Bene F305 Rewire

[rjg23]

Going to update the 12v system on my new, to me, Beneteau First 305. Would like to get feedback from others on my plans starting with my wiring diagram (attached).

Presently there are 3 handles, in the head, that control the power. The first (Black) is the main power and the other 2 (Red) determine which battery bank will be drawn from.

My plan is to change to 1/2/Both switch and move it to under the companionway (above the engine). I've been staring at locations for the switch and the accompanying ACR and busbars and that seems to be the best location (for ease of switching and proximity to batteries and engine). If anyone, with familiarity with the mid-80's First series, has other suggestions please let me know.

Any feedback on wiring diagram is greatly appreciated. Solar panel will be 50W, with Morningstar PWM Controller.

Regards,

Bob
Beneteau First 305

 

[Maine Sail]

Going to update the 12v system on my new, to me, Beneteau First 305. Would like to get feedback from others on my plans starting with my wiring diagram (attached).

Presently there are 3 handles, in the head, that control the power. The first (Black) is the main power and the other 2 (Red) determine which battery bank will be drawn from.

My plan is to change to 1/2/Both switch and move it to under the companionway (above the engine). I've been staring at locations for the switch and the accompanying ACR and busbars and that seems to be the best location (for ease of switching and proximity to batteries and engine). If anyone, with familiarity with the mid-80's First series, has other suggestions please let me know.

Any feedback on wiring diagram is greatly appreciated. Solar panel will be 50W, with Morningstar PWM Controller.

Regards,

Bob
Beneteau First 305

The diagram looks good other than the alt wire. I would measure for voltage drop and I'd be surprised if it did not need to be larger.

Remember even a 3% voltage drop, sounds minimal right, at 14.4V, results in just 14.0V at the battery bank. This is why most builders use the short jumper to the starter post then pick up the HUGE wire because it helps minimize voltage drop. Course we then have multiple rusty engine parts, dissimilar poor conducting metals, and corrosion in the ground path and we have voltage drop anyway.

When converting to house bank direct the wire must be sized accordingly which means the largest wire you can do, comfortably, on a "self sensed" alternator.


Questions:

#1 Is that all you have for a house bank, a single G-27, on a 30' boat?

#2 If you already have two switches why not add a third paralleling/emergency switch between the two on/offs on the loads side of those switches?

Three ON/OFFS is one of my favorite switch configurations. I recommend the 1/2/BOTH version for folks who already have one installed. Nothing wrong with the 1/2/BOTH but when you already have two ON/OFF switches you are most of the way to an ON/OFF-EMERGENCY-ON/OFF setup..

 

[Ron20324]

...Any feedback on wiring diagram is greatly appreciated. ...

Without even getting into the diagram, I just want to say you have a nicely installed system already. My B323 (2006) has those same turn-switches. They allow great flexibility in your DC system. I took out the black (ground) switch and put in another red, to control a third battery I installed. All three reds feed the 12-volt buss, which is actually the heavy wire strapped across the switches. I'd be glad to work with you further, but if you really want the hassle of a new switch and relocate it, that's what you want to do. You have two, SPST switches that you want to replace with a SPDT switch. Why?

 

[rjg23]

You have two, SPST switches that you want to replace with a SPDT switch. Why?

Mostly due to lack of familiarity with the present setup. Using those switches would make the project much easier. However, wiring it properly is a total unknown. I'll have a look at it later today, adjust wiring diagram, and resubmit.

Thanks,

Bob
Beneteau First 305

 

[rjg23]

When converting to house bank direct the wire must be sized accordingly which means the largest wire you can do, comfortably, on a "self sensed" alternator.


Questions:

#1 Is that all you have for a house bank, a single G-27, on a 30' boat?

#2 If you already have two switches why not add a third paralleling/emergency switch between the two on/offs on the loads side of those switches?

Changed alternator wire to 2AWG.

I currently have 3 switches. One is black and 2 are red (one for each bank). I want to mirror the "use" setup, so:

1. Distribution Panel, Starter and both Red switches (individually) go on the
Black switch
2. House bank on one Red switch
3. Reserve on the other Red

4 lugs probably not going to fit on one post so will have to add a bus?

As far as capacity, I will be replacing all lighting with LED's. So only major draws would be on sailing instruments (wind, speed, depth), vhf, and stereo. I could put 2 house batteries in the location where the house and reserve naturally go and bury the reserve under the quarter berth.

 

[Maine Sail]

Changed alternator wire to 2AWG.

I currently have 3 switches. One is black and 2 are red (one for each bank). I want to mirror the "use" setup, so:

1. Distribution Panel, Starter and both Red switches (individually) go on the
Black switch
2. House bank on one Red switch
3. Reserve on the other Red

4 lugs probably not going to fit on one post so will have to add a bus?

As far as capacity, I will be replacing all lighting with LED's. So only major draws would be on sailing instruments (wind, speed, depth), vhf, and stereo. I could put 2 house batteries in the location where the house and reserve naturally go and bury the reserve under the quarter berth.

Can you explain the reasoning behind that switch configuration...?

The most simple thing to do with three ON/OFF switches is

Start Switch = Starts engine with start battery
House Switch = Provides house loads with house bank
Emergency Switch = Provides bank redundancy, paralleling and bank isolation

 

[rjg23]

Hadn't really looked closely at the current configuration due to my original plan to change to 1/2/Both switch.

There are three SPST switches.

One is Black. Panel negative and Engine ground are on load post, both battery negatives on bottom post.

Next is Red and what the PO had labeled as "Motor" presumedly for engine starting. Panel positive, Starter, and jumper to 3rd switch on load post.

3rd is Red and only has jumper from 2nd switch on load post.

Any reason not to leave this configuration? I switch the Black and "Motor" Red and leave the other as reserve. If I put the solar on either load post it will charge both batts via the jumper?

 

[Ron20324]

Next is Red and what the PO had labeled as "Motor" presumedly for engine starting. Panel positive, Starter, and jumper to 3rd switch on load post. ... 3rd is Red and only has jumper from 2nd switch on load post.... If I put the solar on either load post it will charge both batts via the jumper?

Okay, so the third switch(red) only has the "reserve" battery on the other side. The strap between the two "load" sides of the red is, in effect, a "positive" buss bar, but instead of being a real bar of metal, it is a wire. That is good. A large wire, I hope.

The second (red) switch has one side of it going just to the battery? The "load"/positive buss side has the starter and feed to the ckt breaker panel, right? That is good. Now, if you look at it thusly, EITHER battery switch you have on will feed the buss bar/starter/panel. It does not make any difference WHICH switch you have on, so it is not necessary to call a battery a "reserve" battery. Either battery can - and should- be used on occassion to supply the 12 volts to the start&panel. Of course, it is possible to have BOTH red switches on, and supplying double the Ah to the ship's load.

If you save one battery as "reserve", and the "house" battery dies, the reserve battery may have died sometime previous but you didn't know it because you never used it.

If you have solar wired to the positive buss lugs, either or both batteries that are switched on will receive a charge. You really should not have to turn the black(neg) switch off and on unless you service the engine (so it does not accidently operate the starter).

I assume the alternator is wired over to the starter, then the cable from the starter to the battery switch? Some people would say run the Alt out to a battery, but as long as you have one switch on (and never have both OFF- nor turn it off) when the engine is running, you'd be okay.

I don't know if you have a volt meter in the DC panel (T1 wire, maybe), you could put the sensing connection on the pos buss to read whicher battery is turned on.

If you have a bilge pump and/or radio memory wire, you'd put them on the battery side of either switch- always on.

With three group 31 batteries on my boat, when I am going out, I turn on the next switch in line, and turn off the previously "on" one. This way each battery gets exercised, and charged, and I know it has not died. On the hook, I have one battery switched "off" as a backup the next morning.

My opinion is Maine Sail's emergency switch would be accomplished by turning BOTH red switches on, thus both batteries in the circuit.

 

[mitiempo]

My opinion is Maine Sail's emergency switch would be accomplished by turning BOTH red switches on, thus both batteries in the circuit.

In a situation where one battery is discharged the last thing you want to do is combine it with a charged battery. The proper way is to use the good battery by itself, switching the discharged battery out of the circuit.

Maine's 3 switch wiring diagram allows either bank to be used for either engine starting and/or house loads without combining banks. Exactly what you want.

 

[rjg23]

I have the ACR that I was planning on using in the original configuration I put together. So if I leave the system, as is, could I put the ACR on the battery posts of the 2 Red switches and be able to have the solar maintain/charge both banks? That seems like overkill, any other suggestions on wiring the solar so that it is charging/maintaining both batteries regardless of switching or is using the ACR my best option?

 

[Maine Sail]

In a situation where one battery is discharged the last thing you want to do is combine it with a charged battery. The proper way is to use the good battery by itself, switching the discharged battery out of the circuit.

Maine's 3 switch wiring diagram allows either bank to be used for either engine starting and/or house loads without combining banks. Exactly what you want.

Yes, exactly.. A well thought out battery system would include the ability for:

* House to be used for everything, if start battery failed
* Start to be used for everything, if house battery failed
* House to be 100% isolated/taken off line, if it failed and needed isolation
* Start to be 100% isolated/taken off line, if it failed & needed isolation

If a system does not have those abilities, then I would suggest perhaps drawing it again so it does..

I did not mention a paralleling feature above as it is a feature that really has minimal good use. Any good or well designed system that meets the above criteria should already do that, if needed.