Battery/switch systems upgrade

[Scott]

I posted this in the general area a couple of days ago. Since some people go directly to the Big Boats area and not the General posts, I'm posting it here too. Please disregard if you've already seen this elsewhere. Thanks.Issue:I am in the process of upgrading from the 1-both-2-off switch system to the three switch system (House on/off, Emergency Parallel, Starting on/off) on my '85 H-34. I'm using a combiner and three group 31 deep cycle batteries (two house, one starting), as well as the original Yanmar 3GM20F OEM alterator (likely a Hitachi).All the information I've found (Calder, Case, West Advisor, etc.) prescribes running 2 AWG wire from the starter to the starting bank, and a seperate wire from the alternator to the House bank (via the appropriate breakers and switches of course. Banks are seperate during discharge and combinde via the West Marine Combiner during charge from either the AC TrueCharge at the dock, or the Alternator under engine power.My problem/question/concern:The existing OEM alternator (with integrated regulator) BAT wire is currently attached to the Starter only. A 4AWG l wire goes from the starter to the Common side of the present switch. I don't plan to replace this alternator just yet and the rest of the project is well documented.Is it ok to simply:A. Remove the wire that runs between the Alternator BAT post and the Starter ANDB. Run a new 2AWG wire from the Alternator BAT post to the new seperate House Bank?C. Run the existing wire from the starter to the new dedicated starter switch common post.Will this work or will I fry something in the process?Are there other wiring alterations I need to make?Are there sources I can reference other than those listed (tried) above?I have searched extensively using every term I can think of and found nothing in the archives that conclusively resolves this issue within the framework of this configuration (3 switches, OEM alternator, Battery Combiner).

 

[Fred Ficarra]

Wow, much more complex than what I have,

Go to my web site and see what we have done. We are down to ONE bank. Your engine doesn't need all that stuff, trust me. Wire up one bank with as few (larger)(golfcart) batteries as you can. Your one bank will still start your engine until it is nearly DEAD! That is what the compression release is for. West Marine was recommending one bank. Have they changed? They wouldn't do that just to sell a combiner, would they?

 

[Rich Wallace]

Some Thoughts

The first thing to check is to see if the place where the alternator hooks at the starter is always on when the battery switch is on. By that I mean that it is on the hot side of the starter solenoid. I suspect that it is. If that is accurate, then you can hook up where ever there is a hot connection to the batteries. IF you decide to use the common connection on the switch and that connection can be disconnected from the batteries by turning the switch to off, you will blow up the alternator if the engine is running when you turn it off. Either get one of the ZapStop devices and mount it on the alternator, or hook the bat side of the alternator directly to the house bank. The downside of hooking directly to the house bank is that you don't have a positive disconnect from the batteries to the rest of the boat in the case of a fire, or other electrical problem. I vote for hooking to the common and putting in a ZapStop. Hope that helps.

 

[Scott]

Thanks

Thanks.TO be more clear, I'm only employing one starting bank...and one house bank, same as OEM spec. However I am dumping the multiposition switch plan where you have to remember when to switch to what bank all the time, in favor of the simpler on/off plan where you just turn them on when you board and off when you leave. The new plan dictates seperate house and starting banks which are only paralleled in emergencies via a third switch dedicated only to that (see Calder, West Advisor).On the OEM system in the H-34, only one wire ran from the starter to the common side of the 1-both-2-off switch. The alternator is wired only to the starter. The new simpler switching system specifies one wire running from the starting battery switch to the starter, and another wire running from the alternator to the house bank switch, with a combiner to combine the batteries only during charging processes. Since the old system wires the alternator to the starter, I was concerned about cutting that connection and running a seperate lead from the alternator to the house bank switch...Since none of the experts discuss this anomoly in their wiring advice, I thought I'd ping this group for their experience.I'd like to hear that someone else has actually done this and not fried their systems.sbsb

 

[Neil]

two switches

I have two switches. One for the house, two golf-cart in series, and one for starting, one group 27 deep cycle marine. The golf carts are hooked up to the charger, the starting is only to the alternator. Has worked well for 6 years and the golf carts will let me run the house plus refer about two days without rechargeing. Wiring sounds like your original.