Adding a 2nd Deep-Cycle Battery

[chpthril]

Parts List / Price

· Trojan Deep-Cycle Marine Battery $98.00
· Group 27 Battery Box $12.00
· 10ft of 2ga Marine Battery Cable / Black $3.50 p/ft
· 10ft of 2ga Marine Battery Cable / Red $3.50 p/ft
· 6 5/16x2ga Battery Terminal Lugs $8.00
· 2ft of 3/4 Adhesive Heat Shrink $6.00
· 8ft of 1” Wire Loom $6.00
· Perko Duel Battery Switch 1/2/both/off $35.00
· Mics: wire ties, tape, resin core solder.

Tool: Basic hand tools, soldering iron, flameless torch for heat-shrink, terminal crimper.

Diagram: I left the factory EIDB system intact and simply paralleled Deep-Cycle 1 to Deep-Cycle 2 (pos to pos and neg to neg) and ran an additional positive cable to the Perko.

Picture 1: Disconnect grounds from batteries. Test fit battery box into starboard storage compartment

Picture 2: Lay in cables across transom area and check for moving parts, sharp edges, and sharp bends. Cut cables with enough length to allow access to batteries. I cut mine to 8ft.

[chpthril]

Picture 3: Strip cable ends, crimp and solder the terminal lugs to the cables. The solder ensures good conductivity between the cable and the terminal. Add heat shrink to ensure a water tight connection. Put cables into wire loom and wire tie. Take the remaining red wire and make a cable to run from Deep-Cycle 1 to B1 of the Perko.

Picture 4: Run harness along transom area and wire tie in place. Double check fit.

Picture 5: Remove factory On/Off and replace it with the Duel Batt. Perko. C goes to starter, B1 comes from starting battery, B2 comes from deep-cycle. Position 1 and OFF is the same as ON/OFF. The advantage of the Perko is the ability to switch over to the Deep-cycles to start engine if Starting Battery ever fails.

Picture 6: install battery, connect all battery ends – positives first, then negatives. Start engine (making sure you have water supply for engine cooling), check volt gauge for alt charging, check voltage at new Deep-cycle with meter. Place covers on battery boxes.

Last pic is factory installed Isolator

Although my boat does not have a high power consumption stereo, this extra battery will give me more anchor/beach time and the Isolator will prevent the Starting Battery from draining.

[THE g]

I will look tomorrow for mine,I am sure that the deep cycle is just connected in parallel with the starting battery.

[MRMoffat1]

Excellent post. My next project.

[da.bell]

Okay, I got it now... Bad night last night... Why didn't you upgrade your alternator? I think I understand that the isolatopr would allow the batteries to charge, but not sure why you didn't upgrade the alternator to allow more electricity to be made to charge the batteries....

[chpthril]

Why didn't you upgrade your alternator?

Cause you can't put 10# of crap into a 5# bucket Boat has a 90A alt, so charging has not been an issue. If I need, i can throw it on the shop charger overnight and be ready to go.

think I understand that the isolator would allow the batteries to charge

Think of the Isolator as a one-way electrical valve, a diode. With the engine running the Alt will charge both battery banks at the same time (as opposed to a manual switch) up to 90A (max output of Alt) depending on thier state of discharge. But the Isolator will also keep both battery banks separated from each other so I can run the stereo all day with out fear of running the Starting battery down.

Again, charging/re-charging has not been a prob as my stereo sys is not as high amp draw as other. This just gives me more time to run the tunes without running engine.

[da.bell]

chpthril, thanks for the explanation. I think I kind of understand now. It's a little fuzzy but I think of it as your explanation, in time I will get it down.

Thanks,

[tarheeler]

chpthril, thanks for the explanation. I think I kind of understand now. It's a little fuzzy but I think of it as your explanation, in time I will get it down.

Thanks,

it is like he has a bigger gas tank now for his stereo to run off of and he will not run out of gas as fast.

[my86stanggt]

chpthril, I purchased all the parts to do this battery upgrade and had them just sitting in the compartment when we decided to go put the boat in the water today. I went to start the boat and my original crank battery was dead but luckily I had the spare battery sitting beside it, switched over and started right up. Saved me from having to tow my boat out of the water or ask for a jump. If we ever meet, I'll buy you a beer or three.

[MRMoffat1]

Starting to plan on adding that second deep cycle battery. In the "How to" here it was recommended adding it to the stern area on the starboard side. I have not yet pulled the boat out of the garage, but I'm remembering that due to the shower option I have, I don't think I will have room for a battery there. Looking for suggested alternate options, in case my memory is correct.

1. Permanent location
2. Removable option

Removable option may be ok, since there are only a couple of times a year where I really have the stereo blasting all day long without the alternator charging the battery at least sometimes during the day. I don't want to have to remove and install wires, I would want to cap and stow any wires. And I obviously wouldn't want the terminals exposed.

I'm a month off from actually getting going on this. Ideas?

[chpthril]

Starting to plan on adding that second deep cycle battery. In the "How to" here it was recommended adding it to the stern area on the starboard side. I have not yet pulled the boat out of the garage, but I'm remembering that due to the shower option I have, I don't think I will have room for a battery there. Looking for suggested alternate options, in case my memory is correct.

1. Permanent location
2. Removable option

Removable option may be ok, since there are only a couple of times a year where I really have the stereo blasting all day long without the alternator charging the battery at least sometimes during the day. I don't want to have to remove and install wires, I would want to cap and stow any wires. And I obviously wouldn't want the terminals exposed.

I'm a month off from actually getting going on this. Ideas?

Any where you can mount it securely to the floor in a battery box will work. The only other thing to consider is the length of the cable runs will determine the size of cable you run.

[Costigan]

Is two batteries hard on the alternator?

[chpthril]

Is two batteries hard on the alternator?

I wouldn't say it's hard on the alt, just asking it to do more of what it's intended to do. Kinda like upgrading from a 400# V-drive sac to a 750# sac. Your pump will still work just fine, but will just take longer to fill the larger sac.

If someone has a hi amp draw stereo system powered with a multi battery bank, and you spend many hours every weekend cranking the tunes at the sandbar, then you need to consider another means of recharging. You would be better off having the stereo battery bank as a stand alone setup because the alternator will never meet the demand to recharge it. Use something such as an on-board tender/charger, or a shop charger that you can plug up to back at the ranch. I higher amp alt can also be a good alternative, but usually involves some mounting bracket modification, belt reconfiguration, and/or rewiring.

[lee]

Starting to plan on adding that second deep cycle battery. In the "How to" here it was recommended adding it to the stern area on the starboard side. I have not yet pulled the boat out of the garage, but I'm remembering that due to the shower option I have, I don't think I will have room for a battery there. Looking for suggested alternate options, in case my memory is correct.

Put it on the port side beside battery number one. You will need to rotate the battery 90*.

[MRMoffat1]

Put it on the port side beside battery number one. You will need to rotate the battery 90*.

Gotit, if I can rotate (two, not one) batteries 90*, can I get a third battery in the port side. I have a starter and 1 deep cycle in there now. Trying to add a second deep cycle. Won't have the boat out for another month, but if I remember, it didn't seem like there was that much space. Will take a look. Thanks Lee.