1988 Santego 3867 Power issue

[fredricksoncr]

Good day all!

First time poster, long time lurker.

I have a santego 3867, and i noticed an issue. When I'm out and about it feels like my boat isn't getting enough power to run the accessories on 12v.

Like if someone flushes the head, all of the lights go out. The radio some times works, sometimes doesn't, and if i have the 12v refrigerator turned on, it doesn't work at all. If i turn on the lowrance, the autopilot stops working.

I have 3 batteries currently in the engine bay, all 3 test as functional. I was reading the manual and it shows 4 batteries in a picture.

is my boat missing a battery and would that cause all these weird brown out issues?

Thanks!
Chris

[buster53]

Ok, how are your batteries set up? I’m guessing you have 2 house/starting batteries hooked up to your basic 1-2-Both-off battery switch. Do you have the switch set to both. The 3rd battery is probably your genset starting battery. Can you confirm this? When you are out on the water, are you running your genset at all? I’m guessing not.
Have you checked all your battery connections? Get a wrench and snug them down, all of them, at both ends of the cables.
What size batteries do you have? Are they deep cell, starting or dual purpose? How old are they? You say they tested ok…how were they tested? Hopefully, under a load?

Have you checked your engine alternators to make sure they are putting out voltage in the 14 volt range?

[bud37]

Source of the post Have you checked your engine alternators to make sure they are putting out voltage in the 14 volt range?

That first...

I agree with the above....clean all terminals and especially the grounds like buster mentioned.

Welcome to the forum...

[buster53]

I might add, I used to have a 1988, 3807, also with 7.4’s. I’m guessing both our engine room setups were very similar, if not identical. My battery set up was just like I described above…2 house/starting batteries and a genset starting battery. There was space in the bilge for a 4th battery, but it was not needed. My current 356 with twin 8.1 Crusaders is also set up with 3 batteries and no room for a 4th.

[Rocketman]

Like stated, check all connections for corrosion and tightness.
Also, verify your batteries are good using a load tester. Batteries can read correct but once you put a load on them, the voltage starts to drop.

[fredricksoncr]

Hey all!

Ok to answer some questions. I believe the set up is 2 house batts and one gen set batt. Both show 14-15v when i check them on the breaker panel as well as the flybridge. There is def room for a 4th battery, infact there is an empty box there.

Im not running the genset as i havent figured out how to get it to start. it isnt responding to the switch on the breaker panel to start it, and its not allowing me to manually start it so im guessing the next step is to see if its locked up.

All the terminal connections are tight and clean.

Honestly the boat is just acting like the 2 batteries are not enough. Even when im docked and plugged in to shower it has brown outs. From what i can tell with out deep examination, the show power runs the 110 and the battery charger. Then all the lights etc, run off the batteries.

I have 2 brand new lifepo4 deep cycle batteries. I think im going to just swap the batteries and see what happens.

[bud37]

Source of the post All the terminal connections are tight and clean.

I don't think there are any easy solutions to these kind of issues just systematic checking / crossing off possibilities.

Be sure to check all the ground connections that go to the engine blocks/panels as well not just the batteries themselves, usually both engines will be tied together, have a look at that as well. It may well be bad batteries as you say but from the description here it sounds like too much resistance / corrosion from disuse maybe. Have a look behind the 1,2 all main switch as well.

Two good batteries are more than enough to run a few 12 volt loads without drama by the way. I have run entire boats with just 2 house batteries FWIW.

You say there is an empty box, curious is there any wiring laying about there that would have been connected to a battery by previous owner ?

[fredricksoncr]

There wasnt any wires, just an empty secured battery box. Ill start checking for corrosion after i swap the batteries.

The two main things i notice are the lights dim or go out when flushing the toilet, and the radio barely works if it works at all.ill start checking those areas for corrosion as well.

[buster53]

As mentioned, you can’t just look at a voltage meter to confirm if the batteries are good. They have to be load tested. Google, load testing batteries.
Also as mentioned, while you have the space for a 4th battery, you don’t need it. My 3807, very similar to your boat, had the room for #4, but we managed just fine without it.
As asked, do you have your 1-2-both-off, battery switch turned to both. What size are your batteries? Deep cycle? Starting? Dual Purpose?
As far as your genset goes, good chance it is something really simple. Get a boat savvy buddy to take a look at it and go for easy fixes first.

[km1125]

You really need to flush out your current configuration. You say you have two "house" batteries, but likely have two batteries that you can switch to, and either acts as your starting and house, or both would if you have the 1/2/both/off switch set to 'both'

Source of the post ...
I have 2 brand new lifepo4 deep cycle batteries. I think im going to just swap the batteries and see what happens.

Before using them you need to confirm that they could actually handle the starting current for your boat, otherwise you'd likely have to re--configure your wiring to separate the house and engine loads and just use those for the house loads (and then make sure you have paths to charge them).