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Aircraft Battery Replacement Guide — How to Choose the Right Battery for Your Plane
Aircraft Battery Replacement Guide — How to Choose the Right Battery for Your Plane
Everything you need to know before replacing your aircraft battery — voltage, chemistry, Concorde RG series options, aircraft compatibility, and how to make your next battery last 10 years instead of three.
To choose the right aircraft battery: (1) confirm your aircraft’s system voltage (12V or 24V) from the POH or data plate, (2) choose a sealed AGM battery (Concorde RG series) over a standard flooded wet battery for longer life and zero maintenance, (3) match the Concorde part number to your aircraft model using their compatibility chart, and (4) have your A&P install and verify the charging system after replacement. The Concorde RG-25 (12V) and RG-35A (12V, higher capacity) are the most widely used piston GA batteries, with pilots regularly reporting 7–14 years of service life.
Aircraft owners often treat battery replacement as a reactive decision — something they think about the morning the engine won’t crank, preferably not at a remote airport on a Saturday. But the battery is the foundation of your aircraft’s entire electrical system. It starts the engine, powers your avionics during alternator failure, and serves as the last-resort power source for emergency operations.
Making the right battery choice at replacement time — and maintaining it correctly between flights — is the difference between a battery that fails in two years and one that lasts 14. This guide gives you everything you need to choose confidently.
Why your aircraft battery matters more than you think
Unlike automotive batteries, aircraft batteries carry responsibilities beyond engine starting. Your battery must:
- Provide sufficient cranking current to start the engine in all temperature and altitude conditions
- Power all avionics, lighting, and electrical loads if the alternator fails in flight
- Maintain adequate voltage for the minimum duration required to complete a safe landing if on battery power alone
- Store charge reliably between flights — particularly in seasonal or infrequent-use aircraft
- Meet the FAA requirements for your specific aircraft’s electrical certification
A failing battery that starts the engine normally in warm weather may fail to start in cold conditions, deliver insufficient capacity during an avionics-only emergency, or fail suddenly during a flight where you’re relying on it. The annual inspection load test exists precisely because batteries can appear functional while being significantly capacity-degraded.
Your battery should be replaced when it can no longer deliver 80% of its rated capacity under load. A battery at 79% capacity may still start the engine — but it has insufficient reserve for alternator-out operations. Your A&P should perform a capacity test at every annual, not just a voltage check. Voltage tells you if the battery is charged; capacity tells you if it’s still healthy.
12V vs 24V aircraft systems: which does your plane use?
The single most important specification before ordering a replacement battery is your aircraft’s system voltage. Installing the wrong voltage will not work and may damage electrical components. Check your Pilot’s Operating Handbook (POH), the aircraft data plate, or the electrical section of the aircraft maintenance manual to confirm.
Most older and lighter aircraft
12-volt systems are found in most classic and lighter piston GA aircraft. The battery consists of 6 valve-regulated cells in series. If your aircraft is a typical single-engine trainer or older model, 12V is likely your system.
- Cessna 150, 152, 172 (most models)
- Piper PA-28 Cherokee, Warrior, Archer
- Piper PA-38 Tomahawk
- Beechcraft Musketeer / Sport series
- Grumman AA-1, AA-5 series
- Mooney M20 (early models)
- Most light sport aircraft (LSA)
- Many Van’s RV homebuilts
Turboprops & twins
24-volt systems are used in higher-performance piston aircraft, most turboprops, and almost all twins. The battery uses 12 cells in series. Higher electrical loads from more powerful avionics, de-ice systems, and starters require the higher voltage.
- Cessna 182 (T-model, turbocharged)
- Cessna 210 Centurion
- Cessna 310, 340, 414 twins
- Piper Seneca, Navajo, Aztec
- Piper Comanche 260, 400
- Beechcraft Bonanza A36 (most)
- Beechcraft Baron, King Air series
- Cirrus SR22 (and most Cirrus)
- Most turboprop aircraft
If you’re unsure of your system voltage, the fastest way to confirm is to check your existing battery — the voltage is clearly printed on the label. Alternatively, look for “12V DC” or “24V DC” on the aircraft data plate (usually near the firewall or on the door frame) or in Section 7 of your POH.
Battery types: wet flooded vs sealed AGM — what’s the difference?
There are two main battery technologies in GA aviation: traditional flooded wet lead-acid batteries and modern sealed AGM (Absorbed Glass Mat) batteries. Understanding the differences will explain immediately why the Concorde RG series has become the dominant choice for GA pilots.
| Feature | Flooded Wet Battery | Sealed AGM (Concorde RG) |
|---|---|---|
| Electrolyte state | Liquid — can spill | Absorbed in glass mat — non-spillable |
| Maintenance required | Yes — check/top electrolyte | None — truly maintenance-free |
| Orientation requirement | Upright only | Any orientation — fully aerobatic |
| Corrosion / acid fumes | Yes — vent system required | Minimal — recombinant gas design |
| Vibration tolerance | Lower — plate fatigue over time | Superior — AGM immobilizes plates |
| Typical service life | 3–5 years | 5–14 years with good maintenance |
| Deep discharge recovery | Moderate | Poor — avoid deep discharge |
| Cold weather performance | Moderate | Better low-temp cranking current |
| Self-discharge rate | Higher — needs more frequent charging | Lower — holds charge longer when idle |
| Cost | Lower initial cost | Higher initial cost |
| Overall value (5-year) | Lower — more replacements | Higher — fewer replacements, no maintenance |
For virtually every piston GA application, the sealed AGM battery (Concorde RG series) is the superior choice. The longer service life alone — 5–14 years vs 3–5 for flooded batteries — more than compensates for the higher initial cost. Add no maintenance, no corrosion, and better vibration tolerance, and there’s no compelling reason to stay with a flooded battery in most aircraft.
The Concorde RG series: why it dominates GA aviation
Concorde Battery Corporation is the world leader in valve-regulated lead acid (VRLA) aircraft batteries, with more certified aircraft installations as original equipment or approved replacements than any other lead-acid aircraft battery manufacturer worldwide. Their RG (Recombinant Gas) series has been adopted by US and foreign military air forces and is the default choice of maintenance professionals across GA.
How the RG technology works
The Concorde RG series uses AGM (Absorbed Glass Mat) technology with proprietary PolyGuard® separators. The electrolyte is fully absorbed in micro-fibrous glass mat separators at 90% saturation — leaving void spaces that allow oxygen gas to recombine within the battery during charging rather than venting as explosive hydrogen. Each cell is sealed with a pressure relief valve that opens when internal pressure exceeds its threshold, then re-closes.
The result is a battery that is genuinely spill-proof, requires no electrolyte maintenance, produces minimal gas venting under normal charging conditions, and can operate in any orientation — including fully inverted for aerobatic applications.
What pilots actually experience: the service life data
The real-world service life reports from pilots using Concorde RG batteries are exceptional. From verified owner reviews collected across aviation forums and retailers:
- A confirmed 14-year service life on an RG-35A in a Piper installed in 2010, kept on a BatteryMinder
- Multiple reports of 10+ year service life on RG-25 batteries in Cessna 172s
- Consistent 7–8 year service life across a wide range of aircraft and flying frequencies
- 5–6 years even for aircraft in high-heat environments (Arizona) where heat accelerates all battery aging
The key variable reported by every long-service-life pilot: keeping the battery connected to a maintainer (BatteryMinder or similar) during periods of inactivity. Concorde RG batteries are vulnerable to deep discharge — a battery that is allowed to fully discharge and sit may never fully recover capacity.
Unlike flooded batteries that can recover from complete discharge, the Concorde RG series (and all AGM batteries) suffer permanent capacity loss when deeply discharged. If you store your aircraft for weeks without flying and without a maintainer connected, you are shortening your battery’s service life with every inactivity cycle. A BatteryMinder (the Concorde-recommended brand) costs $50–$80 and has saved thousands of dollars in premature battery replacements.
Which Concorde RG battery fits your aircraft?
Concorde uses a logical part numbering system. The number following “RG” indicates voltage: two-digit numbers starting with “2” are 12V batteries; numbers starting with “24” are 24V batteries. The suffix letters indicate series features (XC = extra cranking power; M = mounting provisions; Platinum = premium series).
Aircraft compatibility quick reference
The compatibility table above is a general reference guide. Your specific aircraft serial number, installed modifications, and electrical system configuration may require a different part number. Concorde maintains a comprehensive application chart on their website. When in doubt, contact our team with your aircraft make, model, year, and serial number and we’ll confirm the correct battery before you order.
Warning signs: when to replace your aircraft battery now
Don’t wait until you’re stuck at a remote airport with a dead battery. These warning signs indicate your battery needs immediate attention:
Replace immediately or at next maintenance
This is the definitive replacement indicator. A battery that cannot deliver 80% of its rated capacity under a proper load test is legally inadequate for certified aircraft operation and should be replaced before the next flight. Your A&P performs this test at annual — request it explicitly if not already included.
By the time cranking is visibly slow, your battery has lost significant capacity. In cold weather this is even more pronounced. Don’t dismiss slow cranking as “just a cold morning” — it’s a battery warning that won’t resolve itself.
A healthy Concorde RG battery holds charge for weeks to months without flying. If your battery requires a full charge before every flight or drops to a no-start condition within days of charging, its internal self-discharge has increased dramatically — indicating cell degradation.
For most Concorde RG batteries, the recommended replacement interval is every 5–8 years, though many well-maintained units go significantly longer. A battery beyond its recommended service life is a known risk factor regardless of how it currently performs on a bench voltage test.
If your Concorde RG battery has been fully discharged — from avionics left on overnight, extended ground operations, or a forgotten master switch — capacity loss is likely. Perform a conditioning charge per the Concorde manual and a subsequent capacity test before declaring it airworthy.
A healthy battery that accepted a deep discharge during start will show a high charge rate immediately after engine start, tapering to a lower rate within minutes. An ammeter that shows abnormally high sustained charge rates or doesn’t settle may indicate a battery that is not holding charge normally.
Aircraft battery replacement: the step-by-step process
Aircraft battery replacement must be performed by or under the supervision of a certificated A&P mechanic. The following outlines the correct procedure — bring this to your shop conversation.
Use your aircraft’s maintenance manual, existing battery label, and Concorde’s application chart to confirm the exact part number. Verify voltage (12V or 24V) and physical dimensions — some battery boxes have tight tolerances. If transitioning from a flooded battery to an RG sealed unit, verify whether an STC is required for your specific aircraft.
Always disconnect the ground (negative) cable first, then the positive. This prevents accidental shorts during removal. Ensure the master switch and all electrical loads are off before beginning. Treat the battery terminals as live until disconnected.
While the battery is out, inspect the battery box for corrosion, cracks, and proper vent connection. Check the battery cables for insulation damage, corrosion at terminals, and adequate wire size for the installation. Any corroded or damaged cables should be replaced now — a new battery in a corroded circuit will underperform and may cause charging system problems.
Install the new Concorde RG battery in the correct orientation (upright, unless your installation specifies otherwise). Connect the positive cable first, then the negative. Torque the terminal hardware to the specified value — over-tightened terminals can crack the plastic housing on some RG models. Do not jump-start an aircraft with a dead Concorde RG battery.
After engine start, check the ammeter and voltmeter (or use a multimeter at the battery bus). A properly functioning charging system should show approximately 13.8–14.5V (12V system) or 27.5–29.0V (24V system) in cruise. Voltage significantly outside these ranges indicates a charging system issue that must be resolved — a good battery will not compensate for an out-of-spec alternator/regulator.
Record the battery manufacturer, part number, serial number, and installation date in the aircraft logbook. This is required for certified aircraft and creates the service history that will inform future replacement timing. File the battery’s FAA documentation (8130-3 or CoC) with the maintenance records.
How to make your Concorde RG battery last 10+ years
The difference between a 3-year battery and a 10-year battery is almost entirely maintenance. Here are the six practices that Concorde-owning pilots with the longest service lives consistently follow:
Shop Concorde aircraft batteries at Jet Aviation Spare Parts
We stock the full Concorde RG series — 12V and 24V models for piston GA, turboprop, and experimental aircraft. All batteries are factory-new, shipped with FAA Form 8130-3 or Certificate of Conformance, and eligible for free US shipping. Price match guaranteed.
Tell us your aircraft make, model, year, and engine type and we’ll confirm the correct Concorde part number before you order. All batteries ship factory-new with documentation and a BatteryMinder compatibility confirmation. Contact our team — we typically respond the same business day.
Frequently asked questions
Service life varies significantly by battery type and maintenance. Standard flooded lead-acid batteries typically last 3–5 years. Concorde RG sealed AGM batteries routinely last 5–10 years with proper care — pilots on aviation forums regularly report 7, 10, and even 14 years of service from Concorde RG batteries kept on a BatteryMinder between flights. The single most important factor in battery longevity is avoiding deep discharge and keeping the battery charged during periods of inactivity.
12V aircraft systems are used in most older and lighter piston GA aircraft — Cessna 150/152/172 (most models), many Piper PA-28 variants, Beechcraft Musketeer, Grumman series, and others. 24V systems are used in heavier and higher-performance aircraft including Cessna 182 (T-model), Cessna 210, Piper Seneca, Beechcraft Bonanza, Cirrus SR22, and most turboprops. The 12V Concorde battery contains 6 cells; the 24V contains 12. Never install a 12V battery in a 24V system or vice versa — confirm your system voltage from the POH, aircraft data plate, or existing battery label before ordering.
The Concorde RG series is a sealed, valve-regulated lead acid (VRLA) battery using AGM (Absorbed Glass Mat) technology with proprietary PolyGuard separators. The electrolyte is fully absorbed in glass mat separators — making the battery spill-proof, maintenance-free, and operational in any orientation. Concorde RG batteries are FAA-certified, used by US and foreign military air forces, and have more certified aircraft installations than any other lead-acid aircraft battery manufacturer worldwide. Real-world pilot reports consistently show 5–14 years of service life with proper maintenance.
Replace your aircraft battery when it fails a capacity test (cannot hold 80% of rated capacity under load), when the engine starts noticeably more slowly than usual, when it cannot hold charge between flights, when it has suffered a deep discharge event, or when it is 7+ years old. Do not rely solely on a voltage check — a battery can show full charge voltage while being significantly capacity-degraded. Request a proper load capacity test from your A&P at every annual inspection.
It depends on the aircraft and the installation. For many aircraft where the Concorde RG is a direct replacement for an existing approved battery of the same part number category, no STC is required. For aircraft transitioning from a flooded battery to the sealed RG series for the first time, an STC may be required — Concorde maintains an STC and application list on their website. Always verify with your A&P before ordering. Many Cessna, Piper, and Beechcraft installations are straightforward direct replacements. When in doubt, your A&P can confirm STC requirements in a few minutes.
No — Concorde explicitly warns against jump-starting an aircraft with a dead RG battery. A dead battery has an unknown state of charge and unknown internal condition. Jump-starting forces high current through a potentially damaged battery, which can cause overheating, cell rupture, or explosive gas generation. The correct procedure for a dead Concorde RG battery is to perform a slow conditioning charge per the Concorde manual (outside the aircraft), then conduct a capacity test before reinstalling. If it fails the capacity test, replace it.
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