Can I charge AGM batteries directly from the alternator?

[Pntyrmvr]

You could run an inverter to charge the house side with a 120 volt AC charger. Not very efficient, but would keep them happy. Most realistic way is to use a second alternator regulated to be AGM friendly.


"Talk is cheap. Whiskey costs money."

[daveb]

Originally Posted by BrianW

^^So that makes me wonder: is there any device that can be put inline from the alternator charging cable feed to the AGM house batteries that would take that feed and make it AGM friendly?

One solution is a remotely mounted regulator in combination with a custom high amp alternator. Yes probably a good idea but kind of expensive.

[arctictraveller]

Originally Posted by BrianW

^^So that makes me wonder: is there any device that can be put inline from the alternator charging cable feed to the AGM house batteries that would take that feed and make it AGM friendly?

Sure, here are a couple ways to go about it.

Smart Alternator Regulator, V3

Sterling Power DC Input Alternator to Battery Charger 12 volt, 210 amp dc powered battery charger


The ample power regulator requires an alternator with an external regulator. A wire can also be run outside your stock alternator (most alternators anyway) That connects to the Amplepower regulator

The Sterling is different and I have never taken the time to totally analize what it does, but it goes in line between the Alternator and the batteries. I have to wonder how efficient it is though, and prefer to stay with what I know works, and thats a smart regulator controlling the alternator. Ive had them on several boats, but I have yet to install one in my van, but it's getting higher on the list. It can get expensive installing a proper charging system, but once you do you may never buy another house battery (assuming you start with quality ones to begin with).

[Bbasso]

Jony101, which charge controller are you using?

[boywonder]

Originally Posted by arctictraveller

Sterling Power DC Input Alternator to Battery Charger 12 volt, 210 amp dc powered battery charger

Haywoodphoto has one in his van....

http://www.sportsmobileforum.com/for...ger-11589.html

[daveb]

Looks like I'll be going with an external regulator on my spare XP-270 that's being serviced.

[arctictraveller]

"Looks like I'll be going with an external regulator on my spare XP-270 that's being serviced"

I have that regulator on my boat, and it works just fine. It was part of an upgrade package along with a new alternator.

Also, after looking at the Sterling more closely, I understand how it fools the alternator into increasing it's charge rate and then divides and manipulates the resulting increase for each battery type and state of charge. It looks like a great way to go, albet rather expensive. Running an external regulator might not be any less expensive though if you have to modify or replace your alternator to get the field wire out of the case and attached to the regulator. You also have to buy the regulator, and if your running different types of batterys (say a lead acid start and AGM house) you need to get one with seperate, programable outputs. If all your trying to do is increase the life of your batterys, you may not save much money in the end over early replacement. (depending on how quickly your battery dies that is) You will get the added benifit of much faster recharge times though.

[daveb]

I was told by Sterling that their products could not handle the XP-270's high amp output and being that I already installed the 270 I didn't go that route. The only reason I dug deep in my pockets for the Bal-Mar was that I had an XP-270 laying around & Nations is now combining these regulators with their custom alternators. They've sold enough of them to confirm the engine bay heat isn't an issue on the regulator according to Adam Nation. Man I hope so. The alternator I thought was bad was never put through a load/time test although they said it bench tested OK. I was very surprised when my old XP_270 started putting out 15.2 volts on a trip I took several years back. Lifeline told me that would fry the batteries I pulled that alternator and installed one that had a lower operating regulator voltage but then worried I wasn't getting a full charge to the batteries. At least the solar was helping to top off the batteries. The highest voltage the second alternator ever put out was about 14.3 but normally was outputting a round 13.6v and that seems a bit low. I've been wanting a way to smart charge from my alternator even though I have solar. I've been looking at Bal Mar for a long time.

I like that the Bal Mar can supply a multi stage programmable charge & can adjust for voltage loss in the cable even though I've only found it to be not even a volt. The Bal-Mar also has a temp sensor but I doubt I'll use it being the two banks are under the body and not in a hot engine compartment. I might change my mind about that. Hopefully the new regulator will supply the correct charging parameters the batteries actually need rather than a constant 14 +/- voltage the standard alternators put out.