12 v battery charger.

No, too high Amp rating. Need 4.2 A or less.

 

. See AGM battery charging note!

 

Yeah there's a caution in owner's manual as well. Fwiw might be just fine but I wouldn't chance it.

Smart charger, 4 amp range, is safer.

 

SON-1203B looks good.

 

The battery likely would have to be stone cold dead before any charger would actually deliver it's maximum rated current capacity.
And if it IS that dead, trying to recharge it and expecting continued good service from it is an exercise in futility.

It is HIGHLY likely that a "6 amp" charger would work fine for you in most circumstances.
Especially if there is a meter to show you the actual charging current.

 

I actually tried a 6 A Schumacher unit. It would charge and then note battery was full. If I unplug it and immediately plug back in, battery wasn’t full and it would start charging all over again. (I guess this is consequence of too fast rate)!

 

I think my 4 amp CTEK (multi us 4.3) behaves similarly, always go through a full regimen, no matter how recently you charged, even if you just disconnected. It can go very fast the second time though.

 

I think it was just too fast that the battery built up internal resistance before it was full. My other charger that had 4 A setting would fill up. Then if I disconnect and immediately reconnect, would be at a higher state of charge. The third time it would fill. After which disconnect/reconnect would still indicate full. I ended up purchasing a Chinese LiFePO4 battery because it would never fill with the 6 A unit, and I thought the battery was bad/going bad. I’m still waiting on the battery to arrive, but so far my parents have not had any issues with the original one, (while I’m waiting. I still have all the trunk stuff removed waiting on the new battery for ease of installation).

 

Our car sits on the charger, for days on end. Both me and the wife are retired, and sometimes it's 3~4 days it sits idle. Our location is good too, in that we can pick up light groceries within walking distance. Ditto for a nearby hardware store, coffee shop, pet store, a few others. I'm starting to think we may just walk away from the automobile one of these years.

I feel for people that are in new, remote communities, have to drive to get everything. It's piss poor city planning: all the people here, all the stores there, all the places of work, another place.

 

No it isn't.
Most all chargers will do that......for varying periods of time, from a few seconds to a few minutes, because of the design logic it uses to determine if there really is a full charge or not.

 

I could repeat the disconnect and reconnect ad infinitum and it would always be around 50 % charged once I plugged the charger back into the outlet. (I use 50 % as an example because I forgot the exact % it would display when I plugged it back in). I also neglected to mention that I could hear a slight boiling inside the battery. That is why I ordered a replacement battery, it would not stop, until I tried the 4 A charger....

 

Your conclusion about the old battery probably is right.

But your decision about spending extra money on a Li battery might not be so good.

First Li batteries have different charging characteristics and might not ever charge "right" in an application designed for an AGM lead acid type.
Second, the quality of some Chinese goods is well below acceptable......especially if you got it for a really "good" price.

Good luck.

 

But you missed the point.
How LONG did it stay at the 50% indication ?
If it was hours and hours, then it is a simple matter of the battery being bad.......as you eventually concluded.

 

It would gradually go up, kind of like one would expect, quicker at first and then slowly as it got to fully charged. I got annoyed with the process. Once I decided to heed the note to keep under 4.2 A it changed. I may have started at 50 %, then when it noted full, unplug, replug, and it may start in the 80 % range. Then the next unplug replug would stay full. I left it overnight and measured voltage at the terminals, and got 12.5 V, a passing measure after ridding of surface charge. Manual notes to get rid of surface charge by running high beams I believe 30 seconds. I just let it sit overnight instead.

 

Thanks for the warning. I’m afraid I already ordered it though. I did get a SquareTrade 2 year warranty for it. Braille does not make a size that is an exact fit. I will see when this one comes in, and report. They claim one must use a Li specific charger, but it is a drop in replacement for lead batteries. It is interesting that the voltage is slightly higher than a Pb battery.....

 

Another assumption that is slightly off the mark.
An AGM battery should always be above 12.6 when fully charged.......if it is still healthy, some as high as 12.8.
Having it fall to 12.5 without any actual use is yet another sign that it is going bad.

 

Well think about this for a minute.
The "charger" in the car will NOT be Li specific.

It might work OK......but it might not too.