Charging 24v battery bank with 12vg

[Sunking]

Thanks! Sunking has inspired a new line of thinking though and now I think I'll put all my eggs into a shore based charging station.

That is what smart money would do. The key to your success is properly sizing the battery for your daily needs and size it for 3-day capacity. By doing that will give you 2-days of use without recharge in the event Justin Case shows up with his wet blanket and poops in your Post Toasties.

As a side note I should have thought about Genasun as they specialize in Marine and Golf Cart products which make them a Niche supplier and not many uses for them so they get tossed back in the closet of my mind. Their Boost Controllers are aimed directly at the Golf Cart market using a 24 volt solar panels as the roof to charge 36 and 48 volt batteries. Like I said if given a choice you want to go from Higher to Lower voltage aka Buck Converter which is what 90% of the Controllers use.

[Sunking]

you can, but only one, more than that, and the post goes to moderation as suspected spam

Nah, I can put up as many as I want.

Trojan Battery
Rolls Battery
Morningstar.

VB has so many security flaws you can drive a truck through with no one noticing until it is too late.

[Sunking]

you can, but only one, more than that, and the post goes to moderation as suspected spam

You must have fixed the Security flaw.

[Mike90250]

Nah, I can put up as many as I want......

'cause your'e special !

[Chris1]

Steve AGM does not sulfate like FLA. That is not to say they do no sulfate because they do. The main difference is FLA sulfate accelerates at 50% and lower DOD, AGM can go down to 80% DOD before sulfate accelerates.

Please no one take that as meaning you should or should not use AGM because it does have its application. For Solar the main advantage is you can charge and discharge AGM 2 to 5 times faster. So Steve for example your neighbors to the north in gloomy doomy Seattle and Portland receive less than 2 Sun Hours for several months out of the year. That means you must use much higher panel wattage and run Charge Rates up to 1C. Example you want 1 Kwh of of usable power in a day. You have 1 site in Seattle and 1 in Tuscon, Seattle needs a 1000 watt panel and into a 12 volt battery is 80 Amps. Tuscon only needs 400 watts of panels and 35 amps of current. Both need the exact same 12 volt 400 AH battery but not the same type. In Tuscon you can use a FLA battery that cost half as much as AGM and last twice as long. You cannot do that in Seattle with a C/5 charge current.

Most deep cycle AGM's need to be charged fast, that is what they are designed to do and are cousins of SLI batteries. They need to be pressurized to make them recombine O2 and H with the catalyst used. Bottom line is check what the battery requirements are before you make a selection. It all has to fit and be designed to work with everything.

FWIW Steve AGM batteries were developed specifically for military aircraft where inversion and G forces are encountered and no spills and excess weight can be tolerated. Concorde to this day made the first AGM's and today still make the best AGM's. They are one of the very few that use 100% virgin lead with no alloys like antimony, calcium, tin, or silver. The lead used is not from recycled material contaminated with impurities and alloys. I can only think of two other manufactures that do that, and they are not tailored to RE, rather motorsports made by Odyssey and Optima. You can tell a lot about a battery by looking at the Term Post. When you see Auto Term Post, you know it is made for motorsports. Cycle application batteries have Flags you can use 1 or more bolt through hardware. Now these are AGM batteries with dual Term Post.

Here's another one - I have a high power, short duration demand for my electric outboard. Say 40 amps @24v for an hour pulled from two 12v 125AH AGM batteries. Then maybe no power requirements for a week. Rinse and repeat all summer. Do I still want a largish solar array ( 400+ watts)? Note: I'm in the PNW - a little sunnier than Seattle but not much.