house batteries not charging

[dreamer*65]

My house batteries charge while on shore power, but drain after about an hour while underway causing a low voltage alarm and my Garmin autopilot to stop functioning. Do I need to replace the batteries or is this a bigger problem with the charger, etc. The batteries I believe are the originals in the 2013 R 27 I purchased a couple of years ago.

 

[iggy]

Break out your meter and take some voltage readings. Depending on what you find, I would do a load test on each battery.

With out testing the voltage, you don't know if the charger is really working. Plus do a test with the engine running to see if the ALT is putting out too. If both are good, than a load test.

Also see if the ARC is closing.

 

[dreamer*65]

If one of the house batteries (7 years old) is going bad, should I replace both? Do I need to replace the engine and thruster batteries as well?

 

[BB marine]

My guess is your house batteries are bad. The 120V charger is wired directly to the House batteries in the R27. When the charger is on the charge goes to house batteries first and when the batteries reach 13V or higher for 90 seconds the ACR close and the two other banks get a charge. If you have one battery in the bank that is bad but the other battery takes a charge the bank will only retain that charge for a short time. When you leave the dock and rely on the engine to charge the batteries The engine battery bank is the first to except charge. Once the engine battery reaches 13Volts for approximately 90 seconds the ACR will close and link the banks together. If the house batteries are low in charge now say 12.3 volts and the engine battery is at 13V when the ACR closes this can pull the Voltages down far enough (12.75) if it stays this low for approx. 30 seconds it will cause the ACR to open. Now the house battery has no charge to it the refrigerator, electronics, and any other 12V users will continue to drop the voltage in the house bank. Once the engine battery reaches 13V again the same process happens again. Eventually the house battery gets low enough that it will set off low voltage alarm. The ACR continue to cycle close and open.

If you have original batteries on board I would replace all of them together. Replace with the same chemistry same AH and preferably the same manufacture.

 

[dreamer*65]

Brian, thanks! That is EXACTLY what has been happening. If I can't find original manufacture brand, is it okay to just match chemistry and AH for the four new batteries? And is the replacement job doable for a 68 year old electronics novice of average intelligence 😉

 

[CaspersCruiser]

Brian, thanks! That is EXACTLY what has been happening. If I can't find original manufacture brand, is it okay to just match chemistry and AH for the four new batteries? And is the replacement job doable for a 68 year old electronics novice of average intelligence 😉

The four new batteries need to be same chemistry, i.e., flooded or AGM, and the battery charger needs to be set for the chemistry of the batteries you choose.

Replacing the batteries is not hard physical labor, but there are a TON of connections that have to be properly unmade and then remade. My advice is to photograph the wiring as best you can before starting the job and then use white electrical tape and a Sharpie pen to label each wire as it is removed with where it goes to facilitate connecting the new batteries when they are in place. Take your time!

 

[BB marine]

Brian, thanks! That is EXACTLY what has been happening. If I can't find original manufacture brand, is it okay to just match chemistry and AH for the four new batteries? And is the replacement job doable for a 68 year old electronics novice of average intelligence 😉

Completely doable. I recommend removing battery terminal connections one at a time use a cable tie to keep them together. Mark the battery house (1) house (2) Thruster and engine. Take a few pictures of the install before you start for a reference. Remove the batteries. If they are AGM they may be heavy 60 + lbs. Reinstall the same way you're removed. take your time and make sure all connections are clean and tight.

The manufacture of the battery doesn't matter. I like to install all matching manufactures and chemistry along with same AH. The original battery manufactures doesn't matter unless you wanted to use the same brand again. My original batteries were maintenance free manufactured by Centennial, I installed NorthStar AGM. I just had to change the the charger charging profile from maintenance free to AGM. Replacing batteries is easy to do if you take the time to mark the locations of the battery leads to the proper terminal and keep them together as removed.

 

[scross]

Follow Brian’s advice and you can’t go wrong. Make sure all the rotary switches are off for house, thruster and engine before starting work.
I treat all battery cables and connections as if they were “hot” all the time. That’s probably being way too cautious but it gives me peace of mind when working on them.
Also, I wrap a bit of different colored electrical tape on the cables and wires for each terminal I’m working on. So the house positive cables get red tape, the thruster positive gets green, etc., etc. And take photos after taping like Brian recommends.

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Use dielectric grease on the cable and wire ends at the battery terminals when you are done to prevent corrosion.
Shouldn’t take much more than an hour or two to get it all done.

 

[Cutwater28GG]

also unplug shore power while you are at it.

 

[dreamer*65]

Thanks all. For over three years all I have ever had to do was ask. I was involved in a serious car crash (my SUV totaled) a month ago while on a trip to save my 71 year old sister from Phoenix covid and bring her back to Duluth for the summer, and have a bit of herniated disk as a result, but am waiting patiently to replace (lift) those batteries and get back on the water. Nothing better than owning a Ranger Tugs/Cutwater A pretty good family . . . Best to all you Tugnuts!

 

[Irish Mist]

Sorry to hear about your crash... If you are replacing all the batteries make sure to get all the same manufacture dates.. Sometimes they will slip in a year old one. Take your time and as others said mark the cables . A simple diagram numbering the terminals keeps things straight in your head.. mine anyways. They are heavy so help from vehicle to boat is nice. Good luck