I am looking to charge an auxiliary battery for my motorhome, but am not sure if I can use an isolator given the alternator. It is a Hitachi LR160-78B 60a alternator in a 1985 Nissan 720 pickup (actually a motorhome). I had looked at a few isolators and in the instructions most say some Hitachi's are not compatible with isolators....how can I tell if mine is or isn't compatible? If not then I presume the best thing to do is get a Separator?


  • The alternator is OEM Hitachi LR160-78B. There is a vehicle battery and an auxiliary battery. Currently the auxiliary is solar powered only, and I want to be able to use the engine alternator to charge the auxiliary battery without ever draining the engine battery, One Isolator I had looked at was this images11.palcdn.com/hlr-system/Documents/82/823/8235/… . I am not sure which Group number my alternator is. – Mark Jan 26 '19 at 6:08
  • The details of the isolator with the instructions... you had already put the alternator in your post... and include any wiring diagram suggested or what you have done... – Solar Mike Jan 26 '19 at 6:10
  • Im not sure about the instructions referring to group 1, 2, 3 & 4. Do they mean alternator or isolator? I had emailed them about a week ago but no response. – Mark Jan 26 '19 at 6:13
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    Those groups are about the alternators fitted so that you then connect the isolator correctly. The other possibility is to use a high capacity relay that connects the second battery to the first once the engine is running - the "old-school" method... – Solar Mike Jan 26 '19 at 6:19
  • I am not aware of high capacity relays until now, I will have to look more into that I think. Anything you might suggest? So far I have been unable to ascertain the group numbering of the alternator with my only clue that it has an internal regulator. The other issue is gauge of wire as the auxiliary battery will need 15' of wire to be reached from the engine battery or alternator. – Mark Jan 26 '19 at 6:39

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