battery maintenance questions from newbies

[OHguest55]

We bought 2 6-v trojan T-125s. (We want to add portable solar next year and boondock))
The new batteries are expensive so we want to keep them healthy.
I bought a Battery Tender Jr. 750mA. Is this the right size to use when not using the trailer? I am confused about leaving the trailer on shore power all the time.

We also have a battery isolator that came with the trailer. I am not sure how to best use it.

I would like to buy a easy to understand battery monitor that we can use with the solar panels. With clear percentages of battery life. I was looking at the AiLi monitor but wasn't sure what size to buy or even to buy it.

Last question, I looking for a replacement vented battery box to put the new
batteries in under the front sofa. It will be a tight fit height wise. Any suggestions?

Any help would be appreciated! I pour over the forums trying educate myself and then pass the information to my busy husband.
Maureen
2015 2720QS

[rtcassel]

Originally Posted by OHguest55

Last question, I looking for a replacement vented battery box to put the new
batteries in under the front sofa. It will be a tight fit height wise. Any suggestions?

I am using this in the rear compartment: https://allbatterysalesandservice.co...atteries-gc-g/
I vented it using a small spice container with the bottom cut out.
They also sell a similar box that stores the batteries end-to-end.

[Bill]

Originally Posted by OHguest55

I bought a Battery Tender Jr. 750mA. Is this the right size to use when not using the trailer? I am confused about leaving the trailer on shore power all the time.

I have the BT 750 mA, and it has served me well.

First, the BT is a battery maintainer, not a battery charger. It is intended for use during long-term storage of the battery. "Long term" isn't a well-defined term, but let's say a week or more. For shorter storage time, your TM charger will be fine.

The way to tell if your BT is doing the job is this:
1. Make sure that the batteries are fully charged, and the electrolyte level is proper. If you ask the BT to charge, it will do so - but because of its limited capacity, it will take a long time. I've done it.
2. Disconnect the batteries from everything. The TM, and any other RV, has parasitic loads that slowly drain the battery, even when you think everything is turned off.
3. Connect the BT to the batteries. Power it up, and look at the lights on the front of it. The lights will probably come up as blinking red, meaning "charging".
4. Go away for a few hours. When you come back, the lights will have changed to blinking green, meaning something like "We're just about there"
5. Again, go away for a while - maybe as long as 24 hours for your big batteries. The lights on the BT should become solid green. This means "The batteries are fully charged, and I am maintaining them". In other words, the BT has brought the batteries to full charge, and has sufficient capacity to hold them there, making up for any self-discharge that happens in the batteries. This is exactly what you want, and it tells you that the BT is up to the task. A bigger BT would get to solid green a bit faster, but once it gets there, it would do exactly the same thing as your BT 750 mA unit.

If the BT never gets to solid green, then it may be too small. I doubt that this is the case.

I have left a battery on the 750 mA BT for months, and it always works.

Bill

[wbmiller3]

I use that same battery tender (likely bought after reading Bill's posts) and it works well for me too.

[OHguest55]

Thank you for the advice everyone! I told my husband about the Bargman connector idea that I saw on one of Bill's earlier post. He thought it a good idea. Makes connecting the battery tender so much easier
Maureen

[OHguest55]

Our new battery box arrived in the mail. My husband is getting ready to connect the batteries. He bought a 6 gauge battery cable with the connectors attached to the cable from the auto store. Is 6 gauge the right size to connect the two batteries in series?
Thanks so much for all your help
Maureen

[rickst29]

Originally Posted by OHguest55

Our new battery box arrived in the mail. My husband is getting ready to connect the batteries. He bought a 6 gauge battery cable with the connectors attached to the cable from the auto store. Is 6 gauge the right size to connect the two batteries in series?
Thanks so much for all your help
Maureen

Yes. Unless you will be using a 120v Inverter with big loads, nothing within TM will be needing to work with more than about 55A (that's from the charger, at full bore). 12v * 60A = 720 watts. But If you want to try and run a microwave FROM THE BATTERIES, then you will need AWG-2 or larger to drive your Inverter, and the same wire size between the batteries.

I currently use wire size AWG 1/0, to reach my Inverter, but my batteries are LiFePO4 and not "normal".

[OHguest55]

Thanks for your help. We have a campsite on Lake Superior for the last week in August. First time camping without electricity and just using propane and batteries. I am kind of nervous and want our trip to go well.
I appreciate all the help I find on the forum!
Maureen