Charging, at this time, a single 125aH battery for an offroad m416 based trailer. I will have it wired to the tow vehicle but would like the option to plug the trailer in to shore power or a generator.
With reference to this statement, are you talking about just charging or maintaining the battery while it's in storage, or while actually camping?
If you are talking about while camping, you should first figure out what your maximum daily Ah usage will be. Once this is determined, you can choose a charger size that will be able to keep up with your daily useage. Since the SLR125 AGM is a deep cycle battery, you can safely take it down to 50%, but if the charger is too small you are still going to be waiting on it to bring the battery back up before you can move on. An 8A charger is the
absolute smallest charger recommended for this battery. If you're planning on using 110VAC lights and appliances when shore power or generator power is available, then this may not be an issue.
My advice is to get the largest
4 stage charger this battery can handle, which appears to be 35A, especially if you plan on adding another battery in the future. Charging with your vehicle's alternator or Solar will help offset the smaller charger, but I would still get one larger than 10A, maybe a 25A.
The following is from Mr. Frederick B. Cook (US Ambassador, Retired), who has been all over the world in an Overland Expedition Vehicle called
Ndeka Luka (Sango for “Freebird”
.
How Long Does it Take to Fully Recharge?
In other words, how hard is the problem? Lifeline provides the following formula for temperatures between 68 and 86F.
Time to reach full charge = [(Depth of Discharge/100) x Rated Capacity (Ah) / Rated output of charger (A)] + 2 hours.
Thus a 100 Ah battery, discharged 50% with a 25A charger would take:[(50/100) x 100/25] + 2 = 4 hours to reach full charge.
If a 10A charger is used, it would take: [(50/100) x 100/10] + 2 = 7 hours to reach full charge.
https://cookfb.files.wordpress.com/2015/04/electrical-power-for-the-overland-camper-the-problem.pdf
http://lifelineb.wpengine.com/wp-content/uploads/2015/12/manual.pdf
You may purchase a 10A charger and it work out fine for you, if you don't mind waiting all day to recharge the battery(s). But, I'm the kind of person that prepares for the worst case scenario and tends to overbuild everything, especially when it comes to electrical. In my case, I'm running 4 Trojan T-105 6V deep cycle batteries in a series/parallel configuration. I'm using a
Magnum Energy MS2012 Inverter/Charger (100A charge) to charge them with. I also have a Honda EU3000I generator on board and will be adding 480 Watts of Solar Panels at some point.
See what I mean...overkill!!
