Batteries and Battery switch - Maxum Boat Owners Club

Harley31 · 07-09-2012, 04:34 AM

I just had a battery issue, so I thought, but after some trial and error I found the problem was in the #2 position on my battery switch, so I bought a new switch. I have one battery, 800 amp, for starting and a second battery, deep cycle, for when I'm anchored and listening to the radio. The guy at the marine parts store told me that if I start the boat on one battery, then switch to "both" for my ride, that I am damaging my alternator since you are not supposed to switch batteries while the boat is running. So how do you switch from your starting battery to both without shutting down the engine? It's a catch-22. He said start the boat on "both" setting. This does not make sense. Why do I have a high cranking amp battery for starting the boat when I'm supposed to start it on "both"?? Anybody.................

pascavone · 07-09-2012, 05:22 AM

never start or run on BOTH.... this is only for emergency dead battery.

Run on #1
Run on #2

dose not matter..... the alternator will charge like your car, with the head lights running, when rolling down the road.

When parked..... then switch to the other battery, use it for radio and lights, then switch to other battery to start and go again.

Never switch the main battery switch while running the engine.

AlwaysSober · 07-09-2012, 12:36 PM

This is the one I put my 2400 SC3. It has an alternator field cut-out. Only works with 3 wire alternators.

http://www.wholesalemarine.com/p/PKO...7cPKO_d_8503DP

Other option would be to put a battery isolator in so that both batteries are charged independently.

ImRich · 07-09-2012, 02:04 PM

I'm new, so perhaps I'm wrong. But I thought the marine battery switches were all 'make before break' type of switches.

This would mean that the alternator always sees a load when switching from battery 1, to 2, to both, etc. So I would expect no problems switching the batteries while the engine is running.

My boat is currently setup the same way. Two batteries. One is a starting only battery, the other is a dual purpose (starting/deep cycle). The AC charger is currenly only connected to the dual purpose battery.

I'm debating on either getting a new dual battery charger, or an automatic battery bridge relay which will ensure both batteries are always charged.

ss3964spd · 07-09-2012, 03:10 PM

Quote:

Originally Posted by ImRich

.....marine battery switches were all 'make before break' type of switches. This would mean that the alternator always sees a load when switching from battery 1, to 2, to both, etc. So I would expect no problems switching the batteries while the engine is running.

What Rich said, Harley.

Find out what switch was installed, look up the specs, make sure it is the "make before break" type.

A potential issue you may wanna check has to do with different types of batteries; the usual/typical lead acid (flooded cell) type, Gel's, or AGM's. Each has it's own preferred charging rate. Lead acid and AGM's are closest in how they want to be charged and your alt won't have any issue charging both at the same time (switch in the Both or 1+2 position). Gel's don't play well with the two so you wouldn't want to charge both at the same time.

If neither of your batts are Gel's, and your switch is the MBB type, switch as you see fit. Do understand, though, that if you really drain one batt, then switch to "Both", the charge from the good batt will drain into the dead one, making for two semi-charged batts - which may - or may not, start the engine. Also know that if you have done dead batt, and you re-start on the good one, then switch to both (again making for two partially charged batts) the voltage may be too low to keep the engine running) more of an issue with EFI engines).

Dan

ShoreAcres · 07-09-2012, 04:34 PM

I am slowly discovering how my switch and charger work. I had assumed that the AC charger would charge both, but I believe it only charges #2. I also thought the alterantor would charge both, unless I had the switch set in the "both" position. It now appears that it only charges #1 when set to #1 and #2 when set to #2. Does this make sense?

I had been keeping #2 in reserve, bu I guess I have to start rotating use.

pascavone · 07-09-2012, 04:43 PM

simple to check.

if your have a big fat red and black wire running from battery #1 top post to battery #2 top post, then they are bridged, and they both get charged together.

this is typical.

the battery switch only connects and disconnects loads, the charging circuit is always maintained regardless of the battery switch.

if you have a battery going dead with nothing hooked up, then the battery is shot.

shrew · 07-09-2012, 05:32 PM

Quote:

Originally Posted by ShoreAcres

I am slowly discovering how my switch and charger work. I had assumed that the AC charger would charge both, but I believe it only charges #2. I also thought the alterantor would charge both, unless I had the switch set in the "both" position. It now appears that it only charges #1 when set to #1 and #2 when set to #2. Does this make sense?

I had been keeping #2 in reserve, bu I guess I have to start rotating use.

Yes, the alternator will charge whichever battery the battery selector is set to. The battery charger will charge any battery it is connected to. Start with the battery charger and following the wires to the battery. If the charger is connected to only one, that is the battery that will be charged. If it is connected to both, it will charge both when the battery charger is turned on. Keep in mind that the battery charger will only charge when connected to AC power source (generator or shore power) and only if the main breaker and battery charger breaker is turned on.

I've seen instances where someone installed a single bank battery charger to the house battery and allow the alternator to charge the starting battery. After all, you don't need to keep your automobiles on a battery charger, right?

ImRich · 07-11-2012, 01:43 PM

Quote:

Originally Posted by shrew

Yes, the alternator will charge whichever battery the battery selector is set to. The battery charger will charge any battery it is connected to.

I'll add to this. If your AC charger is connected to only one battery, and you set your battery selector to both (or 1+2), then your charger is attempting to charge both batteries.

pascavone · 07-11-2012, 03:09 PM

I don't believe the battery charger is connect to the battery switch at all.

the battery switch only distributes the load to the boat.

The charger is behind the switch.

I think you have one battery that will not take a load and is shot.

disconnect it for a few days and see if its dead.

ImRich · 07-11-2012, 03:44 PM

Or take the questionable battery out and have it tested. Most places that sell batteries will test it for free (as they will want to sell you a replacement).

As an example, I was pretty sure I had a bad battery. So I shopped around for the replacement battery that I wanted to purchase. I brought in the old battery and asked them to test it for free, which they did and confirmed that it was bad and past its useful life. I purchased the new battery and didn't have to return to the store with the old battery again (some charge a core charge if you don't leave the old battery with them).

Harley31 · 07-13-2012, 01:52 AM

Is this thing working? This is my third attempt to reply, but they don't go through.

Harley31 · 07-13-2012, 02:01 AM

Ok, I figured out how to reply. I appreciate everybody's replies. I have gotten alot of good advice, but I am still confused! I have a Perko, as AlwaysSober, but I have one model below that model. It also says not to turn off while engine is running. The guy at West Marine told me it was ok to switch between #1, Both and #2 while the engine is running, just don't switch "off". This sounds logical, but who knows? I'm not sure if my alternator has 3 wires, but I also don't believe my boat has a battery charger. I assumed the alternator was charging the batteries as I was underway. I should be able to start in #1 position, turn to Both so both batteries charge while underway, then when I anchor for lunch, shut down the engine and switch to #2. But I think to be safe, I will start and run on "both".

My wife said, "Why can't a boat be like a car. Just get in, turn the key and go." Now that wouldn't be any fun, would it? Hello? Hello?.....anybody out there? Besides, we all know what B-O-A-T stands for; Break Out Another Thousand!!

ss3964spd · 07-13-2012, 03:06 PM

Harley,

If you have the model number of the Perko switch you can find it online and look up the specs. It's very likely though that the switch is a make before break design. If the WM guy says it's ok to switch between batteries while the engine is running I assume he knows which model the switch is. He is correct though - don't ever turn the switch to the off position while the engine is running.

The Alt will have only 1 charging output wire. IF the battery switch has been wired in the most normal and simple practice you are correct; with the engine running and the switch in the #1 position the alt will charge only battery #1. If running and in the #2 position only batt #2 gets charged. If running and in the Both position they both get charged. Period.

The most common practice, and this assumes both batteries are fully charged, is to use batt #1 for starting the engine and use #2 for when you are anchored or tied up for hours listing to the radio, using lights, etc. This way, if you drain #2 you can still re-start the engine on #1. Once running and under way you may be able to switch to Both but do re-read the bit I wrote earlier about what happens if you have one really dead batt and you try to run on both.

There are a lot of variables; on-board battery chargers, combiners, isolators, etc that may cloud the picture, and it's impossible to tell what you have without seeing how the switch is wired and what wires are going to the batteries, so all the above assumes you have the most basic set up - which is probably a safe bet in your case.

Assure your wife that there are a lot of boats out there that have just one battery and you can just get in, turn the key, and go - if the battery isn't dead of course.

Dan

ImRich · 07-13-2012, 04:10 PM

Remind your wife, that in a car, you don't tend to sit for long periods of time using the radio, lights, refigerator, etc. with the engine turned off and therefore, not charging the battery.

In a boat, you have a lot of loads on that battery that can drain it (especially the refrigerator, and possibly the radio). Then when you go to start the engine, you can't as you have drained your battery. In a boat, it's a bit more critical that you can start the engine when it is needed. You can't just get out and walk somewhere else if a storm is approaching and you can't get the engine started.

So boats have dual batteries, and various systems to manage them. You have to learn how to manage this, or pay for expensive systems to attempt to do it automatically for you. So it seems more complicated (because it is).

As an example, my boat has the older dual battery system with a "1, 2, 1+2 or OFF" switch. So I have to manually change the switch (as it sounds like you do too). As mentioned, remember never to switch to OFF if the engine is running.

My AC battery charger (and alternator) will charge whichever battery the battery selector switch is set to (1, 2 or both).

I'm considering changing (upgrading?) my battery system to a separate house and starting battery. This will mean some re-wireing. This way the engine will always be connnected to the starting battery (via the switch), and the rest of the boat will be connnected to the 'house' battery which at the moment is a dual purpose starting/deep cycle battery. This just takes some rewiring.

The alternate thing I'm considering is purchasing an automatic battery relay that will charge both batteries as needed. These are about $100.00. This is the device I'm considering:
http://www.westmarine.com/webapp/wcs...roductId=17248

Alternatively, I could get a new dual battery charger, which won't keep both batteries charged when I'm underway, but will (at least) be sure both batteries are always charged when I leave the dock.

My dilema is that I can get a new dual charger for not much more than the cost of the ACR (automatic charging relay), and the new chargers are smarter and help to keep batteries in better shape (tri-charge profile, etc.).

Right now I'm leaning towards the ACR, but I could just manage this manually with the battery switch as has been good enough on this boat so far in it's 22 year life.

digindeep · 07-16-2012, 05:46 PM

This is a terrific discussion. However, I've owned my 3200 for nearly 10 yrs. and still haven't got a clue. Does anyone know the process in which to use the battery switches. There are two batteries, two switches marked port and starboard as well as each switch having the options to select "A" or "B", "BOTH" and of course "OFF". I assume one is the house battery and the other is for engine cranking. What is the logic behind this??

Thanks...Matt

ImRich · 07-16-2012, 08:15 PM

digindeep,

Without knowing for sure, it sounds like someone wired two separate battery switches, one to each battery. And each being a "A,B, BOTH,OFF" type of switch, instead of a simple 'ON/OFFf' switch on each battery.

I would suggest that you have someone that knows how these should be wired open the 'covers' and see how the switches are actually wired on your boat.

You may be able to figure it out yourself, by disconnecting each battery, one at a time, then check all the leads with a volt meter to understand how your two switches are wired. You may find that they are not wired in a way that makes much sense (or I don't know what I'm talking about).

rens914 · 07-16-2012, 08:42 PM

sorry guys
i always have the selector on "both" and never have problems
but
i only use the boat to go from A -> B and back
never use it overnight or in the harbour
never had problems what so ever
it makes sence to select 1 or 2 when you are stationairy to avoid an empty battery when you whant to start the engine
but i dont use it that way
rens

Phillbo · 07-16-2012, 09:12 PM

When one of your batteries goes bad and draws the other one down with it, you will not have one in reserve. Why even bother with the expense of 2 batteries if your not allowing for the benefit of the 2nd one?

Harley31 · 09-26-2012, 01:45 PM

I figured out one of my questions. I used my multi-meter to check my batteries in different configurations. Without the engine on, they both read in the 12+ volt range. When then engine was running, the battery in which I had switched on was charging and was reading 14+ volts. When the switch was on the 1 position, the battery in the number 2 position was not charging, and vice-versa.