u/DannyDodeska

I've got a spare mobility scooter charger with the usual 3 pins to charge the pair of deep cycle batteries (in series) that most have.

There's + and - and a centre "data" one which I gather informs the charger about the charging progress so the charger's amber light turns green when they're fully charged and I believe it floats them thereafter.

What happens if I attach this charger to a 24 V off-grid (AGM?) battery for household use? Can I use this feedback circuit somehow or just monitor the battery manually and detach them when a certain voltage is reached?

Hi all, need ideas or examples (Brisbane). We already have a grid-tied system that's 14 years old but works perfectly. It has a very generous FIT that you wouldn't get today (which we LOSE if we make changes).

There are hundreds of solar panels being removed these days so they're available cheap or free AND I've sometimes seen hybrid inverters in FB Marketplace for $100 or so. The issue is they need batteries, typically 48 volt which cost thousands 😕

If it weren't for that issue I'd have put up some second hand panels, attached the inverter/battery and used it ONLY during the middle of the day to charge an electric car by now. What's holding me back from getting an EV is that we depend on exporting electricity during the day to give us a small tax free income every 3 months in retirement so this has to be quite separate from the above.

24 volt batteries are much cheaper and we only need them to smooth out the fluctuations in mid day production, not as storage for (overnight) charging. So can anyone suggest an economical way around this? The ideal would be someone upgrading a small completely off grid system and getting rid of everything even if the battery is old and tired. I just can't afford to spend thousands of dollars on a new lithium 48 volt battery.

Any polite alternative suggestions welcome thanks 🙏

Hi all. I tried posting before but didn't get much traction, probably because I hadn't scoped things out enough first. Now I'm thinking between 3 KW and 4 KW locally available used solar panels to keep a 24 volt battery happy while I'm topping up a small EV (maybe 40 kWh) battery - daytime charging only needed as we're retired.

I looked at 48 volt lithium batteries which are more common but they're thousands of dollars which defeats the whole idea of having cheap transportation. Has anyone come across a suitable (Hybrid/ Off-grid?) inverter which can supply 240 volts at perhaps 15 amps and maintain the 24 volt battery? I saw a new-ish Goodwe GW5048-EM Hybrid Inverter for $100 recently but it needs a 48 volt battery.

Any suggestions for a suitable battery? I'm unsure how big it needs to be to smooth out the (generous) insolation here in Queensland. Also I wonder if it's worth looking at a pair of AGM deep cycle batteries as they're common here for mobility scooters etc. but obviously lithium is better for this sort of thing.

Any relevant experiences I'd love to hear about. Thanks Danny.