Alternator recommendations
 

'06 Supra 21v, 325 hp with the stock alternator. Pair of Wetsounds Pro 80's with a Hifonics amp, Alpine Type R sub with amp, boat speakers with amp. It seems like the alternator is not charging sufficiently. Was stranded on the lake last Sunday and anchoring in a cove for 4 hours with tunes going. Batteries were dead to the point that the portable battery jump box didn't work. Got towed in, put the boat in the garage when I got home, put on the Battery Tender and everything is fine. Both batteries passed the load test and boat cranked. Haven't had a chance to hook up a water source to test the alternator. So, after all that, what size alternator/brand is everyone upgrading to.

Do you have an onboard charging system that you can hook it all up to. Alternator will have a tough time bringing them back to full after dropping them that far. Most guys have on board chargers to hook em up to overnight to get batts back to full...

I have a Battery Tender that stays plugged in when the boat is stored in the garage. It keeps the batteries fully charged. I've read a lot of people on here on running larger alternators due to the drain their stereo system puts on the batteries.

It may be that your stereo current draw is more than your alternator can keep up with. If you have been trying to extend the stereo playing time by turning the boat on to put a charge back into the batteries....there is a chance you have fried your batteries.

It is not as simple as add a bigger alternator. You may be better off adding more batteries to have more playing time instead of being the guy the in party cove who is churning up exhaust while everyone is having a good time.

I have 4 optima blue tops and very efficient amps...never once have I had to start my boat to keep the stereo going and if the batteries ever do die in the cove, we will be done with the stereo that day. Trying to get my 100a alternator to charge up 4 batteries would kill my alternator.

On board charger is key, glad to see that you have that in place already. It does sound like you need to get a switch to isolate your batteries when in party cove

I'm not that guy who starts his boat in the party cove to charge the batteries. Usually it's just my wife and me chillin in the water. Never start the boat until it's time to go. This is the first time, the batteries were dead. They were charged when I returned home and load tested. They both passed the load test with plenty to spare. We were in the cove 4 hours max, which is about the norm. The batteries were just dead this time.

Randy,
You should always have a starting battery in reserve that is isolated by a dual battery switch while at rest. It doesn't appear that your system is so large as to necessitate an upgrade alternator. There are plenty of other issues to check and to improve before you would get around to a larger alternator.

David
Earmark Marine

I do the batteries run thru a Perko switch. I think part of the problem is all of the amps aren't connected to just one battery where the other battery would be used for starting. I usually set the Perko switch to all which probably defeats the purpose of having it, thereby draining both batteries. I suppose I should rewire so the stereo equipment draws from the same battery and the other battery would be used for starting only.

Pick up a 135 amp marine alternator.. The alternator should carry the complete load of the systems when running.. The batteries are in the charge mode.. Also one of the batteries should not drawn on when hanging out in the cove... Thats your dedicated start battery..

Randy,
There is your issue. When using a dual battery switch nothing but a bilge pump and float switch (if applicable) should go directly to either battery. Everything else wires to the common/output of the switch. While at rest have the switch on a single battery only. Turn it to 'ALL' before starting and when running. You do not need an upgrade alternator. Just correct the wiring and alter your use.

David
Earmark Marine

Any suggestions for a good 135 amp marine alternator?

I'll have to post a pic of what I've wired up then. Sounds like I've completely wired this the wrong way.

Talk to Shawn at:
http://www.amarket.com/

David, I think I would turn the switch to the battery that was not being used and once it is started and running for a a few minutes to "all". This is assuming the switch is a "make before break" type switch. If he turn the switch to all to start the batteries will be running in parallel and the batteries will equalize bringing the voltage down when starting. Although it will probably have enough voltage to start you don't really want to make a habit of starting with low volate(under 12.4). This puts added stress on the starter and cause premature failure. What do you think?


If the alternator is actually dead then I would probably upgrade to a Delco 11si 95 amp unit or a Leece Neville 8MR series at either 90 amps or 105. You should be able to get either unit for $200-250. This is for an OEM, very high quality unit and not a rebuilt or a Chinese clone. These units can be used with a single V belt if you don't have a serpantine belt. Then I would make the system a 3 battery system with one battery on one side and 2 batteries on the other. Then when sitting listening to music you would always turn it to the 2 battery bank. This will give you increased playing time and leave a fully charged battery for starting. Last I would invest in a good 2 bank charger, not a low amp tender. A low amp tender is going to have a tough job charging up a depleted battery bank, especially if it has 2 batteries on one of the banks.

Brett,
I'm afraid of encouraging people to rotate the switch after the boat is running assuming that most have the basic switch. Can you explain the 'make before break' type of switch? Thanks in advance.

David
Earmark Marine

Here's the pics of my setup. Be easy, I'm electrically challenged. :D

That is definitely a worry. A "make before break" switch is selector switch that when you go from say the "1" position to the "both" position it combines the batteries before it actually goes completely into the "both" position. An older style or "non make before break" switch will basically disconnect all batteries briefly when you switch from one position to the next. This will cause a temporary spike in voltage and has the potential to burn up your alternator. The "make before break" type doesn't have this problem as the only time it would completely disconnect the batteries is when you are turning it to the off position which shouldn't be done.

Does that make sense to everybody?

Need some recommendations to clean up my setup. Anyone? I'm not really sure what the common side of the Perko switch is. Thanks.

You should have a large positive cable from the starter to the "common" terminal on the back of the switch. There should be three stud's on the back of the switch. Common, battery 1, battery 2. Then from the stud marked battery 1 connect that to the positive of your first battery. From the stud marked battery 2 run a positive cable to the positive of the second battery. Also connected to the common terminal will be a 2 or 4 gauge cable that will go to a distribution block for your amps. You should have a negative cable that is hooked to the block run to one of the batteries negative posts. Then the negatives of both batteries should be hooked together like you were wiring them in parallel. You should also run a negative from one of the batteries to a negative distribution block for your amps/stereo. The only other thing hooked to the batteries should be the bilge and float for the automatic bilge.

diagram

My god, that came out horrible. The new wakeworld sucks. Unless you have a pic posted online it is hard as hell to get a decent pic.

Thanks. I think I understand most of that. I need 2 distribution blocks, 1 for positive and 1 for negative. The 2nd cable that is hooked to the common stud is positive, correct?

Forgot one question. Do I need the blocks that have fuses or are non fused fine? Thanks.

Amplifier fusing or breakers are generally only used at a single point as close to the battery as possible. Individual fusing is generally not required since the primary purpose of the fusing is to protect the boat. You can protect each amp individually if you choose as long as its not redundant with the amplifier provisions. The helm buss supply should be fused (breaker). Breakers can be used between batteries but this is usually done only when the batteries are separated by a significant distance.

David
Earmark Marine

Nevermind, stupid question. Of course it's positive. :o

Got the batteries rewired Saturday. Took the boat out Sunday and the ipod killed the one battery after about 1 1/2 hours. Other battery cranked the boat up fine. Think I need to upgrade batteries to the Optimas. Any suggestions on which ones to use? Blue or Yellow top? Which models are best? Thanks.

There are a lot better options out there for batteries, especially for the price. I would take a look at Deka's. They make a wide range of batteries depending on what you want to pay. I would look at the deep cycle batteries in either a group 27 or group 31. They will blow the optima's reserve capacity out of the water. They will probably be about $70 less than the optima D34M that most people use in their boats. The other option if you don't mind spending the money is to their AGM battery in a group 27 or 31. They will be close to the same cost as the Optima but each battery will have double the reserve capacity of the optima's.

Some people think it isn't a very good idea to mix battery types and sizes but personally I don't think it is that big of a deal. Plus the deka agm's were designed to have similar charging characteristics as most lead acid flooded batteries.

Hmmmm....who orignally suggested more batteries??????

Optimas are great but your cost per a/h is really high. Like Brett said, the Deka Sea Mates will be the best battery for the buck in the sealed category.

Thanks for the info. I'll check out the Deka's. There's a dealer not too far away.

Looks like Deka's out. 1 dealer within 50 miles and they don't answer their phone and no voicemail. Sweet.

I would call Deka Corporate and ask them where else they are sold?

Website is not always 100% correct

Randy if there are West Marine store's near you they carry the deka's rebranded as their own.

+1 for west marine. I just replaced my lead acid batteries with their AGM's.

Thanks. I'll call corporate and check to see if there's a West Marine close by.