Best way to charge parallel batteries.

[SoonerCamper]

Bringing my Pinnacle home from storage for the winter. Has 3 12volt batteries in parallel. What is best way to charge? Each battery individual? Or where the positive and negative connect to the trailer? Any need to unhook anything? Should I be plugged into shore power when charging?

[Mopar_Earl]

Let the charger converter charge them.


Earl

[GrumpyDad]

Charge them together unless you have some reason to suspect one is bad.

[rodro123]

Yes the campers charger will charge all 3. Fill with water after charging not before.

Watering is the single most important step in maintaining a flooded lead acid battery; a requirement that is all too often neglected. The frequency of watering depends on usage, charge method and operating temperature. Over-charging also leads to water consumption.

A new battery should be checked every few weeks to estimate the watering requirement. This assures that the top of the plates are never exposed. A naked plate will sustain irreversible damage through oxidation, leading to reduced capacity and lower performance.

If low on electrolyte, immediately fill the battery with distilled or de-ionized water. Do not fill to the correct level before charging as this could cause an overflow during charging. Always top up to the desired level after charging.

[RoyBraddy]

I have one of those clamp on DC AMPMETERs from Sears. When charging my multiple batteries from a single Converter/Charger (My PD9260C) I like to occasionally like to clamp around each 4AWG cable that is directly feeding one of the multiple batteries and compare that to the other single battery leads. What you want to see is they are all reading around the same DC AMPS when being charged.

This will tell you something about the batteries internal resistance starting to change on you. If all of the batteries are close in age and charge state then all should re-charge about the same DC Current. When one battery starts giving strange readings you really should pull it out of the multiple connection loop and charge it by itself.

My three 12V batteries show around 53AMP DC Current when my re-charge cycle first starts up with around 60AMPS DC Current available to use when I am reading around 12.0VDC from the depleted battery bank. When I look at each cable feeding the POSITIVE cable of each of the three batteries I see two of them is at 17AMPS DC current and one is at 18AMPS Dc Current. If these numbers get way apart I would want to pull the battery connections of the one that is showing way more or way less DC Current... My setup is using the BLUE SEA Battery switches feeding all of my battery connections. Easy to switch things around...


Roy's image

I started out with four 12VDC batteries in my battery bank and I lost one of them right away (about three months of use camping OFF-GRID) from boiling out its fluids during the un-monitored charge periods. After losing one I started watching them more closely and my three remaining 12VDC Interstate battery finally just stopped holding their charge in early 2017. These were originally installed in 2008 when I purchased my Starcraft R/T14 Off-Road Popup...

Roy's image

I have this DC BATTERY Power meter panel setup on the inside of my camper where I can watch the various DC Voltages and main DC current.




Roy's images

This is what I do at any rate and it works good for me ... I'm sure others have their own method of watching things...

Roy Ken