How cold was it when you were trying to charge them? If it was below 32F, that could cause problems. Li batteries won't charge in the cold. Some chargers and some batteries will shut down until they warm up.
Outside temps today were in the high 50s, and I only had them outside for maybe 15 minutes, tops. Got them in my place, to charge, and the thermostat is at 68. Store felt like mid 60s or so.
