If your lights dim, slides crawl, or the generator won’t crank, your RV batteries are either undercharged or at the end of their life. We test, service, and replace house and chassis batteries on-site in , the same day in most cases. At , our mobile techs handle everything from quick load tests to full system upgrades so you’re road-ready again without a tow.
TL;DR: Most RV battery problems come from low voltage, sulfation, or a bad charging setup. Testing runs $89 to $149. Replacement with mid-grade AGM batteries typically lands between $329 and $689 per battery installed, lithium upgrades from $899 to $1,499 per battery installed. Call to request a free estimate and same-day mobile RV battery repair.
Professional diagnostic before replacement saves money. We check charge rate, parasitic draw, and battery health.
What we include in an RV battery test and why it matters
We run three checks that tell the full story. First, open-circuit voltage after resting, so we know true state of charge. Then a proper load test at the battery’s rated CCA for chassis batteries or a controlled 3-to-5-minute 25- to 50-amp draw for house banks. Finally, we verify charging: alternator output at the chassis, converter or inverter-charger at shore power, and solar controller settings. If any stage is off, you’ll keep killing batteries. Fast.
We do this on-site across St. Lucie County and the Treasure Coast. Ever had a new battery die in a week? That’s a charging problem, not a battery problem. We see it all the time around Tradition and St. Lucie West where rigs sit for weeks in the heat. Bottom line: test the battery and the system, or you’re guessing.
Load testing with a carbon pile reveals real capacity under stress, not just surface voltage.
The most common RV battery failures we fix in Port St. Lucie heat
Florida heat and humidity chew up batteries. Hot days on US-1 or I-95 push temps under the step to 120+ degrees, which accelerates sulfation on flooded lead-acid and dries plates if water isn’t topped up. We routinely find loose lugs, corroded ring terminals, and converters stuck in float. And yes, parasitic draws from propane detectors and radio memory can drain a house bank in 3 to 7 days.
We’re not fans of mixing old and new batteries in the same bank. One weak jar drags the whole set. If your 6-volt pair in series shows more than 0.1 volts difference at rest, replace the pair together. Same story with 12-volt banks wired in parallel near the PSL Botanical Gardens campground scene, where weekend boondocking exposes weak links fast.
How to test your RV batteries at home the same way we do
You can do a solid DIY test with basic tools. Here’s the exact flow we teach customers:
1) Rest the battery: Disconnect chargers and let the bank rest for 4 hours.
2) Measure voltage: 12.6 to 12.7 volts is full for flooded/AGM, 13.3+ for most lithium iron phosphate.
3) Load the bank: Turn on lights, fans, and the furnace blower to pull 20 to 40 amps for 3 minutes.
4) Watch the drop: Healthy 12-volt lead-acid shouldn’t sag below 11.0 volts under moderate load.
5) Recharge check: Plug into shore power and verify 13.6 to 14.6 volts at the battery, depending on chemistry.
If numbers look off, call and we’ll bring the pro gear. Takes about 45 to 75 minutes on-site, including a full charging system check.
AGM vs Flooded vs Lithium for RV house batteries: which should you pick?
Here’s the straight talk. Flooded lead-acid is cheapest upfront, but it needs water checks and hates heat. AGM is cleaner, no watering, and handles vibration better around rough roads out by Savannas Preserve State Park. Lithium iron phosphate (LiFePO4) gives you the most usable capacity per pound and fastest charging, but it needs a charger that supports lithium profiles and usually a battery monitor for accuracy.
We install a lot of Trojan T-105 flooded 6-volts, Interstate 12-volt AGMs, and Battle Born 100Ah lithium. Honestly, we’d skip low-cost no-name lithium packs. Too many BMS issues. According to Battle Born Batteries’ published specs, their 100Ah LiFePO4 provides 3,000 to 5,000 cycles at 80% depth of discharge, which beats lead-acid by a wide margin. For converters and inverter-chargers, Victron and Progressive Dynamics publish profiles that match each chemistry. Follow the manufacturer’s charge profile. No guessing.
Reference sources: Battle Born Batteries spec sheets and Progressive Dynamics charge profile guides.
Real-world battery lifespan here on the Treasure Coast
In our experience, lead-acid house batteries in last 2 to 4 years. AGM stretches to 3 to 6. Lithium runs 8 to 12 if charged correctly. Why the spread? Heat, storage habits, and charge settings. If you store near Hutchinson Island in summer without shore power, plan for a disconnect switch or solar maintainer. A small parasitic draw at 0.3 amps drains a 100Ah battery in about 14 days to 50% state of charge. Do that all season and capacity falls off a cliff.
We see chassis batteries (starting batteries) fail around year 3, especially on gas Class A’s that sit. Keeping a smart maintainer on the chassis side extends life. Cheap trick. Works.
Pricing: testing, replacement, and lithium upgrades
We keep pricing plain. Here’s what we charge on average in St. Lucie County:
- Diagnostic and load test: $89 to $149 on-site, applied to the job if we replace. Flooded lead-acid house battery installed: $189 to $329 each, typical 2-battery jobs $398 to $658. AGM house battery installed: $329 to $689 each, depending on group size and brand. Lithium 100Ah installed with proper settings: $899 to $1,499 each. Battery monitor (Victron SmartShunt) installed and configured: $239 to $349.
Most replacements take 60 to 120 minutes. Battery bank rewires with corrosion remediation can stretch to 2.5 hours. There’s no trip fee for addresses inside during regular hours. After-hours emergency RV repair has a $129 after-hours surcharge.
Why your RV keeps killing new batteries
New batteries won’t save a bad charging setup. We find these root causes again and again around St. Lucie West and River Park:
- Converter stuck in float around 13.2 volts, never reaching absorption. Inverter-charger on the wrong chemistry profile after a reset or power blip. Alternator not feeding the house bank due to a failed isolator or solenoid. Solar controller set for flooded while you’re running AGM or lithium. Loose negative return or corroded frame ground, causing voltage drop under load.
Fix the setting, clean the lugs, and confirm 14.2 to 14.6 volts for lead-acid during absorption, or the lithium profile specified by your battery’s manufacturer. According to NFPA 1192 (RV standard referenced by RVIA), DC systems need correct overcurrent protection and wiring sizing. Undersized cables cause heat and sag. We upgrade cabling when needed. Worth every penny.
For deep specs, see NFPA 1192 from the National Fire Protection Association and Victron Energy charging guidance.
Signs you need RV battery replacement today
Dim lights at idle. Water pump slowing or chattering. Furnace fan starts then stops. Slides hesitate. Fridge switching to propane without cause. If your rested voltage is under 12.2 volts after a full charge and you sag below 10.5 volts under a moderate load, the bank’s done. And if one 6-volt in series is more than 0.2 volts lower than its mate, replace the pair together. Mixing is a common mistake. We see people try this all the time and it just shortens the life of the new one.
Corrosion adds resistance. Resistance creates heat. Heat kills batteries faster in Florida.
Mobile RV battery repair and same-day service near you
If you searched rv repair near me in , you’re in our wheelhouse. We run mobile RV repair trucks across the Treasure Coast daily, from Tradition and Torino to Fort Pierce South and Jensen Beach. Typical drive time from our shop to PSL Community Center is about 15 minutes, to Crosstown Parkway Boat Ramp around 12 minutes. We also cover St. Lucie County parks and most private storage lots with gate access.
Need emergency RV repair? We can jump a dead chassis battery, swap in a house bank, and reprogram your charger in one trip. Call and request a free estimate. Same day in most cases.
We come to you. Driveways, storage lots, campgrounds, and roadside safe shoulders.
Our process: clean power in, clean install, verified charge rates
We start by isolating the bank and removing ground first. Then we photograph cable routing, label every lead, and wire-brush both lugs and posts. We apply conductive anti-oxidant on copper lugs, torque to spec, and finish with a dielectric protectant on exposed hardware. If we’re installing lithium, we update your converter or add a proper charger and program the absorption, float, and low-temp cutoffs per the manufacturer’s manual.
We finish with a full run test on shore power and, for motorhomes, alternator charge verification at 1,200 RPM. You’ll get readings written on a service https://a1rvrepair.com/services/rv-roof-repair/emergency-rv-roof-repair/ tag: resting voltage, load-test result, absorption rate, and final float voltage. Clear numbers. No guesswork.
Local factors that affect RV batteries in St. Lucie County
Summer heat and thunderstorms demand maintenance. Afternoon showers mean humidity, which speeds up terminal corrosion. Storm prep means longer storage, so parasitic draws add up faster. According to the National Weather Service Melbourne office, our warm-season highs often sit in the upper 80s to low 90s with high humidity, and higher battery temps cut lifespan roughly in half for every 15 degrees above 77 F. Keeping shade, ventilation, and correct charge profiles makes a measurable difference here.
We also see salt air closer to the coast. If you frequent Hutchinson Island, clean and protect terminals every 90 days. Small habit. Big payoff.
Brands, parts, and tools we trust on RV battery jobs
We’re picky. For lead-acid, Trojan and Interstate are solid. For AGM, Lifeline and Odyssey have treated our customers well. For lithium, Battle Born and Victron Smart LiFePO4 are our go-tos. Converters and inverter-chargers: Progressive Dynamics, Victron MultiPlus, and Xantrex. Battery monitoring: Victron SmartShunt or BMV-712. Tools: Midtronics battery analyzer, a carbon pile load tester, a calibrated Fluke multimeter, and NOCO or Blue Sea for fusing and bus bars.
Cheap off-brand BMS units? Hard pass. Too many weird cutoffs under load. Spend once, cry once.
Can you prevent another dead battery week?
Yes. Here’s the plan that works. Charge to 100% at least once a week when parked. Keep flooded cells at the correct electrolyte level using distilled water. Program the charger correctly for your chemistry. Add a battery monitor so you see true state of charge, not just voltage. If storing for 30+ days, disconnect the negative or use a maintainer. And if you’ve added solar, verify the controller profile and low-temp charging settings for lithium. Simple steps. Big difference.
Mid-article CTA: Have questions about rv battery repair, solar charging, or charger settings? Call to request a free estimate. We’re licensed, insured, and we back battery installs with a 12-month workmanship warranty.
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A1 RV Repair
RV repair shop
1961 SW South Macedo Blvd #303, Port St. Lucie, FL 34984
Open now
Monday - Sunday
7 AM–8 PM
Veteran-owned
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RV Repair Port St. Lucie FAQ\'s.
What kind of mobile RV repair services do you offer in Port St. Lucie?.
–We provide full mobile RV repair services that come straight to your location—whether you’re parked at home, in a campground, or stuck on the side of the road. From AC failures to slide-out issues, our skilled team handles everything on-site so you can avoid the headache of moving your RV.
Do you work on motorhomes, or just trailers?
- We work on both! Whether you’ve got a Class A motorhome, a fifth-wheel trailer, or a travel trailer, we’re equipped to handle the job. Our rv technicians know the ins and outs of every style of rig, and we bring the tools and parts and accessories right to you.
What’s included in your maintenance service?
- Our maintenance service covers the basics and beyond: roof resealing, battery testing, water heater inspections, diagnostics, plumbing checkups—you name it. Regular checkups help rv owners catch small issues before they turn into big, costly ones.
What areas do you specialize in when it comes to repairs?
– We specialize in non-engine RV repairs, meaning we’re your go-to for electrical, plumbing, appliances, HVAC, slide-outs, and interior and exterior improvements. Think of us as your all-in-one pit crew for everything but the engine.
Can you deliver replacement parts if I already know what’s wrong?
– Absolutely! If you know your water pump’s toast or your fridge’s circuit board is fried, we can deliver the part, install it, and make sure it’s working perfectly. We work with trusted suppliers to get the right rv parts quickly. Just keep in mind, YOU requested that part and/or service, if that’s not the problem, don’t hold us accountable.
What does your repair process typically look like?
– Our repair process starts with a quick chat to understand your service needs. Once we’re on-site, we run full diagnostics, walk you through what’s going on, and then make the necessary fixes right then and there. It’s all done without the hassle of a service center visit.