battery help please!

[Darrin686]

Soooo..... I feel like an idiot with these questions, I have a 2001 Mastercraft pro star and I wanted to run my sound system off a deep cycle battery. I bought a switch for the battery that has 1,2 and 1&2, and off.

I went to take the wires off the battery today and noticed that there are two sets of wires leaving the battery. I ohmed the red wire (smaller conncetor wire) that goes to the 40 amp fuse in the picture and found that it went to under the dash to the breaker button pannel. Im honestly not sure where the solid red wire with the large lugs goes. My guess was this is just for the battery starter controlled by a relay?

my question is, would I be able to run the battery wires with the big clamp lugs to the the starter battery and the other two wires ( the ones that go though the 40amp fuse) to the deep cycle battery and not worry about even installing a battery switch?

Also im prepairng for the MDC delete on the MDC 1600 and the wiring looks the same as the guide except I have 2 brown wires on the output harness (Gauge harness as named in the guide) I don't see the guide mention these brown wires and im not sure what they are for or what do do with them. I do have a clock so im not sure if its for clock adjust? im really just guessing at this point.

[Darrin686]

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[Darrin686]

MDC out harness im not sure what the brown/white and solid brown wires do

[robadele]

Running two different capacity and age batteries without an isolator switch is a recipe for disaster. When one battery dies you can end up not being able to start the engine if you do not have a switch. Additionally if you plan to run all the time in the 1 and 2 both on positioning you may have problems because the batteries charge at different rates. Best solution is two equal batteries and use a switch.

[Darrin686]

Thanks for the reply, thats what I will do then

[dpb185]

Soooo..... I feel like an idiot with these questions, I have a 2001 Mastercraft pro star and I wanted to run my sound system off a deep cycle battery. I bought a switch for the battery that has 1,2 and 1&2, and off.

I went to take the wires off the battery today and noticed that there are two sets of wires leaving the battery. I ohmed the red wire (smaller conncetor wire) that goes to the 40 amp fuse in the picture and found that it went to under the dash to the breaker button pannel. Im honestly not sure where the solid red wire with the large lugs goes. My guess was this is just for the battery starter controlled by a relay?

my question is, would I be able to run the battery wires with the big clamp lugs to the the starter battery and the other two wires ( the ones that go though the 40amp fuse) to the deep cycle battery and not worry about even installing a battery switch?

Also im prepairng for the MDC delete on the MDC 1600 and the wiring looks the same as the guide except I have 2 brown wires on the output harness (Gauge harness as named in the guide) I don't see the guide mention these brown wires and im not sure what they are for or what do do with them. I do have a clock so im not sure if its for clock adjust? im really just guessing at this point.

Lots of good info on adding a second battery here:

https://teamtalk.mastercraft.com/forum/maintenance-tips-how-tos-and-refurbishing-topics/electrical/3608-the-official-dual-battery-thread

Short answer is Blue Sea sells kits to accomplish this:

https://www.bluesea.com/products/category/35/89/Automatic_Charging_Relays/Add-A-Battery_Kits

Make sure you understand circuit protection requirements, otherwise you can burn down your boat. Don't be afraid to ask questions. I just did this job on my 2000 Prostar recently.

Here my mostly completed system:

[ShuManChu]

I would argue that it is never appropriate to use two batteries in parallel without an isolation relay (even if they are the same), if you want to really have a reliable starting battery. But many have been able to run batteries without isolation relays with minimal to no issues assuming they are using identical batteries. YMMV.

If you only have 4 speakers and a subwoofer, say a 400W to 800W system in total, you'll probably be fine with just one deep cycle battery. That's what I use. IF you really want two batteries, you can take a look at the Blue Sea Systems Add A Battery kit which comes with the switch and isolation relay. It makes the job real easy.

https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A

There's also a post on the forum on how to DIY this with just a regular automotive isolation relay:

https://teamtalk.mastercraft.com/forum/maintenance-tips-how-tos-and-refurbishing-topics/electrical/3608-the-official-dual-battery-thread

The wiring harness with the brown/white and brown wires in the pictures has the following pinout:





I think you are right about the brown/white wire being the secondary adjust for the clock.

[ShuManChu]

HAHAHA dpb185 you made your post while I was writing mine up. Great minds think alike!

[dpb185]

HAHAHA dpb185 you made your post while I was writing mine up. Great minds think alike!

Agreement on a TeamTalk thread. What's the world coming to ? I guess this is the opposite of the endless arguing on the oil type/gelcoat compound threads.

[Darrin686]

Thank you everyone for the extreemly fast help on this, DB185 that set up you have ruuning looks awsome, thats a sweet looking amp up as well. Thanks ShuManChu for comfirming the brown wires for me, it makes it way less scary to start cutting my wiring harness off the MDC when I know forsure what all the wires are doing.

[waterlogged882]

I got nothing to add. Good thread, good information.

I will say this; make sure you use all ring connectors for your battery connections. No post clamps.

If you need cable (and I would put in all new tinned wire cables with shrink connectors) I can suggest this site for good service. Quality builds for custom cables. Automotive cable (bare copper strands; non-tinned) is the least of my choices.

When you put in the main switch, strategically place it somewhere that is it easy to reach. Sounds simple and Mr. Obvious but mine is a little bit inconvenient (from the driver's seat) to reach without having to move around. Lay out your setup with user-friendly ergonomics in mind.

Best on the build.

US $0.02

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