Solar Charge controller

This low cost charger controller for under £20 gives better results than an expensive Morning Star £70 controller I had in my last van.

After checking levels and tightness of the connections at the battery and charge controller this week in March 2011, I noticed the pulsing equalization charge to the battery from the controller was 14.9 volts, I was a bit alarmed at such a high voltage at first, until I re-read the instruction manual, it stated that when the battery is fully charged and the ambient temperature is at zero or below, the controller will output nearly 15 volts in the equalisation mode for a short time before going into float mode of 13.8 volts. The equalisation mode will bring all cells in the battery bank up to the same charge level, so conditioning the battery. Seems to work as I have never had an Elecsol Carbon Fibre battery fail me in the last eleven years, the oldest battery being over ten years old, putting an old battery and new battery in parallel is supposed to be a no no, but it worked for me, and the charge controller seemed happy enough.

I am not sure just how happy my unregulated cheapo SMD 5050 LED lighting will be with a pulsating (PWM) line voltage/power, although if the sun is out I suppose I won’t be using the lights anyway.

 

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Hi Pete,

The SMD 5050 leds I have are the two quid variety from China, they have the tiny MB6S bridge rectifier so the led assembly connections are not polarity conscious, and a selection of resistors mounted on the pcb rear, but no voltage stabilisers, so they are rated at 12 volts only. Reading the forums some members have suggested that they should work up to 13.5 volts with not too much detriment to their longevity.

On a fully charged battery and when the controller is in the equalisation mode, the PWM frequency is fast enough not to effect the performance of the leds , i.e. no flickering can be detected, the battery would smooth things out as you remark, but the voltage at the battery terminals is still reading nearly 15 volts, not too good for my cheapo Chinese SMD 5050 leds.

I noticed as the cvan voltmeter was indicating 15 volts (verified) while the ammeter monitoring the controller output power, was cycling very quickly between 0.3 amps to 1.5 amps, now I know the ammeter will lag, but it looks to me as if the PWM is pulsing the power and not the voltage. If we get the same sunny conditions and zero ambient temperature later I will put my scope on the controller output to see what is actually happening.

I think you will find the 12 volt G4 LED types that stand up to 30 volts are the ones that cost upwards of £8 each not the 30 bob ones that I have – I know I’m a cheapskate -

Does anyone else have the combination of Solar Panel and the Cheapo Chinese LEDs ? and could check the battery voltage on a fully charged battery when the sun comes up?

Regards Terry

Nore about LEDs on link below.

www.caravantalk.org.uk/topic/44237-l-e-d-s-m-d-lights/pag...

Done