AGM Battery at rest

ELK

Calling out from battery purgatory here....(my car is now having a battery episode). 

Got my new AGM battery on Wednesday and have been plugged into shore power. Turned off shore power last night...and everything that was on is still on this afternoon and the battery is reading 11.5-12.  So, until I figure out how to install my battery off switch...should I just leave it? Let it work in the trailer quietly? If I plug into shore power on a more permanent basis, will the AC overide the battery, giving the battery a rest?

sigh. thanks!

p.s. I am finding that a basic knowledge of Trailerology 101 soon requires more focused advanced study...like Batteries 201. (keeps us young)

Sharon_is_SAM

@Elk, charge your TaB AGM battery on shore power using the TaB converter.  Once you think it is fully charged, turn off everything possible to limit the draw on the battery, then disconnect the shore power.  Rest the battery at least 30 minutes, then check the voltage using your 12 V meter.  It should be above 12.6 V



Once you are happy that it is fully charged, then you can safely store your battery by removing the battery fuse.  Leave the fuse out until ready to check or use the battery.  Until you learn this new battery’s discharge pattern, I would check the voltage with the fuse in every couple weeks when you are not using the trailer.

If you leave the fuse in and disconnect from shore power, the CO/LP detector as well as other sources of phantom drain will kill your new battery.  With an AGM, there is no reason to stay plugged into shore power - that will just cause your converter to run at intervals.  

ScottG

@ELK, be careful about draining your new battery down below 12V. Doing so repeatedly will shorten their lifespan. AGM batteries may be a little more tolerant of this, but they also cost a lot more to replace.

Along that line, I would not leave the battery connected to quietly do its thing. Until you install a disconnect, pull the fuse at the battery as Sharon_is_SAM suggested. Though a little less convenient, electrically speaking this is the same as using a disconnect switch.

ELK

That is what I did with my last one....Will my solar trickler not keep it maintainned? I suppose I can see if it does. I towed home yesterday...about 1.5 hours...and when I got home I put the trickler on. GZ people said that the inverter (that cord that reverses the polarity, if that is what it is called) won't work and that I had to use the alligator clips....?

thanks

pthomas745

Alligator clips will work...we need some pictures of your setup.....

Trailpixie

I'm not following a lot of what you are saying, but here is some general stuff about AGM batteries and solar.

• AGM batteries will tolerate going below 12V without too much problem. I think at 11.5V you still can get thousands of charge cycles. Going down to 11.5-12V after running a bunch of stuff isn't out of the quested. Don't worry too much.
• Your solar panels will almost definitely keep your AGM battery charged. How many watts do you have?
• If the solar panels aren't keeping it charged, then you probably have some sort of parasitic draw. That means that some device is using power when it should be off. In this case turn off the battery cutoff switch. (this may be a good practice when you leave it if you are conservative about these things).
• Shore power should charge the onboard batteries. If it doesn't, have it checked. There is something wrong. 

pthomas745

And, your new battery will stay charged for a long time, all by itself, if there is no power draw from it.  Pull the 30 amp fuse (I think you said you don't have a switch) from the fuse holder and a fully charged AGM battery:

"has a very low self-discharge - from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than standard batteries."

From this FAQ, the parts about "self discharge."  https://www.solar-electric.com/learning-center/deep-cycle-battery-faq.html/#Battery Size Codes

ScottG

If your 2015 is like mine, I see no difference between using the Zamp port or attaching the GZ directly to the battery with the clips. There is no charge sensor--or anything else--between the Zamp port and the battery, just wires.

Of course, this assumes you have the polarity correct, which I have no way of confirming without inspecting the equipment directly. I'm not familiar with how your GZ maintainer is wired, so I can't say one way or the other whether the adapter (an "inverter" is something else entirely) is actually required.

If you have not confirmed the proper polarity for yourself using the information I provided in your other discussion, then I recommend attaching the GZ directly to the battery using the clips, as this will leave no doubt it is hooked up properly!

Regardless of how you attach the GZ, I still recommend pulling the fuse at the battery so that you are not draining your battery as fast as you are charging it.

Good luck!

Sharon_is_SAM

Elk, you should really measure the battery voltage before putting it on the trickle charge.  You will not be able to measure the trickle charge ability without knowing a baseline.  If your battery was depleted before you put it on the Goal Zero 10 watt solar charger, and you check it later and find that it is depleted, how will you know if the GZ just could not keep up or worked at all?

ELK

that's smart!

ELK

pthomas745 said:

Alligator clips will work...we need some pictures of your setup.....

OK...like the battery? in the tub?

Sharon_is_SAM

Yes

ELK

The green arrow is pointing to the Zamp cable which is connected by the white/yellow cord.  Are there other views you need?   I noticed my meter is reading 12.4 since 12.6 yesterday....after towing. I do have the GZ connected

Sharon_is_SAM

@ELK, if you have alligator clips that came with your GZ, then connect them to the GZ, then connect the positive lead to the positive battery terminal, and last the negative lead to the negative battery terminal.  Check your rested voltage before you do it.  Then check the voltage tomorrow after the panel has been in sun and see if there is any change to the battery voltage.

Did you rest the battery after towing or take the reading immediately after towing?

ELK

Hmmm. As I was setting up and unpacking, I checked. It 12.6

24 hours later it is 12.4. I will do as you suggest. We are due for clouds all week...but it IS summer.  thanks for your help!

pthomas745

Ok, we can see the Goal Zero cabling going to the Zamp plug, with the 027 adapter.  So, that looks good.  Keep in mind, if your battery is still "on", either with a switch or with the battery fuse in, the trailer is still using power for things like the carbon monoxide and smoke detectors, and that can be about 4 amps per day.  I think your Goal Zero might be "only" 10 watts, so it might have trouble keeping up on a cloudy day.  Try to make sure that panel gets as much sun as possible, and keep monitoring your state of charge.

Thanks for the pictures! 

ELK

No. Thank YOU for your help with battery health!

ELK

and yes it is only 10 watts.