Battery Maintainer

msmith1199 wrote:

Gjac wrote:

msmith1199 wrote:

stevenicol wrote:
I keep my two 6-volt AGM batteries charged and maintained with a battery tender. You can keep 2 12 volt batteries charged and maintained the same way; connect the batteries in tandem so that the battery's amp hours are added and the voltage stays 12 volts: a 12-volt charger will keep them "full."

I have a 12 volt Battery Tender charger and it doesn't keep them full. That was the reason for the post.

I would disconnect your neg cable and check to see what your parasitic amp draw is. Mine is about .4 amps if yours is over an amp you may have something left on. A 1.5 amp maintainer should maintain your 12v battery. Like I said in my first post just disconnect the neg cable on your chassis battery after it is fully charged, If it draws down in a week or so you may have a bad cell or sulfated battery. A good battery that is disconnected should last a month in between camping trips even in Ca.

I notice you kept saying "battery" as in singular. The post is about "batteries" as in two 12 volt batteries connected together. I would agree that the 1.5 amp should keep one charged, but based on the research I've done, it isn't enough for two. The only question is what is enough for two? And the biggest problem with the one I have is it will stay in charge mode "red light on" for several days, and then it starts flashing an error code and I assume shuts down. So that is why I'm sure it just isn't big enough. I've never seen it with just the steady green light on which is what it is supposed to switch too when the battery is fully charged and is just being maintained.

Have you checked to see what your parasitic draw is? It sounds to me if your batteries are being draw down in 2 weeks and your getting an error signal that something may be failing in your batteries or your batteries were not fully charged before you put the maintainer on. Do you have a portable charger to fully charge your chassis battery?