RV Solar and Battery System Work in Brea, CA
RV solar panel installation in Brea, CA is a sizing problem before it is an installation problem: how much energy you actually use in a day, how much roof you have, what the controller can accept, and whether the battery bank can absorb what the array produces. We design and install solar arrays and charge controllers, convert lead acid banks to LiFePO4 with the charging changes that conversion requires, diagnose and replace inverters and converters, and add DC-DC alternator charging. All of it installed and tested in shop at our Yorba Linda facility.
This page owns harvest and storage. Everything downstream of the battery and inverter output, meaning the transfer switch, the panels and breakers, the harness, the outlets, and the grounds, is distribution and lives on our electrical repair page. If you are chasing a dead circuit or a breaker that trips, start there. If you are asking how to run the air conditioning on batteries or why your bank never reaches full charge, you are in the right place.
- California BAR licensed ARD00288521
- 35,000 square feet facility
- All work performed in shop at our Yorba Linda facility
- Direct billing with 16 carriers on covered claims
Ready to get this looked at?
Electrical and systems faults get bench time, not guesswork. Diagnostic time is credited against the repair when you authorize the work.
What this repair covers
A house power system has four parts and they have to agree with each other. The array collects energy. The charge controller conditions it to what the battery chemistry wants. The bank stores it. The inverter converts stored energy back to 120V AC for loads that need it, while the converter does the reverse when shore power is available. Change one and you often have to change another, which is the thing most bolt-on solar kits ignore.
The most common job we do here is not a new install. It is fixing a system that was assembled from parts that do not match: a lithium bank on a converter with a lead acid charge profile, an array whose open circuit voltage exceeds the controller input on a cold morning, or an inverter sized for a load the cable to it cannot carry. Correcting those is design work, and we do the math before we quote hardware.
Scope for this page:
- In scope: solar array design, panel mounting, roof penetration sealing, and combiner and disconnect installation
- In scope: MPPT and PWM charge controller sizing, installation, and configuration
- In scope: lead acid, AGM, and LiFePO4 bank design, installation, and cable sizing
- In scope: lead acid to lithium conversion including converter, controller, and alternator charging changes
- In scope: inverter and inverter charger installation and diagnosis, including pure sine replacement
- In scope: converter and charger diagnosis, replacement, and charge profile correction
- In scope: DC-DC alternator charging installation on chassis with regulated or smart alternators
- In scope: battery monitoring with shunt based meters, plus overcurrent protection at the bank
- Out of scope: 12V and 120V distribution, transfer switches, panels, and harness faults
- Out of scope: generators and generator output problems
| Chemistry | Usable depth of discharge | Charge behavior | Practical notes |
|---|---|---|---|
| Flooded lead acid | Roughly 50 percent before life suffers | Slow absorption stage, needs periodic equalization | Lowest cost, requires watering and ventilation, heaviest per usable amp hour |
| AGM | Roughly 50 percent, tolerates deeper occasionally | Accepts higher charge current than flooded, no equalization | Sealed and mountable in more positions, still heavy, sensitive to overcharge |
| LiFePO4 | Roughly 80 to 100 percent depending on the BMS | Absorbs very high current, flat voltage curve, needs a lithium profile | Lightest per usable amp hour, will not accept charge below freezing without heating |
| Lead acid with lithium profile | Reduced, damage accumulates | Overcharged, gassing and plate loss | The classic mismatch after a partial conversion, shortens bank life quickly |
| LiFePO4 with lead acid profile | Never reaches full state of charge | Absorption voltage too low, float holds the bank part charged | Owner reports the bank never fills, blames the panels, replaces the array |
Damage and failure modes we see
Very little of what fails in these systems is a failed component. Most of it is a design mismatch that was tolerable until the weather or the load changed.
Controller input voltage exceeded on a cold morning
Panel open circuit voltage rises as temperature falls, and it does so by a published coefficient per degree. A string of panels wired in series that sits comfortably inside a controller input limit on a warm afternoon can exceed it at dawn in winter, at the moment of first light before any current flows.
The failure is instant and usually terminal for the controller, and it does not repeat when tested later because conditions have changed. The owner reports the controller died for no reason. The correct fix is not a bigger controller; it is doing the temperature corrected voltage calculation for the coldest expected condition and rewiring the array in series and parallel accordingly.
Lithium bank on a lead acid charge profile
This is the single most common finding on a partial lithium conversion. A LiFePO4 bank replaces the old batteries, but the converter, the charge controller, or the alternator feed keeps its original lead acid profile, meaning a lower absorption voltage and a float stage the lithium chemistry does not want.
The symptom is a bank that never reads full, delivers far less capacity than its rating, and appears to be defective. Owners frequently add panels, blaming the array. The consequence beyond disappointment is that a converter designed for lead acid may also lack the current limiting a large lithium bank needs, and the bank will pull the converter well past its rating until it overheats.
Undersized cable and missing overcurrent protection at the bank
A battery bank is a very high energy source, and the conductor between the bank and an inverter has to carry hundreds of amps during a heavy draw. Undersized cable heats, the voltage at the inverter sags, and the inverter shuts down on low voltage while the bank still has capacity.
The more serious version is missing protection. A conductor run from a battery without a properly rated fuse or breaker close to the positive terminal has no way to interrupt a short, and a shorted lithium bank delivers enormous current. This is the most dangerous defect we find in owner installed systems and we correct it as a condition of working on the rest.
Inverter idle draw and load mismatch
Inverters consume power just being on, and that no load draw runs continuously. On a modest bank, an oversized inverter left on all night can consume a meaningful share of the stored energy doing nothing. Owners read this as a battery that self discharges.
The other mismatch is waveform. Modified sine inverters are cheaper and cause real problems with inductive and electronic loads: motors run hot, some chargers refuse to work, and certain medical and audio equipment misbehaves. Replacing a modified sine unit with a pure sine inverter resolves a whole family of complaints that look like appliance faults.
Alternator charging without a DC-DC converter
Connecting a lithium house bank directly to the chassis alternator through a simple isolator is a design that fails in two directions. Lithium accepts current almost without limit, so the alternator runs at full output continuously and overheats, and modern smart or regulated alternators reduce output based on the chassis battery state, so the house bank may barely charge at all.
The symptom set is either a cooked alternator or a house bank that gains almost nothing on a long drive. A DC-DC charger such as a Victron Orion-Tr Smart or a Renogy DCC unit fixes both, because it limits the current drawn from the alternator and delivers a proper lithium charge profile regardless of what the chassis side is doing.
Roof penetration and mounting failures on the array
Solar panels are large flat surfaces mounted on a membrane roof, and the mounting is where installs fail. Brackets bonded with the wrong adhesive release; brackets screwed through the membrane without proper sealing become leaks; and wiring entering the roof without a proper cable gland is a direct water path.
The consequence is not electrical, it is structural. Every leaking solar mount we have opened had wet roof decking under it, and some had rot in the framing. A panel array is also a wind load surface, so a bracket that has released at one corner rapidly becomes a panel departing at freeway speed. Mounting and sealing get the same attention here as the electrical design.
How we perform this repair
Every job on this page begins with numbers rather than with a parts list, because a system that has not been sized is a system that will disappoint at the first cold morning or the first heavy load.
The process, start to finish:
- Build the energy budget. We list actual loads and daily run hours, convert to amp hours at 12V, and add the inverter overhead. That number, not roof space, determines bank size. It is the step that decides whether a project is three panels or eight, and we do it with the owner before anything is quoted.
- Size the array against the budget and the roof. Panel wattage is derated for real conditions, meaning heat, angle, soiling, and shading from air conditioners and vents, rather than taken at the rating on the label. We then lay out the physical array against the actual roof, since usable area after appliances and hatches is always less than the roof dimension suggests.
- Do the temperature corrected voltage math. Panel open circuit voltage is corrected to the coldest expected condition using the panel temperature coefficient, and the series string is arranged so the corrected voltage stays inside the controller input limit with margin. Controller current rating is then checked against array short circuit current. MPPT is specified where the array voltage is well above battery voltage; PWM only where it genuinely fits.
- Specify the bank and the charge sources together. Chemistry is selected against the budget and the weight allowance, then every charge source is checked for a matching profile: charge controller, converter or inverter charger, and alternator path. On a lithium conversion this frequently means a Progressive Dynamics unit with a lithium module or a Victron inverter charger, plus a DC-DC charger on the alternator feed. Low temperature charge cutoff is confirmed on any lithium bank.
- Size cable and protection. Conductor size is calculated from current and run length to hold voltage drop within tolerance, not chosen by what fits the lug. Every positive conductor from the bank gets overcurrent protection close to the terminal at a rating the conductor can carry, using a Class T or comparable fuse where a lithium bank can deliver very high fault current.
- Mount and seal the array properly. Brackets are bonded or mechanically fastened to the specific roof construction with the correct adhesive and sealant, cable entry uses a sealed gland rather than a hole and caulk, and the array layout preserves service access to roof appliances. Roof penetrations are sealed with self leveling sealant appropriate to the membrane material.
- Commission and document. The controller is configured to the battery manufacturer specification, the converter and inverter charger profiles are set, a shunt based monitor such as a Victron SmartShunt is installed and synchronized so the state of charge reading is real, and the system is run under load and under charge while we record output. Settings and readings go on the order so the next person to touch it knows what was configured.
What this costs and how we quote it
Solar and storage is quoted from the energy budget, which is why we build that first. The estimating units are array watts installed, controller and inverter capacity, bank amp hours, and the install labor for mounting, cable runs, and commissioning. Those are separable, and we present them separably so you can stage a project rather than commit to all of it at once.
Diagnosis of an existing system is quoted as diagnostic time and produces a written finding: what the array actually produces, what the controller is configured to, what the bank state of charge really is against what the monitor claims, and where the mismatch is. That report frequently shows the fix is a configuration change rather than hardware. Current diagnostic and estimate pricing is on our pricing page.
Vehicles we perform this on
Roof area, weight allowance, and use pattern differ enough by platform that the same energy budget produces very different systems.
- Class B camper vans: minimal roof area and tight weight budgets, where lithium and DC-DC alternator charging do most of the work.
- Camper van conversions: purpose built systems where the whole design is ours to specify rather than retrofit.
- Fifth wheels: large roof area but heavy appliance shading, so array layout matters more than raw panel count.
- Skoolies: very large roof area and heavy loads, usually a full inverter charger system rather than a bolt-on kit.
- Mobile workshop vans: tool and equipment loads with high surge draw, where inverter sizing and cable runs dominate the design.
What this page does not cover
- distribution, transfer switches, panels, and harness Everything between the source and the load is the electrical page.
- generator service Engine driven generation has its own page.
- roof membrane repair Membrane and decking repair under a mount is roof scope.
Get a written scope before the damage spreads
Electrical and systems faults get bench time, not guesswork. Diagnostic time is credited against the repair when you authorize the work.
If this damage is on an insurance claim
Solar and battery systems are usually aftermarket additions, and that is exactly the problem on a claim. Many RV policies cover the vehicle as delivered and treat owner added equipment as excluded or capped unless it has been declared and scheduled. Owners discover this after a hail event takes out an array or a fire damages a bank.
If you have added an array, a lithium bank, or an inverter system, the practical step is to document the installed value and confirm with your carrier how it is covered before you need to know. We provide an itemized installation record for exactly this purpose. Our page on custom and aftermarket coverage explains how carriers treat added equipment and what scheduling it involves.
Why Brea owners bring this work to us
Our shop is on La Palma Avenue in Yorba Linda, an easy drive from Brea, and these projects are multi day in shop work. An array install involves roof time, interior cable routing, and a commissioning run, and none of that is a driveway job.
Two things distinguish this work. We do the sizing math and show it to you, including the temperature corrected voltage calculation that decides whether a controller survives its first winter, rather than selling a kit and hoping. And because we are a body shop with a roof and structural department in a 35,000 square foot building, we mount and seal arrays to the standard a roof actually requires, and we find the wet decking under someone else's brackets before it becomes a floor. We have been here since 2015 under California BAR license ARD00288521 and EPA ID CAL000367879.
Frequently asked questions
How many solar panels does my RV need?
It comes from your daily energy use, not from your roof size. We list actual loads and run hours, convert to amp hours at 12V, add inverter overhead, then derate panel output for heat, angle, soiling, and shading from roof appliances. A coach running a residential refrigerator and a laptop needs a very different array from one running lights and a water pump. The budget is built first, then the array.
What is the difference between MPPT and PWM charge controllers?
A PWM controller connects the array to the battery and pulls the panel voltage down to battery voltage, wasting the difference. An MPPT controller converts the excess voltage into additional charging current, typically harvesting meaningfully more from the same panels, and it lets you wire panels in series at higher voltage over smaller cable. MPPT is the right choice on almost any array where panel voltage sits well above battery voltage.
Can I just drop lithium batteries into my RV?
Not without changing the charging. LiFePO4 wants a different absorption voltage and no float stage, so a converter, charge controller, or alternator feed still set for lead acid will leave the bank permanently part charged and performing far below its rating. A lithium bank also draws current a lead acid converter was never sized to deliver. The conversion includes the charge sources, the cable, and the overcurrent protection.
Why does my battery bank never reach 100 percent?
Most often the charge profile does not match the chemistry, which leaves absorption voltage too low to finish the charge. The second common cause is a monitor that has never been synchronized, so the reported state of charge has drifted away from reality. The third is a charge source that is being limited, such as a controller with the wrong battery type selected. All three are configuration, not hardware.
Do I need a DC-DC charger to charge from my alternator?
On a lithium bank, yes. A direct connection lets lithium pull the alternator to full output continuously, which overheats it, and modern regulated alternators may reduce output so the house bank barely charges at all. A DC-DC charger limits the current drawn from the alternator and delivers a correct lithium profile independently of what the chassis side is doing. It solves both failure directions at once.
Can I run my RV air conditioner on solar and batteries?
It is possible but it is a whole system decision, not a panel count. Air conditioning is the largest continuous load in most coaches, so it requires a large inverter, heavy cable, a substantial lithium bank to supply the run time, and enough array to replace what a day of cooling consumes. A soft start device reduces the surge the inverter has to handle. We build the energy budget first and tell you honestly what it takes.
Will solar panels damage my RV roof?
Only if they are mounted badly, which unfortunately is common. The failures we find are brackets bonded with the wrong adhesive, brackets screwed through the membrane without proper sealing, and cable entries made with a hole and a bead of caulk instead of a sealed gland. Every one of those leaks. Mounted and sealed correctly to the specific roof construction, an array does not harm the roof.
What is a battery monitor and do I need one?
A shunt based monitor measures current in and out of the bank and integrates it to report actual state of charge, rather than guessing from voltage. Voltage alone is a poor indicator on any chemistry and nearly useless on LiFePO4, whose voltage curve is almost flat across most of its capacity. If you rely on stored power, a synchronized shunt monitor is the difference between knowing and hoping.
Written and reviewed by the OCRV Center Technical Team. Last updated .
Book your paid estimate
Electrical and systems faults get bench time, not guesswork. Diagnostic time is credited against the repair when you authorize the work.
Related repairs and pages
- 12V and 120V distribution and fault findingEverything downstream of the inverter and battery.
- generator repairThe other source of house power.
- roof repair and sealing under an arrayLeaking solar mounts are a roof problem before they are electrical.
- wet decking under leaking solar mounts
- fabricated battery trays and mountingLithium conversions frequently need new bank mounting.
- air conditioning loadsThe load that drives most inverter and bank sizing questions.
- interior work around a system installCable routing and cabinet modification during a build.
- Class B camper van repair
- camper van conversion work
- skoolie repair and build work
- mobile workshop van repair
- coverage for aftermarket equipment
- diagnostic and estimate pricing
- why owners choose our shop