Battery Question

[Brian77]

Okay, I'll start this out by saying that at the end of last season I was in a rush and not thinking.

I just bought the boat last year and it had 3 batteries, (2) 27 series and (1) 24. They were all in generic batteries trays and I removed all 3 batteries at the end of last season. As I said before I wasn't thinking and I failed to note which battery went where. :smt021

Fast forward to this season, I have 3 batteries and I don't know which one goes where (the trays will accept either size so that doesn't help). The battery cables seem to have stayed in position and I found labels on all of the main cables.

Battery 1
Positive Cable labeled Port Motor
Negative Cable labeled Port Motor

Battery 2
Positive Cable labeled Starboard Motor
Negative Cable labeled Auxiliary
Negative Cable going to Battery 3

Battery 3
Positive Cable labeled Auxiliary
Negative Cable labeled Starboard
Negative Cable going to Battery 2

I also have Battery switch that has options for 1, 2 or both. I know this might not be enough information to help and I may need to trace all of the cables, but I was hoping someone may have an idea of which battery should be the smaller 24 series (I'm thinking # 3).

Thanks,

Brian

 

[rondds]

Battery 1 is purely a starting battery for your port engine and your gen if you have one. That's likely the Group 24.

Batteries 2&3 are hooked up in parallel (or is it series - I always get that mixed up). In any event, they are daisy-chained to each other and they start the stbd engine and handle all house duties.

Pretty typical Searay setup.

 

[Iprof]

Battery 1 is purely a starting battery for your port engine and your gen if you have one. That's likely the Group 24.

Batteries 2&3 are hooked up in parallel (or is it series - I always get that mixed up). In any event, they are daisy-chained to each other and they start the stbd engine and handle all house duties.

Pretty typical Searay setup.

+1

Just so you know 12 volts go in parallel and 2- 6volts go in series. In series you add the voltage together and parallel does not increase the voltage.

Ken

 

[Brian77]

Wow...you just saved me hours. Thank you so much! I know over the years previous owners had made a lot of changes and I thought I was going to have to trace everything out to figure out what was done.

I just have a couple of questions to ensure I understand:

The cables that are labeled auxiliary, where are they coming from?
Should I change this setup?
You mention that the 24 should go to the port motor, is that to give the house the most available power? Would it be better for the engine to be connected to the 27?

Also, I do not have a generator.

Again, thank you so much! :grin:

Brian

 

[rondds]

The cable labelled auxiliary may just be the prev owner's terminology for what some call "house" or "accessories."

If your 27s are labelled DEEP CYCLE (by the manufacturer) they are designed for long draw-downs - meaning they can take discharge and recharge cycles better than a standard battery. Wiring them in parallel just makes them like one big huge battery, which is going to last longer when being drawn down. Your 24 may just be labelled "STARTING." Designed for quick, short bursts of draw, like that required to start an engine. Car batteries make no distinction but boat batteries (or RV batteries - same thing) do.

Plan on getting around 3 seasons from the house batteries, possibly double that on the starting if you keep an eye on the water, which you should as part of your normal "snooping around the bilge" regimen.

 

[Nehalennia]

Yes, the 24 is a smaller battery, so the 2 group 27s are your "house bank" and give you your largest amount of power for your accessories. It should be setting #2 on your battery switch.

I had 2- group 27s. I just replaced one of the group 27s with a new one(Interstate) and the other with 2- 6V golf cart batteries. Memorial Day weekend they will get their first long test for longevity.

 

[Brian77]

That certainly clears that up...thanks again!

Brian