How much solar do I actually need?

Work backwards from consumption rather than forwards from roof space. Add up what you run and for how long, in amp hours per day, then size the bank to hold two to three days of that and the array to replace a day of it in usable sun. Most owners who are disappointed by a solar system undersized the battery bank rather than the panels, because panels only control refill rate while the bank controls what you can do overnight.

Is lithium worth the cost over lead acid?

For most people who use their vehicle regularly, yes. Lithium gives you roughly twice the usable capacity per rated amp hour because you can discharge it deeply without damage, it weighs about half as much, it charges far faster, and it lasts several times longer. The purchase price is higher and the cost per usable amp hour over the life of the bank is lower. For a vehicle used twice a year, lead acid remains defensible.

Can I add lithium batteries without changing anything else?

Usually not, and this is the most common expensive mistake. Lithium needs a charge profile that many older converters and alternators do not produce, so charging is either incomplete or damaging. Alternator charging in particular needs a DC to DC charger, because lithium will accept current fast enough to cook an alternator that was never designed for it. Budget for the charging side as part of the conversion rather than as an afterthought.

How much does a solar and lithium system cost?

A basic solar addition with a controller runs $1,200 to $3,500. A meaningful system with lithium and a decent inverter runs $6,000 to $14,000. A full off-grid build with a large array, substantial bank, high-output inverter and DC to DC charging runs $14,000 to $25,000 and beyond. The bank and the inverter are usually the largest line items rather than the panels.

Will drilling into my roof cause leaks?

Only if it is done badly, which it frequently is. Every penetration is a potential leak and the mounting is the part that matters more than the panel. We mount to structure rather than to skin, seal in layers rather than with a single bead of lap sealant, and where the roof construction allows we use adhesive mounting to avoid penetrations entirely. A solar install is also the right moment to inspect and reseal the rest of the roof while we are up there.

RV Solar Installation and Lithium Battery Systems

Solar gets sold as a panel purchase. It is really a system design problem, and the panels are usually the least important part of it.

The useful mental model: the battery bank determines what you can do. The array determines how quickly you can refill it. The inverter determines what you can run from it. Get the bank wrong and no amount of panel fixes it.

Sizing from consumption

The right sequence is to add up what you actually use, in amp hours per day. A residential fridge, a laptop, lighting, water pump, fans, device charging, and whatever else runs. Then:

Size the bank to hold two to three days of that, so a cloudy day is not an emergency and you are not cycling the bank to empty every night.

Size the array to replace a full day of consumption in the usable sun you actually get, which is fewer hours than the datasheet implies and considerably fewer in winter or under trees.

Size the inverter to your largest simultaneous AC load, with headroom for startup surge, which on anything with a compressor is several times its running draw.

Owners who are disappointed with a system almost always undersized the bank while spending on panels, because panels are the visible part.

Lithium versus lead acid

	Lead acid	Lithium iron phosphate
Usable capacity	About 50 percent of rated	80 to 100 percent of rated
Weight	Heavy	About half
Charge speed	Slow, tapers badly	Fast, accepts current to near full
Cycle life	300 to 1,000	2,000 to 5,000+
Cold charging	Tolerant	Needs protection below freezing
Purchase cost	Lower	Higher
Cost per usable amp hour over life	Higher	Lower

For a vehicle in regular use lithium is generally the better economics despite the higher purchase price. For a coach used twice a year, lead acid is still a reasonable answer.

The charging problem nobody budgets for

This is where lithium conversions go wrong.

Lithium wants a different charge profile from lead acid. Many converters and most older ones produce a profile that either never fully charges a lithium bank or damages it.

Alternator charging is worse. Lithium will accept current as fast as the alternator can produce it, indefinitely, which is a good way to destroy an alternator that was designed assuming a lead acid bank would taper its demand. A DC to DC charger is not optional on a motorised vehicle with lithium.

So a lithium conversion is a bank plus a converter or charger plus a DC to DC unit plus usually a battery monitor. Budget it as a system.

What we do

Solar array design and installation, rigid and flexible panels, MPPT charge controllers, lithium conversions with the full charging chain, inverter and inverter-charger installation, DC to DC chargers, battery monitoring, distribution and fusing upgrades, transfer switching between shore, generator and inverter, and complete off-grid systems on conversions and expedition builds.

We also do a steady amount of correcting existing installs, usually undersized cable, missing fusing, or a lithium bank added to a lead acid charging system.

Mounting, and the leak question

Every roof penetration is a potential leak, and a badly mounted array is one of the more reliable ways to ruin a roof.

We mount to structure rather than to skin, because a panel mounted to a thin membrane and its decking will pull out under wind load at highway speed. Sealing is layered rather than a single bead of lap sealant on top. Where the roof construction allows, adhesive mounting avoids penetrations entirely.

A solar install is also the natural moment to inspect and reseal the rest of the roof, since we are already up there with it stripped of clutter. Covered under roof repair.

What it costs

System	Typical range	Hours
Basic solar addition with controller	$1,200 to $3,500	6 to 16
Solar with lead acid bank upgrade	$3,000 to $6,500	14 to 30
Lithium conversion with charging chain	$4,500 to $10,000	20 to 45
Full system: solar, lithium, inverter	$6,000 to $14,000	30 to 60
Large off-grid build	$14,000 to $25,000+	55 to 90

Electrical labor is $260 per hour. Parts over $100 carry 35 percent markup. See the pricing page.

Solar and generators together

Solar and a generator are complementary rather than alternatives. Solar covers baseline consumption silently and indefinitely. A generator covers air conditioning, high-draw appliances and recovery after several cloudy days.

Owners who install solar expecting to remove the generator are usually disappointed the first hot week, because air conditioning is a load that no practical roof array supports for long. The realistic outcome is a generator that runs a fraction as often, which is quieter, cheaper and easier on the machine.

Estimates are $150 and credited back against an authorized repair.

Bring us the job the other shop turned down

We work on all years, all makes and all classes, from Class A diesel pushers down to enclosed cargo trailers. Estimates are $150 and are credited back against an authorized repair, so the money goes toward the work rather than to a shop that never touches your vehicle.

23281 La Palma Ave, Yorba Linda, CA 92887 | (949) 799-3387

Solar, Inverter and Battery Systems