STMATESRATES
Seems like a good price for these which appear to be on their way out to be replaced by the D250SE.
I've been using the D250S for years and it's a great bit of kit.
The Ctek D250SA is an intelligent DC-DC charger which maximises battery capacity as a charging solution where charging from mains power (AC) is not available. This makes it great for extended periods spent on the road or water. The 5 step process supplies 20 As of charging power to any lead acid battery from 40a/h all the way up to 300ah. The charger has multiple-input technology, meaning you can simultaneously supply charge from your alternator (including smart alternators for newer, hi-tech vehicles), solar panels or even from wind power. Once the intelligent voltage sensitive charger recognises that your deep cycle leisure batteries are topped off, it will supply a maintenance charge output to the vehicle's starter battery to ensure you have full cranking power when its time to fire up the beast. The device is an all-in-one in terms of implying and completing your 12v, off grid setup. It removes the necessity for messy voltage sensitive relays used to split charging between batteries and even means you can throw your cheap solar panel regulator in the bin too, thanks to its MPPT (maximum power point tracking) technology. The Ctek D250SA is designed to endure tough conditions including operating temperatures ranging from negative 20 degrees Celsius all the way up to 50 degrees Celsius and with a 2 year warranty as standard you can trust that this 12V solution will go the distance in your 12v setup.
- Ambient operating temperature: -20 ˚C to +50 ˚C (- 4 °F to +122 °F)
- Positioning: Permanent installation / on board
- Warranty: 2 years
- Input: 11.5–23 V, 25 A
- Output: 14.4/14.7 V, 20 A
- Back current drain: Corresponding to less than 1 Ah/month
- Battery types: 12 V:, WET, MF, Ca/Ca, AGM, EFB, GEL
- Battery capacity: 40–300 Ah
- Ingress protection: IP65
- Ripple: Less than 4 %
- Dimensions: 192 x 110 x 65mm (L x W x H)
Just double check this if buying for a lithium battery. I think this model had a desulfation state which pulses a high voltage at the beginning of the charge. Can't be switched off.