Hi everyone, I'm looking for some advice on an idea I've got to keep our 12v tractor batteries fully charged.

Back Story: Basically, my issue is I've got three old tractors that don't get that much use, and either their alternators are broken or not very good and it's really not worth fixing or replacing them in any case since sometimes don't get used for weeks. But then, when you do come to want to use it, for whatever reason, the batteries are often flat or more, they're too low charge left in them to reliably start them more than once or twice at best, if at all. There isn't anything left on the tractor that would drain the batteries and we've tried replacing the batteries before, and I think it's mostly down to the cold conditions, not much use and so on. If we charge the battery up before use, we don't have any issues for some time, and when we're regularly using the tractors for a few days in a row, the alternator seems to keep them going as well.

Main Idea: I've seen these "12V Solar Panel Trickle Charger" kits you can buy pretty cheaply and they look very simple to setup efc, and the basic idea is to fit these to the barn where we keep our tractors and then leave our tractors hooked up to these solar panels (though their charger controller) and then the basic idea is we should have enough sunlight, (other than maybe during the worst parts of the winter) to keep these batteries charged up and ready to go all the time, without having to have them hooked up to a powerful charger that's plugged into the mains and drawing power from the grid at quite a high cost (since we have an expensive tariff rate).

Questions: So I've got a few questions for anyone who knows more about this kinda thing than I do.

1. Will I need to get a separate kit with solar panel and charger for each of the three tractors, or can I connect all three 12v batteries to the same charger by splicing in extra connectors for each, or will that split the voltage or something else that might damage the battery? It makes sense financially to get one powerful solar panel and connect that up to all three tractor batteries at the same time, then getting three small systems that are all independent, but only if that is possible?
2. Will this damage the batteries? I see many of these systems have "overcharge protection" and other features, but is there any issues that I'm not seeing?
3. Is this a good idea? I'm not so worried on the financial side; I understand it will take a lot of time to pay for itself in cost savings if nothing goes wrong with the system etc over the power required to charge up the battery before use on the mains. The main advantage I see of this system is that the tractor battery should always be pretty well charged, if not fully charged whenever it is needed and that isn't really something I think that you can really do with a mains system, without it using a lot of grid power from being constantly connected up?

Thanks in advance for taking the time to read this and any advice you can give!

12v automotive chargers like the ctek have trickle charge mode once a battery is fully charged, and I’d rather use one of those 

Hi

Do you disconnect the battery when not in use? I had the same issue when I used to work on a farm and installed a cutout switch to reduce the rate of discharge.

This helped provided the tractor was not idle for any lengthy periods.

Cheers

Sean

On 2024/02/29 at 1:45 PM, vrystaat said:

Hi

Do you disconnect the battery when not in use? I had the same issue when I used to work on a farm and installed a cutout switch to reduce the rate of discharge.

This helped provided the tractor was not idle for any lengthy periods.

Cheers

Sean

Thanks Sean! That sounds like an interesting idea, I might give that one a try!

What about a cheap 1A trickle charger running of the mains? If the leads are too short you can extend them and cable tie the charger against a column or something. 

We use 12v isolator switches on our machines to lock them out. The advertised rating is 125A instantaneous but it has been working for a couple of years breaking the negative wire just after the battery connection. 

Www.colehersee.com 

E2484 bought from Midas I think.