Mastervolt Alpha High-Output Alternator Temperature when charging LiFePO4

Dean Gillies

Hi all,
This question is for owners with installed LiFePO4 batteries using the Mastervolt Alpha alternator (110A or 150A) as originally installed on many 54s. 

Mastervolt state that these alternators do not require a temperature sensor to monitor alternator temperature, the implication being that they will not overheat,  There is no graceful degradation built-in, and presumably if the alternator really does overheats then it will simply fail completely.

I wonder if this statement by MV holds true in practice with the large LiFePO4 banks now being installed, where the alternator could be asked to deliver maximum power continuously for a period of 4, 5 or more hours?

Has anyone experienced an alternator failure caused by overheating when charging for long periods?

Mastervolt offer a temperature sensor for third-party alternators which can be used via the Alpha Pro II/III regulators’ Masterbus interface. This allows the regulator to first derate, and then safely disable the third-party alternator if the temperature becomes too high. Has anyone felt the need to install this option with a Mastervolt alternator?

I will be changing to LiFePO4 when I return to Stella and I’m just planning my approach to managing the alternator interface.

SV Stella, A54-154

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