Requirements for Upgrading Alternator?

[cptbraine40]

My Boating Brothers and Sisters,

Good afternoon. Here are the spec on my boat:

1995 SeaRay Signature Bowrider
Mercruiser 5.7 Liter

I am looking at upgrading my current alternator (OEM 65 Amp Delco Alternator) to a high output 220 amp alternator from DB Electrical.com. I have added a ton of electronics (3 amps, 8 speakers, lights) to my boat and I really want to get the maximum charge when cruising down the lake. I have already added a dual battery system (2 Interstate 27 Series Marine Batteries) with a battery switch.

Will I need to do any type of other upgrades before moving up to a high output alternator or will I be able to to just plug and play? Also the new alternator has a single wire whereas my current alternator has 3 wires. Anything I need to be aware of when it comes to that also?

Any advice and input is always greatly appreciated.

Thanks,
Brian

 

[alldodge]

With only 2 group 27 bats, the 220 amp ALT is over kill. The bats cannot take all the ALT can put out. That said the ALT should keep it regulated. You have 2 bats but one needs to be used only for starting, so you actually only have one for the stereo

Need something to connect bats together after motor is started for charging. ACR is best, then Isolator then battery switch

Wire from ALT to Bat
Less then 5 feet 2-AWG
5 to 10 feet 0-AWG
10 to 15 feet 2/0-AWG
15 to 30 feet 4/0-AWG

Need a inline fuse between ALT and BAT
Battery Switch needs to be able to handle 220 amps
Take the 2 wires going to the old ALT and tape them up out of the way but do not connect them together

Only time you will need a lot of charging is after you have

I would suggest
I would suggest no more then 120 but 100 amp ALT should be fine.
Can use smaller cables.
If your going to play a lot, get a couple group 31 deep cycle bats just for the stereo
Install an ACR so after the motor is started the ACR will combine the bats and the ALT will charge All

might even think about AGM bats so they can be charged faster

 

[Bondo]

Ayuh,.... Sounds like yer buildin' a Welder, rather than chargin' batteries,.....

As AD said, batteries will only take so many amps per hour,......
'n at the upper limits, or an over-amperage situation, the water boils out,....
Then they go BOOM,....

Ya size yer alternator to the batteries yer wantin' to charge,....

 

[Watermann]

A few thoughts. Some new alts don't come with the screened cover on the back that shields the brushes from being an ignition source so check on that. The cover looks like this.

Your old harness is 3 wire and the new is 1 wire alt? So that would be 1 wire to the solenoid on starter. Not sure about your set up but I'm thinking you may not have power to your ignition. Is one of the wires from the plug purple?

 

[Bt Doctur]

you looking at a wire size of about the size your thumb The #10 is not going to carry the current thru the system

 

[Scott Danforth]

AD already covered the batteries and everyone covered the cables

you cant drive a 220 amp alternator with two v-belts. and unless you step up to at least a 14 rib belt, a traditional serpentine wont hold it either. upgrade to a 120 amp alternator and you can manage it with traditional twin belt pulleys or a traditional serpentine. Also, wiring a 220 amp alternator requires some seriously large cables. where 120 amp only requires 4 gauge from the alternator to the starter post and from the starter post back to the batteries, 2 gauge is all that is needed.

on another note, if your stereo requires 220 amps of juice to power it, the hull and your heart and other organs wont take the acoustical wave from the speakers.

 

[thumpar]

Make sure the alternator you choose is marine rated. You don't want to blow it up.

If it was me I would probably keep the stock alternator and spend the money on an ACR, 1 starting battery and 2 deep cycle batteries. I know for me most of the time spent using the equipment is when the engine is not running so you want more battery capacity and wired up right you could run the batteries all the way down and still have the starting battery to get you going again.

 

[cptbraine40]

Wow, like always, great answers to my question. I think I am going to follow everyone's advice and just keep my current alternator, look at ditching the battery switch, install an ACR, keep one of the Interstate batteries for starting, and get 2, 31 Series AGM batteries for the stereo. Of coarse, anything I buy is always for marine. So this is my question (and hopefully my last one):

If I have 3 batteries, one for starting and 2 for stereo, I ditch my battery switch and replace with ACR, how/can the ACR know to use the 2 deep cycle batteries for the stereo when engine is off and isolate the starting battery. I just don't want to get stuck on the lake because of dead batteries. Please forgive my lack of knowledge on this subject, I have never been good with electrical components.

Sincerely,
Brian

 

[thumpar]

When you wire everything up with the ACR you have the starting battery and the aux batteries isolated. The critical functions to make the engine run are hooked to the starting battery. The electronics are hooked to the aux batteries. With the engine off the starting battery is isolated from your electronics. You could run those things that are hooked to the aux batteries until they are drained and when you go to start up the engine the starting battery is there to do it's job. Once the engine is running the ACR would switch to provide a charge to the aux batteries.

 

[cptbraine40]

Yes sir, after looking online some I think I am seeing how the whole entire system will work. I realize now that I will just keep my battery switch and purchase the ACR. For the time being though I am just going to replace one of my batteries with a 31-series AGM deep cycle battery and keep the other for a starting battery. Thank you again for all the input from everyone, I really appreciate it.

 

[R055]

I recently bought the vmax mr137 group 31 amg, had good reviews and 125ah. I only have 1 amp with 4 channels with 100rms to each channal so I'm using the battery as a starting battery and deep cycle stereo battery. Should be able to play atleast 1.5-2 hours for me and still start the boat. I bit pricey at 280$ but was apparently one of the best deep cycle agm group 31 batteries.

 

[R055]

^Ment 100 watts rms^, can't find the edit button on mobile browser anymore.

 

[cptbraine40]

Yeah, I am going to get a ACR and upgrade one of my batteries to a 31-series, AGM deep cycle battery. My boat has the following:

1. 1 Rockford Fosgate 400 Watt, 4 channel amp (4 Fusion speakers in the boat)
2. 1 Rockford Fosgate 400 Watt, 4 channel amp (4 Fusion tower speakers)
3. 1 Rockford Fosgate 200 Watt, 1 Channel amp (1 Sub)
4. 1 Farad Hybrid Digital Capacitor

I have a Perko battery switch for my dual, Interstate 24-series battery (yes, I lied, I thought they were 27 series). My goal is to be able to sit in the cove and have a good battery for playing music, isolate my starting battery, and get maximum charging to both batteries when on the move.

Everyone on here has been great and I think I know my solution now.

 

[Scott Danforth]

Yeah, I am going to get a ACR and upgrade one of my batteries to a 31-series, AGM deep cycle battery. My boat has the following:

1. 1 Rockford Fosgate 400 Watt, 4 channel amp (4 Fusion speakers in the boat)
2. 1 Rockford Fosgate 400 Watt, 4 channel amp (4 Fusion tower speakers)
3. 1 Rockford Fosgate 200 Watt, 1 Channel amp (1 Sub)
4. 1 Farad Hybrid Digital Capacitor

I have a Perko battery switch for my dual, Interstate 24-series battery (yes, I lied, I thought they were 27 series). My goal is to be able to sit in the cove and have a good battery for playing music, isolate my starting battery, and get maximum charging to both batteries when on the move.

Everyone on here has been great and I think I know my solution now.

As Bondo stated in post #3 your charge rate is based on your batteries. maximum charging is determined by the battery reserve capacity and the battery architecture. Note: if you continually run the batteries down to fully discharged (about 12 volts), the batteries will eventually fail.

without knowing your specific amp part numbers or knowing their efficiency, we cant answer as to their current draw in amp-hours. you probably have that information somewhere. pair that up with your batteries reserve time and discharge rate to determine how long you can play tunes before re-charging

if your goal is to sit for a long time to play music, simply get more batteries or bigger batteries with a higher reserve capacity. Just remember, recharging takes a while, its not a listen for 8 hours, charge in 20 minutes type of thing. a fast charge will take about half the time you took to deplete the batteries, a slow charge rate will take about as long as it took you to deplete the batteries.

I have seen a few installations using a bank of high-reserve capacity group 31's or even a few using group 8D's. most of these are charged by shore power with an intelligent multi-battery charger.

 

[cptbraine40]

I fully understand now. I do appreciate all the input and advice on here. I have a good idea what I need to do and also what my limits are now.