Re: [Amel Yacht Owners] Leece-Neville 175 amp alternator and smart regulator modification

Alan Leslie

Well.....lots of discussion on this I see.....

We have been off air for the last 3 weeks....14 days sail from Auckland to Raivavae (one gale for 3 days -v but overall avg 170 miles / day) and then 3 days to Papeete.

Currently in Taina Marina.

OK, our smart reg and alt mod is working well.

One issue...the Leece Neville alternator is not a hot-rated or KKK type alternator, so it can't put out the 175 A for very long without burning up.

Our batteries were down somewhat when we started the motor....LN putting out max current 175A...started to smell hot...what to do ?...started the genset and put the 100A charger on to take some of the load away from the LN, and watched the Xantrex monitor until the current dropped to about 130A...then turned the genset off....and continued with the LN.

So that's a trap to be aware of if you have AGM batteries.

AGM batteries have a very high charge acceptance rate compared to flooded lead acid batts, so if they're down they will take the max current you can deliver, and that;s a problem for non hot rated  alts as the smart reg increase the field to get max output and the current that flows is dependant on the battery bank acceptance.

Regarding the discussion about the standard reg in the LN alt....its designed to charge start batteries with thin your car battery, they don't mind being at 28.8V for hours on end.

Deep cycle batteries in your house bank are a different beast altogether.

ALL deep cycle battery manfrs recommend the 3 stage charging system, bulk, absorption, float.

In a deep cycle application, the issue with the standard automotive reg is that it ramps up to 28.8V and stays there...whatever current flows at that voltage flows (limited by the alt capacity) and the voltage stays at 28.8V

Cheers all from Papeete.


SV Elyse SM437


Join to automatically receive all group messages.