Load dump module
#1
04-21-2014, 05:52 PM
Load dump module
My '87 V12 came with the Bosch 75 amp alternator, and showed the not uncommon tendency of not truly charging until the RPM got up to 2K or so.
I just replaced it with a Delco 95 amp unit. The swap had brought my idle voltage up to just shy of 14, but I still have the issue of no charging until about 2K rpm. In other words, with a DVOM on the system, the voltage stays around 12 or so, then if I rev up to 2K, the master warning and battery warning lights come on, the in-car meter jumps to just above the mid point, and the voltage on the DVOM jumps to 14. The warning lights go off, and when the RPM drops back to below 2k the voltage happily stays at 14.
So...it's not a big issue...after all in just a few minutes of driving I'm eventually going to hit 2K, but it would be nice if it would just start charging right away. I've not had much luck in finding a "load dump module" that supposedly fixes this issue. Anyone familiar with where to obtain one...or any other potential fixes?
Thanks,
John
1987 XJ-S V12
64,000 miles
I just replaced it with a Delco 95 amp unit. The swap had brought my idle voltage up to just shy of 14, but I still have the issue of no charging until about 2K rpm. In other words, with a DVOM on the system, the voltage stays around 12 or so, then if I rev up to 2K, the master warning and battery warning lights come on, the in-car meter jumps to just above the mid point, and the voltage on the DVOM jumps to 14. The warning lights go off, and when the RPM drops back to below 2k the voltage happily stays at 14.
So...it's not a big issue...after all in just a few minutes of driving I'm eventually going to hit 2K, but it would be nice if it would just start charging right away. I've not had much luck in finding a "load dump module" that supposedly fixes this issue. Anyone familiar with where to obtain one...or any other potential fixes?
Thanks,
John
1987 XJ-S V12
64,000 miles
#2
04-21-2014, 07:27 PM
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Not quite sure if I understand.
Are you wanting to *install* a load dump module? The more common thing if there's a charging problem is to disconnect it. And I'm 99% sure your '87 never had one to begin with.
Sound like the 'excite' circuit is not working. Do you have a 'key on, engine off' charging system warning lamp on? Where did you wire-in the excite circuit for the Delco alternator?
From memory there are two charging system lamps. A conventional ignition/alternator warning lamp and an overcharge warning lamp.
Cheers
DD
Are you wanting to *install* a load dump module? The more common thing if there's a charging problem is to disconnect it. And I'm 99% sure your '87 never had one to begin with.
Sound like the 'excite' circuit is not working. Do you have a 'key on, engine off' charging system warning lamp on? Where did you wire-in the excite circuit for the Delco alternator?
From memory there are two charging system lamps. A conventional ignition/alternator warning lamp and an overcharge warning lamp.
Cheers
DD
#3
04-25-2014, 07:14 PM
Yep...that wasn't the clearest working in that post was it :-)
Basically, I'd like the thing to start charging when I start is. Right now the voltage stays low until around 2K rpm, then things get happy (voltage goes from 11 something to around 14).
In Palm, there is a discussion about a "load dump module" that, if I read it correctly, I supposed to fix this issue. I can't seem to find this device, hence my post.
It's not a big issue, more of any annoyance I'd like to correct more that an operationally significant issue.
Thanks,
John
1987 XJ-S V12
64,000 miles
Basically, I'd like the thing to start charging when I start is. Right now the voltage stays low until around 2K rpm, then things get happy (voltage goes from 11 something to around 14).
In Palm, there is a discussion about a "load dump module" that, if I read it correctly, I supposed to fix this issue. I can't seem to find this device, hence my post.
It's not a big issue, more of any annoyance I'd like to correct more that an operationally significant issue.
Thanks,
John
1987 XJ-S V12
64,000 miles
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