Adding a second battey. Perko Switch, stereo, amp and accessories questions.

[madurodave]

Hello iboats. I have been running one battery with no issues all summer. On this one battery I have all the typical stuff being used, plus a stereo, amp and tower speakers. To make a long story short, the last few outings the AMP cuts out. I assume the draw is just too much for this one battery to handle. Plus, I realize the power wire from the amp to the battery is probably just too long. I recently picked up a second battery (deep cycle) and a Perko switch to isolate my engine and starting battery from the toys.

I have a few questions before I tackle this project. Thanks in advance for any guidance and any help you may be able to provide.

Perferred option: I want to place the second battery and the perko switch in the cuddy. Is it ok to have a long run of wire from the front to the back of the boat between batteries and ground to use the switch?

Alternate option 1: I would just place the second battery in the back of the boat but that would mean I would need a long run of wire from the amp to the battery in the back....is this the better option? If so, on a 21'boat, what gauge wire should I use?

Alternate option 2: I would put but both the battery (and switch) and the amp in the back of the boat but I don't know where to locate (or if they are available) the preamp output wires - rca cables from the head unit to the amp?

As you can see, this rookie needs a little help. Thanks so much.

 

[Silvertip]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

You need to understand that wherever you place the switch, the cables from the batteries needs to be the same size as those that currently go from the starting battery to the engine. Remember, a dual battery switch allows you to select BAT 1 for starting, charging, and running accessories, so does BAT 2 and so does BOTH. If you use too small a wire on BAT 2 and attempt to start the engine, you would toast that wire. A dual battery switch should have EVERYTHING, including the ENGINE connected to the COM TERMINAL. That provides the most flexibility. There are other schemes but all of them come up short on flexibility/cost.

This topic is discussed over and over and over - so use the SEARCH feature to make sure you understand what you are getting into.

 

[Augoose]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

I went over those same questions when I did mine- eventually decided to leave both batteries and switch by the engine. The first reason was the price of copper wire - as Silvertip already said, its extremely important to use the correct gauge wire for this application, which is thick and fairly expensive. The second reason is you will face a certain amount of drain over extreme lengths of wire from the engine compartment to the cockpit, or wherever you are planning on installing the switch - so 10 feet or more from the engine to the cockpit is significant. Lastly, you'll need several lengths of wire to run the switch from the cockpit all the way to the back for 2 batteries- to me, running that much wire wasn't worth saving the couple of steps it to walk to the back to flip the switch whenever I needed it. There are several diagrams on-line with various amounts of complexity, not to mention the one that comes with the perko switch which is also easy to follow- here is the one that I used. Its easy and serves as a nice backup and a way to store the boat long term without much battery drain.

 

[veritas honus]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

The "One for dummies" that Augoose so elequently stated, is actually the configuration which is instructed by Perko. It's simply a different picture. It's really simple.

I shopped around for battery cable and found the average price to be around $4.00 per foot for 2ga... Then I found that Advance Auto has clear insulated 2ga battery cable for only $1.88 per foot. SOLD!!! Bought 14', and had 3' left over. If you use this stuff as speaker wire, you'll be amazed with the improvement in sound quality. At only 1.88 per foot, it's a steal!!! Oh, and by the way, yes, it is pure copper.

I would go with alternate option 1 or 2... Whichever floats your boat...

 

[madurodave]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

Thanks so much guys.

 

[brianvolt7]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

I would recommend that you purchase an amplifier capacitor. Mount it in line with your cables to the amp. These are designed to resolve the exact problem that you are describing in your initial post.

If your amp is outdrawing your original battery it will continue to outdraw an new one. Here is a link for you to check out http://www.crutchfield.com/shopsearch/capacitor.html

 

[Scott Danforth]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

you do not want to put a battery in the cuddy. the risk of issues from degassing not to mention potential for acid leak are not worth it. put both batteries in the bilge where they are supposed to be and run the shortest lenght of wire you can get. I also recommend 2 gauge minimum. then get an amp installation kit (power cables, fuses, terminals and RCA wires, along with the blue remote wire) and a few capacitors.

4 Gauge wire is only good for 100 amps, and in short lengths is fine. for long runs, remember to increase the gauge size to account for voltage drop. here is a good source for an on-line calculator http://www.powerstream.com/Wire_Size.htm

I myself am running a dedicated 6 gauge wire from the batteries to the cabin for the head unit, all additional electronics and small forward amp. the rear amp is in the bilge area for a nice short run to the speakers and batteries.

 

[brianvolt7]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

In my truck, I had this same problem with my Alpine M1000 and two 12 MTX's running in 2 ohm. I use 8 AWG for + from battery, 30 amp fuse at batt, and 8 AWG ground. My Ground run is about 12" from amp and the + run from battery is about 14'. This thing would cut out when the bass hit hard. I installed the cap and have not had problems since. Has not dropped once.

Make sure your ground wire is the same size as your + run as well.

Good luck!

 

[hrdwrkingacguy]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

I shopped around for battery cable and found the average price to be around $4.00 per foot for 2ga... Then I found that Advance Auto has clear insulated 2ga battery cable for only $1.88 per foot. SOLD!!! Bought 14', and had 3' left over...

I usually use welder lead wire from an electrical supplier like summit electric here in phoenix...0ga is like .65c a foot I did my truck for like 25$

 

[hrdwrkingacguy]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

In my truck, I had this same problem with my Alpine M1000 and two 12 MTX's running in 2 ohm. I use 8 AWG for + from battery, 30 amp fuse at batt, and 8 AWG ground.

Good luck!

You are running a 1000watt amp @ 2 ohms with 8 gauge wire? I would run 2ga or 1/0ga...Not that you asked anyone's opinion but that seems quite a bit to small...

 

[brianvolt7]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

hrdwrkingacguy,

I thought about changing the wiring out to a 1/0 when I changed out my first amp. At the time I did not want to spend the extra $. When the new amp was in place I decided on the capacitor instead. I guess I just wanted to try it out. I have not had any problems since I added it so I think I will continue to run 8. I am adding a small amp for the back doors because I am putting 8" woofers, (long story and lots of customization) running a crossover rolling off at 2000hz and picking up a set of 4x6 for mid/tweet filtered at + 800. When I do this I may change to 1/0.

 

[TSL812]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

In my truck, I had this same problem with my Alpine M1000 and two 12 MTX's running in 2 ohm. I use 8 AWG for + from battery, 30 amp fuse at batt, and 8 AWG ground. My Ground run is about 12" from amp and the + run from battery is about 14'. This thing would cut out when the bass hit hard. I installed the cap and have not had problems since. Has not dropped once.

Make sure your ground wire is the same size as your + run as well.

Good luck!

You dont blow the 30a fuse with that amp?

 

[brianvolt7]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

No it does'nt blow, it seams to function fine.

 

[Silverbullet555]

Re: Adding a second battey. Perko Switch, stereo, amp and accessories questions.

Not sure why you are not blowing the fuse other than perhaps the wire is keeping that from happening.

Yes, you need a second battery. Not to power everything, but to ensure you can start the boat after hanging on the hook for a while.

Wiring is an important factor here.

Remember, your ground wire size needs to match your power wire size. Electricity is a loop and you need a large enough path for it to return. Many often overlook the ground wire thinking that it is not needed.

Also, use bigger wire. I run 1/0 awg to the distribution block and then split to 4 awg to the amps and all mine are 600 watt amps.

You could be losing enough voltage with the 8 awg wire to be causing issues. I wouldn't bother adding a capacitor until you have put in wires of the right size. You could probably get away with 2 gauge, but just put in 1/0 so you can upgrade later. Don't forget to fuse it at the battery.

I didn't wnat to have to rewire everything so I wired all my amps to the stereo battery and left the deck wired to the main battery. The deck draws almost nothing because I am not using the amp.

Also, install a combiner so when the boat is running both batteries are being charged and when it is off, the batteries are isolated. Gives some peace of mind.