Selecting The Right Cable Size For Your Battery Bank
Are you putting together a battery bank for an alternative energy system? Or just wondering what gauge wire to connect 12 volt batteries?
Maybe youre trying to determine the correct size of interconnecting cables between the batteries themselves and the charger / inverter.
How big should the cables be? What size? More accurately, what gauge ?
Read on or go straight to the chart at bottom of page.
I recommend getting yourself a clamp meter that measures DC current! This will help verify whats actually going through your cables! The most popular and reasonably priced clamp meter is this one
Consider The Size Of The Power Cell You Are Going To Purchase
To be able to select the right battery for your boat and your needs, you also have to make sure that you determine the right size of battery you need. We mentioned earlier that size of battery you are going to purchase would have to depend on how much power your boat needs. It means, the larger your boat is and the larger its electrical load it has, the larger size of power cell it needs to keep up with its demand. To guide you on this aspect, you can refer to the battery size section of this article above.
Power Lug Die Settings
Lets look at the settings for the 1/0 Heavy Duty Power Lug that youll see crimped later in this article. The chart shows that you pick the lug with BLACK markings and adjust the dies to E and A.
NOTE: With a 2 GA wire and a heavy duty power lug the H& H dies and pink color code are selected.
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What # Gauge Cables Are Battery Cables
You might be able to find pre-crimped cables from an auto parts store or marine chandlery. I don’t recommend crimping your own unless you have a hydraulic crimper. Ideally, one also does a destructive pull test to ensure crimp quality.Ideally, get marine tinned cable as it resists corrosion better and is flexible.
kennetht said:I have a 2013 AR190. Im going through my dewinterization process getting the boat ready for the upcoming season, and I discovered a lot of rust on my battery terminal positive wire . As you can see there is considerably more rust on the battery end, than on the perko end.
Flared Starter Lug Die Settings
These are the die settings for Starter Lugs. In the last image, for Power Lugs, a 2 GA wire took H& H/pink. Youll see here that a 1/0 wire using a Flared Starter Lug takes H& H. This is due to the smaller OD of the Flared Starter Lug as a result of the thinner walled copper used to make the lug..
That is a two whole die size difference due to the quality and raw thickness of the lug. Same wire 1/0 vs. 1/0 but two whole die settings apart. Be very careful to not to confuse flared starter lugs with true heavy duty lugs.
Once again, true heavy duty power lugs will be both color coded and die stamped. Starter lugs are flared at the end and simply marked with the wire gauge.
I personally try and use the heavy duty power lugs when I can but there are some applications where their larger and thicker form factor is a poor fit. There are good applications for both flared and heavy duty lugs. In a high vibration environment, such as an engine, the heavy duty lug is usually the better choice.
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It’s Important To Use The Right Sized Electric Cabling For Any Project Aboard Using The Wrong One Could Create A Plethora Of Problems
One of the common questions DIY boaters ask is what size wire they need when performing an electrical accessory installation. This is a good question to ask for safety as well as for performance reasons. Electrical equipment simply cannot deliver its best performance if it’s not getting enough power, and wiring too small for the task is one surefire way to ruin an otherwise neat and orderly installation and limit the capability of the equipment. From the safety side, wire too small for the job creates excessive electrical resistance. The primary side effect of excessive electrical resistance is heat, and enough heat can start a fire.
Are Battery Cables Universal
Compare the new battery cables to the old battery cables to ensure that both are the same design. Note: If the cables are universal fit, they may need to be trimmed to length and/or have the terminal ends replaced. Make sure the battery cable connection points at the vehicle are free of any rust or corrosion.
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Dc Cable Size Between Connections
How big should the cables be?
First you will need to calculate the maximum current that could flow through the various interconnecting cables before you choose the proper cable size.
Cables must be sized to carry the maximum load that the system could deliver. Undersized cables will result in overheating, and even melted connections. Worse yet, it could become a potential fire hazard.
There are three maximum DC current specifications to figure out:
1. DC Charger charging current .2. DC Load demand from the inverter .3. DC current flow within the battery bank interconnects.
Picking The Correct Battery Cable Size
RV battery cables are a small but essential part of a complex and integral system in your RV. Choosing the wrong size battery cable can lead to extra cost, frustration, and potentially even a fire.
However, picking the correct battery cable size for your system doesnt need to be stressful. Use the tips above or reach out to a Battle Born expert with any questions to help make your RV battery upgrade project a success!
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What Size Battery Cable Do I Need For My Boat
4.7/5Battery Cable Sizewouldbatteriesthesizeyourneedthethe
Keeping this in view, what size battery cables do I need?
Battery Cable Amperage Capacity Chart
| Recommended Length and Amperage for Battery Cable while maintaining a 2% or less voltage drop at 12 volts | |
|---|---|
| Battery Cable Size | |
| 29.8 ft | 9.9 ft |
One may also ask, how do you determine wire size? To calculate the gauge of stranded wire, you’ll need to double the diameter. So, if you’ve measured a wire’s diameter to be 0.005 inches , multiply this value by itself. The result will be 0.000025 in . Multiply the result by the number of strands in the wire.
Just so, what size wire should I use to wire my boat?
The ABYC recommends wire conductors of at least 16-AWG for lights and other similar equipment. That’s minimum, and heavier gauge isn’t much more expensive and generally no more trouble to install. We suggest you use 12- or 14-AWG to minimize your voltage drops, or more if the manufacturer suggests it.
What is the proper battery cable connection?
The proper battery cable connection when jumping two automotive batteries is : negative to negative / positive to positive. Connect the red cable from the car with the bad battery to the red on the good battery.
For Very Long Cables For Example
Battery cable size chart. Weight per 1000 ft. Battery Cable Amperage Capacity Chart Recommended Length and Amperage for Battery Cable while maintaining a 2 or less voltage drop at 12 volts Battery Cable Size 50 Amps 100 Amps 6 Gauge AWG 118 ft 59 ft 4 Gauge AWG 188 ft 94 ft 2 Gauge AWG 298 ft 149 ft. Cable Size AL Cable Size Cu 011.
As far as I know these values are valid as of today. For more detail though check with the National Electrical Code as well as your own zoning laws. The current drawn in the conductor can be obtained using the formula.
Single Phase Amps Three Phase Amps 15. AWG to Metric Conversion Chart AWG Number Ø Inch Ø mm Ø mm Resistance Ohmm 40 0000 0460 117 107 0000161 30 000 0410 104 850 0000203 20 00 0365 926 674 0000256 10 0 0325 825 535 0000323 1 0289 735 424 0000407 2 0258 654 336 0000513. This means if you cable length to your application is 10ft then you will look at a the 20ft options.
10 gauge works for accessory leads low power alternators and starter trigger wires 8 Gauge Buy 8 Gauge wire. Rate of Discharge When sizing a battery we must account for discharge rates in addition to total energy Larger nominal capacity required for higher discharge rates For example consider a cell with the following constant-current discharge data for a minimum cell voltage of 18 V Discharge Time hr. 4Find Your Correct Cable Size.
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Cable Size Ampacity Chart
The following maximum amps versus cable size come from the NEC version 2011. As far as I know these values are valid as of today. For more detail though, check with the National Electrical Code as well as your own zoning laws.
Note: I would NEVER design interconnecting cable size anywhere near its maximum amps! Thats too hot for me! Heat loss equals efficiency loss! Give yourself a wide margin.
Copper Conductor Ampacity based on 75°C reference Cable Types: RHW, THHW, THW, THWN, XHHW, USE, ZW
| Cable Size |
Sizing For Ac Circuits
Because AC circuit wire sizing is a bit simpler than DC, we’ll start there. Again, with AC, our primary concern is heat buildup as cables get routed through your boat. Sizing of individual conductors is based on three things: how much amperage the circuit is going to have running through it, whether the cable is routed through a hot engine room space, and the temperature rating for the cable insulation. An additional concern is when multiple cables are bundled together, which increases the potential for even more heat.
Cables are rated for their insulation temperature rating how much heat they can tolerate. This rating is particularly important for AC cable routed through engine room spaces.
AC wiring is primarily what we call “triplex” and sometimes “four-conductor” cable. The green grounding conductor is not counted when considering bundle size. You only need to count normal current-carrying conductors. So a single piece of triplex cable has two current carrying conductors: the hot wire and the neutral, or the black and white wires. In the case of 240-volt four-conductor cable, there are going to be three current-carrying wires per cable: two hot wires and a neutral. Again, the green grounding wire does not get counted.
Wiring that is too small for the job can generate significant, dangerous heat.
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Various Marine Connectors And Adaptors
One of the biggest things to remember is that your terminal size must match up with your cable size and the connector that you are using. With that in mind, you may want to choose a that has pegs and wing nuts to keep your cables securely attached to the battery. Whether you opt to cover them with plastic or not, you do have options when it comes to how well it will fit onto your battery. In order to help you see some of the connector options, you may want to take a look at the battery terminals below.
This terminal kit is designed to help you convert a car battery and make it ready for marine use. It has standard lead terminals and plastic coated wing nuts. These terminals are suitable for both 12 and 24 volt applications.
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Schumacher BAF-MT1 Terminal Ends
These terminal connectors are zinc plated and fits either a 3/8 inch or a 5/16-inch terminal post. The fact that it is zinc plated gives you three times more conductivity. This increases the power the battery can put out to your equipment.
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This clamp easily attaches to a 3/8 stud and connects or disconnects easily thanks to the wingnut. It is rust resistant and zinc galvanized. The tension bolt is made of steel which ensures to be a good conductor of power.
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What Size Cable Do I Recommend
#4 wire gauge makes great accessory leads and alternator wiring. Many new sub-compacts use this as battery cable.
Use #2 wire for 4 cylinder and small 6 cylinder automotive engines, hi-power accessories , golf cart battery banks and tow truck jumper cable kits.
1/0 makes great battery cable for large or hi-performance 6 cylinder engines and small V8s.
Use 2/0 for hard to crank engines , electric vehicle battery banks , and large RV power converters.
3/0 and 4/0 are for very large marine or heavy equipment engines and high power alternative energy battery banks.
For very long cables go one size larger.
Please note: You can probably get by using a size or maybe even two sizes smaller than what I am recommending. HEy, the factory does. They make the cables as small as possible but still get the job done. Copper is expensive.. if the manufacturer saves a few bucks on millions of cars..pretty soon it adds up to real money. I recommend using cables larger than the factory because I believe they will work better and last longer. Isnt that what you want for your car or truck? Something that will work better and last longer.
Just how big is that 2/0 cable? Check out the Wire Gauge Chart.
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/0 Lug In The 1/0 Die
Here we go, this picture is an HFT 1/0 labeled die with a 1/0 lug in it. Yeah, that fits.
The lugs used in this demonstration were all starter lugs or the smallest OD lugs that will fit over 1/0, 2GA or 4GA wire. These were not the heavy duty power lugs.
The heavy duty lugs are considerably larger, OD wise. In fact a 1/0 heavy duty lug will not even fit between the jaws of this crimp tool when wide open.
Should Ac And Dc Grounds Be Connected On A Boat
On a boat, things are considerably more complicated. In addition to the AC ground, we need a DC ground or return line, a lightning ground, and a RF ground plane for the radio systems. The boats electrical system should be connected to seawater at one point only, via the engine negative terminal or its bus.
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Different Types Of Battery Chemistry
Now that you are familiar with the different types of batteries available in the market, this is the time to learn about the different types of battery chemistry. Which is another crucial aspect in choosing the right type of battery that can keep with the needs of your boat. To be familiar with this different battery chemistry, refer to the list below:
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Can 10 Gauge Wire Handle 40 Amps
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| NM, TW, & UF WIRE | SE CABLE |
|---|
Can I Mix 12 Gauge And 14 Gauge Wire
More specifically, can you connect 14-gauge wire to 12-gauge wire? While this is possible, it is not recommended in order to prevent overloading. For example, if the amp capacity of your breaker is 20 amps, you should only use 12-gauge wire, and if its 15 amps, the entire circuit should be 14-gauge.
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It Makes A Beautiful Lug
Again here is a positive battery cable & lug made with the rotate method so all corners are nicely rounded. You can see how it physically reduces the OD of the lug.
NOTE: This tool makes such a perfectly crimped lug that when I experimented and tried to also solder one, after crimping, no solder would flow beyond the first crimp band. This crimp tool makes a completely water tight and solder tight joint. In the aerospace industry they refer to this as a gas tight crimp.
Determine The Needs Of Your Boat
If you are trying to find the right suitable power cell for your boat, you first have to determine the entire electrical load of your boat and the current that it needs to start its engine. As we mentioned above, your marine battery will have to handle two tasks. Starting your boats engine and running its entire electrical grid. If you have an estimated value of these two things, then you will have an idea of what kind of battery you need to handle these two crucial tasks.
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Benefits Of Learning How To Recondition A Battery
After equipping yourself with all the information that you need that will help you pick the best suitable marine battery for your boat. It is important to remember that at some point, the perfect power cell you purchased will eventually die. With this, the most affordable option you have is to attempt to revive it or recondition it, which is a lot cheaper compared to purchasing a new replacement battery.
Availing this service can also be pricey, but doing by yourself will be a lot cheaper. So it is very beneficial for you if you can learn how to carry the process of battery reconditioning.
