Wiring alternator/regulator questions

[dodgydingo]

I am doing some electrical work on my boat and have some questions :

1)Should my external regulator/alternator charge my house batteries only or both my starter battery as well. My house batteries are a pair of 6volt golf cart batteries (deep cycle) while my starter is a standard starter battery from West Marine.
Currently only my house batteries get charged from the alternator (14volts) unless I move my battery switch to "both". Is this the recommended method? I am wondering if this will cause problems as my house batteries may need different charging than my starter battery. Should I leave my switch on my house batteries while motoring or on both so both batteries are charged. I am concerned I may be overcharging my starter. Is there external regulators that properly handle two different sets of batteries properly?

2) My Alternator is connected with a breaker/switch on the main DC panel. If I leave the switch on, my alternator gets warm to the touch. (continuously, even when I haven't run the engine in a few days). I assume this isn't normal as it must be a short somewhere and wasting energy. This is the main reason I want to sort out my electrical issues. The previous owner left me with a wiring rats nest to sort out.

3) Does anyone recognize the make/model of this alternator. It looks like has been upgrade to a larger size by the previous owner but I am unable to figure out what brand/model it is. I would like to finally get a tachometer working and I don't know where it would attach on this alternator.

4)Would the tachometer cable go on the connector labeled "R"?

[erps]

I think that's a Delco 10DN type alternator, or at least has a similar wiring configuration.

http://alternatorstartershop.blogspo...gn-part-1.html

[dodgydingo]

Hmm I google searched images of Delco alternators and I think you are right, but I think its another model. At least I know what brand to start searching through. Thanks

[btrayfors]

Dodgydingo,

The preferred method of wiring alternators these days is to connect it directly to the house batteries (only), using an appropriately sized fuse located near the batteries.

Then, the start battery is maintained using a voltage-follower device (EchoCharge, DuoCharge, etc.) or a battery combiner. Some installations use battery isolators, but I don't like them and they're not recommended these days. I just removed a (new) isolator from a client's boat yesterday; it had failed and wasn't putting any charge at all into the batteries. But, mainly, they involve an undesirable voltage drop.

For most cruisers, a Xantrex EchoCharge is all that's needed. Easy to install and totally automatic. I like these voltage followers better than battery combiners, since they have no moving parts (no relays to fail) and they don't combine deeply discharged batteries with near fully charged batteries, causing an undesirable in-rush current.

RE: your alternator switch on the panel, it is NOT a good idea to place a switch in the alternator output line; this could cause an almost immediate destruction of the diodes in the alternator. It may be that the switch is instead wired to cut off the field current (that's OK) or to reduce the output of the alternator, depending on the type of regulator used. Some external regulators, like the Balmar MC-612, 614, etc., have provision to wire a simple toggle switch which will cut the alternator's output in half in situations where that may be desirable (e.g., overheating, less drag on engine, etc.).

Good luck with sorting out the PO's wiring mess. That's not a job I enjoy!

Bill

[mitiempo]

I agree with Bill, the Echo Charge is my choice as well.

Here's a link to anything you ever wanted to know about alternators in a downloadable pdf.
http://kb-kbh.dk/shipslib/el_ombord/...ndbook_ocr.pdf

[dodgydingo]

Thanks for your help guys. I spent the past week tracing wires and researching online.
It looks like I do have a Delco 12SI alternator (internal regulated) with the optional "Remote" terminal.
I drafted up a diagram (from memory.. hopefully its correct) of how it is setup.

1) I'm puzzled why this internally regulating alternator is connected an external Xantrex Voltage Regulator.
I understand I should move that directly to the housebank instead of to the switch. As you can see in my previous photo, there is nothing on my "S" terminal. Now some documentation online says it is the Stator terminal, while I found other sites saying it is the "Sense" terminal. Are they the same thing? At first I thought this is where my Tachometer should connect to, but after reading documentation online.. I am not sure now if the Tach goes onto the unused "Remote" terminal on my alternator, or onto the "tach" terminal on my Xantrex.

2) I will get a Xantrex echo charger for my starter battery. My starter batt and house bank are both connected to a charger.. With the Echo Charger installed, should I remove the starter battery from my Xantrex true charger so it only gets the echo charger in this case.

3) Even if the starter battery is getting a trickle from the house battery. If i switch to "both" on my master switch.. wouldnt that defeat the echo charger as both banks would now be connected to (the charger when on AC) or (the alternator when motoring)?

I am new to this electrical work and am spending every night knee deep in Nigel Calders book and surfing documention on websites so it will take me some time to figure this all out. Your help is really appreciated.

[BigNige]

Originally Posted by btrayfors

Some installations use battery isolators... they involve an undesirable voltage drop...

IMO the best solution is a Voltage Sensitive Relay (VSR) which combines the banks automatically. However, a diode splitter is OK so long as the battery sense wire is downstream of it.