Batteries

[Rokefin]

Time for me to think about new batteries....and I believe I am starting to get a little understanding of the systems from reading older posts.

First off what I have are two Everstart marine 24 DC batteries, 690MCA, 101 1 amp hours powering my 115 yami, 9.9 yami kicker, both 4 strokes, fish finder/gps, down riggers, no radar, batteries are in the stern.  My battery switch is the (old style) off, 1 bat, both batteries. The batteries are cabled together.
These two batteries have lasted a couple years but got real weak (slow to turn over the main) last year so I gave them a good charge during the off season and now with less use this year they are weakening again needing a charge - I do not have any "battery savers" hooked up to them when not in use.

So for now, I should charge these two again or maybe just buy another dual purpose marine battery but with a higher MCA - CCA?  My thinking is the existing batteries rated a little low?


In the off season I may go to a newer "blue sea" switch with the "add a battery kit" and go for a "starter" battery and a "house" battery as this seems to be the desired set up - I think
If I go with the new system it will be because I decided to do a complete rewire. Besides the weakening batteries, I have not had any other battery issues, no dead batteries and no house issues concerning any of the electronics....

[Threeweight]

Good idea to charge/maintain batteries if they sit for long periods.  Flooded cells will self discharge just from sitting, and if left that way over time it can cause premature battery failure.  If it isn't too much hassle, giving them a charge once a month is great.

I fish offshore and I'm paranoid about maintaining batteries.  If they are suspect, I replace them.  Do you know what the manufacture date on your batteries was?  Should be a sticker on them somewhere.  Flooded cells are good for about 4-5 years if well maintained, 3 if not.

I have an on-board charger and a Blue Sea ACR (what comes in the add-a-battery kit.)  Had the Blue Sea set up on the Arima to.  It's nice and a great way to go, but you can do fine just keeping the batteries maintained with a good charger once a month.

[Rokefin]

Battery stickers have a 6/14 date.  One battery charged quickly and the 2nd battery is taking quite a bit more time. If I stay with the same set up I'll try to charge batteries more often than once a year.

The past 2 years I ran the battery switch on "both" all year long, this year I ran "one" battery the first half dozen trips then started running the switch on "both" - with my system "both" should be ok?

[Threeweight]

When you run on "both" you are combining the two... instead of two isolated batteries, you have one big battery.  It won't hurt anything, but it kind of negates the benefit of having two batteries.  A short will kill both batteries, and if one battery is failing it can kill the other.

Both is intended to be your "get home" option if neither battery on its own has enough charge to start your motor.

[Rokefin]

Thanks for the info 3weight. One battery is weak so I think I will replace it for now, Ill decide at a later date whether to do an electrical overhaul with a complete battery conversion.

[troll4fish]

I start on my "starting" battery and run on it while heading to the fishing grounds to recharge it then start my kicker and then switch to my deep cycle while trolling and running the FF/sonar, radar if needed and my black box electrolysis unit so the deep cycle gets kept up by the kicker charge. That way I have the start battery fresh for restarting the main motor to get home. I pretty much count on replacing batteries every 2-3 years since I buy Interstate wet cell batteries instead of Optima's!

[First Cabin]

Over the years I've learned that if you deeply discharge a battery even just once, it will probably never be the same and you may as well plan on replacing it early.

I watch my system voltage carefully and try and make sure my voltage never goes below 12.0 volts.  If it gets below 11.9 volts, damage is being done.  If it gets so low that it won't start a motor, I consider it toast.  Rather than recharge and wait for it to become an issue, I change them out.

Now that I have installed an ACR and have an onboard charger that I plug in when I get home, my batteries are lasting 5 plus years even with my super heavy load.  I replaced batteries last year after I noticed the batteries would drain(fishfinder voltage would drop from 12.6 down to 12.0) relatively quickly when I was sitting on anchor.

I really like having the ACR.  The voltage shown on my fishfinder is from the house battery.  My motors are hooked up to first charge the starting battery, and then when it is topped off, the ACR switches over to charge the house battery.  Throughout the day I can watch the voltage on the fishfinder go up when the ACR switches over and my house battery is being charged.  Gives me a good feeling to watch the ACR cycle on and know it is all working as designed.

[DevMah]

When you run on "both" you are combining the two... instead of two isolated batteries, you have one big battery.  It won't hurt anything, but it kind of negates the benefit of having two batteries.  A short will kill both batteries, and if one battery is failing it can kill the other.

Both is intended to be your "get home" option if neither battery on its own has enough charge to start your motor.

Threeeweight is correct if both batteries are identical that it becomes one large battery...
But many issues that can arises by manually combining, see the below link there are many factors to consider before you put them in parallel.

This is why a ACR is perferred as the charge relay will manage the charge.

https://www.optimabatteries.com/en-us/experience/2014/04/can-i-connect-dissimilar-batteries-parallel

Dev

[Rokefin]

Thanks for all the info, I think it best to finish the year ( only a couple more planned trips) with these two batteries then pencil out a plan for an electrical upgrade in the off season.

[DevMah]

  My motors are hooked up to first charge the starting battery, and then when it is topped off, the ACR switches over to charge the house battery.  Throughout the day I can watch the voltage on the fishfinder go up when the ACR switches over and my house battery is being charged.  Gives me a good feeling to watch the ACR cycle on and know it is all working as designed.

This is not true the ACR dose not manage wich battery is charged first nor dose it charge the battery that needs it the most.
It will manage when to safely combine and disconnect the batteries in parallel.
It simply relys on the system charge voltage to be above 13v for two minutes it then combines the two batteries so that one charge source can be used. It will also not combine if one of the batteries is below it's under voltage lock out threshold (9.5v) or the charge source is over 16v.
If the voltage across either batteries drops below 12.75v for 30 seconds it will disconnect and isolate the batteries.


https://www.bluesea.com/resources/1366

Dev

[First Cabin]

  My motors are hooked up to first charge the starting battery, and then when it is topped off, the ACR switches over to charge the house battery.  Throughout the day I can watch the voltage on the fishfinder go up when the ACR switches over and my house battery is being charged.  Gives me a good feeling to watch the ACR cycle on and know it is all working as designed.

This is not true the ACR dose not manage wich battery is charged first nor dose it charge the battery that needs it the most.
It will manage when to safely combine and disconnect the batteries in parallel.
It simply relys on the system charge voltage to be above 13v for two minutes it then combines the two batteries so that one charge source can be used. It will also not combine if one of the batteries is below it's under voltage lock out threshold (9.5v) or the charge source is over 16v.
If the voltage across either batteries drops below 12.75v for 30 seconds it will disconnect and isolate the batteries.


https://www.bluesea.com/resources/1366

Dev

You are correct.  I should have used the word "combine" instead of switch over.  In practice, on my boat, it combines the batteries once the starting battery voltage goes above 13v and I can watch that happen by monitoring the system voltage on my fish finder.  In practice, my house battery discharges while I'm bottomfishing or anchored and then once I start the main, the ACR verifies the starting battery voltage is over 13v and then combines them to recharge the House battery.

I endorse the ACR!

[GregE]

Good explanation Dev   :applause:

[Markshoreline]

Do ACR's fail?  Is there a way to test to see if they are operating properly?

[DevMah]

Yes they do fail but it is rare...
Testing/troubleshooting
http://assets.bluesea.com/files/resources/technical_briefs/Technical_Brief_ML-Series_FAQ_Matrix.pdf
http://assets.bluesea.com/files/resources/technical_briefs/Technical_Brief_7610_FAQ_Matrix.pdf

I have a ACR combine led on my dash and dual battery digital meters.
I can watch them combine and disconnect just like First Cabin.

Dev.

[Markshoreline]

Thanks Dev, you're a great asset to our forum!

[Rokefin]

 
Agree, love the great info shared.

[Holoholo808]

Dev,
Don't want to thread jack but since we're sorta on the topic...

Is it necessary to add in the start isolation on the smaller blue sea ACR?

My mechanic friend wasn't too keen on tapping into the start circuit when I asked him about it but he doesn't get too deep into electrical.

I don't have a voltage indication other than the warning light (though I'm not sure it/my eye would pick up the transient voltage drop on a gauge when cranking) so I can't tell if voltage is dropping low enough to damage the electronics.

Mods,
Let me know if this should be a separate thread.

[DevMah]

 Start Isolation is always good when cranking your engine over it protects sensitive electronics from voltage spike and drops.
When the SI (start isolation) is activated  the ACR is disengaged and both batteries are isolated. This isolates the house battery (electronic side) as you apply the cranking load to the start battery any voltage spike or drop that is created is not passed over. As the design of the ACR will not allow it to recombine until there is a 13v charge any voltage spike oscillation has stabilized (oscillation is caused by back EMF of the motor).

This is dependent on the system also ...batteries (age, type, CCA,...) the starter draw,voltage drop, and amount of electronic load.
I have installed some systems that the battery are so large and the starter draw so small that the voltage drop dose not go below 12V.
For example a new Group 34/78 battery with a 800 CCA installed on a 60 hp motor the start draw is less than 80A, and only one fish finder.

However I always recommend Start Isolation of some type there are many ways to do this...
-simply turn off your electronics when starting your engine
-Switch off the house battery during cranking(if no ACR installed)
-Install the Start interrupt on your ACR

Dev

[Holoholo808]

Thanks Dev, appreciate the quick reply! Guess I'll be wiring up the start interrupt. Since we start and stop the main throughout the day.

[Arimadrifter]

Excellent thread. So many great questions and so many great answers. One question I've had for a long time is is it OK to switch the battery switch from battery "1" to battery "2" while under way? I've heard yes and no but thought I'd throw it out here to get everyone's thoughts.
Thank you.

[First Cabin]

Excellent thread. So many great questions and so many great answers. One question I've had for a long time is is it OK to switch the battery switch from battery "1" to battery "2" while under way? I've heard yes and no but thought I'd throw it out here to get everyone's thoughts.
Thank you.

Most(all?) of these Marine switches are "make before break" switches, which means they combine the two batteries briefly as you cycle the switch and never interrupt the flow so everything is fine.

Still makes me nervous though and you need to verify your switch.

[DevMah]

Excellent thread. So many great questions and so many great answers. One question I've had for a long time is is it OK to switch the battery switch from battery "1" to battery "2" while under way? I've heard yes and no but thought I'd throw it out here to get everyone's thoughts.
Thank you.

May I ask what is your reason to switch the batteries?
Why while under way not idle?

IMO
If I was to switch in the correct make before break switch direction I would do it idle.. not while under way.
Assuming that your switch is a make before break.
Dev

[Arimadrifter]

I normally charge my starting battery while running and never switch over while the engine is running. I've heard both sides of the argument and I haven't been willing to take the risk. If I've been charging the starting battery for several hours, I'd like to switch over and charge the "house battery" but never do as I'm more concerned with keeping the starting battery fully charged.

[DevMah]

I normally charge my starting battery while running and never switch over while the engine is running. I've heard both sides of the argument and I haven't been willing to take the risk. If I've been charging the starting battery for several hours, I'd like to switch over and charge the "house battery" but never do as I'm more concerned with keeping the starting battery fully charged.

You can switch both batteries here is what I would recommend:
-Make sure your switch is make before break
-Have battery meters installed to make sure the battery's are between 11 to 12.75v...
-Switch at idle so that the alt output is low


Once again an ACR is one of the safest ways to combine and charge batteries.


Dev

[Arimadrifter]

Thanks Dev. Any recommendations on how to determine whether or not my switch is Make before break? My boat is a 1991 and I believe the switch is original.