Batteries for solar

FnOzi · Member

Batteries for solar

Bent Axle Bob · Senior Member

IF you are only going to run your LED lighting why do you need solar. These lights draw very little current and many run 12 OR 24volts. A solar system for this application seems a little "overkill". However a smaller amp hour , AGM battery coupled to a medium sized panel (80 watts) would be more than ample.for your application

jimricho · Guru

Hi FnOzi,

I assume your reference to 24 v appliances is just a simple typo and you mean 240 v. This implies regular "camping" on powered sites.

As BAB has pointed out, these lights are very economical in regards to their power requirements and I agree with his comments about the need for solar. You can always add solar later if you find you need it.

A 50ah AGM coupled to a "smart" charger (240v) such as a "Ctek" should be more than adequate for your needs. A charger in the 4-7amps range would be fine and any larger would be overkill. The charger would power the lights and recharge the battery when on "ground" (external 240v) power.

If you intend to use a laptop and/or 12v TV when not on power you may need to think about a 100ah AGM and a smart charger in the 7-15 amp range.

I believe you are "on the right track" in economising your power requirements rather than going overboard with a large 12v battery/charging system.

Jim

FnOzi · Member

Hi Friends,thanks for your replies,

I am half-way through converting a 40ft Bus,so 24v is what I intend to use for fridge and TV.24v for running the fridge permanently and the TV occasionally.

I have 260w solar panels(24v) for keeping the house batteries topped up,and was inquiring as to the batteries that would suit 12v ,for LED lighting needs.

Although I have a generator (5.5kw pure sinewave inverter)for air con needs,I wish to be totally independent when I embark.

Q/,what battery would be most suited for ,say a 120w solar panel,running only LED lighting ?.

I have 12v and 24 v LED lighting to accomodate

PeterD · Guru

Have you done the costing for converting your lights to 24 V? The cost of providing a 120 W panel and a battery to match will purchase a lot of 24 V lights. You seem to have an extensive system already in place (or planned.) Running a few high efficiency lights on this would probably not stress it at all.

-- Edited by PeterD on Wednesday 10th of August 2011 12:30:26 PM

gubby · Guru

If the LED's are rated at 12v all you have to do is connect them in pairs, wired in series, to run them on 24v..

jimricho · Guru

So much for my comment about going overboard with a battery/charger system!

Why not just stay with the 24 v battery system and fit a 24v - 12v switchmode power supply to power your 12v loads such as the lights, also other 12v appliances such as phone charger, radio/CD, etc.

I would suggest you purchase the relevant publications from http://www.caravanandmotorhomebooks.com/books/index.htm

(Disclaimer: I have no connection with the publisher of these books)

-- Edited by jimricho on Thursday 11th of August 2011 07:41:00 AM

FnOzi · Member

Hi Jim,thanks for your reply,

In reference to a "switchmode",are you describing a 24 to 12 reducer ?,if so,I reckon your on the money.

My question is ;will 10 amps be sufficient to run several outlets at the same time,as I have a 10 amp reducer already ?.

cheers FnOzi...

jimricho · Guru

FnOzi wrote:
Hi Jim,thanks for your reply,
In reference to a "switchmode",are you describing a 24 to 12 reducer ?,if so,I reckon your on the money.
My question is ;will 10 amps be sufficient to run several outlets at the same time,as I have a 10 amp reducer already ?.
cheers FnOzi...

I think that would be fine as long as you don't "stretch the friendship" with it by connecting devices such as inverters (probably unlikely as it seems to me that you've taken care of this with your 24v system), tyre compressor, possibly water pump, a whole bunch of fluoro/ halogen lamps (likewise taken care of with the use of leds), etc.

I think all the later 24-12v reducers would be "switchmode" types and therefore reasonably efficient.