2nd Gen Non-Engine/Transmission battery charging question

[TLanier]

Just replaced my five year old beat batteries with two optima sc34u red tops, and thouroughly cleaned the terminals. Got the optimas last saturday, and hooked them up separately to my black and decor smart charger on the 10 amp cycle to top them off. each charged for about and hour or two, and read "full".



i installed them today, and hooked them up to the charger again just to check, and each took another hour of charging before they read "full" again. is that normal? i thought optimas did not have much discharging? its only been five days. is this just the charger overcharging (its a microprocessor smart charger, so it shouldnt, right?)? maybe im not understanding the basics.



last, how can i check the truck while shut down to make sure i dont have a small load on the batteries (not relavent in this case, but just to check while im on the subject).



cheers,

thomas

 

[Silver_Ram]

My understanding is the gel batteries like the Optima take longer to charge. Take a volt meter and check the voltage. If it's 12. 6 or better, install them & drive it.

 

[Thomas]

My understanding is the gel batteries like the Optima take longer to charge...

Actually the Optima batteries are absorbed glass mat (AGM) rather than gel batteries.

 

[TLanier]

well, i understood that the optima was neither a gel nor agm, but a type of sealed wet cell (in spirals). sound off you optima guru's, inquiring minds want to know!

Oo.

 

[Thomas]

well, i understood that the optima was neither a gel nor agm...

Google optima agm and you'll get a lot to read.

This link seems to support the absorbed glass mat point of view: http://www.dcbattery.com/optimacatalog.pdf

 

[kscheffler]

Never trust any battery chargers always check the voltage output. One-half of the battery charges I have checked are not providing proper charge volatage and/or float voltage. Read the Optima technical specifications both of these charge rates are different than lead acid batteries. Optimas are an AGM battery they just sprial roll the glass matt material. Your charge is likely taking one hour to get to full charge voltage not a problem with the battery. A full charged optima battery should read 12. 9 to 13. 1 volts after sitting for 12 hours.

 

[TLanier]

thanks thomas, i found that optimas are indeed AGM. I have a smart charger that has a selection between 40/20/10/4 amps and wet/agm/gell settings. I charged my new batteries on the 20 amp initial setting and "wet" type selected. the charge quickly went to below 10 amps and into the second phase of the charging. since i selected "wet", have i damaged these?

 

[TLanier]

ok kscheffler i just went out and checked the voltage at the posts with my multimeter, 12. 37v. i just installed the batteries yesterday, and took two trips @about 5 miles each.



???

 

[kscheffler]

no harm done. The different battery types have different float and charge voltage. THe wet values are lower than the AGM values. Do charge on the AGM setting. You can use the 40 amp rate the Optimas are great at accepting a charge rate.

 

[TLanier]

kscheffler,



since the wet has lower values, is this why my batteries are reading 12. 37v? i remember when i checked them before installing them yesterday, after i had charged them the first time five days prior, that they were 12. 5v. if they should be up closer to 13v, do i need to charge again with the 40 amp "agm" selection? 12. 3 seems low.

 

[kscheffler]

Yes it is telling you they are not fully charged. You can use the 40 amp but be safe and but it on the 10 amp AGM. The voltage should not exceed 15. 6 volts I preferr 14. 7 for AGM. Once it finishes charging it should go the float mode which should be 13. 2 to 13. 8 V