Quickest way to charge battery

ScottG

According to the literature that came with the onboard WFCO 8735P converter, it only kicks into "bulk" mode (14.4V) when the battery dips below 12.2V--and then only for "up to four hours."

For those of you that monitor such things, has anyone ever seen the converter put out 14.4V? If so, did you note how long it remained in bulk mode, and what the battery voltage settled to after that?

I've only ever seen 13.6V from the converter, but with my current setup my battery has never been below the 12.2V threshold for triggering bulk charging.

Photomom

We've never let the battery get below 12.2v. I have seen the charger output 13.7 volts at most.

db_cooper

I've never seen more than 13.7v from the converter,  TV alternator has shown 14.4v.   I'm willing to test my battery by going below 12.2 since I'm planning on replacing it.

wizard1880

Sorry everyone, no insult intended.  Let me explain what I've experienced and read online about the WFCO converter, and some science behind lead acid charging technology.

Let's start with your average 3 (or more) stage charger.  It starts first by pushing in as many amps as its rated for into the battery.  This is known as the bulk charge.  The voltage will slowly rise from 12-something volts (depending on how discharged it is), all the way to 14.4 or so.  Then, it reaches stage 2, the absorption phase.  At this point, your battery is 80% charged.

In stage 2, the voltage holds steady at 14.4, and the amps begin to taper off.  This stage can take many hours, and it continues until the amps drop to less than 1, give or take.  At this point, it now reaches stage 3, and your battery is 95-98% charged.

In stage 3, the volts drop to 13.2 or so, and your battery very slowly charges to 100% over the next couple hours.  It then stays here, indefinitely, at 13.2v, until the charger is disconnected, or sometimes automatically, depending on the charger's programming.

Here's some trivia if you happen to own a battery tender (Deltran) branded charger: Phase 1 is a solid red light.  Phase 2 is flashing green, and phase 3 is solid green.  Other chargers that claim to have multiple phases (more than 3)  like the CTEK line, are actually just exaggerated parts of phase 1 and 2 usually.  For example, the CTEK 7002 has a light for <25% charge, and another for >50%, and while it cycles through those lights, it's actually just splitting stage 1 into two parts.  It's just marketing, really.

There's also an Equalization phase, but let's talk about that later.

Now, let's bring in the WFCO.  They claim to be a 3-way charger, but it's actually just a glorified power supply with variable voltage outputs.  It has no concept of constant current or constant voltage, like a true battery charger does.

The WFCO has a default voltage output of 13.7, at 35 amps.  When the voltage output at the converter itself, not the battery, drops below 13.2v for more than 2 minutes, it kicks up to what they call bulk charge mode, which is 14.4v.  Where the trouble with our wiring comes in, our T@B is wired with 10 gauge cable, at about a 6-10 foot run (depending on your model).  Over this long of a run, there's a high amount of resistance in the cable.

Here's a scenario.  Let's say your battery is very low, at say 11.8V, which is around 20-30% charge.  (Don't do this, if you can avoid it!).  Now you plug in your camper, and the converter comes on at 13.7v.  Since the battery is just an electron "sponge" (or what have you) at this point, it will absorb any juice it can.  The converter is pumping 35 amps, but due to the high resistance in the battery cable run, the battery terminals may show 12.6 or the like, and only 25 or so amps are flowing.  The rest of the energy is heating up the battery cable.  As a result, the converter end of the power cable is actually reading 13.4 volts.  No boost for you!

One way try working around this is by installing thicker cables between the battery and the converter.  When I installed my 2 golf cart battery system last summer, I used 2 gauge cable, and replaced the entire run.  That's almost twice as thick as jumper cables!  But guess what, I'm STILL unable to kick it into boost mode!   The deepest discharge I've done is about 60%, or 12.2v.  When I plug in the converter, the battery voltage jumps to 13 3, and no bulk mode.  :(

I haven't tried going deeper discharge than that, since I'm still easing these new batteries into service.  But why should I need to drain my battery to death, in order for this WFCO to properly charge my battery??  And this, right here, is the root of complaints that plague the WFCO.

The Progressive Dynamics converters, as well as IOTA and a couple other brands out there, will jump into boost charging (14.4) immediately when the converter is plugged in.  Battery full? It tapers back to 13.7 in a couple minutes so it doesn't overcharge.  After a couple hours, as long as the current is low enough (I.e. you're not using your trailer), it drops to 13.2 and stays there.

Speaking of 13.2v, the WFCO is also designed to drop to 13.2 after approximately 28 hours of idle time (little to no current in use).  The trouble folks run into, is that they can't get it to drop into this rest mode, even after several days.  Sometimes the current draw from your smoke alarm, co2 alarm, and entertainment system is cooling the converter into thinking you're using it.

Personally, I wasn't able to get my WFCO to drop to 13.2 until I disconnected everything from it first (pulled all fuses out except battery fuses), and gave it 3 days time.  Once it finally dropped down, I plugged all fuses back in, and it seemed to stay at 13.2.  This worked for about 2 months.

But now, my converter seems stuck at 13.2, and it won't climb back up to 13.7, even when I plug it out and back in!  Worse, it suddenly jumped into boost mode on me, without warning, just last month before our camping trip!  I left it that way overnight (figured the batteries could use a top-off before the trip), but it's stuck at 13.2 again.

I've found many others have had a similar experience to mine, and have either had it repaired under warranty or just swapped it out with something else.  And others have just added their own battery charger, as many of you have.

Oops, before I forget, let's talk briefly about equalization mode.  Very few battery chargers support it, and the CTEK is probably the most affordable brand that comes with it.  When you choose equalization, the charger first fully charges your battery.  Then, it hops the volts up to 16v, for up to 4 hours.  This literally boils your battery, mixing up the acid, in order to prevent acid stratification ( this is when acid on the top is weaker than acid on bottom of the plates).  Also, it helps remove any light sulfation that may have built up on the battery's plates.  How often you equalize is debatable, and every battery manufacturer has a different opinion on it.  Doing it too often will erode the positive grid plates in your battery, and can shorten its life.  Consult yourself battery manufacturer's web page or owners manual for recommendations.  AND--if you have an AGM battery, avoid equalization!  Only Concord Lifeline AGM batteries state that it's OK to do so, but only in very certain conditions.

I hope this helps some folks out.  I'm not against WFCO converters, heck I still have mine.  I hope this sheds some light on your experiences and expectations of them.

Nomad

Good writeup Wizard.
My charger says it has a desulphating mode. Presume that's the same as equalization - True?

Ratkity

PXL - yes. Usually lasts 2 hours or has a variable switch if you want to do 2 or 4 hours. Good chargers give you a choice because manufacturers sometimes only want 2 hours of equalization (14.8V).

Edit: Before I knew better on my reverse TD, I had put a meter on a negative terminal block connected to the battery (so I was measuring the battery, not any phantom charges). I was following someone else's instructions and serendipitously did it correctly. I accidentally let the battery get to 11.9V and was afraid I fried my battery.

Friend said go ahead and try plugging it in (had an early WFCO with 3-stage). That was the only time I saw the meter register bulk mode (battery lived!). I put solar in shortly thereafter (was always the plan). I put the same setup in the T@B - like PXL, I've never let the battery below 12.1V ever again and have never seen anything, but 13.7. I have seen 13.2 with the fuse pulled in the T@B and on solar. BTW, with these setups (Little Teardrop and T@B) were connected to solar, the gauge wire was calculated to have resistance below 2% over the length. Still never let the battery drop below 12.1V, but the Bogart has battery type selector, true 3-stage charger and an equalization mode if needed. Now that I've seen the Victron, I'm inclined to use this on the new camper.

ScottG

@db_cooper, a test sounds like a good idea. That was my original thought, but my battery is not quite ready to be sacrificed for the sake of science! Let us know what you find.

@wizard1880, thanks the informative write up.

One thing I should have clarified in my earlier post... Suspicious of the information in WFCO literature about when "bulk" mode kicks in, I contacted them for clarification. They responded promptly and confirmed that bulk mode activates at 12.2V, not 13.2V. There is a typo in both the printed and online manuals.

If what they tell me is true, the converter won't even attempt 14.4V until your battery is already depleted to the point of potential damage. Since most of us who've learned the hard way don't let our batteries get that low, we rarely see that 14.4 on our monitors.

ScottG

PXLated said:

Good writeup Wizard.
My charger says it has a desulphating mode. Presume that's the same as equalization - True?

My CTEK (MUS 4.3) has a "desulphation" mode as the first stage of charging. This appears to involve pulsing of both the voltage and current (amperage). It has a theoretical 8 hour maximum, but in practice with a decent battery, it only seems to run for a few seconds.

The MUS 4.3 also has a separately selected "reconditioning" function. This adds an extra step to the charge cycle, just what wizard1880 described as equalization.

While both stages involve voltages up to 15.8V, the manner in which the voltage and current are delivered varies. What that actually means to the battery is beyond me, but--at least in the case of my charger--they are not the quite the same thing. 

rfuss928

Some chargers, BatteryMinder and Ctek I know for sure, use a very brief (milliseconds) repeating high voltage pulse for "constant desulphation" during the maintenance stage of their operation.  Other brands use a similar pulse but only for a fixed amount of time.  I have a Vector brand that has a 24 hour "reconditioning" mode that operates in this manner.  The sustained high voltage method of desulphation is quickly becoming less common on general purpose chargers because of the complications and risks associated with some battery designs such as gel, AGM and "sealed" wet cells.

Many batteries and charging systems are optimized for specific applications.  Golf cart batteries are a good example.  These batteries are designed for very high current draw during use and often are depleted well below 50% discharge in just a few hours.  They receive daily maintenance such as electrolyte pH and level checks, and are connected to charging systems designed specifically for them.  When choosing to use these in an RV, the current draw is much lower and the general purpose charging system and low maintenance requirements of stock equipment need to be reconsidered for optimum results.  These type batteries are not designed for install and forget it type of installations.

My current WFCO converter does run all three charging modes.  The first unit suffered several vibration related mechanical failures of components on the circuit boards and the associated operational malfunctions.  Troubleshooting and repairing these were sometimes a topic on the Yahoo T@B forum and are documented in it's files.  I reinforced the mounting of the troublesome components before installing the replacement converter and it has performed as designed for three seasons.  My 136w solar with a MorningStar controller is constantly running in parallel.  I use a BatteryMinder maintainer during storage.
 
My two six year old Optima AGM batteries are out of their cases for the first time since new and have just been "performance tested" on a large auto shop's analyzer.  They both still exceed their "new" manufacturers specifications for AH capacity and CCA.

Each individual needs to access their requirements and desired involvement to determine the best solution in their case.  The best solution for someone who always opts for full hook-ups is much different than someone who prefers boon-docking.

Lots of good info in this thread to assist choosing your solution.

db_cooper

Well,  I pulled the trigger on the CTEK 25 amp charger.   I want to be able to put a good charge back on the battery in a couple hours of generator time,  so I figure this should do the trick.  I've got the 80 watt Zamp solar panels too, so I should be set between these two sources of recharge.   I was going to sacrifice the Group 24 for the good of the group,  that came with the T@B  (somewhere in the comments above).  But it's in pretty decent shape,  so I think I'll try the desulphation mode on this battery, and try and get a good full charge on it, to see how it does.  With this charger and the solar,  I shouldn't really need a new battery just yet.

https://www.amazon.com/gp/product/B0045F3SGY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

ChanW

wizard1880, thanks for taking time to write that up. Good information.

db_cooper

One more question regarding generators and charging.  Let's say I'm running the Alde on propane for heat and hot water, and an inside light.   I'm going to use the generator for a couple hours in the evening to bring the battery back up, using the 25 amp charger.  Should I pull the fuse on the battery, and hook the charger to it,  and run a separate power cord to the trailer?  That way I run the Alde/lights off the generator while isolating the battery for charging.   Or just hook the charger to the battery, and let the battery keep running the Alde/lights?   I'm assuming the first way will leave me with a bit more juice in the battery?