AGM Battery maintenance/charging for dummies?

[Xterabl]

Well, I did call the technical support to inquire about how the 16.5V "boost" desulfation actually worked. The person definitely knew more about battery tech then the dude(s) in all the videos. I, on the other hand, could obviously not keep up with him. When I tried to parrot then line about pulsing for desulfation, he got slightly defensive and claimed that rapid pulsing isn't the only way to desulfate, but that very low current at higher voltage also works. He also claimed that the charger was outputting variable voltages during the desulfation process based on sensing, algorithms, etc.
At the end of it all, we basically concluded / agreed that I recovered some capacity but probably not a lot; and a test with heavy loading would be required in order to know the state of the battery with any reasonable amount of confidence.
Anyways, if someone more knowledgeable than me (ahem dwh) wants to have a chat, their open until 5PM east coast time and the number is 1-800-456-6626. I think you press 3 for tech support.

EDIT to add: Drove the rig to work & back; parked, and a few hours later measured the voltage and got 11.5V. Ugh. Disconnected battery negative from ground post and observed sparks between the two. And the ground post showed +11.5V relative to my battery negative...and electrical continuity between ground post/engine block and the battery positive...WTF??? This persisted for a minute or two, then it stopped. Seems like some shorting. Sheesh...forget the charger/desulfation stuff...seems I got some real work to do.

[dwh]

<Don Johnson Sonny Crockett voice>
Not me, bubba.
</end DJ SC v>

I think Martyn at Adventure Trailers said they are using the Genius chargers now...he knows about batteries and is...I guess...a dealer. Let him do it.

[Pathfinder]

I have had dozens of chargers over the years, and still use Battery Tenders for my motorcycles, but for Optima and gel cell batteries I use a CTEK-7002. It works better than any charger I have previously used, and brought back to life Optimas that I thought were gone for good!

http://smartercharger.com

[teotwaki]

I have had dozens of chargers over the years, and still use Battery Tenders for my motorcycles, but for Optima and gel cell batteries I use a CTEK-7002. It works better than any charger I have previously used, and brought back to life Optimas that I thought were gone for good!

http://smartercharger.com

I am lusting for a CTEK 250S dual to install in the truck and take care of my second deep cycle battery. If I can beat this eBay price I may go for it.

http://www.ebay.com/itm/CTEK-D250S-D...0255c1&vxp=mtr

[Xterabl]

Huh, comparing CTEK with Noco genius, Noco seems to win. For similar price point (actually Noco 10-15% cheaper), both offer similar features: microprocessor controlled, regular vs. cold/AGM charge modes, 13.6 supply modes...and actually, Noco has a higher voltage recovery mode (Noco "boost" mode is 16-16.5 V vs. CTEK 15.7V).
Noco seems to win, especially considering their 7.2A model is the same price (actually $6 cheaper) than CTEK's 7.0A model.

But, now that I look more closely, CTEK calls their cold/AGM charge mode "snowflake"...obviously this is a reason to choose them over the Noco's...LOL.

Also, teotwaki, at a glance,seems you could save some $$$ by going with Noco's GEN2 onboard charger:
http://www.amazon.com/NOCO-GEN2-On-B.../dp/B003JSJS5I

[teotwaki]

Also, teotwaki, at a glance,seems you could save some $$$ by going with Noco's GEN2 onboard charger:
http://www.amazon.com/NOCO-GEN2-On-B.../dp/B003JSJS5I

Ummm, that NOCO has an AC plug on it. How'z that gonna' work while I'm driving?

[Xterabl]

What, no inverter???
Yeah, sorry, I totally missed that "detail".
So this actually "goes between" the alternator and battery(ies) and properly adjusts charging? Yeah, OK, sound like a definite battery life extender.

[teotwaki]

What, no inverter???
Yeah, sorry, I totally missed that "detail".
So this actually "goes between" the alternator and battery(ies) and properly adjusts charging? Yeah, OK, sound like a definite battery life extender.

LOL! They are actually a full service charger and use a DC-DC converter to provide what is needed regardless of the alternator's output voltage. being a gadget geek makes them even more attractive but it is a shame to have to add a $200 gadget to keep a $200 AGM battery alive.

[dwh]

and actually, Noco has a higher voltage recovery mode (Noco "boost" mode is 16-16.5 V vs. CTEK 15.7V).

I'm not sure that's really a good selling point, considering that either 15.7v or 16.5v would exceed most manufacturer's specs for just about any VRLA battery.

Optima is one of the few who state that you can take their battery that high under certain circumstances:

"Rapid Recharge:
Maximum voltage 15.6 volts (regulated), no current limit as long as battery temperature remains below 125°F (51.7°C). Charge until current drops below 1 amp."

http://www.optimabatteries.com/produ...t/charging.php

[Xterabl]

Interesting. Their "Genius" line still seems to be same price.

By the way, I just read more about the CTEK D250S mentioned in previous posts and learned it has auxiliary charging input i.e. from solar, and there is built in MPPT capability for that.
So, seems like a really nice feature set for just over $200, if you're currently looking to install 2nd battery + solar. Max input voltage is 22V, I'm not sure how that compares with most dedicated MPPTs.