If you really want to hot load test the alt and accurately and safely dial back the current
then you will want a cheap
HF inverter. They work fine for this and after ruining a couple of more expensive ones, by lugging them on and off boats, getting them wet etc., I now use a cheap
HFT inverter for alt testing. If I break it who cares, it was cheap.. You will also want a hair dryer or small electric
heater. If all you have is a hair dryer be careful. You can place it facing the ceiling in the dry galley
sink and it will be pretty safe.
Start at Belt Manager Level 3
Install a remote
temp probe on the alt and close up the engine
bay like you normally would run it. Many DVM's offer this feature.
Run the boat, away from the dock
, up to engine temp for at least 30 minutes, while loading the alt with the inverter & heater. Take note of cold output and hot output.
Return to the dock
and allow the engine to "fast idle". This is the hardest load on a HO alt, heat wise, because they can put out a sizable % of their current
even at low alt RPM
but they lack the RPM
for adequate fan cooling
in a tight hot engine bay. Keep the alt fully loaded while you monitor
alt case temp..
Continue monitoring alt temp. If it exceeds 215-220F drop Belt Manager down another step to level #4. If it does not get over 190F it is often safe to go up one step to level #2...
You can probably just get away with BM Level 3...