Solar powered trickle chargers

Post by **Axolotl** » Tue May 22, 2007 4:03 pm

Does anyone know if these things actually work?

The sort that sits on your dashboard and plugs into the cigar lighter socket.

They claim they can keep a battery from self-discharging when left on a vehicle that isn't used very often. Don't need direct sun, just daylight.

Has anyone used one, and what were the results?

I only ask because Maplins are flogging them off for a tenner at the moment, so I thought it might be worth a punt.

Post by **Rob_Jennings** » Tue May 22, 2007 4:13 pm

They seem to work Ok, I know of friends that use them on their boat to keep the batteries in fair condition.

They don't provide much of a charge current, and so only really account for natural battery loss (caused by temperature cycles) and very low drain (clocks and general leakage in the loom). They cannot save you from a bad battery, but can keep a good one topped up.

Post by **rayofleamington** » Tue May 22, 2007 6:30 pm

I've also been interested in these - for a tenner I'm even more interested!

Post by **les** » Tue May 22, 2007 9:14 pm

There was an ad in practical classics or similar ages ago, regarding an exide solar charger, I phoned the manufacturer who said they stopped selling them, seems the units (made by others but badged exide) were not too good. Maybe they are better now.

Post by **Axolotl** » Tue May 22, 2007 10:17 pm

£9.99 actually. There, I've already saved you 1p

Here's the description on their web site:

http://www.maplin.co.uk/module.aspx?Mod ... 8&doy=22m5

I'm off down the local shop tomorrow to invest in one.

I'll let you know what it is like.

Post by **grahamt7** » Tue May 22, 2007 10:52 pm

Cigarette lighter?

Post by **RogerRust** » Wed May 23, 2007 5:53 am

No good for you, Graham. They need sunshine. I didn't see the sun for years at a time when I lived in Manchester!!

Post by **Axolotl** » Wed May 23, 2007 8:44 am

Cigarette lighter?

Cigar lighter. It goes next to the brandy balloon holder so you can have a smoke and a drink while you are waiting for the man to fill up the tank.

I fitted one so I could charge my mobile.

Post by **bmcecosse** » Mon May 28, 2007 9:39 pm

It's a stunning 1.5 watts !!! You would need 10 of them to get a worthwhile charge going!! And even then it will only be 1 amp!!!

Post by **alex_holden** » Tue May 29, 2007 8:44 am

It's not going to recharge a flat battery, but you don't need much power to keep a good battery topped up.

Post by **Axolotl** » Tue May 29, 2007 9:34 am

Well, I bought two, one for the Rover and one for the Morris Minor.

Measuring voltage at the terminals without a battery connected, the output varies from about 5v indoors away from the windows, up to 23v outdoors facing direct bright sun.

Connected to a battery, you just get the battery voltage.

In power terms, even on a very sunny day, I couldn't measure anything like the 135 mA they quote. More like about 10 mA.

The battery voltage on my Rover 75 was still going south at an alarming rate when left for a couple of days even with the solar charger plugged in, but I suspect that battery (3 years old, 75 Ah) is on the first of its last legs, and it has to power the alarm system and central locking gubbins.

Using a Draper digital meter, I measured 12.61 v at the start, and 12.36 v after standing three days.

On the Morris, (one year old 45 Ah) I measured 12.76 v at the start, and 12.77 v after three days. Possibly evidence that the trickle charge will keep a good battery topped up. More likely that the battery would have stayed good anyway.

That battery doesn't have to power anything when left.

I don't have any "without" charger numbers for comparison.

On balance, I'd say, spend the money on a couple of pints down the pub.

Post by **8009STEVE** » Tue May 29, 2007 5:42 pm

On balance, I'd say, spend the money on a couple of pints down the pub

Sounds good to me.

Hic.