Hello Kevin,

My marine electrical system currently includes one maintenance free starting battery (Group 24) and one AGM maintenance free deep cycle battery (also Group 24). I have the Guest 2611A battery charger attached to these two batteries for charging at the dock.

I was considering putting in a second deep cycle battery to provide more accessory time while out on the water and my plan would be to configure the boat wiring to connect it to the other deep cycle battery ‘in parallel’.

Would my 2611A charger be capable to charging these three batteries?

Thank-you
John

Hi John,

YES, but it will take a very long time to completely recharge.

The 2611 only puts out five amps max on each leg. Two dead batteries connected to one of the legs will take close to 2 days to recharge. Guest makes excellent products, but you may want to consider one of their larger units for your marine electrical system.

Kevin

Kevin,

Thank you for your response.

Generally when our charger is on it has a couple of days between uses so I’m not as concerned about the time it would take to recharge. And I would think that making the 5-6 mile run back to the marina with the Switch in the “All” setting would give the batteries a bit of a charge from the alternator as well.

I just wanted to make sure there were no safety issues. So if I put a third battery (a deep cycle) in the boat and connect its positive to the other deep cycle’s positive with a jumper and similarly connect up their negative terminals – when I put the switch on “2” the accessories would pull from both deep cycles and, in theory, I would get more accessory time?

I guess I just want to see if I can get by with my current switch and charger or do I need a more robust switch and charger to have three batteries.

Thanks again (and I will make a contribution via PayPal)

John

Hi John,

Adding a third battery in parallel to your second is a very common boat wiring practice.

When you do this, make sure that you use cables that are at least as large as the largest cables that are currently used on the battery switch system.

Kevin

Kevin,

Thanks again.

I was hoping to get the cables this week and won’t have access to the boat before then so I may have to guess. Do you think four AWG would be safe for a basic speedboat (24’ Malibu Wakesetter)?

John

John,

It’s really funny that you should ask that!

I’m just finishing a downloadable Battery Cable Calculator. I’ll post it in the next day or two for all of our readers.

Kevin

Kevin,

I am installing the EzAcDc marine shore power system. Could you please clear something up for me?

Is it OK to have the AC and the DC panels in the same area as long as you don’t group the wires together?

I had read to keep the AC and DC apart in marine electrical systems, but I am not sure if that meant just to space wires apart so they don’t chafe through and connect systems or if they needed further separation.

Thanks.

Mike

Hi Mike,

Yes. It is OK to have both panels in the same area.

Per the American Boat and Yacht Council, if the AC system and DC system are on the same panel, then the AC system needs to have an enclosure to prevent accidental contact when you are working on the DC side. Even though it is not required, the EzAcDc Easy Add AC panel has rear safety enclosure.

When installing AC and DC boat wiring, it is a good practice to separate the AC and DC wiring because most AC HOT wires are black and most DC GROUND wires are black. Accidental swapping would be very dangerous.

I hope that this is helpful. Please let me know if you have any other questions about your project.

Kevin

Kevin,

I was reading up on adding shore power and came across your site and thought I’d consult someone who knows what they are doing. I want to add AC power to my boat and plan on running one, possibly two AC GFI outlets and a battery charger.

I want to be able to run the DC power on the boat (Stereo, cabin lights) while not draining the battery.

I plan on installing a proper 30 amp shore power inlet and connecting that directly to an AC distribution panel with three breakers. One breaker will go to the outlet. One will go to the battery charger. One will remain open or will be connected to the second outlet.

My questions are:

• Is my thinking correct?
• Is my wiring scheme proper?
• If I have the battery charger connected will I be able to run the DC on the boat without draining the battery?

No one at the marine shops I go to seem to be willing to offer an opinion. Maybe that is out of ignorance or maybe out of fear of liability. What do you think?

Garrell

Hi Garrell,

You thoughts are correct, but the number of breakers that you are planning on may be overkill.

If you are only running outlets and a battery charger, you could easily use an AC panel with just a single 20 amp main breaker with outlets connected through it.

When your shore power is connected, the battery charger will be on and your outlets will be live. The charger will draw a maximum of 5 amps leaving 15 amps (1800 watts) to run everything else.

The simplest system that I have seen for your application is from our partners at EzAcDc.

They have a new marine shore power kit that gives all of the components that you are looking for. The panel has a main breaker rated at 20 amps. There is a GFCI on the panel. This system also comes with a remote outlet kit that plugs directly into the back of the panel. The wire on this remote kit is 10′ long. The AC panel has an outlet on the back. This outlet is ideal for built in battery charger applications. It provides a handy location to connect to AC power and allows for the built in look.

All outlets in the panel are protected by the GFCI. All components are rated at 20 amps.

The kit also includes the power on light, reverse polarity light, and AC to DC grounding wire required by the US Coast Guard.

Installation is simple and safe.

Please let me know if you have any questions,

Kevin

Hi Kevin,

Very interesting site.

I have a challenge. Switched my boat stove from Origo alcohol to a Kenyon single burner electric. My boat wiring had a spare breaker switch on the 120 volt panel and I decided to hook it up there.

I have to admit I am not very knowledgeable about marine electrical issues, so I paid very close to attention to how all the other 120 volt appliances (water heater, battery charger, etc) were wired and duplicated it. To my delight it worked.

However, at the time of connection I was using a normal extension cord with 30 amp adapters on both ends because the newly acquired boat didn’t come with a cordset. A couple of days later I went to West Marine and bought a 30 amp cable. When plugged in, I now have a reverse polarity light, and any and all 120v appliances trip the local and the main breaker.

Your thoughts would be very appreciated.

Shawn

Hi Shawn,

You may be dealing with an extremely dangerous problem, so either get professional assistance or use extreme caution.

I would say that some component in your shore power system has the black and white wires swapped. Or maybe the black and green.

Most reverse polarity lights are basically a light bulb between the white (normally neutral) and the green. If the white is accidentally wired to 115v, the light will turn on. If the green is accidentally wired to 115v, the light will also turn on, but all grounded items on your boat will be at 115v AC. This includes the engine and all metal thru hull fittings.

On 30 amp service, the “L” shaped terminal is the ground (green), the foot of the L points towards the neutral (white), and the last terminal is the hot (black).

I would use an ohm meter and test your new cordset to make sure the wires do not swap terminals inside. It is also possible that your old system has a reverse polarity item and a second item was wired backwards to solve the problem.

Again, please be careful.

Kevin