Battery Charge

[rustyrivet]

Boy, you guys are scaring me with all this technical talk. I just added a second battery (actually replaced the original and added a new second battery). The original was out on the tongue of the trailer, the second is in the storage compartment under the bed. Both are new Lifeline 12 volt batteries. When I bought batteries, I also bought a "Battery Minder" slow charger. I am really confused about how to use the Battery Minder. Do I have to remove the batteries and slowly recharge each of them individually over the winter, or is there a way to charge both of them at the same time and maintain them on the batteryminder. Or???? should I just forget about the Batteryminder and simply plug the shorline in and let the converter charge the batteries all winter long? My AS is a 2005 Safari and the converter is a newer model. jc

[bryanl]

The BatteryMinder(tm) is a good device for storage maintenance. First make sure your batteries are fully charged by leaving them on a good charger (your converter should do) for a couple of days. Then disconnect them from any load or charger so you can leave them alone with the BatteryMinder. It should be able to handle both batteries connected together as usual, in parallel, for storage.

Do check every month or two to make sure that you have a good battery float voltage (13.2 or so depending upon temperature) and everything looks OK. Read the manuals for both the BatteryMinder and the AGM's to see if they have any concerns or caveats to worry about.

[jamesardis]

no need to be rude or feel personally attacked gentlemen-if Lieppers battery facts dont hold water-post your own--

Liepper-what is the reason that my battery tender wont bring a discharged batt up?

thanx for sticking on point-jim

[bryanl]

what is the reason that my battery tender wont bring a discharged batt up?

It will, over time, as long as it can provide a charge current greater than the bank's internal self discharge rate. Multiple batteries in the bank extend the time as can battery age and condition. It is generally better to not have batteries sit around without a full charge so a charge that will take days or weeks (or more) is not as good as one that will take less time.

Battery charging and battery maintenance, while related, are two different tasks requiring two different approaches.

When the batteries are charged and the task is maintaining the charge for storage, the challenge changes. There you want to keep sulfation from forming. This means keeping the electrolyte mixed and the battery fully charged. Those tasks don't take a lot of current capability but can involve a rather tricky balance as 'fully charged' depends upon temperature and other things. Don't do enough and the battery grows sulfate crystals. Do too much and you boil off the electrolyte and wear the plates.

facts dont hold water-post your own

We should all be sharing the same facts. Explaining how we interpret them and the rationale we use to draw conclusions based on them can help others understand how things fit together, what is perceived as important and what isn't, and consider what might be missing.

This process is especially valuable on some of the more technical issues. It also seems rather rare so working towards an intellectually honest discussion remains a distant goal, it seems. A first step is probably to get everyone on board that it is a desirable goal worth working towards.