CTEK 250S Dual DC-DC Charger project

PigPen’s power requirements are mainly the Waeco compressor fridge (I estimate it uses about 20 ah/day) and nominal use for LEDs and water pump.

To maximise the amount of power available, PipPen’s  power solution now consists of the following:

1. Ctek DC-DC 20amp charger
2. 120w flexible solar panel permanently on the lid
3. A folding 2x50w panel for when camped up
4. The factory fitted 2x95Ah AGM with the 240v Ctek M200 charger for using on grid or generator (I am told there are parts of Australia where it does rain)
5. A NASA BM1 battery monitoring system
6. A mobile MPPT solar regulator and 240v Ctek MX 5 as back-up and for charging Waeco PowerCool (for car freezer) and car battery if required.

Using Richard Graylin’s solar usage spread sheet, I estimate I can go now go 6-7 days based on 5 hours/day on solar. The spread sheet can be found here http://www.campertrailers.org/solar_spreadsheet.htm

The way I physically installed the Ctek 250s was to fit the device and fusing to a solid piece of ply which is bolted into the battery box using the same bolts from the battery securing angle bracket. This fitted neatly at the rear of the battery box under the fuse box. I continued to use the triangular aluminium brace from my battery monitor installation for the shunt (and all earthing) and an Anderson plug for the folding solar panel.

The semi-flexible solar panel on the lid is attached using to use 3M VHB (very high bond) tape – I used type 4910 which is waterproof and very thin, then Sikaflex’d around the sides.

Fusing is:
1. 40amp manual reset ANL fuse on alternator + cable before CTEK 250
2. Blade fuse box with:
a. 10amp blade fuses on each of the solar + inputs (probably not necessary but protects panels in case of malfunction)
b. 30 amp blade fuse on CTEK + out (to protect camper devices on CTEK malfunction)

On reflection the blade fuse box was probably not required.

Project cost – Ctek 250S – $250, about $100 for wiring, fusing, plugs and fixing, approx $210 for each solar panel, $185 for BM1 battery monitor system, $35 for portable MPPT – say $1000 all up.

CTEK Fitted

CTEK Fitted

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