DC-DC battery charger - Is the Grail hunt over ?

SoundGuy wrote:
I'm just thinking out loud here but maybe instead of the single G31 for the trailer I should buy two G24 AGMs, put one in the trailer as planned & the second in the truck, and invest in this new CTEK 12 volt charger to maintain this truck auxiliary battery.

Do NOT replace the flooded lead acid battery in your truck with an AGM battery ! Your trucks charging system will NOT properly charge it, leading to a short life.

theoldwizard1 wrote:
While "wandering around" the internet, I found a relatively new product. It is a DC-DC battery charger, designed SPECIFICALLY for charging a "house" battery from your vehicle charging system while driving ! In theory THE GRAIL QUEST IS OVER !!
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The CTEK D250SA takes current from your vehicle charging system as low as 11.5V and boost it up to the appropriate level for doing a multi-step charge on your house battery ! Additional features:

• Isolation between vehicle battery and house battery when the ignition is OFF
• Input from solar array (up to 23V and 300W) and does propper MPPT charging
• Different charge profile for AGM house batteries
• Back "trickle charge" vehicle battery if it is low and there is adequate solar power

INTERESTING! :B

I recently ordered a Deka G31 AGM to replace my aged tongue mounted flooded G27. This new G31 is going in the trailer's front pass through cargo compartment so I can use short 18" 1 or 2 gauge cables to connect to my 1000 watt PSW inverter. I already own a CTEK Multi US 7002 that properly bulk charges at 14.4 volts and will use it instead of the trailer's WFCO which never charges beyond ~ 13.7 volts. Yes, it's only a 7 amp charger and no it doesn't offer temp compensated charging but since we normally camp on electric sites I don't significantly draw the battery down more than a few times each season and therefore don't often have the need for significant recharging.

As such, I only use the inverter a few times each season when shore power fails or isn't available and because of this I've been reluctant to invest in two batteries when I otherwise have no need for that much reserve. Those few times each season I do use the inverter I've found that load supporting the one battery with the truck (running) by connecting to it with heavy gauge booster cables is sufficient to prevent excessive voltage drop when the inverter is under brief but heavy load measuring up to ~ 60 amps from the toaster or coffee maker. Now here's the interesting part - my 2012 Silverado has an empty spot next to the under hood fuse box that's designed to hold a second battery up to G24 size, but no larger ... for what reason this space is there I don't know, it just is. :h I'm just thinking out loud here but maybe instead of the single G31 for the trailer I should buy two G24 AGMs, put one in the trailer as planned & the second in the truck, and invest in this new CTEK 12 volt charger to maintain this truck auxiliary battery. The one G24 in the trailer would certainly serve our normal needs yet still get us through one night of camping without shore power. On those few occasions when I do use the inverter I could load support the trailer battery with the second auxiliary battery in the truck, knowing it would always be maintained at a 100% SOC. It therefore seems to me the only drawback is that on occasion I might have to swap out the trailer battery with the truck aux battery for recharging with the DC charger ... OTOH that certainly would be convenient to be able to recharge while just driving around in the truck! Hmmmm, maybe this new CTEK DC charger is indeed the Holy Grail for those of us with limited battery requirements, who don't want to drag along a genset, or aren't really all that interested in solar that only works when the sun is out anyway. Hmmmmm.

Thoughts anyone? :@