Solar Panel

[Guest]

I have a solar panel 14 watts and I want to connect it to two 110 Amps leisure batteries. I dont want to buy expensive controllers etc. I think that the only thing that I need is to put one or two diodes to ensure that the current does not flow back into the solar panel at nigh. I am correct ? If so, can I buy diodes from High Street stores like Maplin and what do I ask for?. How do I connect them? Many Thanks in advance.

 

[salamicollie]

Normally solar panels are supplied with a blocking diode (it is sometimes potted inside the connection to the panel) to stop your batteries discharging into the solar panel at night- check with the manufacturer. If you need to source one you need a diode that will rated for 20v and 2A

With a 14W unit you may be at the limit for charging without a regulator for a 220 Ah battery - if it is used to top up the batts over the week, don't be suprised if the voltage reaches 15 - 16V in bright sunlight. Unisolar reccmnd a cell not more than 1.5% of the batt cap - so you should be OK

 

[Shanty]

If your panels don't already have blocking diodes, go to Maplins or whoever, and ask for Schottky diodes. Why? Because all diodes will introduce a voltage drop into the circuit. Schottky diodes produce about half the drop of conventional diodes. Won't matter too much in bright midday sun, but will make a difference in more marginal conditions. The Schottky diodes are about twice the price, but, hey you can afford it (10p as against 5p from memory).

 

[billskip]

there are other threads on this..and one that gives a supplier for regulators..less than £30 i think..your going to spend a couple of quid on diodes etc..i think its worth getting a regulator..could save a forget to disconect/overcharge mistake...unless you get your batteries free..I made same inquiry.and opted for regulator...best of luck..

Bill
www.aegeansailing.co.uk

www.macsyachting.com

 

[ccscott49]

With a 14watt panel, I don't think you will have any trouble with overcharging, just leave a light on in the boat if you are worried about it, but 14 watts is not a very big panel for 220 amp hour batteries. Especially in the UK

 

[onenyala]

I have had an 18 watt solar panel charging two baterries in parallel (80amph and 110 amph) for about four years. It has never been disconnected and is not fitted with a regulator - only a blocking diode which as one other correspondent states is built into the panel. The SG of the batteries is always very healthy.
Stuart Jones