Battery or batteries

[shasta24]

Im getting ready to istall a battery or 2 on my trailer. Im not for sure what size of fuse I need to install just after the battery. My converter is 45 amp. And I was wondering how important it was to have a shut off switch for the batteries. Thanks for your help, and any pictures you can share.

[Bucky_Badger]

tenbear wrote:
Trailers have a break away emergency brake wired off the battery. You should not place the battery cut off switch where the voltage to this emergency brake is cut off. That precludes putting the cut off in the negative lead.

Mine is on the Negative, as long as the switch is on during travel, no worries

[tenbear]

Trailers have a break away emergency brake wired off the battery. You should not place the battery cut off switch where the voltage to this emergency brake is cut off. That precludes putting the cut off in the negative lead.

Your 45 amp converter may not supply 45 amps to the batteries. If it is a 3 stage converter, such as the Progressive Dynamics converters it could. If it is the older Parallax or Magnetek it will not charge your batteries at 45 amps since the voltage is limited to 13.8v.

[2oldman]

shasta24 wrote:
I was told by an rv pro to put the cut off switch on the negative side so it doesn't spark. Does this make sense?

What makes even more sense is to ensure there's no big draw on the batteries when you throw that switch.

[westend]

shasta24 wrote:
I was told by an rv pro to put the cut off switch on the negative side so it doesn't spark. Does this make sense?

Either location, (-) or (+) will interrupt the circuit. A spark might happen on either polarity, it shouldn't be an issue as long as you have the battery box free of fumes.

You could also switch all of the parasitic draw devices inside. It's a pretty good bit of work so I wouldn't do it because of the small current of the spark. If everything is turned off and not drawing any electricity, the amount of spark is only that created by the different voltages between two batteries or the momentary tiny milliamp draw when connecting just one.

[pianotuna]

Hi,

The cut off switch will spark equally on either "side". Mine is from Napa auto and is 100 amps contacting and 1000 amps continuous. All for only $5.95!

shasta24 wrote:
I was told by an rv pro to put the cut off switch on the negative side so it doesn't spark. Does this make sense?

[shasta24]

I was told by an rv pro to put the cut off switch on the negative side so it doesn't spark. Does this make sense?

[OhhWell]

2 GC6 batteries wired in series will get you about 220Ah rated capacity. Common wisdom is that you should not drop below 50% capacity if you can help it.

[ksg5000]

Go with 2 - a second battery doesn't cost that much and stuff happens - it's nice to know you can survive a few days in comfort without having hookup.

[2oldman]

Depends on your camping style.

[RoyB]

Keep in mind that the fuse or circuit breaker you are talking about is there to protect the battery cables from short circuit. Your batteries can probably produce a couple hundred AMPS for a short period of time and of course your 45 AMP Converter/charger can produce 45AMPS of DC current.

I have three batteries in my battery bank and when I am using my PD9260C 60AMP smart mode converter/charger in charge mode I will see around 52-53AMPS being drawn by the battery for the first 15-20 minutes of the initial charge cycle.

I would think you should have a fuse or circuit breaker rated at the highest output of your converter/charger unit. In your case higher than 45 AMPS.

We do alot of camping off the power grid and I would say a minimum battery capacity should be around 220AHs. This would require a couple of batteries at a minimum in my thinking.

You may want to add a 300-400WATT PURE SINE WAVE Inverter down the road to run your home entertainment items and cell phone and computer chargers etc. Once you start doing this you most likely will want to run some other low wattage items from the INVERTER. Inverters love large battery capacity...

We get by very successful using our 255AH battery capacity but do have to recharge every day at 8AM during breakfast when allowed to run my 2KW Honda generator at most campgrounds. Once the battery bank is back up to its 90% charge state than we can do this all over again for the next day/night run off the batteries.

Just my thoughts...
Roy Ken

[Oasisbob]

If you never camp without hook ups one battery is fine. We dry camp often and can go 3-4 nights watching a movie every night on our TV running through a power converter. We use twin group 27 deep cycles bought at Costco. All depends on your style of camping. A cut off switch is great for several reasons. I use a simple push pull switch mounted atlo the battery box.

[westend]

The fuse should be sized to protect the wires from the batteries to the 12V distribution panel.

A battery master disconnect switch should be installed in every RV, IMO. Most newer RV's have parasitic draw that is drawing down the battery 24/7. Those devices are things like alarms, circuit boards, radio and TV memory/standby, etc. It's a good idea to wire the emergency brake power lead bypassing the switch. If you forget to select the "on" position before hitting the road, the E-brakes will still work.

[the_bear_II]

Go with two batteries
Use at least a 30 Amp circuit breaker instead of a fuse. You can get the circuit breaker at auto parts stores.
A cutoff switch is a good idea. When storing the trailer the cutoff will prevent parasitic draw from some appliances to run down your batteries.