Install a battery switch so that you can keep one battery charged at all times for starting the boat while you drain the battery for entertainment or navigational purposes. Attach the existing house battery to the new addition by connecting neutral port to positive port. A series does not give longer battery life, but lets you plug in more appliances and other electrical equipment. On most boats, DC power is distributed via some sort of master switch panel or panels.

Averaged Voltage, Averaged Cranking Current, Duration of Start  (Loaded to Unloaded), Circuit Resistance

As it takes longer for the weaker batteries to charge the other batteries will start to get overcharged. This is the point when you can start to bring a whole pack down, with even one battery in a bank starting to get overcharged, and in the end damaged from overcharging. I have a 48v inverter solar system with 8 102ah 12v deep cycle batteries connected 4 in series and both strings parallel. What is the best to connect such 16 batteries with max capacity. Optimal charging is 10% of the amp/hour of your battery pack.

Protecting the Alternator from a BMS Disconnect (LOAD DUMP):

Cables should have “marine cable” stamped on the insulation. Size 2/0 cable handles most outboards and gasoline inboards. Connect the positive terminals of batteries 1 and 2 to the corresponding posts on the back of the Hiki browse switch, and then connect the positive cable from the engine to the output post of the switch. Also connect the positive accessory wire to the output post. Wiring a dual battery switch is one of the easiest chores.

Batteries in Series and Parallel Revisited

For newcomers to marine electricity, though, what you really need to be aware of is the importance of matching your boat’s charging system to the needs of your battery. The diagram below is one that works well when an owner desires a dedicated starting battery but also want to retain the flexibility & isolation of the 1/2/BOTH switch. An expensive scenario is that happens all too often, is when an owner has forgotten to switch off of BOTH and killed both banks. Doing this leaves no second / reserve battery to start the motor with. You’d be surprised how many calls we get each year for this exact issue. This article is only intended to showcase how the 1/2/BOTH switch can be used in an easier and often less confusing manner.

A voltage setting, usually programmed using the float voltage settings on a lead acid charger. This voltage should be one that results in the battery discharging to just below the full charge point of the battery or 90% SoC to 98% SoC, an being held there. Just like over charging over discharging can actually result in a polarity reversal and destruction of the cells.

Voltage for SoC is pretty much meaningless, for most owners, with LFP, unless at the top or bottom. You really don’t want to float LFP, in a lead acid manner, so, unlearn float. Get out of the habit of routinely charging to full, it’s just not necessary, like it is with lead acid. Just put in the energy you need for the next day or two and stop.

It really wouldn’t be recommend, as you would start to unbalance the battery pack, which could later result in a battery getting overcharged. If this happens too often the battery could fail and bring down the whole pack. If you are putting a battery in parallel it is then one battery pack. So, you would only need one gauge, and the gauge would need to be the system voltage of the battery pack.

How to Fix Your Marine Toilet

So I am here to put all those experiences into good use for other boaters who want to have a safe and fun trip with their friends and families. While joining two batteries, ground both of them in the same engine’s common ground. After finishing the preparation, it is important to examine the following factors before practicing the installation.

Some can be flush-mounted for a cleaner look above decks, but make sure it’s protected from spray. Hold off on final installation until after you have connected the positive cables to the posts in the back. Installation should comply with Coast Guard and ABYC standards. Wet-cell batteries should be secured in a battery box. Both need tie-downs or brackets, and the positive terminals should be covered with nonconductive boots. Please visit the US Coast Guard website for more information about safety standards.

Once the terminals are clean, you can start connecting the battery. If you’re not sure which terminal is which, most batteries will have a label that indicates which is positive and which is negative. Once you’ve got the right terminal, simply attach the corresponding cable .

You can see it just under the switches facing the camera smothered in good old vaso. You can also see the 3white fuses in the charging circuit in the photo. A lawyer by training, for most of his career Tom has been an editor and columnist at national magazines such as Cruising World, PassageMaker, and Soundings. He wrote the acclaimed memoir All In The Same Boat , as well as Chesapeake Bay Cruising Guide, Vol. These days, Tom and his wife Mel enjoy cruising their 2006 Camano 41 Chez Nous with their grandchildren.