Alternator and Charge Controller Installation

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Published Monday, November 27th, 2017 | 974 Reads

Recommending the Electromaax 165 Amp Hairpin Alternator, EMaax Pro Controller, and Serpentine Belt Kit on my Islander Freeport 36, Subira. I have a Volvo MD2040 engine and a 470 AMP/hour battery bank consisting of four 135AH six-volt golf cart batteries and two 100 AH batteries for engine starting.

I purchased an Electromaax 165 Amp alternator, the EMaax Pro charge controller with remote display, and a serpentine belt kit based on my research, and had discussions with John Stevens at Electromaax. The ability to view and modify the charge parameters at the remote display is a great feature, and something that other external charge controllers do not offer.

When the parts arrived I found that the serpentine pulley for the crankshaft would not fit. Discussing the situation with Rob at Electromaax we discovered that over the four MD2040 models Volvo made slight modifications to the crankshaft pulley. I ended up sending my crankshaft pulley to Electromaax who had a custom pulley made to fit my engine at no cost.

Having solved the serpentine belt problem with the new crankshaft pulley, I completed the installation of the alternator and EMaax Pro CPU and remote display. Unfortunately I started having problems with the charging system. The system wanted to overcharge my battery bank sometimes and other times would not go into charge mode at all. This was very perplexing in that I had installed all new power and control wiring for the system and the original 70A Volvo alternator always worked properly.

To their credit Rob Bell and the technical support team at Electromaax spent the necessary hours needed to work with me as I did field testing and data collection that I sent to Rob to analyze. Initially there was an issue with the remote display not being able to access the programming mode. When I contacted Electromaax, they immediately sent a new display – we traded many hours of data on the alternator including field voltage readings, alternator current and voltage output, as well as alternator and battery temperature readings, Rob also sent me a new charge controller (CPU), but the mystery remained.

I ended up sending the alternator and CPU and remote display back to Electromaax where they did extensive bench testing but could not recreate the problems I was seeing in my installation. We determined that there was nothing wrong with the Electromaax alternator and charge controller which meant that the problem was somewhere within the boat’s wiring.

After checking all of the engine’s control wiring connections and continuity, I could not find a specific problem but on a hunch I added a dedicated ground, (12V negative), from my battery bank to the charge system’s control wiring in place of relying on the engine’s control system ground.

After the addition of the dedicated ground, the system operated properly including alternator current and voltage output as well as field voltage all within spec anticipated specs.

I’ve included a lessons learned below, hopefully this will save someone the time I spent troubleshooting my system.

Lessons learned:

  1. I assumed the engine’s control wiring was OK based on the original alternator’s operation. The original alternator had an internal regulator including alternator B+ output and a ground connection
  2. Although I had checked the engine’s control wiring connections and done a continuity test, and found no obvious problems there was some issue within the battery negative through the engine control wiring that was causing the Electromaax charge controller CPU to not operate properly
  3. I relied on the original wiring because the original alternator operated properly, but I believe because the Electromaax system has an external charge controller vs., the Volvo’s internal regulator, the Volvo’s system ground did not provide an adequate ground for the new CPU’s control
  4. When changing from an alternator with an internal regulator to a remote regulator, a new dedicated ground (battery negative) should be installed, at least on a Volvo engine
  5. When purchasing a serpentine belt kit for a Volvo MD2040 it is important to know and verify which engine model to obtain the correct crankshaft pulley

The Electromaax technical support team, and John Stevens spent many hours studying data, exchanging emails, and sending new components, as well as ultimately bench testing my complete system in an attempt to determine why my installation was not operating properly.

Thank you Rob, John, and your staff for your time and assistance troubleshooting my alternator and charging system, I highly recommend the Electromaax system to anyone wanting a new alternator, charge controller, and serpentine belt kit.

Patrick Fox
S/V Subira

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