Battery Question-Newbee

V

vv1212w

Member
Joined
Oct 14, 2003
RO Number
12327
Messages
32
Have three batterys and need some guidence. Boat usage. No hooking. The boat is either at my marina or at a visiting marina or under power getting there. All under shore power. Options are to set for one or both on the settings. With three instead of two batterys I do not know which seeting is for my usage running and in port.We use the air and micro while in port. Any advice? Thank you-

Bill
St Clair shores, MI
 
Bill,

I'm sure one of the more experienced guys here will have better advice for you, but here goes:

- Your battery position doesn't have anything to do with your air or microwave as you probably know. They are almost always AC devices.
- If you have three batteries, is one dedicated to a genset? if so you only need to worry about two in most instances.
- The most commonly accepted practice is to leave your battery switch to both while connected to shore power and switch to either battery 1 or battery 2 while on the hook. Premise being, if you drain one battery dead you will have the other to start your motor/motors. Your third battery being dedicated your genset, which when running should power your charger and replenish all your batteries.
- There are however, upteen million other combinations of isolators and combiners, so if this situation doesn't apply, post more info on your particular dc system and someone (even as junior as me can provide more specific advice).

Dan
 
Thanks for your reply Dan. First I do not have a Genset. Also there are only two settings for the Batteries. One or both although I do have three batteries. If leaving the setting on both while under shore power should I leave it on both when underway or at all times. As I mentioned the boat is either at my marina, or under power to a weekend marina and under shore power again.
 
Only set them to both when you need both or you want both to charge. If one of your batteries goes bad a switch is set to both it will kill the other batter too.
 
I guess that you have to be an old salt and a regular to get some advice beyound two.Thanks Dan and Bob for your input to the newbee. Thought I would get more replies.
 
If the boat is either plugged in at a marina or underway I would recommend only having one battery.

I am going to take a guess that the three batteries are dedicated to each engine: port, starboard and generator. The battery switch allows you to combine the two main engine batteries while the generator is always on its own circuit.

What is the configuration of your battery charger? Does it have three outputs to charge all three batteries independently?

If it has three outputs and is connected to all three batteries then I would NOT combine any of the batteries unless you had trouble starting. Then make note of it and plan on replacing batteries at the earliest opportunity.

If the battery charger has only two outputs then I would connect one to the generator battery and the other to one of the engine batteries. Leave the battery switch to BOTH while you are plugged in and charging. Switch to one to start and make your cruise. Note: I suggest crusing while switched to one because it is possible to run a battery dead even while the engine is running. If the batteries are separated you will always have a fully charged battery to switch to.

Rod
 
Isn't there a "deep charge" battery? The boat I'm negotiating on has one for port engine, one for starboard engine and another they call a "deep charge" battery since there is no generator on board.

Jeff
 
I have three identical group 27 deep cycle batteries on our boat, but that's because we anchor out a lot, often for week or more.

It's a single engine boat. Battery 1 is used as the starter battery. Batteries 2 and 3 are house batteries. The boat has a two bank (two battery) three stage AC powered smart charger that is used at the marina. I wired the charger so I can charge/maintain batteries 1 and 2 together, or battery 3 separately.

At the marina and under shore power, all batteries are switched OFF, but auto bilge pumps are hot wired directly to battery 2. The charger is left on, and directly wired to the positive battery terminals.

Under power, battery 1 and either 2 or 3 are switched on.

At anchor, battery 1 is alway switched off and either 2 or 3 is switched on. The boat is designed to get by with very low battery power (usually less than 30 amp/hrs per day). Batteries are recharged at anchor with thin film solar panels. One house battery is used for one day, then shut off and recharged the next day.

vv: How many engines on your boat?
 
Jeffrey:

The proper term is "Deep Cycle" battery. It is simply a battery that is built with extra heavy plates to withstand the errosion of the plates that happens when a battery is deeply discharged.

The typical "starting" battery is built with very thin plates to provide the maximum surface area, which is what you need for maximum current (starting situation). A battery designed this way will not tolerate being discharged a fair amount for too many times.

Unless your deep cycle battery is very large and coupled to an inverter then it isn't exactly a replacement for having a generator!

Rod
 
Some boats combine 2 batteries for one motor and one battery for the other motor. The theory is that the 2 battery bank is the starting battery AND the house battery while the single battery is used for starting the other motor only. So if this is the case then the battery switch just isolates them like a 2 battery configuration.

Not sure if your boat is like that, but I hope this helps.
 
You must log in or register to reply here.
Back
Top