alternator is crook.
I spoke to two auto-sparkies today, one said I may need a new alternator (something like $700!), the other didn't have much of an idea & said he'd need to run some tests to find out what's going on.
Is there anything I can do to maintain a higher voltage during hot weather?
Is it likely that my alternator is crook & will a new one fix the problem?
All ideas & assistance appreciated.
Cheers
Craig
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