Old(er) CTEK… New AGM Battery confusion

A CTEK normally charge for a maximum of time (36hours?), then pause for a couple of days and starts again. If your 95Ah battery is depleted it may take quite a few cycles to recharge it.

I prefer the low power 0.8A no-frills CTEK compared to the high power 5A unit (I have both). I think that with a new battery you will be fine with your current charger unless it is faulty.

see : https://www.ferrarichat.com/forum/threads/older-ctek-battery-tender-ok-to-be-used-with-an-agm-battery.683135/#post-149329556

 

The agm battery has to be overcharged sobas to crack the internal shorts (calmed dendrite) that buildup across the finely packed lead plates. This overcharging process is temporary. Your modern car does already manage to perform these burdt charges, so a regular charger that goes up to 12.7v should be enough. What is more the CTEk performe some burst charges that does the same as an overcharge.

An old school car that uses an AGM battery should use a specific charger as the old alternator do not perform the desulfation process. That's still not as good as when processed by the car that can crack the dendrite with the 90A current flowing from the alternator.

 

Agreed. I'd suggest that you save time and not muck about any longer with your existing CTEK charger. Rather, upgrade to a newer, more modern generation CTEK which has a specific AGM charging configuration.

I bought the CTEK model MXS 5.0 under these exact same conditions as you, and I have had no battery-related issues since.

DM

 

Op, the Ferrari/Ctek "should" work just fine (it is rated to work with AGM)...but many of the factory Ferrari ones are or become defective. I have that same exact charger and mine would do the same, it would always show charging. The only way I could get it to show fully charged after a day or two, was to unplug from the battery, then plug back in, and it would then show a charged indication. I believe these are defective and may overcharge your battery. I would discontinue its use.

I made an SAE adapter cable (using a tutorial on this forum) and now use a much nicer, Battery Minder charger that is designed specifically for AGM batteries and has many additional features such as automatic temperature compensation, and desulfation.
https://www.batteryminders.com/2012agm-12v-charger-maintainer-sealed-agm-lead-acid-batteries (2 amp)

One of the Ferrari technicians here, Rifledriver, prefers the Granite Digital "Save a Battery" charger/maintainers. I have a couple, and they are nice as well, but do not have the temperature compensation feature. They are available in two sizes, and either would work fine for charging and maintaining. It is also appropriate for flooded or AGM batteries.

https://www.batterysaver.com/store/p78/2365-lcd.html (roughly a 4 amp)

https://www.batterysaver.com/store/p16/3015L.html (roughly a 2 amp)

Size is not critical for a battery maintainer, as someone posted above, a 0.8 amp would work just fine. In fact Granite Digital makes a version that size: https://www.batterysaver.com/store/p102/1000.html

 

Do you guys change your alternator when you switch to an AGM battery??

 

Did Ferrari when they put the Optima red top AGM as standard in the 430 Scuderia and 16M, or does it have the same alternator as the F430?

 

Easy to figure out..head on over EuroSpares and compare part numbers.

 

It's more than just changing the voltage regulator of the alternator, it's a process that's supposed to be managed by the ECU: burst charge for a small period then get back to regular voltage.

If you use an optima battery that requires "deep desulfation", one could use a voltage regulator with higher voltage, but that's band-aid unless you have a separate charger that performs what the car's ECU is supposed to do.

There are some smart voltage regulator that do perform the maintenance routine and even include temperature compensation. Not cheap and require some unnecessary mess in the engine bay.

 

Me, I wouldn't even consider messing about with the car's OEM alternator or voltage regulator. That could easily open up a whole can of unanticipated electronic worms.

Rather, just drive the car as you would normally do, and simply plan on placing the car's battery on the proper CTEK AGM tender (per my earlier post) overnight every couple of weeks.

Seems to me that this procedure should be enough to keep the AGM battery properly "exercised" ... and that's exactly what I have been doing with no worries for my other "modern" Italian car where I have retrofitted an AGM battery, an Alfa Giulia.

DM

 

Or you could make it do with the regular battery and it's lower power to weight ratio: an Excide 90A battery will deliver more amps than an optima RT 3.7, will last much longer, but weights 20kg (compared to 15kg for the optima).

I prefer to use the battery that was meant for my car: a high quality regular battery is far less hassle in an old-school engine bay. Just my 2cts.