I have a question on charging batteries. I killed mine when I left the interior lights on about 24 hours. My question is when I charging do I charge one battery at a time with the cables removed or charge them together with the cable connected. Thanks for any help

 

I would bring them inside and let the batts warm up for a few hrs first. A dead batt can freeze fast. then charge 1 at a time.

 

Not saying what is correct but I left the ignition on and had a dead bat. I jumped it and drove off, they both charge up ok with no noticeable problem. It has been sitting for the past few weeks and I am now charging both at one time as we speak(write) Ed

 

Of course you could remove, hook in series and charge reel well with 24v charger.
Probablly good ideal to disconnect one battery and charge individually. If one is failed won't waste time.

 

It depends on what kind of charger you have .
Dead batteries do freeze , and dead batteries take a lot of amps at the beginning before they will take a charge , depending on conditions , you may need 30 - 100 amps to get a completely dead battery to start charging , also it may take 10 min.s to 1/2 hr at a high rate for the dead battery to take a charge , from an auto matic charger [ most chargers are auto , less amps as the battery starts charging ] .
There so many types of batteries & chargers out there that there is no way to give one answer with out all the details of the battery & charger .
You can charge many batteries in parallel if you have a charger that has enough amps for the batteries being charged .