Any real difference?
Looks like the trickle charge ( battery Tender JR) is .75 amps and could take 40 hours....which kinda sucks

Any issue with using car charger on 2 amp to speed it up a bit?
I'm thinkin not

 

Ok, the battery tender is not a charger. Also, you need to have some battery life to recharge even on the car charger. Hook it up, there should be at least 10-20% voltage left....if it has no voltage retained when hooking up it ...sorry....most likely it will not recharge no longer how long you leave it connected at 2 amps. In that instance, time for a new battery. You can try, but 3 amps will take 10-12 hrs.

 

12.8 = fully charged

12.6 = 75% charged

12.3 = 50% charged (Lot of new modern cars with system protection will not even click at this point but will have good headlight beams showing)

12.0 =25% charged

When you start getting below 12 volts DC, the battery is pretty bad off. and probably will never come back 100%. If it is below 3 volts, most maintenance chargers will probably not come on.

If you just hook a meter to them, they show nothing.

A maintenance tender is a charger with solid-state control. Depending on the size of the battery, there are 3 ranges. Harley calls them tenders. Bell calls them Chargers.

Take it out of the bike. Hit it with the 2 AMP couple hours. Then overnight on maintenance or until you get the green light. Then take it and have it load tested with their tester set to correct CCA and see what you have.

 

You can charge with a 2 amp charger.

 

When the battery is totally dead it's good to hit them with a higher voltage until they start to take current. On older timer based or cheaper chargers, you simply turn the charge rate up until you start to see current flow then back off to a few amps. Make sure the battery does not get too hot.

 

Once a battery goes “dead” (less than 12.0 volts) you’ve permanently damaged the battery. Time for a new one.

 

Well according to the table that would be 11.8..