Buyer's guide
AGM vs EFB: which start-stop battery wins?
AGM costs more and lasts longer. EFB costs less and tolerates heat. The right answer depends on whether the vehicle has regenerative braking, what the climate is, and how the buyer values upfront cost vs. lifecycle. Here is the side-by-side and a clear decision tree, drawn from Lingyun's OEM-validated start-stop platforms.
Premium chemistry
AGM
Absorbent Glass Mat. Electrolyte is held in fiberglass mats compressed between plates. Sealed, spill-proof, vibration-resistant. Accepts the high charge currents of regenerative braking systems.
- check_circle 1,000-1,200 cycles at 50% DoD
- check_circle Spill-proof, any orientation
- check_circle Accepts regen brake charge bursts
- check_circle Vibration-rated for off-road, marine
- warning 30-40% cost premium over EFB
- warning Heat-sensitive above 45°C ambient
Entry-level start-stop
EFB
Enhanced Flooded Battery. Carbon-doped negative active material with conventional flooded electrolyte. Doubles cycle life of standard flooded at modest cost premium. Tolerates heat better than AGM.
- check_circle 600-800 cycles at 50% DoD
- check_circle Heat-tolerant for tropical markets
- check_circle Lower cost — 30% premium over flooded
- check_circle Field-serviceable (not fully sealed)
- warning Not for regen-brake systems
- warning Slower charge acceptance than AGM
Side by side
AGM vs EFB at a glance.
| Spec | AGM | EFB |
|---|---|---|
| Cycle life (50% DoD) | 1,000-1,200 cycles | 600-800 cycles |
| Cost index (vs flooded = 1.0) | 1.7× | 1.3× |
| Best application | Premium start-stop with regen brake | Entry-level start-stop, hot climates |
| Climate tolerance | Avoid sustained >45°C | Better in hot climates |
| Charge acceptance | High — accepts regen bursts | Moderate |
| Spill-proof | Yes (sealed VRLA) | No (flooded with vents) |
| Vibration resistance | High | Moderate |
| Field serviceable | No (sealed) | Yes (vent caps) |
| Charging requirement | 14.4-14.7V, temp-compensated | 14.2-14.4V standard |
Decision tree
Which one for this vehicle?
1. Does the vehicle have regenerative braking?
→ YES: AGM. Regen brake voltage spikes destroy EFB plates within months.
→ NO: continue to question 2.
2. Does the vehicle have stop-start (without regen)?
→ YES, premium budget: AGM (longer life, ECU happier).
→ YES, value budget: EFB (proper start-stop battery, lower cost).
→ NO: conventional flooded or maintenance-free is sufficient.
3. Hot climate (Middle East, SE Asia, Australia Outback)?
→ EFB is often the better economic choice — AGM grid corrosion accelerates above 45°C.
→ AGM still works if engine-bay temps stay reasonable and you specify high-temp grid alloy.
4. Marine, RV, off-road, or vibration-heavy use?
→ AGM. Spill-proof, vibration-rated, deep-cycle capable.
AltusVolt's recommended Lingyun platforms
OEM-validated start-stop range.
AGM start-stop
For regen-brake vehicles
- 6-QTF-60 — 60Ah / 580 CCA AGM, compact start-stop (Lingyun, available via AltusVolt)
- 6-QTF-70 — 70Ah / 720 CCA AGM, mid-size start-stop
- 6-QTF-105 — 105Ah heavy-duty AGM, parking-AC dual-purpose
Frequently asked questions
What is the main difference between AGM and EFB? expand_more
AGM uses absorbent glass-mat separators and compressed plates — sealed, spill-proof, with 1,000-1,200 cycles at 50% DoD. EFB is enhanced flooded — same liquid electrolyte as conventional, but with carbon-doped negative plates yielding 600-800 cycles. AGM costs roughly 30-40% more than EFB but lasts 50%+ longer in start-stop service.
Can I replace EFB with AGM? expand_more
Yes. AGM is a direct upgrade — start-stop ECUs designed for EFB will accept AGM. Reset the BMS battery code where required. Do not replace AGM with EFB downward — most regen-brake systems will overcharge an EFB and shorten its life dramatically.
Which lasts longer in hot climates? expand_more
EFB tolerates sustained heat slightly better. AGM grid corrosion accelerates above 45°C, so in tropical or desert markets EFB is often the more economical choice for entry-level start-stop. For premium AGM in hot climates, ensure proper ventilation and avoid engine-bay placement.
Is AGM worth the extra cost? expand_more
Yes if your vehicle has regenerative braking, runs heavy electrical loads (premium audio, refrigeration, accessories), or operates in vibration-heavy environments (off-road, marine). For city cars with basic stop-start and modest accessories, EFB delivers 80% of the benefit at 70% of the cost.
Do AGM and EFB charge differently? expand_more
Yes. AGM accepts higher charge currents and benefits from temperature compensation. EFB charges similarly to conventional flooded but tolerates partial-state-of-charge cycling better. Modern smart alternators handle both, but aftermarket chargers should be set to the correct profile.
Which Lingyun models cover AGM and EFB? expand_more
Lingyun's AGM start-stop range (available via AltusVolt) includes 6-QTF-60, 6-QTF-70, and 6-QTF-105 (heavy-duty AGM dual-purpose). EFB start-stop platforms include 6-QTPE-70 and 6-QTPE-80. Both ranges are produced in JIS, DIN, and BCI footprints for global export.
Can I mix AGM and EFB in a dual-battery system? expand_more
Not recommended. Different charge acceptance and internal resistance — the lower-resistance battery takes the brunt of charge bursts and degrades first. Use matched pairs from the same chemistry and ideally the same production batch.
Ready to specify the right chemistry?
Tell our export team your target market, vehicle mix, and annual volume — AltusVolt will return a distributor pricing matrix covering both AGM and EFB Lingyun platforms.
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