Charging your boats batteries with an extention cord at the dock?

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Newbie111

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It's a 208 adventure and doesn't have a shore power plug. How do I go about being able to use an extention cord to charge batteries incase I'm not on the boat for an extended period of time or want to use the batteries while at the dock without turning the motor on and draining my batteries. My slip neighbor brought it up to me and said he would help me install it but don't remember what it's called
 
check out marine battery chargers. single ,double, triple.. promariner is common
 
There are a bunch of good ones out there. Check out at Amazon. I'd say 10A per bank would be sufficient but you could jump up to a 15A per bank.
 
FYI: I top off my 208 batteries in the fall, disconnect the ground cables and store the boat on a trailer for the winter. Been doing that for 15 years. Boat always cranks over in the spring ( I have replaced batteries twice in that time). My point is that the batteries retain a charge for a pretty long time. In your case there are other factors to consider. If your bilge gets water ( the 208 is essentially a dry bilge design) and the pump cycles, one battery will get drained eventually. The other (assuming two) should not.
If you have other loads connected like a radio station memory lead directly to the battery, that will drain but over a pretty long period.
Some electronic bilge pumps run every few minutes to check for water. Those pumps can drain a battery quicker.
Make sure your battery switches are in the OFF position when the boat is stored at the dock.
 
If your battery can't survive a month (or whatever) without needing to be charged it's time for a new battery.
 
Awesome thanks for all the information. I really appreciate it.
 
It's a little bit of an apples to oranges comparison but I've had the Optima red top battery in my 1965 mustang fastback for around 12 years now and she still cranks up every time. There's been 6 months or more when I haven't started up the car and she still starts up and runs just fine, even after letting the car sit for a year and a half. All that to say I agree, if the batteries can't sit for a few months then I'd look at getting new/different ones. I also never swapped out the twin batteries I had on my previous 21' Arima, which I never used a battery tender or charger on. I'd winterize the boat in around late October or so and then take her out again around mid June and never had an issue with the batteries not starting up.
 
So I have a new question about the battery switch and hopefully everybody is still looking. The previous owner said he would just put the switch to 1 and it powered everything. From motor starter up to electronics. Is that normal? I thought the switch on one would be electronics and switch 2 would be for motor start up or vis versa. Then the all switch would make both work. Am I wrong about this? What does the red box with the 40 button on it do?
 
It depends on how the battery selector switch was wired (I believe).

The red button with a 40 on it is a circuit breaker.

Regarding the battery & charger:

It's good to have it on a charger, just in case the bilge pump needs to run continuously (or often) due to a water intrusion issue (one never knows), if for no other reason. In other words, it's a good thing to have on the boat.

IMO: You want to set it up to run via "Shore Power", rather than just a standard extension cord. The marine may even require it.
 
The 40 amp breaker (red box with 40 button) is for the fuse block under the helm.

Its a loaded question with battery wiring, In theory it should be house (1) and engine (2), previous owner of my boat has made an absolute mess with the battery wiring. Things hooked to things that shouldn't be. Its wired so everything runs off either battery 1 or battery 2 or both. Basically one battery is just there for backup. That will be changed shortly. 2 house batteries wired parallel thru selector switch, with the engine battery isolated but switched to house batteries for backup. All hooked together with an ACR (automatic charging relay) Sounds more complicated than it really is..... :p
 
Newbie111 said:
So I have a new question about the battery switch and hopefully everybody is still looking. The previous owner said he would just put the switch to 1 and it powered everything. From motor starter up to electronics. Is that normal? I thought the switch on one would be electronics and switch 2 would be for motor start up or vis versa. Then the all switch would make both work. Am I wrong about this? What does the red box with the 40 button on it do?
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That is how my two batteries are wired. Like a lot of folks with two batteries, I typically run on 1 battery only. I alternate which battery it is, 1 or 2. Sometimes after a longish trip, I will switch to BOTH for the trip back home, That is done to top off both batteries.
The practice of using one battery only hopefully stops you from accidentally discharging both batteries as might be the case on a day to have loads running a long time with out the motor on. Stereo, livewell, plotter, spot light, nav lights etc all can drain a battery if used long enough. If you drain the battery you are using, you have the other to get you started and back home.
The red button is as mentioned a breaker and it is the main power source for your fuse and/ or breaker panels. Basically everything runs through it except your automatic bilge pump which is wired directly to a battery through an inline fuse near the battery connection.

The 208 is a small boat and doesn't normally have a lot of accessories and associated loads. I really don't see a great need to wire in an isolator and secondary charge circuit.
 
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