In Need of an AGM smart charger for a red top optima. Looking for the reliable better brands. Mine crapped out today at 41 and I need to get one before next weeks festivities at Indy. Keith

I have (4) cars all with Optima batteries, on 1 car I left the interior lites ON w/yellow top and battery ran down. Pulled out my expensive Sears smart charger, set it to AGM but the battery wouldn't come up.
Next I decided to try the Optima charger so I bought it through Amazon, knowing if it didn't work I could send it back. I was pleasantly surprised the yellow top charged rite back to full charge.
Being an electronic engineer I was mystified why one charger set to AGM would work and not the other. Can't really explain it but can confirm the Optima charger worked like advertised.
I did notice that during the charge cycle with the Optima charger it did go in defined, calculated voltage/time steps. I do know that certain later battery technologies for cell-phones, laptops are very sensitive to the charge cycle, so that each step keeping the battery temperature under control as if it goes too high the battery will never charge properly....

No I don't work for Optima, just my personal experiences....

Just my $0.02...

I have 4 Optima batteries ( 2 Red,2 Yellow) 1 Red good , 1 Yellow good. 3 AGM chargers NoCo and Optima
I also left the interior lights on w/yellow top and battery ran down. Have tried every trick to bring back but only get 12.4V so I use it for my winch.
I found a old Red top in the corner of my shop completely dead .3v. got it up to 8v.
For me ,the Optima charger did not work like advertised and is worthless like its over-priced batteries. My Noco did bring back a small 6v AGM battery that was for my scales.

Thanks for the replies. I went ahead and ordered this one from summit since I am in a time crunch.
https://www.summitracing.com/parts/ult-150-33508

Sintro I had the same experience with MSD ignition and timing lights. The MSD timing light worked the best at least for me. The timing mark was bouncing around with borrowed timing lights. Keith

I've have 2 Optima Red and have always used my "ancient" Schumacher charger with 2A / 10A options, plus a 50A "boost" toggle for starting a dead battery.

Something I heard about years ago w/ the Optima stuff is using a low charge rate like 2A doesn't do much. As such, I always put it on the 10A setting and watch the charge meter closely to make sure I don't leave it on longer than it takes to reach 95+ % charged.

YMMV, but this approach has worked OK for me.

2 amps is only a good charge rate for very small batteries or topping off a battery that is already charged. It will never make a real dent in a heavily discharged battery.

For charging optima batteries and other AGM batteries it is good to use a charger with an AGM setting. AGM batteries like a different charge voltage for peak performance and efficient charge times. Personally I have the smaller 4amp Optima charger and it works great on Optima and other AGM batteries. I never felt the need for the larger one because any charging I do at home is just maintenance charges to make sure my battery is topped off. My car has an alternator and is driven too and from the track so I rarely have the need to charge it. It can sit several months with zero issues.

Age of the battery matter if it is drained. AGM that are drained to a low voltage normally trick a small AGM into thinking it is charged when it is not. You have to trick charger with jumping another battery to it for a while or use a higher amp charger to get the surface charge up. Then the AGM charger can do the charging. I have had no problem charging a red top with my 2 Amp Schumer, just takes a few day. Works great as a maintainer on one of my cars that can drain a battery in 2 -3 weeks if not driven. I have had red top last 9 years, other just 3-4 years.

Remember if the battery is below a certain % you have to have a fully charged battery in line with the charger to get back up from dead.

This part is important.


I have this charger from NAPA and have been very happy with it.
https://www.napaonline.com/en/p/SOR...lowproductdescription&ppid=BKHFMC15A

Thought I said that :-)

Ive had and used a Rock Battery charger for years with zero issues. Does 12 and 16 volt AGM batteries. Moroso charger is the same one.

I use this Battery Tender charger to Charge my XS power D1200 AGM battery. I Always charge AGM at 15 Amps.

https://www.batterytender.com/products/15-amp-selectable

Man they have went WAY up in price. Payed 79.95 for mine.