Ring Solar Power Battery Maintainer RSP150

Ring Solar Power Battery Maintainer RSP150

After buying my Autolite Sta-Ful replica battery I have found out that these sort of maintenance free batteries should not be run down to nothing as it will cause permanent damage to the battery and will not recover to hold the full charge again, or any charge again come to that. So I got a bit worried about the battery. I have been told that for every month the battery is not used it looses 10 – 20% of its life. Considering that it will only take a couple of months before there is not enough power to turn the engine over. The weather will also add to the failure of the battery, cold will shorten the life considerably or even cause it to fail big time. This goes for modern cars as well as classic and vintage cars.

The solution – Ring Solar Power Battery Maintainer RSP150 = £10 – £20

Ring Solar Charger Box RSP150
Ring Solar Charger Box RSP150

In the Box

Inside the box is a plastic encasing packaging that houses the solar panel, direct battery connection leads, cigarette lighter plug, 4 rubber suckers and a tiny a5 warranty and instruction sheet. Oh, and a bit of foam to cover the glass.


This is simple, there is a choice for a live feed cigarette lighter plug that will then sit inside the car stuck to windscreen or left on the dash. The wiring is such in my car that I didn’t want that option or have it, so I have taken the clips to the battery direct approach. There is a useful function that prevents reverse polarity and will also stop a drain on the battery when there is not enough light to charge it. As my car is under a cover most of the time I could not really use it inside. But, saying that it did work under the cover on a bright day, not so much when it was overcast under the cover which is only to be expected.

To wire it up I have placed it outside at the front of the car,  to attract the sun as much as possible. When the same weather was overcast the solar power was still providing power and I was really quite impressed at just how little light it needed to work. Obviously, the less bright the sun there’s not quite as much power produced. The instructions say that in order for this unit to be outside you need to seal the gap from the case to the glass with some silicon sealer. Considering theat would always be an option for users I am not sure why this was not done to seal the water and moisture out! And that is my only small gripe, and lucky I had some sealer!

Ok, the clip leads are long as they are approx 2.7m long and will comfortably stretch to where you want them. Mine is on the front of the car up through the grille to the battery.

Ring Solar charger
Ring Solar charger


This is going to be a short section , you plug the end to the unit and the clips to the battery. You know when it’s working as there is a small blue LED that flashes when it has power to produce a charge. The brighter the light the brighter the flashing (to a point that is). I plugged it in and connected up and checked it with a multi-meter. Power output, that’s it!

The directions and specs state that the output is 1.5watts, 12v nominal and current at max is 85mA. There are higher spec versions out there but I only wanted a trickle top up charge, not recharge a caravan battery after a bit of usage.

There is a handy cut out in the product that will stop charging the battery if it gets too much. I am very surprised that the makers don’t make more of this feature as it was one of the major factors when I was looking around for my options. Overcharging is just as bad as under charging!


I regularly check the battery voltage after disconnecting the unit and it shows 12.75volts just under the max of 12.84 volts for my type of fully charged battery. I will review my Autolite battery at a later date and put pictures up.


If you have a car you use now and again, you have got to have one. There are mains powered ones (which a friend of mine has on his 1965 fastback), or this solar type, also made by other people. For the money it’s a brilliant buy and take a worry out of the winter a little. Watch out for special offers on this as the prices can vary quite a bit, the RRP is £20, I got mine for £8.99 with a promotion. Bargain 🙂

There is another upside, the flashing blue light that is on the front faces the road, so passing people will see it flashing and think it is alarmed or something. Shame it doesn’t flash at night to though to keep the illusion going. It keeps undesirables at a distance which is the main thing till I get her in my garage. This product by ring may well have got full marks if it was already sealed with sealer, I don’t see why I should have to do it. Perhaps that’s how they keep the costs down? for £8.99 I can’t complain, in fact I think I just did! All in all its a good product, and quite sturdy piece of kit.

Will it keep the car charged over the winter? We shall see, but I’m quietly confident it will be fine.

Rating – Original score = 9 / 10

                 Revised score = 7 / 10

Update: 22/4/2016

This solar powered trickle charger died after a year and a half or so and was not keeping the battery topped up unless in full sunlight. My confidence was not fully rewarded as the trickle charge in overcast was just barely enough to keep the charge full on the battery. During the summer it was OK, but the winter it needs more to keep the battery topped up. Not a bad unit for the low price and the job it performed. Great to use solar power and it don’t regret that part, shame it just died, nothing to go wrong surely.

But I have since purchased a CTEK MXS 5.0 charger, click here for the review.

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3 thoughts on “Ring Solar Power Battery Maintainer RSP150

    1. Yes, the stronger the sunlight the brighter the flash becomes. Easy way to test that is to shine a bright LED torch onto the cells and it will flash brighter. It also looks like a car alarm warning flash too.

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