CTEK 40-256 20A Off Grid Bundle - D250SA and Battery Monitor

This is a bundle package of the D250SA 5 stage DC-to-DC charger and the fancy LCD display that shows full status of the battery. You can buy the stand alone D250SA module for over $100 less but I fancied the LCD display kit too. I've made the installation in our Dodge B-Series RV which had 2 x 6V deep cycle (golf cart style) batteries in the rear of the van. For years it never seemed that we could get the batteries fully charged (or how they say a 100% full 'State of Charge') because the distance of the long cable was a problem. I've even used 4 awg size wire over 19 feet and on my DMM I saw well over a 1 volt drop from the alternator (13.5 volts), while the front starter battery saw 14.5VDC. There was no way 13.5 volts would fully charge the batteries (or it would take 20 hours of diving time which is impractical). So what the D250SA module does is boosts the low DC voltage from the alternator to the battery ; i've tested it by plugging in a 20A battery charger to the input and while the charger only outputs 14V initially, my DMM shows at the deep cycle battery end I see over 15V. Then in a short period of time, it lowers the voltage down (hence being a smart charger 5 stages). Also confirmed voltages on the separately installed, LCD display of the charging voltage (and also shows discharging of the amps). It's a great way to see how much current is being charged and being drained. Have not fully tested the accuracy of the % capacity left (as have not yet drained the battery dead), the LCD can be set to show how many hour capacity left of the battery at the going current draw.Installation-wise wasn't difficult - it won't be if you've had car audio installation experience. Keeping wires neat, pay attention to proper cable connections, terminal & fuse blocks, you will have no problems. But if you cheap out on connectors and not using the correct size ring terminals, then you would be asking for trouble. Most RVs i've seen do not have a full proper battery status display. So this LCD product shows current draw & can calculate the capacity left in the battery at a going amp draw rate.The only negative is the price. I paid $380 and I see today, it's gone up to $435 (probably because of the Trump tariff). Generally speaking, most RVers wouldn't bother with such a device as the cost of 2 new 6V golf cart batteries would be far less. Though if you value full 100% capacity charge on the battery while you travel (and never having to rely on a separate AC plug in charger), then there is no other cheaper option. There is the Sterling brand but they're much bigger units and much higher capacity charging (I think 50A) and the price tag is in the $500+ range. If you bring the RV out of winter storage, I use a high amperage conventional AC to DC charger (no more than 20A as the D250SA module max output is 20A or around 250 watts) and charge the front battery + terminal. Also it's important to know that this the D250SA replaces a battery isolator or a battery voltage / solenoid switch setup. Electronics in the unit are very smart that it knows when to take on a charge and when to disconnect (isolate) from the front battery. It senses when the voltage goes high (ie from the alternator after starting the engine), then it delays to being the bulk charge. When you turn the engine off, the module sense a drop in voltage and waits for about 30 seconds to fully disconnect from the front battery. Very high tech IMO.

Well worth the price. Once installed, I don't even need to think about my batteries. I know they're being correctly and well charged. The monitor helps when I do bother to look, only to find that evrything is working as it should with optimal charging.

I have used these chargers before and they are very good, normally I would use the smart sensor to connect to my phone but decided on the LCD screen. Very easy to use but it is supplied with a non insulated shunt that needs to be covered in case anything falls across it. No cover supplied

After spending £440 on this product it would of been nice to have all of the required cables, leads, crimp connecters included!