Perko switch help
 

Ok...this topic I'm sure has been beat to death. I've done searches and with such an abundant amount of information I have become more confused than when I started.

I just got a boat and installed a stereo with 2 amps. We parked in the cove and I killed the battery listening to the stereo with the motor off. The boat does have a PERKO switch, however, I don't believe it's wired right. It looks like it's wired in a series (I'll take a pic when I get home) How should I reconnect them? Should I have 1 position for starting the engine, 2 position for the stereo when the motor is off, and put it in the both position when the motor is running to charge both batteries?

Also, I would like to accomplish this without spending more money...at least not now...I've spent so much money on sales tax, registration, stereo, insurance, etc, that I'm sick to my stomach!

oh...and there are 2 batteries in the boat...

The batteries could be in series but only if you have two 6 volt batteries.

Ok...well I guess they're not in a series...the 2 negatives of the batteries are connected together....

One way to wire it is to have the Main Starter positive cable hooked to the "common terminal on the back of the switch. Then the battery 1 terminal will be hooked to the positive of your starting battery and the battery 2 terminal will be hooked to the positive of the stereo battery. All stereo(amps and deck) should be hooked directly to the stereo battery(battery 2) through distribution blocks. This way when you stop the boat you can move the switch to the battery 1 position to have the batteries isolated from each other. At this point you would only draw down the stereo battery leaving you with a fully charged starting battery. When you start it will only use the full starting battery. Once the boat is up and running for a bit then you can switch to both to start charging both batteries. Keep in mind that if you have a big battery for the stereo and you completely drain it you run the risk of burning up your alternator. It might be wise to go to the both position for a while then switch back to battery 1 for a while and keep doing this. It is kind of annoying but if you want your alternator, starter and batteries to last like they should you need to do this. In addition you could get a Voltage sensative relay of some sort like a sure power 1314 and it basically does all this automatically. Investing in a good 2 bank onboard charger is also a very good move.

By the way. The negatives of the batteries should be hooked together.

I've heard about battery isolators...is this the same thing as the voltage sensitive relay you mentioned?

A lot of people use the terms interchangeably which isn't exactly correct. When someone is talking about an "isolator" they are generally referring to a diode type isolator. It looks like a little amp with cooling fins. Most of them seem to be blue. They have a common positive and then how ever many outputs for the number of battery banks. They also may have another terminal that would be hooked to voltage sense or the ignition terminal on the alternator/key switch. These work ok but in the case of boating they aren't ideal. First they give no priority to which battery they are going to charge. The battery that is more depleted gets the charge whether it is the starting or stereo bank. Second they generally cause a 1v drop. This means your batteries aren't going to be receiving the full 14v and will never charge up all the way shortening your play time and battery life.

A VSR/smart solenoid/battery combinor isolator basically is just a solenoid that breaks the connection between 2 banks of batteries when the voltage lowers to a certain set point. The one we sell is a sure power 1314. It is super easy to install, fairly inexpensive and basically does everything automatically for you. It also gives charging priority to the starting battery so you don't get left with a boat that won't start. They also don't cause a voltage drop. Being used in conjunction with a perko style battery selector switch and an onboard 2 bank charger you should be able to keep your batteries in good condition for a long time.

Thanks for the reply! Do you know of a shop that sells the Sure power 1314 locally. I'd like to get all of this sorted out tomorrow.

And what is the purpose the 2 bank charger?

I would just google and find the wiring diagram. I think that would be the best way to make sure its correct. Schematics ROCK!
Cant find the one I printed out the other night, but i know its on the net (just cant seem to find the exact one I used)

Ben, I am not sure where David's shop(Earmark Audio) is but I think it is somewhere in Texas. If that doesn't work go to surepower's website and find a dealer.

Ben,
Pollarbill is one of the few who really understands charging systems from top to bottom including where all the dominoes fall as you get into more complex systems.
We are in Dallas so we're one day away for freight. I have friends at Custom Sounds who can do the installation in San Antonio. In any case we can do a package that is designed to fit your needs, budget and tolerance for technology. Plus we supply schematics for wiring that pertain to your particular scheme.
If this hasn't already been addressed by the time I post (slow typing) a dual bank charger profiles and conditions each battery separately so that neither is over or under charged given that for a variety of reasons each battery will be at a different state when your boat is put up in storage. You will match a charger capacity to the battery(s) capacity. The right multi-stage charger will dramatically extend battery lifespan and give you longer playtime at rest for the following weekend as well as season to season.

David
Earmark Marine

David, I don't know if I have talked to you about this before but when someone uses 2 seperate banks but uses all the same batteries it is a good idea to rotate the batteries. Probably every time they change their oil or once a year. This will help battery life some as well.

Brett,
When using a Perko switch only I like the idea of using two identical deep cycle banks (warm weather and small blocks) and rotating their use each weekend. And yes the same rotation scheme makes sense to me on a little less frequent interval as applied to VSRs. Anything to limit or balance the number of cycles per battery or to limit the depth of the cycles. Is that what you mean?

David
Earmark Marine

Exactly