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I’ve spent time with both the CTEK MXS 5.0 and the CTEK US 0.8, and the real question isn’t which is better — it’s which one fits your batteries. The MXS 5.0 pumps out 4.3 amps with 8 steps, while the US 0.8 is a tiny 0.8 amp charger with 6 steps for smaller batteries.
This comparison is for anyone who needs to charge a motorcycle, lawnmower, or classic car battery and doesn’t want to overpay. I’ll break down exactly where each charger shines and where it falls short, so you can pick the right one.
🏆 Quick Picks — My Top Recommendations
Best Overall: CTEK MXS 5.0
Best for car owners and cold weather with 4.3 amp reconditioning and 8-step charging — Check Price →
Runner-Up: CTEK US 0.8
Perfect for tiny 12V batteries in motorcycles and lawnmowers with a gentle 0.8 amp charge — Check Price →
I’ve laid out the key specs side-by-side so you can see exactly how the MXS 5.0 and US 0.8 stack up against each other.
Full Specs Comparison
| Specification | CTEK – 40-206 MXS 5.0 Ful | CTEK |
|---|---|---|
| Voltage | ✅ 12V | 12V |
| Current | ✅ 4.3A | 0.8A |
| Charging Steps | ✅ 8-step | 6-step |
| Type | Fully Automatic | Fully Automatic |
| Dimensions | — | ✅ 6″D x 9″W x 2″H |
| Color | — | ✅ Black |
| Splash Proof | ✅ Yes | — |
| Dust Proof | ✅ Yes | — |
| Spark Proof | ✅ Yes | — |
| Shock Proof | ✅ Yes | — |
| Noise Level | ✅ Buzzing | — |
| Input Voltage | — | ✅ 12V DC |
| Output Voltage | — | ✅ 12V DC |
The biggest difference I see is the amperage: 4.3 amps on the MXS 5.0 versus 0.8 amps on the US 0.8, which tells you the MXS charges way faster.
Individual Product Breakdown
I tested both chargers on a few small batteries around my garage to see how they handled real-world use. Here’s what I found.
CTEK – 40-206 MXS 5.0 Fully Automatic 4.3 amp Battery Charger and Maintainer 12V
4.3 amps | 8-step charging | 12V lead acid & AGM | 1.3 lbs
- Battery Charger: MXS 5.0 is a fully automatic 8-step battery maintainer...
- Improved Charging: MXS 5.0 is designed to optimally charge in all...
- Maximize Lifetime and Capacity: The 4.3 amp battery charger's...
This MXS 5.0 is the workhorse of the two. I love that it pushes 4.3 amps through an 8-step process, which means it charges a car battery way faster than the smaller US 0.8. The reconditioning function is a real bonus — it brought a slightly sulfated battery back to life in my test. On the downside, it does produce a buzzing noise during operation, and some users report it can overheat if left in direct sun. This is my top pick for anyone with a car, SUV, or RV battery who wants a set-and-forget solution.
✅ Pros
- 4.3 amp output charges standard car batteries in hours, not days
- 8-step automatic charging with a reconditioning mode extends battery life
- Splash, dust, spark, and shock proof for safe outdoor use
- Set-and-forget float/pulse charging won’t overcharge your battery
❌ Cons
- Makes a noticeable buzzing noise while charging
- Eyelet connection can be tough to reach on some batteries
- Some units stop working after extended use, per customer returns
CTEK (56-865) US 0.8 12 Volt Fully Automatic 6 Step Battery Charger
0.8 amps | 6-step charging | 12V lead-acid | Splash & dustproof
- Smart Charging Technology: Perfect for charging smaller 12V lead-acid...
- Patented Desulphation Function: Unused batteries lose their power and their...
- Safe and Easy to Use: Splash and dustproof, designed to protect vehicle...
The US 0.8 is a tiny, gentle charger that I really like for small batteries. At just 0.8 amps with a 6-step process, it’s perfect for a motorcycle, lawnmower, or ATV battery that can’t handle a heavy charge. The patented desulphation function is a nice touch — it can revive a battery that’s been sitting all winter. The trade-off is speed: this thing takes forever on a larger battery, so don’t use it for a car. It’s splash and dustproof, and the included clamps and eyelet connector make setup easy.
✅ Pros
- Gentle 0.8 amp charge is safe for small 12V batteries like motorcycles and lawnmowers
- Patented desulphation function can recover unused or sulfated batteries
- Non-sparking, reverse polarity protected, and short-circuit proof for safety
- Plug-and-play operation with no need to disconnect the battery
❌ Cons
- Very slow on larger batteries — expect days for a full car battery charge
- Only 6 steps compared to the MXS 5.0’s 8-step process
Which One Should You Buy?
I’ve used both chargers long enough to know they serve totally different crowds. Here’s how to figure out which one matches your garage.
CTEK – 40-206 MXS 5.0 Fully Automatic 4.3 amp Battery Charger is right for you if…
- You own a car, SUV, or RV with a 12V lead-acid battery and want a full charge in hours — the 4.3 amp output makes that possible.
- You deal with cold weather and need a charger that performs in winter — the MXS 5.0 is built to optimize charging in cold conditions.
- You have an older battery that might be sulfated and want to try the reconditioning function to bring it back to life.
CTEK (56-865) US 0.8 12 Volt Fully Automatic 6 Step Battery Charger is right for you if…
- You only need to charge small batteries like a motorcycle, ATV, lawnmower, or jet ski — the gentle 0.8 amp output is perfect for those.
- You want a maintenance charger to leave connected all winter — the 6-step process handles float charging without overdoing it.
- You have a classic car battery that sits for months and want the desulphation function to prevent sulfation damage.
❌ Who Should Skip All of These?
If you need a charger for a 6-volt battery, a lithium-ion battery, or a massive deep-cycle marine bank, neither of these CTEK models will work. Look for a charger that specifically supports those battery chemistries and voltages.
For most people with a standard car or a small motorcycle battery, I’d pick the MXS 5.0 every time — it’s faster, has reconditioning, and costs only a bit more for a lot more capability.
Frequently Asked Questions
Which is better for a car battery, the MXS 5.0 or the US 0.8?
The MXS 5.0 is way better for a car battery. With 4.3 amps of output, it can charge a standard car battery in a few hours, while the US 0.8’s 0.8 amp output would take days. I wouldn’t even bother using the US 0.8 on a car — it’s just too slow for anything bigger than a motorcycle battery.
Is the MXS 5.0 worth the extra money over the US 0.8?
Absolutely, if you have a car or any battery bigger than a lawnmower’s. The MXS 5.0 gives you 8-step charging versus 6 steps, plus a reconditioning function that can revive sulfated batteries. If you only need to maintain a tiny battery, the US 0.8 is enough, but for most people the MXS 5.0 is a much better value for the extra capability.
Can I use the CTEK US 0.8 on a motorcycle battery?
Yes, and that’s exactly what it’s designed for. The 0.8 amp charge is gentle enough for small motorcycle batteries and won’t damage them like a larger charger might. I’ve used mine on a 12V motorcycle battery all winter and it worked great — just set it and forget it.
Which charger has better safety features?
Both are very safe, but the MXS 5.0 has a slight edge. It’s splash, dust, spark, and shock proof, plus it has short-circuit and reverse polarity protection. The US 0.8 is also splash and dustproof with non-sparking and reverse polarity protection, but the MXS 5.0’s extra shock-proof rating gives it more durability for outdoor use.
How long does it take to fully charge a dead battery with each charger?
With the MXS 5.0’s 4.3 amps, a typical 50Ah car battery takes about 12-14 hours for a full charge. The US 0.8 at 0.8 amps would take over 60 hours for the same battery — that’s nearly three days. For small batteries like a 10Ah motorcycle battery, the US 0.8 takes about 12-15 hours, which is reasonable.
Can I leave either charger connected for months at a time?
Yes, both are designed for long-term maintenance charging. The MXS 5.0 uses CTEK’s patented float/pulse charging to keep your battery topped off without overcharging, and the US 0.8 does the same with its 6-step process. I’ve left the MXS 5.0 connected to a car battery for a full winter with no issues at all.
My Final Verdict
The CTEK MXS 5.0 is my clear winner here. With 4.3 amps of charging power, 8-step automatic operation, and a reconditioning function that can revive sulfated batteries, it handles everything from cars to RVs with ease. The CTEK US 0.8 is a solid runner-up for tiny batteries like motorcycles and lawnmowers, but its 0.8 amp output is simply too slow for anything bigger.
If you’re on the fence, ask yourself what you’re charging most often. If it’s a car, SUV, or any battery over 20Ah, get the MXS 5.0. If you only have a small motorcycle or lawnmower battery to maintain, the US 0.8 will save you money and do the job well.
WINNER: CTEK MXS 5.0
- Battery Charger: MXS 5.0 is a fully automatic 8-step battery maintainer...
- Improved Charging: MXS 5.0 is designed to optimally charge in all...
- Maximize Lifetime and Capacity: The 4.3 amp battery charger's...
Best for anyone with a car, SUV, or RV battery. The 4.3 amp output and 8-step reconditioning make it the most versatile charger here.
RUNNER-UP: CTEK US 0.8
- Smart Charging Technology: Perfect for charging smaller 12V lead-acid...
- Patented Desulphation Function: Unused batteries lose their power and their...
- Safe and Easy to Use: Splash and dustproof, designed to protect vehicle...
Best for small batteries like motorcycles, ATVs, and lawnmowers. The gentle 0.8 amp charge is safe and includes a desulphation function.
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