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I did this exact thing to my RC trailer, and have a solar panel to keep the better topped when not using it during the summer (since the panel is not large enough for the short winter days), and have it hooked up with a 7 pin. I tapped into the 4 pin, which has a cover to prevent shorts, and extended the 12+ into the trailer and attached it to a fuse block with a 30 Amp fuse, then to the positive post of the battery. This protects the harness in case of a short on the 7 pin. I then have a fuse block for interior lights, and the 1500 watt inverter.
The red/yellow is the 30 AMP fuse from the truck. the Blue box is the charging unit from the solar panel. I had to replace the batter with an AGM because the solar panel I had prior to this did not have the charging unit and overcharged the battery, essentially killing a cell, hence the 9.6 volt readout.
How big of a battery is required to run a few LEDs? I haven't looked at it yet, but my trailer has a small battery for emergency breakaway braking. So it's supposedly already hooked up to the plug to the truck. I'm guessing I could jyst switch the wire to the lights to the small battery. Obviously, if I kill the battery, I wouldn't have emergency braking. But if it works, I could always swap out to a bigger trailer battery. I was thinking just one or two I of those flexible strip lights a few get long each. I have 2 dome lights now, but they are incandescent, and hang a few inches low. I already hit one loading cargo in with a hand truck.
How big of a battery is required to run a few LEDs?
Depends how much current the LEDs draw, and how long you want to run them between charges (driving the truck). Most batteries have a "reserve capacity" rating, or a mAh (milliAmp-hour) rating that describes how much energy is stored in the battery. Bigger numbers will run more lights, or the same lights for more time.
For example: if you have a grand total of 5A (5,000 mA) of load on the battery (including lights of any kind), and the battery stores 50 Ah (50,000 mAh), then you'd expect the load to run roughly (50/5=) 10 hours before killing the battery.
Reserve Capacity is a little harder to explain, but it refers to a standardized load size at a particular temperature, and a minimum voltage. Read more here: http://www.batteryfaq.org/
Our original idea was to mount a smaller/mid-size deep cycle battery in the V nose of the trailer (inside as there's not enough room on the tongue to mount on the outside cleanly).
Remember a mid-size deep cycle battery is a 30+ lb object; secure it appropriately - you wouldn't want an 8.5 x 11 dent in your tailgate after I accidentally cut you off in my concrete truck and the battery continued at 55mph even after you hammered on the brakes.
2nd lead acid batteries create hydrogen gas when charging & discharging, so should be outside, in a vented environment or use a sealed battery.
Remember a mid-size deep cycle battery is a 30+ lb object; secure it appropriately - you wouldn't want an 8.5 x 11 dent in your tailgate after I accidentally cut you off in my concrete truck and the battery continued at 55mph even after you hammered on the brakes.
2nd lead acid batteries create hydrogen gas when charging & discharging, so should be outside, in a vented environment or use a sealed battery.
Reason why I went with the more expensive AGM. No fumes. A battery box screwed down the the floor secures the battery.
That little battery for the break-away should not be used for anything other than its intended purpose. Also you should check it at least twice a year as they can discharge over time and die.
AGM batteries use exactly the same chemistry as flooded-cell Lead-acid batteries, and produce the same fumes. Their cases ARE vented; usually through the felt disc on top. Only SLA batteries (sealed Lead-acid) are actually sealed, but they're flooded cells.
A battery is a battery; the fact that the trailer was built with nothing more than brakes connected to the battery doesn't mean the battery can't be connected to other things, as long as it remains charged by the tow vehicle. If yours isn't, connect it so it is. You CAN connect several batteries in parallel on the trailer to the truck's charging circuit. Just make sure they're close to fully-charged before plugging up the trailer, or their combined draw may exceed the truck's wiring's capacity, and blow the truck's trailer charge fuse (usually ~30A on Fords).
I built a little device for my truck to prevent that. So if I'm towing a trailer with a stone-dead battery or heavy load (one that's trying to draw <30A), it won't blow my truck's fuse. It will just keep supplying up to 30A until the load drops, or I unplug.
AGM's do produce hydrogen gas just like a flooded battery BUT at a significantly reduced rate. The batteries in my 5th wheel (RV) are in an externally vented box but I still was experiencing quite a bit of terminal corrosion inside the box. After switching to AGM's the corrosion is almost non-existent.
To avoid confusion, Sealed AGM do not gas when being charged, but they are equipped with VRLA.
www.victronenergy.com 1. VRLA technology VRLA stands for Valve Regulated Lead Acid, which means that the batteries are sealed. Gas will escape through the safety valves only in case of overcharging or cell failure. VRLA batteries are maintenance free for life.
...I still was experiencing quite a bit of terminal corrosion inside the box. After switching to AGM's the corrosion is almost non-existent.
Hydrogen is not corrosive. It's only highly-flammable. Corrosion comes from acid leaking out of the case around the battery terminals. Cheap batteries are more-likely to leak & corrode than expensive ones, but it's a possibility for all.
Originally Posted by acdii
To avoid confusion, Sealed AGM do not gas...
Maybe your understanding of the word "sealed" differs from mine. If something has a valve that can open & allow material to move from inside to outside (or vice versa), it's not "sealed" IMO. It's "usually closed, but able to open". Optimas are not sealed. They've gone from having a single visible vent on top (years ago) to having 2 smaller vents on the sides where you may not notice them. But they're still (& always will be) vented.
In any case: they have worse performance, worse warranty (with more fine-print exclusions), and higher cost than a top-quality flooded battery like MC TTM.
Steve, I enjoy your posts; you're a very knowledgeable guy. I wanted to pick your brain for a suitable differential for my 2-wheel-drive F150, but that's another topic.
One small point I might make regarding a true AGM battery is that they are known as VRLA (Valve Regulated Lead Acid). The relief valves are there only! in case the battery is somehow overcharged (rarely possible with any microprocessor-controlled "smart" chargers) they will vent excess pressure. Otherwise, an AGM *is* effectively sealed, and can be installed in a non-vented space, and in nearly any orientation. Optima, for example, used to claim their battery could be mounted upside down... these days, makers of quality AGM batteries claim they can be mounted in any orientation except upside down, fwiw.
I use an Odyssey 100 amp-hour AGM (a Group 31) in a small camp trailer to power an Engel fridge and a small, 100-watt inverter for things such as a laptop power supply, cellphone charger, etc, and for trailer interior 12V lighting. I charge this battery with either one of two chargers: an Odyssey OMAX-50A-1B when parked or with one or two 100W monocrystalline photovoltaic panels, 10AWG to a Morningstar SunSaver MPPT charge controller with a 20" run of 8AWG to the battery. Works quite well.
01-16-2018, 05:22 PM
