Charging a Battery Bank

Scroll down for a charging profile chart I did and a photo

http://forums.trailerlife.com/index.cfm/fuseaction/thread/tid/24655789/gotomsg/24671457.cfm#24671457

Also the 5400s have PF correction but the 4400 does not.

All converters and chargers over 70 amps that are not PF corrected need 20a circuits for their input.

BFL13 wrote:
The 4400s were a prototype for the 5400s, which are expensive for sure. You had to get the TC attachment or else the unit was a single voltage at 13.6ish, same as the old Parallax units like the 7300s.

Ah Ha ... so the 5400 series is more recent? One thing I noticed about the Parallax 5400 Series that some may not care for is that the cooling fan runs constantly whereas the Parallax 4400 Series cooling fan only runs when necessary. The largest in the 5400 series, the 5490(TC) also requires a 20 amp feed circuit. I also notice the 5400 series features what Parallax calls "active power factor correction" - not sure what that is but it sounds good! :p

2 x Duracell Ultra 6V Deep Cycle Battery $250
70A PD9270c $200 add jumper cables $50
Battery disconnect switch
100 watt solar panel for storage, can be used camping $100
Grape 40A control (temp comp) with bluetooth $45
wire, fuses, connectors, tools etc $hundreds.

I got one of those 4455s six years ago but something went in it after a few months to let the smoke out. I admit I also used its internal voltage pot to raise its voltage, as was described on Randy's site, but that was not what "did it" AFAIK. That's based on Mena661 on here got one too, but he did not change its voltage.

His also let the smoke out. However, Mena then sent his to another member on here who fixes converters and uses them for jobs around his shop. He reports that Mena's old 4455 is still going strong since it was fixed. (It needed a new part for the circuit board) he says the 4455 is no better or worse than the other converters available for failures.

While mine was working it worked very well. It did constant amps at around 60 amps with short #4 to the battery bank, and the temp comp actually did vary the voltages as advertised. (I played with sticking the sensor in some ice cream to see the output voltage rise, etc)

The 4400s were a prototype for the 5400s, which are expensive for sure. You had to get the TC attachment or else the unit was a single voltage at 13.6ish, same as the old Parallax units like the 7300s.

http://forums.trailerlife.com/index.cfm/fuseaction/thread/tid/25086719/srt/pa/pging/1/page/2.cfm

RobWNY wrote:
I appreciate not wanting to spend "my" money but really you wouldn't be. At the end of the day, it's my decision and it's all on me whether I end up making a good choice or not. I was just making the challenge to avoid further twists and turns in what I should buy.

OK, so since you insist I'll spend your $$$. :W Since you're not talking about full time dry camping I personally don't see the need to go to the expense of premium priced Lifelines and would instead choose those Duracell 6 volts you mentioned earlier, and despite potential reliability issues of the Parallax brand inferred by full_mosey I'd match those batteries to a Parallax TC converter with temp compensation, which we know East Penn (manufacturer of those Duracell a.k.a. Deka batteries) requires. Along with temp compensation this converter offers charging profiles that correctly match East Penn's recommendations for these batteries. My only question is - what is the difference other than current rating between models available in the Parallax 4400 and 5500 series? :h

To enjoy full benefit of this converter I'd mount it in the trailer's front pass through cargo compartment where it's protected from the elements but is close to the batteries, just as I did with my own inverter installation. I too would agree that your assumption your current WFCO converter is faulty may not be accurate - so your next task should be to establish the true condition of your WFCO and whether it could just be left in place.

Hey, this is FUN spending your money! :p

BFL13 wrote:
Because it will be tight, and you don't know your actual daily, but can control that to fit the circumstances, you will need a battery monitor like the Trimetric. That will show your AH usage as you do it, so you can adjust your 12v usage as required.

Great suggestion, but yet another example how costs can rise exponentially once you start thinking of anything more than just one garden variety flooded cell battery! :E Let's see - multiple AGM batteries, new charger, heavier wiring, generator, now a Trimetric, maybe solar down the road, and hey don't forget about an inverter ... for a few days of dry camping? :h Where does it end? ... or does it? :p

Two batts at 200AH, a 50-90 is 40% so 80AH, so you are looking at recharging that every day. Approx recharge time for that is
-70 amper 2 hr 10 min
-55 amper 2 hr 20 min
-35 amper 3 hr

70/200 is 35% charging rate, so above that 30% spec for those AGMs but not Lifelines which can take a way higher rate.

You can juggle that but it will be tight, but doable with a 60 amper. Because it will be tight, and you don't know your actual daily, but can control that to fit the circumstances, you will need a battery monitor like the Trimetric. That will show your AH usage as you do it, so you can adjust your 12v usage as required.

It is true that you need the whole scenario to build your system (excellent point that it is a system) Most of us build our systems by trial and error. Not likely to get it right the first time out.

Mainly because once you do try it you learn what you really want to do and every trip you see new things that you could do to modify your system. Renovations!

Don't worry about wasting money buying the wrong things if you think ahead. EG, a 60 amper is not a 120 amper that you might wish you had later, but you can get another 60 amper later and use both of them at once. You can get trapped with the wrong thing for later, but you are ahead already by having a big gen, which avoids that particular limitation.

On the WFCO, you need to see if it works or not by testing at the DC panel where it is connected (with the wires off the battery so there is no 12v from them confusing things). It could be getting no 120v input (breaker or GFCI issue) It could be your battery fuse or disconnect switch if you only check at the battery cables. It should be easy--with shore power on and no batteries, do your DC lights work? Yes? Converter works.

I appreciate not wanting to spend "my" money but really you wouldn't be. At the end of the day, it's my decision and it's all on me whether I end up making a good choice or not. I was just making the challenge to avoid further twists and turns in what I should buy. For my amp hour usage, I have no idea. Like I said, this will be my first dry camping trip. I'd like to say we will be ultra conservative but I know that won't be the case. My wife or I will forget to turn off a light or will power up something that probably shouldn't be powered up if trying to conserve. From different readings, it sounds like about 35-60AH would be conservative and 80-100AH would be normal usage for a 24HR period for many campers so put me in the 80-100ah category. Generator run times will be limited where we're going. They allow for 2 hours in the morning and 2 hours in the evening. I'm going to count on one of those 2 hour periods to work with. I doubt I will be at the campsite for both of the daily time frames. I might be kayaking or hiking or doing some other activity. As for my WFCO unit, I don't think it's charging anything at all. After our final camping trip this past fall, I plugged the camper in. When I removed the 12v battery for the winter to put on my BatteryMinder, it was dead. So even though it had been plugged in for several weeks and supposedly charging or at least maintaining the battery, it was dead. Fortunately, the battery has recovered with the BatteryMinder. When I plugged the camper in and put a voltmeter on the bare cables, there was no reading showing that a charge was being sent to them. So after checking the cables the best I could and the fuse, I came to the conclusion that it's a faulty WFCO unit. Since I will only have 2 hours of generator time, fast charging will be important so considering the units that have been discussed, the PD9260 is a smart charging unit with a remote to force longer bulk charging times. That's a plus but doesn't have temperature control. The Parallax ParaMode does have Temperature Control but maybe not great reliability and not much as far as reviews or literature to make an easier decision. So I have further confusion.

BFL13 wrote:
I pity the poor guy who wants AGMs with just a converter that does whatever it does, and he is stuck with that.

Hey .... I really resemble that remark! ;)

I've intentionally left only the stock Parallax 7345 converter in our 2005 Itasca Class C cuz I think it's a great ~$200 piece of equipment - why fix something that ain't broke.

The motorhome came with two 12V Group 24 wet cells that lasted six months after I bought it due to (I think) mistreatment by the dealer when the rig was sitting on their lot the year before I bought it (I bought the RV "new" in 2006).

I had the dealer (under warranty) install a couple of 12V true deep cycle Group 29 100 amp hour AGM wheel chair batteries with a specified float voltage of 13.6 volts - a perfect match between those AGM batteries and the stock converter. Those two AGMs went about 8 years before I replaced them "just in case" ... they were still functioning fairly well when I got rid of them .

I replaced them with two 12V true deep cycle Group 31 115 amp hour AGM batteries with a specified float voltage of 13.5-13.8 volts - again a perfect match between those AGM batteries and the stock converter. I considered Lifeline AGMs this time around, but when I contacted Lifeline regarding specifications they refused to endorse my use of the Parallax 7345's 13.6-13.8 volts as a float voltage for the Lifelines ... insisting that they would gradually dry out unless I used a float voltage of ~13.2 volts. So instead, I went with a couple of Fullriver AGMs that cost about as much as Lifelines.

My RV AGM batteries see the Parallax converter 1000's of hours per year and the engine alternator a few hundred hours per year. So far, I can't find anywhere statements or data saying that AGM batteries are ruined by not seeing 14.XX volts very much for charging - other than occasionally when exposed to the V10 engine's alternator when traveling. However, I do completely charge them up all the time using this combination of converter plus alternator.

full_mosey wrote:
RobWNY;

I believe you will find the Deka/Duracell battery to be faithful and forgiving.

I used an 8A24 Deka for five+ years. It was my first AGM and it suffered badly due to my ignorance. I discharged it often at its C1 of 79AH, or around 79A and recharged it often between 25 and 50A. Only near the end did I learn about the 30% limit which is was 23.7A. The battery was exposed to parking lot temperatures as it was installed in my van in summer conditions of 130F ambient. Very few RVers have any clue about their battery's temperature. I do now.

My charging advice is to leave the WFCO connected. The WFCO can be relied on for only 13.6V which will be safe at least at any temperature. As a supplement, you need a, possibly portable, charger that defaults to 14.4V when initially powered up as would happen when starting a genny. In summer heat you can charge early in the day.

I rely on a solar system with temperature compensation to supply the 14.4V each day. Temperature compensation manages battery temperature by reducing Volts if needed.

Get the batteries. You will be fine.

I too am reluctant to spend your money. :W I'm also hardly the "expert" that others here are but I think full_mosey's approach is probably what I would do myself, partly because Lifelines are so costly & therefore hard to justify unless one dry camps a lot, regularly subjecting those batteries to deep discharges. This spring when I assess whether to upgrade from my current but aging G27 flooded I'll be faced with a similar issue - what to upgrade to and what charger to use to best maintain it. :h My current CTEK portable charger does do 14.4 volts properly but it's connected directly to the battery, not 25' away as is my trailer's WFCO which never delivers 14.4 volts to the battery. The CTEK is just a 7 amp charger though so if I invest in a larger AGM, or pair of AGMs, I need to address my charger issue as well. The PD9260 looked like a good alternative except it doesn't offer temp compensation so I'm still leaning to a CTEK 25 amp or NOCO 26 amp portable since I'm not concerned about genset run time. Either would handle a pair of 6 volt AGMs as well but with a 25 / 26 amp limit would obviously take more genset time to restore those to 90% than would be the case with a single G31 ... not an issue for me but could be for you. Both offer temp compensation which Deka insists is necessary for proper care of their AGM batteries and I'm hardly qualified to disagree. That Parallax ParaMode which offers 14.4 volt bulk AND temp compensation seemed like just about the ideal answer to all these concerns but there's not much point if it's not reliable as full_mosey suggests might be the case. Big help, huh? :W