AA 4.8W Solar Charger versus my 100Ah Camper Van Battery versus the Scottish Weather RND Diaries 

I tried one of those earlier this year, in the winter, for use on a Toyota Hybrid with quite a small 12V battery. Unfortunately, it failed quite soon, and was evidently damaged in transport by the well known A firm. Didn’t attempt to return it, and it did have a useful EODB plug. It’s not easy to access the battery in this car, with it being under the back seat, and is not set up for easy access. Thus I bought one of the Halfords ones for £22.99 (which does not come with an EODB plug), with a similar rating - but a lot smaller, so presumably using more efficient cells. The car is located in central southern England, broadly parked south, but by a building so that the direct sun hours are around 6 hours peak. So far, so good - although if the hours used are low, I do top it up using an older automatic mains charger. The main thing with this type of car, having a built in Battery Management System (BMS), is not to clash with it by connecting external devices with the power switched on. Note that the capacity of the battery, and the voltage of it depends on the temperature. They always quote a value in large text, and either nothing about the temp at which it is valid, or in small text! The standard temp is 20 °C, but in a typical winter the capacity could easily be 50% down due to the weather.

Just tried a 5W charger from Halfords. It says it's for small cars... which mine is (60AH stop-start) Like you I'm in Scotland East Coast. Car battery seems to be worse than without it. I leave it for 1 week at a time, use it at the weekend. Maybe a 20W charger would be ok, but it's quite big, so i wouldn't want to leave it on top of the car, so it would be behind the windscreen, which would block light meaning it's a waste of time. I bought a lithium battery jump starter instead. It works well. Maybe I'll just jump the car every weekend...

That's fantastic , thanks for all the hard work you did gathering data. Batteries are a complex science and I am hoping you can help me. My car battery was losing charge, driven quite regularly, but resting was 12.1 Volts, it`s quite new After starting it would go to normal range of 13.5-14.5. Maybe it hadn't been driven enough , anyway I got a solar battery charger (4.8) AA , do you think that is a good move ? Thanks Red 🙂🙂🙂🙂

Thanks for making this Vid. It was helpful to be able to see in advance some of the instructions. Being one of your south of the border cousins, I think I would get enough sunlight hours to maintain the battery on my Transit. I am actually worried it could overcharge the battery. I appreciate an optimal 4.8 watts is a very small output but, the Transit is an older 2008 model and I don't think it loses very much voltage. The trouble is I only use it as a shed so I only need to move it to load and unload. It only really runs once a month for about 2 minutes. But if I need to get access quick I don't want to be naffing about with jump leads. Plus I have ruined batteries before by over discharging them etc. Can you tell me, does it have protection from over charging. Also if you don't mind, do you have an update on performance in the 8 months since you posted this video!! Thanks

Can I use the as solar charger on a 2023 bmw f40 128 ti because I don’t use the car all week I use to use it on my 2022 Vw golf to keep the battery topped up thank you mike

Get two and wire them up in parallel