The D250SE (CTEK Part No. 40-315) is a DC to DC fully automatic charger that’s designed to charge a Service Battery and is powered by the alternator/starter battery. With dual inputs the D250SE is also solar compatible (a standard solar controller is not necessary). The D250SE charger supplies up to 20A of power to any 12V lead-acid or lithium service battery from 40–300Ah. It also works if the starter battery and service battery are different chemistries, for example if the starter battery is lead/acid and the service battery is lithium. (Note: a service battery may also be called an auxiliary/aux battery, house battery, secondary battery, or backup battery.) This is a great charger for our V1 and V2 Lithium Deep Cycle Batteries.
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Description
CTEK D250SE 12V Smart Charger 20AThe D250SE (CTEK Part No. 40 315) is a DC to DC fully automatic charger thats designed to charge a Service Battery and is powered by the alternator starter battery. With dual inputs the D250SE is also solar compatible (a standard solar controller is not necessary). The D250SE charger supplies up to 20A of power to any 12V lead acid or lithium service battery from 40300Ah. It also works if the starter battery and service battery are different
Dual Inputs
The D250SE CTEK Charger has dual inputs and can charge the service battery from the alternator or a solar panel or both. The charger is designed to work with smart alternators and can still operate if the alternator is shut off but the vehicle has access to solar or wind power. So it can use power from the alternator, solar panel, wind power, or any DC power source can be used through the solar input port (within voltage spec). The D250SE can also charge the service battery from the solar input and the alternator in parallel using its built-in regulator to save fuel.
Optimum Charge
Continuous charging while the vehicle’s on the move means the batteries are fully charged in the shortest possible time. The built-in temperature sensor compensates for hot or cold conditions to prevent the battery from overheating or overcharging, so it always gets the optimum charge.
When the service battery being maintained is fully charged, the D250SE will automatically redirect overflow charge power to top-off the starter battery. The D250SE can maintain a stable output up to 20A to vehicles fitted with smart ECU controlled alternators.
LITHIUM
5-Step Program
- Accept*: Tests if the battery can accept charge. This step prevents that charging proceeds with a defect battery. (*Step 1 for lead/acid is Desulphation)
- Bulk: Charging with maximum current until approximately 90% battery capacity*. (80% capacity for lead/acid.)
- Absorption: Charging with declining current to maximize up to 95% battery capacity*. (100% capacity for lead/acid.)
- Float: Maintaining the battery voltage at maximum level by providing a constant voltage charge.
- Pulse: Maintaining the battery at 95–100% capacity. The charger monitors the battery voltage and gives a pulse when necessary to keep the battery fully charged.
Video about D250SE Charger
Specs
- CTEK PN: 40-315
- Input: 11.5–23V, 25A
- Output: Max 14.4/14.2/14.7V, 20A max
- Back-Current Drain*: Less than 1Ah/month
- Ambient Temperature: -4°F to +122°F (-20°C to +50°C)
- Battery Types: 12-Volt WET, EFB, Ca/Ca, MF, AGM, GEL, Lithium (LiFePO4, Li-Fe, Li-iron, LFP)
- Battery Capacity: 40–300Ah
- Insulation class: IP65 (splash and dust proof)
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.6 ★★★★★
Based on 1616 reviews
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Product Reviews
★★★★★ 5
Survived the sun like a pasty legend
Style: SPF 50, Size: 8 Fl Oz (Pack of 1)
I bought this sunscreen because I’m basically a human marshmallow — one hour in the sun and I’m toasted. This Amazon Basics Sport SPF 50? It’s like armor for the pale and easily crisped. I slathered it on before a full day of hiking, sweating, and pretending I enjoy direct sunlight, and guess what? No burn. Not even a pink glow. Just victory.
It goes on smooth, doesn’t feel greasy, and somehow stayed put through sweat, water, and my dog licking my arm. It’s fragrance-free, which means I didn’t smell like a coconut smoothie or a chemical spill — just clean and protected.
Pros:
• High SPF that actually works
• Sweat and water resistant — like, impressively so
• No greasy residue or weird smell
• Affordable and comes in a big ol’ bottle
• Didn’t turn me into a lobster (the bar is low, but still)
Minor feedback:
It’s not fancy or trendy, but honestly, I’m here to not burn — not win a skincare award. Also, it takes a bit of rubbing in, but once it’s on, it’s locked and loaded.
Final thoughts:
If you want solid sun protection without the drama, this stuff delivers. Whether you’re hiking, swimming, or just trying to survive summer, it’s a reliable sidekick. Would absolutely buy again — my skin demands it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 7, 2025
★★★★★ 5
Great Sunscreen at a Great Price!
Style: SPF 50, Size: 8 Fl Oz (Pack of 1)
Love this sunscreen. I live in FL and like to walk most mornings, and need a good sunblock. This Amazon Basics is far better than my previous, far more expensive brand. It's a great price for great quality. I've been using it on my body & face, it's non-greasy, absorbs well, and really seems to offer very good sun protection. And I really appreciate the next day shipping on my past two orders, Amazon. Thanks for the great product & great service!
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Reviewed in the United States on April 20, 2026
★★★★★ 5
Works when working outside and heavy activities
Style: SPF 50, Size: 8 Fl Oz (Pack of 1)
I use it as an Amazon delivery driver, and it works in the heat and sweat is no issue it does last for 2 hours. Reapplying it is extremely easy, no burns or sun damage to my skin. I can tell you it works cause I’m recovering from skin cancer and it works no problems or anything.
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Reviewed in the United States on May 19, 2026
★★★★★ 3
Just ok - too thick to apply evenly
Style: SPF 50, Size: 8 Fl Oz (Pack of 1)
Just ok - very thick, so difficult to apply evenly. I use this for outdoor cycling and it works, but it's so thick that it tends to clump instead of smoothly covering the skin.
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Reviewed in the United States on April 16, 2026
★★★★★ 5
Favorite sunscreen
Style: SPF 50, Size: 8 Fl Oz (Pack of 1)
Doesn't go on greasy. Doesn't stink. Don't get sunburnt wearing it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 6, 2026
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