Cold weather gets the blame. Heat does the damage. And a parked car has no alternator working for it, which is why a stored battery fails on a completely different clock to a daily driver’s.
Ask most owners when batteries die and they’ll say January. The failure shows up in January. The damage was done the previous July, in a garage nobody thought of as dangerous, while the car sat still and the plates quietly corroded in air that had been over 110°F since breakfast. Heat wrecks batteries. Cold just presents the bill. REVCity Auto Storage at 7185 Bermuda Rd, Las Vegas NV 89119 holds every vehicle at 50 to 70°F and 40 to 50% relative humidity, with a quality battery tender at every space. Call 725-272-1803 about space for a car that is about to sit.
A battery is a chemical reaction in a box, and every chemical reaction runs faster when it is hot. That includes the ones you want. It also includes all the ones you don’t: grid corrosion creeping across the positive plates, water leaving the acid through the vents, and the whole cell drawing itself down a little further every day it sits in the heat. None of it reverses when the weather cools. The damage is cumulative and it is permanent.
The working rule of thumb is simple. Battery wear roughly doubles for every 15°F of extra heat. That is not a precise engineering constant and nobody should treat it as one. It is a rough guide, and it is enough to explain the gap. The same battery that gives seven years in Seattle gives a fraction of that here.
Cold gets the blame because cold is when you find out. A battery at freezing puts out far less cranking current than the same battery at room temperature, so a unit that summer quietly cut to 60% of its capacity will still turn the engine over on a mild October morning and then fail completely on the first properly cold one. That is the whole illusion. The Valley sees 310+ sunny days a year and peaks at 115°F. Summer does the work. Winter just sends the invoice.
Almost every guide to heat and batteries is written for a car that gets driven. The advice assumes an alternator putting charge back in. It blames short trips for not putting back enough. A stored car has no alternator running at all. The drain never stops. It runs faster in the heat. Nothing replaces what leaves. That is a different failure and it needs a different answer.
The first is self drain. The battery empties itself through its own chemistry whether it is wired to anything or not. The second is parasitic draw, and on a modern exotic it is the bigger of the two: the alarm, the immobiliser, the tracker, the keyless entry receiver and the ECU keep alive memory are all awake and sipping current every hour the car sits there looking switched off. Nothing about that stops when you walk away.
Both get worse in heat, and they stack. A car parked in a plain Las Vegas garage through July drains faster than the same car in a 70°F building, and it keeps doing that for months with nothing anywhere in the system putting charge back. The battery does not reach flat and wait politely. Below roughly 12.4 volts, sulfate starts setting on the plates in a crystalline form that an ordinary charger cannot convert back, and from that point you are not looking at a discharged battery but at capacity that is simply gone. That is sulfation. It does not come back.
| Condition | Driven car | Stored car | What fixes it |
|---|---|---|---|
| Charge replaced | Alternator, every trip | Nothing at all | A tender on the battery |
| Parasitic draw | Offset by driving | Runs day and night | A tender, not a cut off |
| Rate of loss | Slow, offset daily | Doubles per 15°F | Hold the car at 50 to 70°F |
| Typical failure | Slow capacity loss | Deep drain, then sulfation | Keep it above 12.4 volts |
| When you find out | First cold morning | The day you collect it | Test it every six months |
The last row is the one that matters to an owner. A daily driver warns you. A stored car does not, because nobody turns the key between July and October to find out.
“It is in the garage” is the objection we hear most. It answers the wrong question. A closed garage keeps sun off the paint. It does not hold a temperature. A Las Vegas garage with no cooling tracks the outdoor high with a lag. One on a west facing wall can sit well above house temperature all evening. A car in direct sun reaches 190°F inside. A garage stops that extreme. It gets nowhere near a storage temperature.
What matters is the gap between a building that is merely closed and one that is actually conditioned. Our guide to climate controlled versus temperature controlled storage covers that split. Batteries show it most clearly. The damage is chemical, it adds up, and you cannot see any of it happen. The same heat works on the rest of the car at the same time. The Las Vegas heat damage guide covers the rest.
There are three common answers to a stored battery. Only one of them is right. A trickle charger pushes a steady current. It keeps pushing after the battery is full, which boils off the acid. That is the same damage the heat is already doing. A quality battery tender watches the voltage and floats. It gives current only when the battery asks for it. That is not brand marketing. It is a different circuit doing a different job, and battery tender versus trickle charger sets it out in full.
The third answer is starting the car once a month and letting it idle. Avoid it. A short idle does not recover the charge the start used. It also puts raw fuel past the rings and water into a cold exhaust, and it never reaches working temperature. Hagerty, the collector car insurance authority, is clear that monthly start ups are not a storage plan. If a car is going to sit, let it sit properly. How often to start a stored car goes through the reasoning.
Chemistry matters too. An AGM battery handles deep cycling better than a flooded one. It is also less tolerant of overcharging. A lithium pack needs a charger that speaks its language or it will not take a charge at all. Matching the tender to the battery is not optional on a modern collector car. See AGM versus lithium for storage. For the general routine, whatever the climate, read keeping your car battery healthy in storage.
Pulling the negative terminal stops the parasitic draw. It does nothing about self drain. On a modern car it also wipes adaptive gearbox and throttle learning, radio codes, and sometimes stored driver aid calibration. If the car sits under an agreed value policy, keep the storage paperwork intact either way. For anything built this century, a tender on a connected battery is the cleaner answer.
Interstate Batteries recommends a battery test every six months. That is sensible for a driven car. It is the bare minimum for one that sits, because a stored battery gives you no other signal. A voltage reading on its own is not a test. A sulfated battery can read close to full and still collapse under load. A conductance or load test tells you whether the capacity is still there.
AAA puts typical battery service life at three to five years. Treat that as the mild climate figure it is. This valley runs to 115°F, and the doubling rule works against you every summer. Plan on the short end of that band or less. A car that spends its summers at 50 to 70°F is not subject to the same sums at all. That is the case for conditioned storage, made in the one part where it is easiest to measure.
Heat is not selective. The same summer that costs you a battery is working on the interior, the tyres and the paint. UV and heat can take up to 10% off what a car is worth. Climate control cuts corrosion risk by up to 90%. It extends interior life by up to 50%. The battery is simply the part that fails first and shows it soonest.
Putting a car away for the summer? Ask what the building holds, not what it is called. Long term car storage in Las Vegas covers what to check.
Call 725-272-1803REVCity is at 7185 Bermuda Rd, just east of the resort corridor and minutes from Harry Reid International. Owners come in from Henderson, Summerlin, Southern Highlands, Seven Hills and The Ridges. Out of state owners ship straight to the building. The drive in is short, which matters when the car you are moving has been sitting.
Every space includes a BendPak four post lift, covered in BendPak lifts in storage, and a quality battery tender.
Heat does the damage. Cold reveals it. High temperatures speed up corrosion on the plates, drive water out of the acid, and make the battery drain itself faster. The rule of thumb is that wear roughly doubles for every 15°F of extra heat. Cold simply cuts the current a battery can deliver, so one that summer already weakened fails on the first cold morning.
With a quality tender fitted and a conditioned building around it, indefinitely. That is what proper storage is for. Without one, a modern car with an alarm and a tracker can pull itself below the sulfation point in weeks of summer heat. The damage from there is lost capacity, not a flat battery. The answer is a tender, not a shorter gap between start ups.
On a pre electronic classic, disconnecting is reasonable. On anything modern it costs you adaptive gearbox and throttle learning, radio codes, and sometimes stored calibration data. It still does nothing about self drain. For a car built this century, a tender on a connected battery is the better answer.
That depends on your policy, and collector cover differs from standard auto cover. Hagerty writes agreed value policies for exactly this case and expects proper storage records rather than monthly start ups. Confirm agreed value and the storage terms with your carrier before the car goes in. Keep the facility paperwork with the policy.
REVCity holds 50 to 70°F and 40 to 50% relative humidity all year. That keeps the battery out of the band where wear speeds up, and keeps humidity away from both extremes. The number to avoid is a garage with no cooling tracking a 115°F outdoor high. Call 725-272-1803 for current availability.
Interstate Batteries recommends a test every six months, and that is the minimum for a car that sits. Use a conductance or load test, not a voltage reading. A sulfated battery can show near normal voltage and still fail under load. AAA puts typical service life at three to five years, which is a mild climate figure worth discounting here.
Climate controlled storage for exotic, classic and collector vehicles at 50 to 70°F and 40 to 50% relative humidity, with BendPak lifts, quality battery tenders and 24/7 monitored access. 7185 Bermuda Rd, Las Vegas NV 89119.
REVCity Auto Storage · 7185 Bermuda Rd, Las Vegas NV 89119 · 725-272-1803
