AGM as second Battery, also Ctek XS1500 Help

Ctek informed me by email that my XS25000 can be used on any 12 volt battery, either AGM, MF, Lead Acid and Gel....plus its also written in the manual on page 5 under speciifications.

Page 7 of your manual also states the same thing.

CtekXS15000 Manual

Brett...

Hi Haza AGM batteries are lead acid. The AGM part is a matting that wraps around the lead plates to help with storage power & stabilty check with someone like Battery world for a better explanation Ctec charger will do the job hope this helps PS ok for solar

I also run an AGM in the rear tray and use a CTek 7000. Its a good setup!

There are no issues with charging both AGM and cranking battery off the alternator, but they should be isolated when the motor is not running.

Re Redarc Isolator: The redarc leaves the batteries connected after you turn the vehicle off. If the voltage of the cranking battery drops to about 12.5, the batteries are then isolated. I don't believe it is good to have your wet call and AGM paralleled when the vehicle is not running. You can get around this by using a different isolator (eg Rotronics) that isolates when IGN is turned off. Alternatively wire a relay to turn off the small earth lead on the Redarc when IGN is off.

You only get voltage drop when there is current, and the drop is directly proportional to the current. So you'll get a fair bit of voltage drop when the AGM is down, while you'll get almost no drop when the AGM is fully charged and the vehicle is running. So the voltage drop will only affect the speed at which the battery recharges. Will the AGM become fully charged by the alternator? The answer is yes if the regulated voltage is high enough (say above 13.8V) and you drive the vehicle for long enough.

Your CTek is fine for both batteries. I sit mine in the cab and just hook it up to my power outlets from each battery. I think the XS15000 will charge your batteries at 14.4V, while the XS7000 gives you the choice between 14.4 and 14.7V. Both voltages are fine for your batteries. I think 13.6V is the power supply voltage and 16V is to try to bring dead batteries back to life.

Cheers
Phil

Great, thanks everybody for answering all my questions and even elightening me on a few others.

Haza,
You ask: "I've using a Redarc isolator. My 2nd battery is fitted in the rear tray away from any heat - but **I lose .3 - .5 Volts**"

You can read further information on Redarc isolators causing Voltage drop which were posted recently, where the exact same information is contained and pondered on by all and sundry, you will see they are prone to creating their own Voltage drop, even when the correctly sized battery cable is used.
I'm sure some one will drop the thread number here for you, as I did not find it just now, just too many to read on similar topic.

AGM as second battery is OK, as is 100W Solar panel, BUT you don't mention any solar regulator ???

Hint: I originally had a Mechanical Solenoid like you, then changed to an "electronic battery isolator" now have Nill Voltage drop.

Mainey . . .