英国采购需求：5kw逆变器、车载电源逆变器、正弦波逆变器、电池充电器、汽车电池充电器、太阳能逆变器

I'm reaching out regarding a charger I recently purchased but haven't used yet. Unfortunately, it remains stuck at stage 1 and isn't providing any charge voltage. I've tested it with three different batteries, and each time it fails to progress beyond the initial stage, even though the batteries themselves are in good condition. I noticed that this charger is no longer available on eBay, which complicates things further. Can you provide any insights or options for troubleshooting this issue? I'm looking for a resolution, whether it's a repair guide or a replacement solution. Your expertise would be greatly appreciated.