Battery 1, 2 or Both?

[Joe317]

Hello all. New here to the forum. Just picked up a new 21 Freedom. Battery question. Dealer told me to start on one or two then switch to both during normal use? Grady manual says says start with one two or both but operate on one or two not both. I know someone here knows the answer. Greatly appreciate any info.

Best Regards and Thanks in advance,

Joe

 

[seasick]

The reasoning behind nor running on Both is to protect you from unintentionally running both batteries down and getting stranded.
Many boaters, myself included try to alternate which battery to start on. Sometimes I use the date, odd date, battery ONE, even date battery TWO
Assuming that you do not trickle charge the batteries when not in use (at the slip), I will when far enough out that I will be running for 20 minutes or more to get back home, will switch to BOTH to give both batteries a top off charge.
I am sure you know this but do NOT turn the battery selector switch past OFF when the motors are running. That can damage the charging system.

 

[SkunkBoat]

the Only time to use Both is when desperately trying to start because it won't start on 1 or 2. NEVER leave it on Both.
When on Both, a bad battery will drain the good battery in short order. On Both, you effectively have one battery and when its dead you are screwed.

I will never understand why Dealer's don't install the Aux charging cable on motor and then both batterries will charge independently, all the time, no switching.
The alternative to the Aux charging cable is a VSR/ACR charging relay.

Look into that because having to remember to switch batteries is STUPID.

 

[Joe317]

The reasoning behind nor running on Both is to protect you from unintentionally running both batteries down and getting stranded.
Many boaters, myself included try to alternate which battery to start on. Sometimes I use the date, odd date, battery ONE, even date battery TWO
Assuming that you do not trickle charge the batteries when not in use (at the slip), I will when far enough out that I will be running for 20 minutes or more to get back home, will switch to BOTH to give both batteries a top off charge.
I am sure you know this but do NOT turn the battery selector switch past OFF when the motors are running. That can damage the charging system.

Hello seasick!
I use the odd even day for the 1 or 2 start of the day also. Thanks for-the heads up. Manual say to run on 1 or 2 just wanted to make sure no harm with running in both.

Regards

Joe

 

[Joe317]

the Only time to use Both is when desperately trying to start because it won't start on 1 or 2. NEVER leave it on Both.
When on Both, a bad battery will drain the good battery in short order. On Both, you effectively have one battery and when its dead you are screwed.

I will never understand why Dealer's don't install the Aux charging cable on motor and then both batterries will charge independently, all the time, no switching.
The alternative to the Aux charging cable is a VSR/ACR charging relay.

Look into that because having to remember to switch batteries is STUPID.

So it is correct to assume that the engine will only charge the selected battery. And both when selected to both? But both is not SAP.

 

[SkunkBoat]

yes

 

[Blaugrana]

Definitely check to see if an aux cable was installed already. I had no clue until I unscrewed the switch and saw the extra cable in there.

No expert here, but I think you can check by having your switch on battery 1 and then measure battery 2 to see how many volts. At idle, mine was around 13.2 or so.

I switched mine over to one of the Blue Sea switches ($40-50 or so) that allows two separate circuits as I got tired of switching between 1 and 2, especially when drifting. So now I have a cranking battery and house battery. You can still combine if you want, but can just turn the switch on...My setup only works if you have that aux charging cable, which skunk boat highlighted above. Otherwise, VSR/ ACR

 

[Fishtales]

I run one motor off each bank, thus one switch is set to 1 and the other switch set to 2. Only run both if one bank has a prob to get in.

 

[seasick]

I run one motor off each bank, thus one switch is set to 1 and the other switch set to 2. Only run both if one bank has a prob to get in.

On one of my boats with Merc Optis, I usually run each motor on a separate battery BUT, 9 out of 10 times when first starting those motors, I can't get them to fire unless I select BOTH. I gave up trying to figure out why that is but Optis are quite particular about voltage at the motor when crankng.

 

[Recoil Rob]

My (new to me) came with an Interstate grp. 24 starting battery which I'm sure the seller got locally so he demo the boat. I got a Interstate grp 24 deep cycle and am planning on using the Blue Sea 7650 Add a battery kit. This has an ON/OFF switch and both batteries charge independently but I'll use the starting battery for the engine and the deep cycle for the house. It also has a COMBINE position for when you need it.

I was thinking it might be good to put the deep cycle inside the console, better for weight distribution, I'd just have to run the heavy cable back to the switch.
Good/Bad idea?

 

[seasick]

To meet ABYC specifications, it is not as simple as just relocating the battery. Disconnect devices ( battery switch) and any direct feeds have to be within a certain distance from the battery. Direct feeds would be the case for automatic bilge pump feeds. The main DC breaker also has to be within a certain distance.
The battery cable gauge may need a significant increase in size depending on the load requirements and the added wire run length.
The job may not be worth the effort.

 

[Hookup1]

the Only time to use Both is when desperately trying to start because it won't start on 1 or 2. NEVER leave it on Both.
When on Both, a bad battery will drain the good battery in short order. On Both, you effectively have one battery and when its dead you are screwed.

I will never understand why Dealer's don't install the Aux charging cable on motor and then both batterries will charge independently, all the time, no switching.
The alternative to the Aux charging cable is a VSR/ACR charging relay.

Look into that because having to remember to switch batteries is STUPID.

Skunk Boat has this nailed down correctly. I'm not sure why there is so much confusion and misinformation on this topic. It really is simple.

Your motors have alternators that will charge their respective starting batteries. If your boat has a house battery (third battery) one of the motors has a charging shunt that will charge the house battery too. If you have a fourth battery the other engine needs to have a charging shunt installed that will charge the fourth battery too.

Each motor should be set to its own battery ie port battery to port engine. You should only use the "both" position if one of your batteries is failing to jump start the motor or just use the switches and put it on the other battery. The "both" position is a bad idea especially if you are connecting (paralling) a good battery to a bad battery via the switch. You should never run in the both position.

As far as batteries I'm using all Duracell AGM's purchased at Sam's Club.

Group 34 43.10 lbs. 955 MCA 55 AH. $119.32
Group 24 52.40 lbs. 800 MCA 78 AH. Did not see availability at my store.
Group 27 61.55 lbs. 900 MCA 92 AH. $158.88
Group 31 67.35 lbs. 1,000 MCA 105 AH. $179.74

I used a Group 34M Duracell Marine AGM for my Yamaha F150's. About 9 lbs lighter than a Group 24 and 17 lbs lighter than a Group 27 with higher MCA rating but less capacity. Also used for my 4th battery, a Group 34M Duracell Marine AGM, for bow thruster, windlass and bait tank pumps.

For the house I use a single Group 27 AGM. You could parallel two new ones. Or do a Group 31. I don't like parallel battery setups but if you do this they must both be new and replaced together later on. Mixing confuses the charger and possible battery explosion risk.

Both engines wired with charging shunts. One connected to house the other to the 4th battery. When underway all 4 batteries are charging.

 

[FLWhaler]

I was always taught to never switch the battery switch with the motors running as this would blow the power pack on the motor. Was this bad information?

 

[Hookup1]

There is some truth to that. I don't know the details but some switches have field disconnects on them. Not sure I have ever seen one installed. I just don't mess with them if the motors are running.

Alternator Field Disconnect - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

 

[Recoil Rob]

Your motors have alternators that will charge their respective starting batteries. If your boat has a house battery (third battery) one of the motors has a charging shunt that will charge the house battery too. If you have a fourth battery the other engine needs to have a charging shunt installed that will charge the fourth battery too.

Seeing as I have a single engine boat (Honda 150) would there be a shunt for a second battery? Would this negate the need for the Blue Seas system?

 

[Hookup1]

Yes you should have a charging wire coming from the engine.

I don't know anything about a Blue System you are talking about. Yes the charging wire would negate it.

This is what I had to install on my second motor. It was already installed on the first one.

Yamaha - Battery Isolator Lead with 50A Circuit Protection - 13.5 ft -

Yamaha - Battery Isolator Lead with 50A Circuit Protection - 13.5 ft - MAR-69JIS-0L-ED

www.partsvu.com

 

[seasick]

There is some truth to that. I don't know the details but some switches have field disconnects on them. Not sure I have ever seen one installed. I just don't mess with them if the motors are running.

Alternator Field Disconnect - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

I have never seen one either but after digesting the posts about secondary charging leads I did some reading and learned something .
I read that all Yamaha outboards manufactured after 2003 do have a secondary charging lead that is capped under the cowling. What I don't know is how that charge circuit is engineered; is it totally separate circuitry or is it just bridged and isolated off of the alternator or inverter? If totally separate then is seems to me that running with the charge lead not connected won't harm the motor.

 

[Hookup1]

When I bought my boat it had been repowered by the previous owner. One engine came with the aux charging cable installed and the other one didn't. I purchased the second cable and installed it myself. It has a fancy Yamaha connector on it that snaps into the existing harness, a piece of wire and a waterproof fuse holder. Overpriced but I bought OEM to keep it simple. Everything to isolate this connection is already inside the motor.

So on your point about running with no harm - mine came that way from the factory and ran for years with no problem.

I don't know what the "default" rotation on the engines are but I suspect Yamaha installs the charging shunt and fuel water alarm on all of them. On the other rotation they don't. Easy to add the charging shunt but not practical to do the water alarm.

 

[JJMag]

On this topic I have already ordered a blue sea add a kit, and what this will do able to charge both batteries ,when starting battery get up to a certain amperage also able to use both battery to start in emergencies, also if electronics are on it will isolate it so you don’t have to turn your electronics off on starting Your engine

https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A
Also are you the code to get 15% off at West Marine MK57356
I saw the code on the hull truth
And used it 4 days ago and it worked for me

 

[Hookup1]

That will work and it does give you the ability to use both to start.