Charging dual batteries

[steeler]

I'm not very bright especially with electrical wiring.
I have dual batteries, with a Blue System switch, that has a #1 and combined seting.
Can I charge up or maintain both batteries at one time if I set the switch on the combined setting?
Presently I disconnect them and do them individually.  Just wondering if I can save some time and my back.

[First Cabin]

They should be charged separately.  Combining them to charge will make one battery become the master and the second a slave.  The charger won't properly charge the slave.  The slave will get weaker and weaker over time.

To make it easier, I installed a two bank on-board charger.  Turn the switch to "OFF", plug the charger in and forget it.

[La-Z-Buoy]

This is what I have. Leave it plugged in all the time. Makes it really nice not having to worry about getting to  the water and finding a dead battery.



https://www.amazon.com/Battery-Tender-022-0165-DL-WH-12-Volt-Management/dp/B000NCOKV0/ref=sr_1_8?s=automotive&ie=UTF8&qid=1495323682&sr=1-8&keywords=battery+tender

[DevMah]

I use a dual bank Marinco charger

http://www.marinco.com/en/products/convert/battery-chargers/onboards


Dev

[steeler]

Thanks, I didn't know there were dual chargers,  will be looking into them and see what I can come up with.

[Markshoreline]

When running the boat should the switch be on rather than combine?  My boat is almost never on a charger.

[steeler]

Where I have my Suzuki serviced the tech said I should run with both batteries some times to keep them both charged.

[DevMah]

Mark
Do you have a ACR?

Dev

[Tunacious]

I mounted two CTEK battery chargers into my boat.  One goes to each battery.

I also set my boat up for onshore power which is explained in the sticky that is stored in the sticky section of this section labeled ON SHORE POWER.

When my onshore power is plugged in the batteries are always being charged.

If the boat is home in my shop for the winter I unplug the chargers from the On Shore Power and can then plug them into a regular extension cord inside my shop.

It is working great.  I keep my boat moored a great deal of the time.

My experience that it is much cheaper to take care of your batteries and learn to maintain them than let them go dead, then try and revive them when you should be fishing or forced to buy new ones again.

Batteries are like babies.  You have to take care of them and feed them everyday.

[First Cabin]

When running the boat should the switch be on rather than combine?  My boat is almost never on a charger.

If you have the ACR system set up properly, you should never need to switch to "combine".  The ACR system should automatically first charge your starting battery and when it is fully charged it should then combine the second battery to charge it.  The only time you're should use "combine" is in the emergency situation when the starting battery is drained and won't start the motor on its own.

I have my fishfinders hooked up to the house battery so monitor the house battery voltage on them.  With the ACR system, I can see when the batteries combine because the voltage on the fishfinders suddenly jumps up.  I like this system because I can see that everything is working as it should.

[DevMah]

When running the boat should the switch be on rather than combine?  My boat is almost never on a charger.

If you have the ACR system set up properly, you should never need to switch to "combine".  The ACR system should automatically first charge your starting battery and when it is fully charged it should then combine the second battery to charge it. 

The ACR dose not manage which battery is charged first....this is not correct.


From Blue Seas website.
Question
Will the ACR manage my the charge of my individual battery banks?
Answer
An ACR does not direct the charge to the battery that "needs it the most" or has the lowest terminal voltage. If there is a charge present on either battery, indicated by a high enough voltage, the ACR will combine the batteries.


How does an ACR work? (Automatic Charge Relay)
An ACR senses when the voltage of either of the batteries rises to a level indicating that a charge source is active (13.0V for 2 minutes). The ACR′s contacts then connect and the ACR applies the charge to both batteries. If the voltage on both of the batteries subsequently drops to 12.75V for 30 seconds, the ACR will disconnect, isolating the batteries.

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

This issue is discussed in this post in more detail
http://www.arimaowners.com/index.php?topic=13682.0;all#lastPost


Dev

[Hydroman]

My 27' Thunder Jet OS has two 12   deep cycle batteries in parallel for cabin and dedicated starting  batteries for each engine.  The are 2 ACR's on board, one combines the two starting batteries and the other combines the starboard engine starting batteries.

I questioned this configuration with both the boat manufacturer who rigged the boat and Suzuki tech representative at time of purchase, both a sure me that is was fine and t h at it wouldn't cause harm to the batteries or to the charging circuits on either engine.

I have owned the boat for 8 years and I am just now replacing the staring batteries, I replaced the cabin deep cycle lead batteries a couple of years ago. At time of replacement of all batteries, they were still functional.

Forgot to mention that the system also has a 3500 watt inverter/charger  connected to the cabin batteries.

In observing the ACR's I  have find all batteries combined most of the time, the only exception is when the cabin batteries drop below approx. 12.2 v.

I have experienced NO problems with this setup.  Check electrolyte annually, add distilled water as needed.

Jim

[DevMah]

Here is a good article by Optima batteries on parallel charging of batteries.


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


Dev

[DevMah]

My 27' Thunder Jet OS has two 12   deep cycle batteries in parallel for cabin and dedicated starting  batteries for each engine.  The are 2 ACR's on board, one combines the two starting batteries and the other combines the starboard engine starting batteries.

I questioned this configuration with both the boat manufacturer who rigged the boat and Suzuki tech representative at time of purchase, both a sure me that is was fine and t h at it wouldn't cause harm to the batteries or to the charging circuits on either engine.

Jim
You comment dose not seem correct is it suppose to read
"2 ACR'S on board one combines both starting and the other the deep cycles"

Please clarify

Dev

[Hydroman]

Dev

Bad on my part.  One of the ACR's ties the two starting batteries together, the other combines the starboard engine battery to the cabin batteries.

As I mentioned previously, the only time that I not found both ACR's combined is when there has been heavy use of the cabinet batteries (ACR between starboard engine battery and cabin battery was off.) The starting batteries remained combined.

Jim

[DevMah]

Thanks Jim

Dev