Nope. Apply a charging current as close to 5-amperes per 100 amp hour rating capacity as you can get. A 50 watt 12-volt light bulb from an auto parts store automatically limits current when connected in series
Charger + > light bulb in > light bulb out > battery positive post
Charger - > battery negative post
This is great CHEAP current limiter. Use a FIFTY WATT bulb.
Connect to a manual not an automatic charger. Automatic chargers are smarter than battery design engineers, Werner Von Braun, Einstein, and Stephen Hawking all rolled up into one.
Even a six amp charger will work. 10 amps is better.
Monitor voltage. Slowly but surely it will rise to 15.0 volts. Then stop the charge. It's best to let the batteries sit overnight before putting them in service.
Nor only does this shortcut the multiple cycles needed to reach full capacity, it will allow higher amp hour capacity (modest but definitely there) and a longer lifespan.
Battery manufacturers can only assume customer are going to flay and torture their batteries right out of the box. usually they are correct. Even a stupid NiMH battery has a big notice (charge before using). But too mmany people stick a replacement cyclable battery in a rig, run it flat then complain (It don't last so good - wotsamatta with your junk product?)
Recap: To make things clearer (I hope) Run a 16 gauge wire from charger positive to one of the two screws on the light bulb plastic or ceramic base. You'll then have one screw not connected yet. Run a wire from that unconnected screw to battery positive. Run the second wire, the ground wire from charger negative directly to the battery negative post.
If you have a large charger, use a 100-watt 12-volt light bulb and do both batteries at thesame time. But do not set the charger dial higher than "Medium"
And yes, all this is "worth-it"
