Stairs won't go all the way back in

I lubricated everything I could see to lubricate, BUT I found it is the HOUSE batteries because when I plugged in to AC electric they work like a charm now. So am charging batteries while plugged in but when I bought it the man said he had it plugged in for a few days so the house batteries are either without water or kaput. Sucks but if that is the only thing I find wrong with the unit will be very happy even though house batteries are EXPENSIVE for deep cell batteries and need two. Supposedly there is a solar thingy that supposed to charge the batteries but not sure it really is doing anything. HOPE I did not buy a lemon but think not.