An LQ trailer lives two lives. Up front it is an RV, with a fridge, lights, a water pump and usually a television. Underneath it is a heavy gooseneck that hauls a ton of horse to a show and then parks in a field for three weeks.
Both halves get neglected the same way, and the search results do not help. The page that ranks first for living quarters upgrades lists slide-outs, awnings and horse cameras, and says nothing about power, axles or brakes. The page that ranks first for LQ lithium belongs to a company that sells the batteries. Here is the version with the part numbers in it.
The battery and the converter
Most LQ trailers leave the factory with a pair of flooded lead-acid batteries and a converter. The converter is an AC to DC power supply. When you are plugged in, it runs the 12 volt loads and pushes a charge back into the battery.
Two complaints repeat on the horse trailer boards. Owners report batteries that boil over after being left plugged in for weeks, and owners report lights going dim and the pump stuttering by the second night of a show. Those are two ends of one problem. A basic converter holds a single output voltage forever, and a pair of flooded batteries gives you roughly half of its rated capacity before you start shortening its life.
Lithium iron phosphate fixes the second complaint and changes the first. It gives you nearly all of its rated amp hours, it does not mind sitting part charged, and it weighs a fraction of the same capacity in lead. Our 12V 280Ah LiFePO4 is listed with Bluetooth and low temperature protection, which matters if the trailer winters somewhere that freezes.
Sort the charging before you buy the battery. LiFePO4 needs roughly 14.2 to 14.6 volts to reach full. A converter that sits at a fixed float voltage will run your 12 volt loads happily and never finish the job. Three ways out:
- Replace the converter with a unit that has a lithium profile.
- Leave the converter running the 12 volt loads and add a smart AC charger set to lithium.
- Fit an inverter and charger in one box, such as the MultiPlus-II, which charges the bank properly and gives you 120 volt output from it as well.
We do not stock a replacement converter. If you want one, that is a parts-counter conversation rather than an add-to-cart, and our converter upgrade guide sets out what to look for.
An inverter in the living quarters
An inverter turns battery power into 120 volts for the outlets. In an LQ that usually means the coffee maker, the microwave, clippers and chargers. Two rules keep people out of trouble.
First, size it to the largest thing you will run, then check the battery can feed it. A big inverter on a small bank simply shuts down under load. Second, treat the roof air conditioner as a separate project. It is a far larger load than everything else combined, and the only honest way to plan for it is to measure your own unit and size the bank from that number. Our inverter sizing guide walks through the arithmetic.
Charging while you are hauling
The 12 volt feed in the truck's 7-pin was designed to keep a breakaway battery topped up. It will not meaningfully charge a lithium bank, because the voltage it delivers at the trailer is often lower than the battery's own resting voltage. The fix is a DC-DC charger mounted near the battery, such as the Orion XS. It takes whatever arrives, boosts it, and charges the bank on a proper profile while you drive.
Set its input current limit below the fuse that protects the truck's charge circuit, and use its engine detection so it does not drain the truck overnight. The full version of this, with the fuse ratings for Ram, Ford and GM, is in our 7-pin charging guide.
Solar for the weeks it sits
Between shows the trailer does nothing, and that is when a stock system quietly flattens itself. A panel and a SmartSolar MPPT 100/30 or 100/50 keeps the bank full in the field with nothing plugged in.
Put a SmartShunt on the negative lead while you are in there. Lithium voltage tells you almost nothing about state of charge, and the shunt turns "I think we are fine" into a number on your phone.
Fuse the battery properly. A MEGA fuse in its holder covers the inverter and distribution feeds. On a large lithium bank the main battery fuse needs an interrupt rating to match, which our fuse sizing guide explains.
Underneath: the running gear
A horse trailer has a bearing problem that has nothing to do with mileage. It sits for weeks, then does a hundred loaded miles, then sits again. Moisture settles into the grease while it stands, and the heavy run happens with no warm-up.
Service once a year, before the first haul of the season, whatever the odometer says. For a trailer in regular use, 12,000 miles is the mileage figure. Pull it apart sooner if it was hauled through deep water, if it stood a full season without moving, if you do not know its history, or if a hub ran hot on the last trip.
The bearings a 7,000 lb axle takes
| Kit | Inner | Outer | Seal | Listed size |
|---|---|---|---|---|
| 12-inch Timken kit | 25580/25520 | 14125A/14276 | 10-36 double lip | 12 inch, 5.2K to 7K axles |
| 10-inch Timken kit | L68149/L68111 | L44649/L44610 | 10-19 double lip | 10 inch, 3.5K axles |
Those are the numbers on our own product pages, and the 12-inch kit is the one that suits a 7,000 lb spindle.
Read the numbers off your own bearings before you order. LQ builders buy axles from several suppliers, they change suppliers between model years, and a previous owner may have swapped a hub. The cone numbers are stamped on the face of each bearing. If the stamping is gone, measure the drum across the friction face and measure the bore of each cone. Then send us those three figures and we will tell you which kit fits. Our kit by axle rating and lug pattern guide has the wider table.
Two honest notes on the related parts. Our brake drum hub is listed for Black Series HQ Series fitment and comes pre-greased with two bearings, so check with us before buying it for another brand. Our electric brake pair is sold as two brakes for one axle, and the listing does not publish a drum diameter, so measure yours first.
While the hub is off, replace the cotter pin rather than reusing it, and replace any wheel cap that has gone soft or cracked. A cap that lets water in undoes the repack you just did. If the trailer pulls to one side under braking, or the brakes grab, work through our brake troubleshooting guide before you buy parts.
One thing we do not stock
Long RV extension cords. People ask, so it is worth saying plainly. Our 30 amp item is a 20 foot, 10 AWG generator cord with an L5-30P plug and a TT-30R receptacle, which connects a generator to an RV inlet. Our 50 amp item is a breaker, not a cord. If you need 50 feet of shore power cable to reach a pedestal at a show ground, that comes from somewhere else.
Related guides
- Horse trailer wheel bearings: how often to repack
- Oil-bath versus grease hubs on 7,000 lb axles
- How big a lithium battery does your RV need
- Show ground RV power at dog and livestock shows
Send us your axle rating, the numbers off the cones and a photo of the converter label, and we will put a list together. Everything ships from Upland, California.