Battery charging

[Rick Templeton]

I have an inverter/charger that's got some issues with an internal relay/contractor. I need to remove it from the boat and take it in for repairs.

The system has one 12 volt battery for the starter/motor and 4 6volt in series for the house. They are tied into a combiner. It appears to me that I should connect a maintainer to the 12 volt starter and let the combiner engage to charge the 6volt side. Anyone have any experience with this ? Would appreciate any help.

Thanks

 

[JohnShannon]

? 4 six volt in series = 24V ? 2s2p would be 12V more likely. What is your worry? You have only one maintainer and how to deploy it?

 

[Rick Templeton]

Maybe I used the wrong term. The proper terms should be two sets of two in series and then connected those in parallel as you suggested. My concern is connecting the charger improperly and sending 12 volts into a 6 volt battery and having an early 4th of July? Not even sure what would happen , I just want to connect it properly to avoid any other damage. Figured it would be safe to connect to the 12 v side. Do you have experience with this? Will the combiner work under these conditions and charge the house side ok?

 

[JohnShannon]

So both sides of the combiner are at 12V right? On one side you have a 12V start battery, on the other side you have 4 6 volt batteries connected in a 2 parallel strings of 2 each but in total forming a large 12V battery. Combining and charging both sets with one charger should work OK. Are all the batteries the same technology? Like all AGM or all flooded? Is this just to get you by until your inverter is repaired? For a short time you could probably just disconnect your start battery and leave the charger on the house bank. Which represents the most $$$.

 

[Rick Templeton]

You got it. I just want to keep them (all AGM) in a decent state until the charger can be reinstalled. One parallel on each side of the aft of the boat. Figured if I could connect to the 12v I could keep the charger/maintainer all under the starboard settee. Just wanted to make sure the combiner would kick in and keep the house side charged. If not ,would connecting the charger to the parallel pair on the starboard side pos to bat1, neg to batt2 keep both sets of parallel up?

 

[Stu Jackson]

Put the charger to the house bank and let the combiner do its job. Done.

 

[Rick Templeton]

Please see the previous posts, the question is how to connect the charger

 

[Head Sail]

+1 for Stu. Your combiner will charge both sides when it detects a charge is present.

 

[JamesG161]

Since without an inverter you have no onboard use of 120VAC and if you are 12VDC powered down, why use a charger at all? How many months to fix your IC? Your temporary charger should be a "smart" charger if you leave it unattended.
Before going to sea, put your charger on a few hours before setting sail, to top them off.
Jim...

 

[Maine Sail]

Please see the previous posts, the question is how to connect the charger

Your house bank has 12V connection points, where the inverter and DC system takes offs are. Connect your charger to the house bank or the ACR relay may simply cycle on/off if placed on the start battery when using a trickle charge.. If the trickle charger can maintain the house bank at 13.0V+ then the ACR will combine and both banks will get charged.

 

[Rick Templeton]

We do not live in California where the boat is slipped. I want to leave a charger on the battery bank so we can leave the refer on and assure there is 12v to the bilge if necessary. Plus I am not sure how long the repair of the inverter will take and we use the boat every couple of weeks and would like to continue using the lights, fans, etcc while we are there in the slip. I purchased a dedicated smart charger that will remain on the boat attached to the shore power. It varies fron 0 to 30 amps depending on the state and need of the bank. It will be disconnected when we sail and reconnected on return to the slip.

Now I would like to get to the original question. I have 2 sides to the system. The motor has a single 27 12v for the starter, and the house has 4. 6v with 2 on each side of the boat wired in series, and each side joined in parallel to form one large 12v bank. They are all AGM batteries, and they are interconnected with a combiner. Originally I thought it would be best to connect the charger to the single 12v but was not sure it would work with the combiner to keep the house side topped off. It sounds like everyone is in agreement that the combiner will work under theses circumstances. Johns suggestion to connect the charger to the house bank since it is the most $$$. Is probably sound. Stu backs it up but now the question is how to connect the 12v charger to the bank made up of 6 v batteries. As mentioned earlier there are 2 sets of 2 on opposite sides of the boat. If I connect the charger to the bank on the starboard side with the pos of the charger to pos of bat 1 and neg of charger to neg of bat 2 , will it charge that side as well as the port 6v bank and the starter side through the combiner?

 

[Rick Templeton]

Sorry Maine Sail, your post did not show up on my screen this morning when I made my last post. Your statement is exactly what I was looking for and makes sense. I will connect the charger to those points and monitor the state of charge to see if it takes the charge to 13.
Thanks for your input.
Also thanks to all who responded. I will let you know how it works out.

 

[Benny17441]

I have only one comment to add; since the boat will be unattended it would be prudent to insure the charging leads from the charger are securely connected (hardwired) to the battery system.

 

[Rick Templeton]

As promised I would like to update anyone interested in this thread.

I went ahead and removed the inverter/charger last weekend and I connected the smart charger to the positive and negative terminals that used to lead to the inverter unit. It appears that the entire bank charged somewhat but it never seemed to get up to a full state of charge as I had hoped. Not sure exactly why, but I felt uncomfortable leaving it connected.

Worked out ok though. Magnum service was able to diagnose and repair the unit while I waited. Magnum even picked up the bill under warranty 100%(after 2 years). If you are in the market Magnum really stepped up, I wouldn't hesitate to buy their products (Coast RV, Augora Hills)

Thanks for your comments and help!