About this item
Jump-starts a dead car battery
Built-in tire inflator for low tires
Flashlight doubles as emergency roadside lighting
Compact enough to keep in a glovebox or trunk
Can trickle-charge a phone or tablet in a pinch
Product details
One compact unit that jump-starts a dead battery and inflates a low tire, so a dead battery and a flat on the same trip don't need two separate tools. A built-in flashlight doubles as emergency lighting if you're stuck on the roadside after dark.
It ships uncharged — give it a full charge before the first jump-start so the battery breaks in properly and lasts.
Specifications
Setup guide
- 1. The unit ships empty — turn on the flashlight briefly to fully discharge it first.
- 2. Charge the unit for at least 4 hours before your first jump-start. This step protects long-term battery life.
- 3. Don't charge and discharge (e.g. jump-start) the unit at the same time.
- 4. Recharge the unit every 3 months, even if unused — a low charge can cause a failed jump-start.
- 5. Use it to charge a phone or tablet only occasionally; battery-to-device charging efficiency is roughly 50%.
- 6. Charge/discharge speed increases in the final 15% of charge — this is normal high-rate lithium battery behavior and doesn't affect quality or safety.
FAQ
What do I do when it arrives?
Turn on the flashlight briefly to discharge it, then charge it for at least 4 hours before the first jump-start — it ships empty, and this protects battery life.
How often should I recharge it?
Every 3 months, even unused — a low charge can mean a failed jump-start when you need it.
Can it charge my phone?
Occasionally, yes — but efficiency is about 50%, so treat it as an emergency backup, not a daily power bank.
What's the difference between the models?
J23 includes the air pump for tire inflation; J40 is the jump starter only.
Why does charging speed up near the end?
That's normal for high-rate lithium batteries in the final 15% — it doesn't affect quality or lifespan.