At a show ground your electrical system is not decided by your rig. It is decided by the rulebook. Some grounds hand you a 50 amp pedestal at your door. Some give you 20 amps shared across a row of grooming tents. Some give you nothing at all and ban generators on top of it.
Here is what the rules actually say at three grounds near us, then how to build a system that works under the worst of them.
Read the rule before you pack
San Diego County Fair livestock camping. The 2026 junior livestock entry document is blunt. Rule 13 reads: "RVs must be self-contained. Water hookups are available. No electrical or sewer hook-ups are available. No generators." A camping space is $100 with a limit of one per exhibitor, tents also need a space, and septic pumping is $50 per week. There is a second rule worth knowing before you load the truck. Rule 43 says no fans or generators may be brought onto the grounds without prior approval from the livestock coordinators. If you plan to run box fans on the animals, ask first.
Kennel Club of Palm Springs, at Empire Polo in Indio. As published on the club's space reservation page, "NO PERSONAL GENERATORS WILL BE ALLOWED ON THE SHOW GROUNDS", with exceptions for the club, its contracted businesses, and built-in RV units in standard overnight RV parking. Reserved grooming space is listed with 20 amp power, and exhibitors are told to bring "a three (3) prong, 50 Ft. extension cord" to reach the distribution boxes. The club's own site confirms covered grooming spaces with electricity and lighting. One caution: when we read the reservation page it still showed a past show cycle, so treat those figures as the published version and check the current page before you rely on them.
Fairplex RV Park, Pomona. The easy one, and five miles from our counter. Fairplex lists "(183) Full RV hook-ups 50/30". If you are staying in the park rather than parked in a show lot, you have shore power. Exhibitor lots elsewhere on the grounds run under different rules that are not published, so ask the competition office.
The pattern holds everywhere. Check the venue's own current page or premium list, every year. Clubs change grounds, grounds change contractors, and a rule you remember from two seasons ago may not be the rule you arrive under.
Sizing a bank for a multi-day show
Do not start with a battery. Start with a list.
Write down every 12 volt load, the amps it draws and the hours per day you will actually run it. Amps times hours gives amp hours. For anything rated in watts, divide watts by 12 to get rough amps. Add it up, then add a third for the things you forgot.
The honest way to get real numbers is to run the rig at home for a day with a SmartShunt fitted and read the total off your phone. Nameplate figures are optimistic and fans in particular draw very different amounts on different speeds.
Once you have a daily figure, multiply by the number of nights before you can recharge. That is your bank. Lithium iron phosphate is the right chemistry for this because you can use nearly all of its rated capacity, where a lead-acid pair gives you about half before you start damaging it. Our 12V 280Ah LiFePO4 is the usual single-battery answer for fans, a compressor fridge, lights and charging.
A roof air conditioner is a different category. It is a far bigger load than everything else put together, and anyone who quotes you a battery size for it without measuring your unit is guessing. Measure yours, then size from that number. Our inverter sizing guide covers the method.
For 120 volt loads you need an inverter. A MultiPlus-II does both jobs, inverting from the bank and charging from shore power, and its AC input current limit can be set to match a weak pedestal so you do not trip a 20 amp breaker shared with three other exhibitors.
Fuse the bank. A MEGA fuse in its holder belongs on the main positive feed, and our fuse sizing guide covers what a large lithium bank needs.
Putting the charge back
Three ways, and a long show usually needs two of them.
Solar is the only one that works at a ground with no hookups and no generators. A panel and a SmartSolar MPPT 100/30 or 100/50 puts amp hours back every day you are parked.
The tow vehicle charges the bank while you drive between grounds, but only through a DC-DC charger such as the Orion XS. The 12 volt feed in a 7-pin will not do it on its own, for the reasons in our 7-pin charging guide.
Shore power, where a pedestal exists, through the inverter and charger with its input limit set sensibly.
Cords and adapters, honestly
We do not stock RV extension cords. Our 30 amp item is a 20 foot, 10 AWG generator cord with an L5-30P plug on one end and a TT-30R receptacle on the other, for connecting a generator to an RV inlet. Our 50 amp item is a breaker, not a cord. We would rather tell you that than sell you the wrong thing on the way to Indio.
So buy the cord elsewhere, and buy it right:
- Length. Fifty feet is the figure show grounds keep quoting, because the distribution box is rarely next to your space. Ask the venue where power actually is.
- Gauge. Voltage drops over a long cord, and the thinner the conductor the worse it gets. A cheap 12 gauge cord at 50 feet is not the same product as a 10 gauge one.
- Adapters. If you have a 50 amp inlet and the ground offers 30 or 20 amps, you need the step down adapter, and you need to accept the lower limit. We do not stock these either.
- Do not daisy chain household extension cords to make up length.
Keeping animals cool, and what not to rely on
This is the part worth reading twice. Three failure modes come up repeatedly in owner reports, and all three catch people who thought they had a backup.
- Owners report that an automatic generator start triggers on high temperature, not on loss of shore power. If the pedestal dies and the inside temperature has not climbed yet, the generator may not have started.
- Owners report that a 120 volt thermostat loses its settings when shore power drops. When power returns, the thermostat may not be set where you left it.
- Owners report that Wi-Fi temperature monitors stop alerting when the router loses power, so the last reading you see on your phone can be an hour older than the problem.
None of that is a reason to panic, and none of it means a battery bank makes an animal safe. It means the alarm chain has to be tested rather than assumed. Practical steps: run the monitor and anything it depends on from 12 volts so a shore power drop does not take them out, keep a second alert that does not share the first one's power source, and test the whole chain at home by pulling the plug and watching what actually reaches your phone.
An inverter and a lithium bank do one specific job here. They carry the fans, the fridge and the monitor through a pedestal failure instead of everything stopping at once. That is worth having. It is not a substitute for someone being near the rig.
Related guides
- Living quarters horse trailer power and bearings
- Shore power versus generator versus solar and lithium
- Toy hauler lithium versus a generator
- How to use a 30 amp generator cord safely
- RV fridge not cooling in hot weather
Send us your load list and the ground's power rule and we will size the bank against it. We are twenty minutes from Norco and five from Pomona, so collection before a show is easy. Everything ships from Upland, California.