Battery Question - Altenator doesn't charge and batteries keep failing

[jwhposon]

Over the past several years I have been struggling with batteries on the boat. I have had multiple setups; where you have a stereo battery and starter battery. This year I added a total of three amps and have been having the same issue so I thought to ask the pros. At one time I had the common from my perko switch going to the starter and to my positive dist. block and I had severe engine noise. So, I went back to running the amps directly off the stereo battery.

General question: Battery 2 has a negative wire connecting to one side of the engine, shouldn't all negatives ground at the same spot? So I have a ground to the frame around the engine (aluminum or steel) and I ground everything but battery 2 there.

Symptoms:
When perko switch is on battery 1, the alternator will not charge, it shows 8-9 volts via the digital readout - this is a new deep cell costco battery - the question is why doesn't it charge?
When perko switch is on battery 2, the alternator will charge at 14v, but after heavy music the stereo battery drops low and I have to then manually charge it at night.
When perko switch is on BOTH, the alternator drops its charge to 12v or below, but I think its masking the drop because its running both batteries.

Ideally I wanted to run the positive block off the same line as the starter but engine noise was an issue - especially when battery was low.

I still have issues, when the stereo battery gets low - engine noise is bad and just get general white/blank noise bleeding through.

i would appreciate any ideas or comments as this has bugged me for years.

I have attached a diagram demonstrating my design, please offer some insight.

[mrbobolina]

Okay you may want reread what you posted before hitting send. Either you are missing some explanation or your system is a cluster fk. As far as setup goes with a 2 batter 3 amp setup it is very simple.

battery 1 = boat battery. This is for all intensive purposes the stock battery in the boat. In a stock setup the batter pos runs from the battery to the master solenoid then splits to the starter and the alternator. There is a ground that will have run to the block.

When you introduce the perko, you cut the (+) that went to the batter and make it go to the perko main (+) the batter 1 line from the perko then goes to the boat batter (+) terminal. You need to make sure you have the right gauge wire for the distance of the battery to the perko. I run a 0 AWG or 00 I think. There are plenty of faq on this to understand what size you should have for this part of your setup.

For battery 2 (stereo battery). you run the (+) on the stereo batter to battery 2 on the perko. Again make sure you have the right wire size for the distance. The stereo boat battery (neg) has 2 options. One option is to run the negative all the way back to the block and again you need a heavy cable for this. It will likely be about a $100 ground cable. Most shops will instead run the ground from battery 2 to the negative of battery 1 in a loop which then of course goes back to the block through the stock battery. All of your amps (+)should run to a central power distribution block, from the block to the stereo battery. Each amp needs to then run a negative wire to a ground. In a car you would run all the grounds to separate areas on the chassis someplace. A boat has less options. You are fine running the ground from the amps to the boat battery. As with your battery cables. Your amp wires need to be the right size based on distance from the battery and the proper gauge recommended by the manufacturer.

Your perko should have bat1, bat2 and both as switches I presume? If in this setup you are getting power to only battery 2 and not 1 when isolated then your perko is faulty. The perko is nothing more than a railroad track switch. It simply moves the power where you desire.

In this wire setup something to always remember. Your batteries are basically wired in a series when you have the switch to both and are blasting music in the cove. To safeguard 1 battery from sucking the power from the other and giving not enough volts to start the boat you need something like a Yandina in between to make sure you are covered. The Yandina safeguards us from ourselves. It is overkill, however being the last boat out or the only boat on a weekday hurts when you are stuck.

Fast forward for a sec. If you have your setup as described, then look for obvious things. Your cable conections need to be tight. If the cables can wiggle in the posts or the connectors you have added they will ground out. This will cut power as well as ruin batteries. Batteries do not like damaging cells. If you are all set as described and are still not getting power and your perko is okay. Look upstream. Your starter can do fun things like stick open when you start the engine and simple suck power and deny the battery. Your alternator will show 14.2 and your volt gauge on the cluster will as well. The starter can suck up all the power and starve the battery from getting juice. Why I know this is a whole other tale. Point here if your parts are right in the battery side which is not rocket science, then look at your starter and starter solenoid. Also look to your master solenoid. Bad grounds will detract power. Electrical will always go to the path of least resistance.

Hope this helps

[mrbobolina]

One other thing. Always ground to the block when you can. On something like battery is a must. Aluminum is a really bad conduit - always.

[jwhposon]

Thank you for your input, not sure what you mean by read before sending - I think I left a few things out but I didn't think they were pertinent - but then again, if asking others to help troubleshoot I shouldn't minimize anything. I certainly truly appreciate your time to respond so thoroughly. The stock battery is #2, its just the way they were hooked up and it's a pain to change because of where the perko is located. Now there is no gauge issue - it is all copper strands, 0 gauge or "ott" something like that and yes ridiculously expensive. However, in one stretch I used welding wire as a short positive run (on battery 2) to perko, he assured me it's just as good as other wire, just more pliable (which it is, but doesn't have much shielding). Loose connections were non-existent - yahoo.

But what did catch my eye is running the negative all the way back to the grounding position on the boat (it's port of the motor and where the engine ground is). I tried this, and had several people tell me the amp ground needs to be to the negative side of the battery. An issue I had that made them even look at it is engine noise bleeding through.

I hope the system is as clustered as you suggest - but then again maybe this is why I have been having problems. It is generally a simple process, but what gets me freaked is when you get that engine whine bleed through - especially when using a line driver that amplifies everything.

Thanks again for your time and effort - will go out and see if anything is popping up.

[mrbobolina]

Your stock battery can be battery 1 or battery 2. It is not relevant. The amp grounds do no need to be on the negative of the stereo battery, it is however optimal. Your ground wire needs to be thicker based on distance from the amp. I have my amps near the front and the cables would need to be like 8' to reach the block. That is silly. It is 3' to the stereo battery at most. Also your amp(s) would have a max length on the ground wire as well. This is pretty vital to adhere to. If a ground cannot travel the length of the wire it will go back upstream. This literally means up into your amp and fry stuff or back through the positive. (No **** - this can happen. I have seen some hooky setups with odd noises and fuses popping). Another thing is a loose ground wire. Any vibration can create distortion. Also be sure your stereo is not sharing a common line like a bilge or a tach or speedo. This should not be the case as you have two batteries.

If you are getting engine whine there are a few reasons. 1st, it could be that you are grounded to the same point as the starter or alternator. You do not want this same bolt. It could be that you are running a wire to close to the alternator. This is very common in a car, however harder occur in a boat. You can also have your RCA cables to close to your power cables. Another one which you will not like. If you do not have shielded power lines which you do not have using welding wire, you can get interference. At the end of the through lessons I have learned. Use good if not great RCA cables, and shielded power and ground lines. Many people will say it is overkill, and they are right except when they are wrong and you are then trying to find out why distortion.

Personally without seeing what you have picture wise. I think you have what you need, it is just a matter of how you have things set. My order of edits would be:

1- Move your amp grounds to the stereo battery (be sure the lines are shielded to prevent interference)
2- Move your ground from the batteries to another side of the engine separate from your alternator and starter for the batteries.