I have a small cheap battery tender, it works nice for keeping batteries fresh when sitting around(i usually keep the batteries out of vehicles I junk). Anyhow I was considering trying something new, instead of switching the tender around every once in a while I was thinking maybe put all the batteries on it at once, using short pieces of wire with large alligator clips at either end. Is this safe for long term use? ie months at a time. Thanks in advance.

 

I believe it would be safe. But I am not sure you would want to do this, if you have some marginal batteries and also some good batteries. The batteries that are poor would tend to drag down the better batteries.

 

Do not connect them in parallel.

The batteries should be isolated with diodes.

Steve