• From: Vancouver
  • Registered: 2006-08-26
  • Posts: 6

Topic: DC Charging System

Hello:

I am thinking of making some changes to my DC charging system (25amp prop shaft-driven alternator with integrated regulator, 7hp Faryman diesel, battery isolator, alternator "on/off" switch, two Group 24-sized batteries (75ah deep cycle and engine cranking), and battery selector switch) and would appreciate any comments as to the practicality/usefulness of the following:

(1) Upgrade 25 amp alternator with a larger one (perhaps 50 amp?)
(2) Remove battery isolator
(3) Install external multistep regulator
(4) Replace alternator on/off switch with a field disconnect switch
(5) Upgrade batteries to two deep cycle/dual purpose Group 27-size batteries
(6) Install metering for alternator output and battery voltage

My thoughts are that the driving factor for the whole charging system is the size of the engine rather than anticipated daily ah usage; I'm not sure but I think I could accept a drop in engine hp when the alternator is running and charging if I could turn it off when I need the engine power (i.e., remove the load if this would significantly affect the hp required to turn the alternator-since it runs off the prop shaft).   I am also thinking that since the engine is easily hand cranked (but only if necessary!) the precaution of having a designated engine cranking battery is not needed, but I am not sure if two deep cycle/dual purpose batteries (each with a 100ah rating) is the best way to go.

Any experiences would be gratefully received!

  • Registered: 2006-08-30
  • Posts: 10

Re: DC Charging System

Jonathan:
I think I saw a way to compute all the loads, battery and alternator needed, and stuff like this in Calder's book. See if it's of any help.
Neko

  • From: Vancouver
  • Registered: 2006-08-26
  • Posts: 6

Re: DC Charging System

Thanks!  I picked up a copy and am battling my way through it a bit at a time.  It's all good stuff of course - too much of it though and I suspect one would never leave the slip!

  • From: Victoria B.C.
  • Registered: 2006-03-11
  • Posts: 171

Re: DC Charging System

It's rather expensive,but you might be able to use an electric clutch to disengage the alternator.A three stage regulator should also drop the load,I think,when you are topped up.Does any one know if you can use a three stage regulator on the Farryman.A photo of the shaft driven alternator would be really interesting to me.