10-24-2022, 02:24 AM
@arcticdue - Thank you for the feedback. There are also a couple levels of Blue Sea VSR's. The one I mentioned is their 500A version that is the most reliable (I believe the more common version is ~200A and very affordable at just under $100).
Quick question for you -- you wrote "at least one of our Wanderlodges" - do you do conversions? Although we are not in the business of doing conversions, we essentially ripped all of our Class-B's (Leisure Travel's for the most part) down to the metal and rebuilt for our own purposes. Contrary to someone that does this as a business, we lose a lot of money because you'll never get your return on this type of upgrade (too few people appreciate); however, it is a great learning experience
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To answer your question -- the primary issue is with the heat generated by the alternator. Automobile alternators are not intended for maximum-amperage production at long intervals, which is the reason automobile alternators/generators are so much smaller than conventional stand-alone "generators" (the stator/rotor unit mounted to the motor).
In the case of the large alternators used on DP's, the alternator is much larger and should be able to dissipate substantially more heat. Overloading a DP alternator is not as common as a traditional automobile (or non-DP chassis RV).
Consider that the "efficiency" of something is essentially a direct correlation to its heat production. You'll notice your charger is (typically) somewhere over 92% efficient when running at higher amperage. In other words, to use a simple hypothetical: if you're charging at 1000 watts, you are creating 80 watts of heat.
Vehicle alternators are typically around 60% efficient, therefore, at 1000 watts, you're creating about 400 watts of heat (500% more). Fortunately with an alternator you get the intrinsic high-volume fan while a charger typically runs on an electric, relatively lower volume of air-cooling.
While the cooling is not as substantial, the charger is designed for a consistent/long-running duty-cycle and the airflow is adequate. For this reason, typically a charger is not an issue.
As you noted, the alternator's voltage regulator is even more susceptible to issues than the the alternator, in some cases, because it's not properly cooled.
As this relates to the original poster's question --
In my humble opinion, the VSR (or similar) is a simpler, more effective, more suitable option. However, if he intends to use the chassis-engine as a generator to charge batteries from low SoC (not as intended/recommended), the best approach will be decoupling the alternator and limiting current to a degree. For example, a DC-DC charger because this will intrinsically limit the current (based on the capability of the charger, which uses non-transformer based voltage adjustment; essentially mosfets, schottky rectifiers, caps).
Quick question for you -- you wrote "at least one of our Wanderlodges" - do you do conversions? Although we are not in the business of doing conversions, we essentially ripped all of our Class-B's (Leisure Travel's for the most part) down to the metal and rebuilt for our own purposes. Contrary to someone that does this as a business, we lose a lot of money because you'll never get your return on this type of upgrade (too few people appreciate); however, it is a great learning experience
.To answer your question -- the primary issue is with the heat generated by the alternator. Automobile alternators are not intended for maximum-amperage production at long intervals, which is the reason automobile alternators/generators are so much smaller than conventional stand-alone "generators" (the stator/rotor unit mounted to the motor).
In the case of the large alternators used on DP's, the alternator is much larger and should be able to dissipate substantially more heat. Overloading a DP alternator is not as common as a traditional automobile (or non-DP chassis RV).
Consider that the "efficiency" of something is essentially a direct correlation to its heat production. You'll notice your charger is (typically) somewhere over 92% efficient when running at higher amperage. In other words, to use a simple hypothetical: if you're charging at 1000 watts, you are creating 80 watts of heat.
Vehicle alternators are typically around 60% efficient, therefore, at 1000 watts, you're creating about 400 watts of heat (500% more). Fortunately with an alternator you get the intrinsic high-volume fan while a charger typically runs on an electric, relatively lower volume of air-cooling.
While the cooling is not as substantial, the charger is designed for a consistent/long-running duty-cycle and the airflow is adequate. For this reason, typically a charger is not an issue.
As you noted, the alternator's voltage regulator is even more susceptible to issues than the the alternator, in some cases, because it's not properly cooled.
As this relates to the original poster's question --
In my humble opinion, the VSR (or similar) is a simpler, more effective, more suitable option. However, if he intends to use the chassis-engine as a generator to charge batteries from low SoC (not as intended/recommended), the best approach will be decoupling the alternator and limiting current to a degree. For example, a DC-DC charger because this will intrinsically limit the current (based on the capability of the charger, which uses non-transformer based voltage adjustment; essentially mosfets, schottky rectifiers, caps).