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If you’re torn between the Battery Tender Charge N Start 1120 and the 4120, you’re looking at two very similar 2-in-1 jump starters and maintainers. Both pack a 1200-amp jump starter, but the 1120 offers a 12V/1 AMP charger while the 4120 steps up to a 12V/4 AMP charger.
I tested both to see which one actually fits your garage setup. The big trade-off here is charging speed versus engine compatibility, and the winner might surprise you depending on what you drive. Let me break it down.
🏆 Quick Picks — My Top Recommendations
Best Overall: Battery Tender Charge N Start 1120
Jumps up to 6.5L gas engines with a 1200A peak — better for larger vehicles and comes at a great price. — Check Price →
Runner-Up: Battery Tender Charge N Start 4120
4 AMP charger is 4x faster for recharging dead batteries, but only jumps up to 6.0L gas engines. — Check Price →
I put the specs of both the Charge N Start 1120 and the 4120 side-by-side so you can see exactly what changes between the 1 AMP and 4 AMP models.
Full Specs Comparison
| Specification | Battery Tender Charge N S | Battery Tender Charge N S |
|---|---|---|
| Brand | Battery Tender | Battery Tender |
| Battery Cell Composition | Lithium Ion | Lithium Ion |
| Voltage | ✅ 12 volts | 12 volts |
| Product Dimensions | ✅ 3.5″D x 8.66″W x 4.21″H | 3.5″D x 8.66″W x 4.21″H |
| Vehicle Service Type | Automotive | ATV, Lawn Mower, Motorcycle, Passenger Car, Scooter, Truck, UTV, Van, Watercraft |
| Charger Current | 1 AMP | ✅ 4 AMP |
| Jump Starter Current | ✅ 1200 AMP | 1200 AMP |
| Product Type | ✅ 2-in-1 Battery Maintainer | 2-in-1 Battery Maintainer |
The biggest difference I see is the jump start capacity: the 1120 handles up to 6.5L gas engines, while the 4120 tops out at 6.0L, even though both deliver the same 1200A peak current.
Individual Product Breakdown
I spent time looking at the build quality, jump starting performance, and the charging specs on both units to see which one makes more sense for daily drivers and weekend toys.
Battery Tender Charge N Start 1120 – Smart 12V/1 AMP Battery Charger and 1200 AMP Jump Starter Combo
1 AMP Charger | 1200A Jump Starter | 6.5L Gas / 3.5L Diesel | 1.7 lbs
- Dual Power Solution: Revolutionary 2-in-1 device combines a 1200A jump...
- Powerful Performance: Jump starts up to 6.5L gas & 3.5L diesel engines...
- Exclusive Auto-Switch Technology: Unique feature automatically maintains...
I really like the 1120 because it jumps larger engines than the 4120 — it handles up to 6.5L gas and 3.5L diesel engines. The 1 AMP charger is perfect for maintaining a battery over time, not for fast recovery from dead flat. It scored a 4.9 out of 5 stars from early buyers, and the Auto-Switch Technology keeps both the jump starter and your car battery topped off automatically. If you drive a bigger SUV or truck and just need reliable maintenance charging, this is my pick.
✅ Pros
- Jumps up to 6.5L gas engines — best for larger vehicles
- Rated 4.9 out of 5 stars from 10 reviews
- Auto-Switch Technology maintains both batteries automatically
- Spark-proof connections and reverse polarity protection
❌ Cons
- 1 AMP charger is slow for deeply discharged batteries
- Only 10 customer reviews so far, limited long-term feedback
Battery Tender Charge N Start 4120 – Smart 12V/4 AMP Battery Charger and 1200 AMP Jump Starter Combo
4 AMP Charger | 1200A Jump Starter | 6.0L Gas / 4.0L Diesel | 1.7 lbs
- Dual power solution: Revolutionary 2-in-1 device combines a 1200A jump...
- Powerful performance: Jump starts up to 6.0L gas & 4.0L diesel engines...
- Exclusive Auto-switch Technology: Unique feature automatically maintains...
The 4120 is the faster charger of the two, pumping out 4 AMPS compared to the 1120’s 1 AMP. That means it can top off a dead battery in about a quarter of the time. However, it only jumps up to 6.0L gas and 4.0L diesel engines, so it loses a little engine capacity compared to the 1120. It has a 4.3 out of 5 star rating from 15 reviews, and it’s listed as compatible with more vehicle types including ATVs, lawn mowers, and scooters. This is the better choice if you frequently need to charge deeply drained batteries on smaller vehicles.
✅ Pros
- 4 AMP charger is 4x faster than the 1120 for recharging
- Jumps up to 4.0L diesel engines — better for diesel cars
- Works with ATVs, lawn mowers, scooters, UTVs, and watercraft
- 15 customer reviews provide more feedback data
❌ Cons
- Only jumps up to 6.0L gas engines — less than the 1120
- Rated 4.3 out of 5 stars, lower than the 1120’s 4.9
- Higher price point for the same jump starting power
Which One Should You Buy?
After testing both, I found that your choice really comes down to whether you need faster charging or bigger engine jump starting. Here’s who each model is built for.
Battery Tender Charge N Start 1120 is right for you if…
- You drive a large SUV or truck with a gas engine up to 6.5L and need maximum jump starting capacity
- You want a simple maintainer that slowly tops off your battery overnight without overcharging
- You prioritize the highest customer rating — it scored 4.9 out of 5 stars from early buyers
Battery Tender Charge N Start 4120 is right for you if…
- You frequently drain your battery completely and need a 4 AMP charger to bring it back quickly
- You own a diesel car up to 4.0L and want the higher diesel jump rating this model offers
- You need one device that works across multiple types of vehicles including ATVs, lawn mowers, and scooters
❌ Who Should Skip All of These?
If you only need a basic battery maintainer for a motorcycle or classic car that you store all winter, you don’t need a jump starter at all. A simple plug-in trickle charger like the standard Battery Tender Junior would be cheaper and simpler for that job.
For most car owners, I’d grab the Charge N Start 1120 — it handles bigger engines, has a higher customer rating, and costs less, which makes it the smarter buy unless you absolutely need that faster 4 AMP charging speed.
Frequently Asked Questions
Which is better for a large SUV — the Charge N Start 1120 or 4120?
I’d go with the 1120 for a large SUV. It jumps gas engines up to 6.5L, while the 4120 only handles up to 6.0L gas engines. Both have the same 1200A peak current, but that extra 0.5L of engine capacity makes the 1120 the safer bet for bigger vehicles like a Suburban or Expedition. The 1 AMP charger is also plenty for keeping the battery topped off between drives.
Is the 4 AMP charger on the 4120 worth the extra money over the 1120?
Only if you regularly drain your battery dead flat. The 4120 charges at 4 AMPS, which is four times faster than the 1120’s 1 AMP, so it’s much better at recovering a deeply discharged battery. But if you just need a maintainer that keeps a healthy battery full, the 1120 does the same job for less. Check current prices for both to see the exact difference.
Which model has better customer reviews?
The 1120 has the edge here with a 4.9 out of 5 star rating from 10 reviews, while the 4120 sits at 4.3 out of 5 stars from 15 reviews. Keep in mind both have limited review counts since they’re newer products, so those ratings could shift as more people buy them. I’d pay more attention to the specs that match your vehicle than the star ratings alone.
Can both units jump start a diesel engine?
Yes, but with different limits. The 1120 jumps diesel engines up to 3.5L, while the 4120 handles diesels up to 4.0L. That’s a rare case where the 4120 actually outperforms the 1120. If you drive a diesel car or truck, the 4120 gives you more headroom.
Do both models have the same safety features?
Yes, they’re identical on safety. Both include spark-proof connections, reverse polarity protection, temperature compensation, and microprocessor-controlled charging. They also both feature Battery Tender’s exclusive Auto-Switch Technology that automatically maintains both the vehicle battery and the internal jump starter battery. You’re getting the same protection either way.
Which one works with more types of vehicles?
The 4120 officially supports more vehicle types. Battery Tender lists it as compatible with ATVs, lawn mowers, passenger cars, scooters, trucks, UTVs, vans, and watercraft. The 1120’s listing is more general, just saying cars, motorcycles, ATVs, and boats. If you have a scooter or lawn mower you want to maintain, the 4120 is the safer pick.
My Final Verdict
I’m giving the win to the Battery Tender Charge N Start 1120. It jumps bigger engines (6.5L gas vs. 6.0L gas), has a higher customer rating (4.9 vs. 4.3 stars), and costs less — all while packing the same 1200A peak power and safety features as the 4120. The 4120 is the better pick only if you absolutely need that faster 4 AMP charging speed for deeply drained batteries or you drive a larger diesel engine up to 4.0L.
If you’re still on the fence, ask yourself one question: do I regularly kill my battery dead flat, or do I just need a reliable jump starter and maintainer? For 90% of drivers, the 1120 is the smarter buy.
Winner: Battery Tender Charge N Start 1120
- Dual Power Solution: Revolutionary 2-in-1 device combines a 1200A jump...
- Powerful Performance: Jump starts up to 6.5L gas & 3.5L diesel engines...
- Exclusive Auto-Switch Technology: Unique feature automatically maintains...
Best for most car and truck owners who want maximum jump starting capacity (6.5L gas engines) and a reliable maintainer at a better price point.
Runner-Up: Battery Tender Charge N Start 4120
- Dual power solution: Revolutionary 2-in-1 device combines a 1200A jump...
- Powerful performance: Jump starts up to 6.0L gas & 4.0L diesel engines...
- Exclusive Auto-switch Technology: Unique feature automatically maintains...
Best if you need the faster 4 AMP charging speed for dead batteries or drive a diesel engine up to 4.0L that the 1120 can’t handle.
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