1) Basics: 12V, cranking & peak current

• 12V Booster = high discharge lithium battery + electronics which delivers a current peak (peak) for a few seconds to start the starter.
• Peak : maximum instantaneous value (e.g. 1000–2000 A). Marketing comparison , useful for classifying ranges.
• Cranking current : sustained intensity 3–5 s (e.g. 400–700 A). More telling to know if it really starts.
• Voltage : All these boosters are for 12V (car/motorcycle/light van). 24V (trucks/heavy goods vehicles) = dedicated equipment, do not use a 12V.
• Lead batteries : AGM/EFB/lead-acid, the voltage drops when cold/discharged. The booster compensates for the lack of current during the start .
• Quality of cables/clamps : the thicker and shorter they are, the less loss there is → more straightforward start.

2) Gasoline vs. Diesel, Engine Size & Compatibility

A diesel requires more current (high compression ratio, glow plugs). Useful points of reference:

• Motorcycle / scooter / lawnmower (≤1.0 L petrol) → boosters 400–600 A cranking .
• City & compact petrol cars (1.0–2.0 L) → 500–700 A cranking .
• Light diesel (1.5–2.0 L) → 700–900 A cranking (peak 1500–2000 A).
• Diesel 2.0–3.0 L / utility → aims for a high-end model (high cranking, thick cables).
• Hybrids & recent vehicles : there is always a 12V battery for the electronics. Starting possible according to the manufacturer's procedure (beware of "voltage jump" mode).
• 100% electric EV : you don't "start" the traction battery, but you can back up the 12 V (dashboard) by carefully following the instructions.

3) Safety: smart clamps, protections & standards

• Smart clamps (module on the cable):
  • Spark-proof : no arcing when connected.
  • Polarity reversal : alarm/LED if +/− reversed, cuts off the power.
  • Short circuit & overload protection : automatic cut-off.
  • Overvoltage/undervoltage protection : protects vehicle electronics.
• Housing : fireproof, shockproof, sometimes IP rated against light rain. Jumper cable connectors must be kept clean and dry.
• Standards & quality : CE, grade A cell batteries, high-section copper/alloy cables.
• “Force/Boost” mode (depending on model): for very low batteries. Only use if the manual provides for it.

4) USB-C PD ports, lighting & powerbank functions

• USB-C PD : 30–45W for smartphones/tablets; some boosters go up to 65–100W (laptop).
• USB-A : 12–18 W for accessories (watches, dashcam, 5 V router).
• LED light : SOS torch/flash mode, practical at night.
• Air/power : few boosters have a built-in 12V compressor (tire inflation). Otherwise, power a compressor via the car's 12V socket after starting.
• Booster charging : via USB-C (e.g. GaN 65–100 W) or 12 V car. Typical times 1.5–3 h depending on capacity.

100W USB-C Cables (5A e-marker) | 65–100W GaN Chargers

5) Step-by-step procedure: how to start safely

1. Safety : Turn off the ignition, lights and accessories. Apply the brakes and put the gearbox in neutral/P.
2. Connect the clamps : red to the + of the battery, black to a ground point (or the − if the manual indicates it). The smart clamps should display OK .
3. Turn on the booster (or “Start” mode). Wait for the LED/audio ready signal.
4. Start : Crank the engine for 3–5 seconds. If it doesn't start, wait 30–60 seconds and try again (max 3 attempts) to avoid overheating the booster and starter.
5. Disconnect : first the ground/− , then the + . Let the engine run for a few minutes to recharge the alternator.
6. If the battery is very flat : some boosters have a Boost/Force mode. Use only if the instructions allow it.

Tip : Turn off the blower/defroster/radio before the maneuver to keep all the intensity for the starter.

6) Winter & cold: succeeding in starting at low temperature

• Keep the booster “warm” (in the passenger compartment) before use. Lithium cells deliver better when warm (10–25°C).
• Two short cycles are better than one long one: 3–4 s then rest 30–60 s → less heating, better voltage.
• Headlights 10–15 seconds before attempting: on some cars this “wakes up” the electronics & stabilizes the battery voltage.
• Diesel : wait until preheating is complete (spark plug warning lights) before operating the starter.
• Dead battery (very old/swollen): booster = troubleshooting, but replace the battery quickly.

7) Booster care, storage & maintenance

• Maintenance refill : Top up every 2–3 months (or as per instructions). Stores around 50–80% .
• Temperature : Avoid a hot chest in summer and prolonged freezing in winter. Ventilated, dry and clean case.
• Condition of cables/clamps : check tightening, traces of oxidation, sheath intact.
• Updates (if applicable): some models have micro-firmware for security management.
• After starting : let the booster cool before recharging it.

8) Choice tables (practical benchmarks)

8.1 Cylinder capacity × recommended starting current

8.2 Key functions

9) Ready scenarios

10) Express shopping checklist

1. Engine type : petrol/diesel & displacement (table 8.1).
2. Cranking & peak : aim for 500–700 A (2.0 L petrol) / 700–900 A (2.0 L diesel).
3. Smart clamps : anti-spark, reverse polarity, complete protections.
4. USB-C PD : 30–45 W (phone/tablet) or 65–100 W (laptop).
5. Fast charging : USB-C input 45–100 W (GaN recommended).
6. LED lamp : useful at night (SOS).
7. Maintenance : Recharge every 2–3 months, storage 50–80%.
8. Kit : gloves, microfiber, instructions, 5A cable pouch.

11) LymobileShop selection (boosters & accessories)

12) 12V boosters FAQ

13) Trust & Services LymobileShop

• Delivery : free in France, fast shipping.
• Payment : secure, several methods to choose from.
• After-sales service : team in France, help with choosing cranking/cylinder capacity , USB-C PD , accessories.
• Returns & Warranty : 14 days to change your mind, 2 year warranty .

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