Using a second battery charger

[ruffis]

My factory WF-9855 refuses to function in bulk, can I simply hook up a portable charger to help speed up the process? Thinking of using a 50 amp (max allowed based on 25% Ahr capacity) "dumb" ie cheap charger connected to batteries, powered by the genset (Honda 3000is) while its powering the 30 amp shore power. The converter will be charging as well so really I am attempting to add bulk phase the WFCO cannot. This converter has to go and I will replace the battery to converter wiring with welding cable but is this a viable quick fix? I will have to be on top of the battery SOC of course, I'm hoping I can achieve 80+% Recharge in 3 hrs. I still don't understand the relationship between volts and amps tho, will this second charger at 50 amps read something like 14.6 volts at the post? Higher voltage allows higher current flow? Do I risk damaging the batteries if not very diligent? Your input is appreciated and very instructive, thanks.

[ScottBrownstein]

You can, but you need to closely monitor the situation. You don't have a reliable ammeter and you should keep the voltage below 14.5 or so. I suspect that the current will taper anyway but I wouldn't do it for more than a few hours. It wouldn't be a bad idea to leave a cap off to make sure you aren't losing too much electrolyte. It will "boil" but that isn't heat, it is Hydrogen outgassing.

Don't let the batteries get too hot.

Now, why do you think that your 9855 won't go into boost? Voltage? Current? Wire size?

[ruffis]

Took batteries down to 12V, recharge voltage at battery terminals never got over 13.49 V. Wiring, distance to batteries and WFCO reputation on these forums all point to the this being the case.

[ScottBrownstein]

Originally Posted by ruffis

Took batteries down to 12V, recharge voltage at battery terminals never got over 13.49 V. Wiring, distance to batteries and WFCO reputation on these forums all point to the this being the case.

You could be right, WFCO has a very bad reputation. If you never get above 13.6 at the converter output lugs...you are right! Measuring at the batteries also includes the voltage drop of the wiring.

[325BH]

I never saw my WFCO converter go into boost mode. I was over analyzing things thinking I was doing something wrong. I replaced it with a Progressive Dynamics unit and things have been great.

My Jensen In-Command automation has a voltage display, which allows me to cross-check what the Charging Wizard is doing and what the pendant says it is doing.

This made it clear to me that ditching the WFCO was a good thing.

[ruffis]

That's the main driver here, last thing I want is to replace the problem only to discover the same problem. Everyone has been so much help here in learning the proper approach to isolating the Issue. I am still not comfortable with my electrical knowhow but am moving forward with confidence due to these forums. Thanks to all!

[camaraderie]

You might also want to check voltage at the back of the converter when the batteries are run down. If there is a significaant difference between the reading at the converter and the reading at the battery terminals then you may have a wiring or clean connections issue.
If you're not seeing over 14V then I'd get a Progressive OR Iota DLS with the smart charging module that is rated at 25% or so of your battery amp hour capacity

[pgandw]

First of all, you cannot fully recharge a battery from 50% to 100% in 3 hours. If you have a charger in bulk mode, and it holds bulk mode to 90%, you MIGHT get to 90% in 3 hours. It will take at least another 3 hours, quite likely more, to get from 90% to 100%.

I replaced my WFCO because 1) it never would go into trickle mode regardless of how long you waited, and 2) I never caught it going into bulk mode. WFCO, unlike Progressive Dynamics, has no specs on when a WFCO should go into or out of bulk mode. WFCO does say that after 44 hours with no significant change in current, their converter will go into trickle mode (mine didn't).

I replaced the entire WFCO 8735P panel and converter with a "drop-in" Progressive Dynamics 4135 replacement. I simply moved each circuit over to the PD one at a time, including the circuit breaker or fuse. I also cleaned up the wiring rats nest by replacing series of crimped wire nuts with bus bars for the 12V grounds, and on the positive where there were multiple wires on the same circuit.

I also installed a digital voltmeter (with a rocker on/off switch) by the entrance door, tied into the same circuit that has the porch light, night light, stereo, etc. That enables me to easily monitor battery voltage, both when the converter is running and when we're dry camping. I can tell by turning the volt meter on momentarily what charge stage the converter is on, or a guess at how depleted my batteries are when we are not hooked up.

The voltmeter allowed me to verify the PD converter was using all 3 modes correctly.

Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan

[zuterbru]

Replace the converter with a Progressive Dynamics unit: Progressive Dynamics Inteli-power RV Converter PD9245 | eBay You might even want to go up a step in amperage. Get it with the charging wizard so you can force it to rapid charge when on the generator to recharge the batteries. I boondock all the time and it works great. You can bring your batteries back to almost fully charged in a few hours on the generator.

[KyDan]

Not trying to side track this thread but I'm in a similar situation.

WFCO "3 stage".
We rarely go off grid but get there maybe once a year for a few days.
Recently spent 3 days at Mammoth Cave NP off the grid.
I ran my honda for a couple hours on the 3rd day and didn't feel like
I got a great charge either. Not sure...

I also have a digital meter installed at my main control panel, where lights
and awning and slide switches are located. 8 feet from the converter.
I never saw it go above 13.4 while charging.

We are going to the Smokies later this month for 6 days off the grid.
I'll take a digital volt meter and measure volts at the converter DC terminals.
What should I hope to see there when the genny is running and I'm plugged into it?

Assuming battery is around 12.1/12.0 with very light load and no generator
that means I'm at around 50% charge right?
What initial voltage should I see at the converter terminals when I start
the genny?
What would you expect after an hour or 2 hours?
I don't know exact amp hour but I've got 2 6v golf cart batteries that are
3 years old.

Thanks!

[pgandw]

Originally Posted by KyDan

Assuming battery is around 12.1/12.0 with very light load and no generator
that means I'm at around 50% charge right?
What initial voltage should I see at the converter terminals when I start
the genny?
What would you expect after an hour or 2 hours?
I don't know exact amp hour but I've got 2 6v golf cart batteries that are
3 years old.

Thanks!

The 3 stages of a 3 stage charger:

Bulk mode: 14.4V PD converters will switch to bulk after a few seconds IF 1) they are set up to use bulk to 90% SOC, and 2) battery is less than 90% SOC.

Normal mode: 13.7V Both PD and WFCO converters stay here when camping, after exiting bulk mode (if bulk mode was entered). This voltage tops off your battery, and keeps up with normal loads. It is not enough to push serious amps into your batteries. It will take 12 hours or so in normal mode to fully charge a battery that is down to 50%.

Trickle mode: 13.2V Both PD and WFCO converters enter trickle mode after 40+ hours (close to 2 days) in normal mode, and no significant current flowing.

Because WFCO won't release the spec as to when their converters go into or out of bulk mode, you can't say it's not in spec. But fact is those who actually measure what's going on seldom see a WFCO in bulk mode, which means a slow charge with your generator (converter using normal mode).

If you go to a PD converter, bulk mode works and you can usually get your battery to 90% with 3 hours of generator run time.

Fred W
2014 Rockwood A122 A-frame (also 2 6V GC-2 batteries)

[ruffis]

Not sidetrack in at all Kylan, my converter is in a ridiculous location but I will be checking it's output tonite. Hoping it's putting out its promised 14.4V in bulk so I can blame the factory wiring/distance to battery design. The WF-9855 has to go but my second charger idea with close monitoring on my part should buy me the time till I can properly rectify this all too common FACTORY failure. Why this isn't a warranty issue....
My unit is brand new, my 5th RV and this remains a common (engineered?) issue. My 90 day "repair all issues free" appointment is coming up soon and I fully intend to bring this up if it's the wiring /distance factory design. Why buy a car with 3 wheels.....

[KyDan]

Thanks!
Not sure I'm ready to take the plunge due to limited off grid camping but it's
definitely on my radar!
Momma made me get the Honda a few years ago
Guess it makes sense to couple that with a converter/charger that can get the job
done when I need it.

This thread really got my attention because I used to also use a 2nd
stand alone charger when trying to boost batteries on genny power.
It is apparently out to lunch as it gives "open cell" error on every battery
I connect it to.
Rather than spend $~60 for a new charger I might as well spring for a really
good power converter.

This is our "forever" trailer.... at least after 2 years we still have no plans
to look at others.

[Bluepill]

I use a stand-alone battery charger to properly charge my battery. The WFCO is useful only as a converter, not a charger. The charger's higher voltage will buck the WFCO, so only the charger will be supplying current during charging.

[clr]

The converter charger and most auto battery chargers are really very simple devices. A general rule of thumb here is that you should never use two chargers on the same battery at the same time. More exotic chargers have electronics to share the load (charge that is going into the battery. A normal converter and auto type battery charger has no provision for load sharing. One charger may well trick the other into thinking that the battery is fully charged because it is seeing the voltage output of the other charger and not the voltage of the battery. So one cannot predict the charge each charger will provide.

[ruffis]

Well the 2nd charger was my "hail Merry" pass, looks like I'm in the market for a PD charger. If the wiring impedes the charge voltage to batteries I'll change that too. Pretty disappointed, with the Investments we all make in our units, to find they don't have the basic quality to deliver sustainable battery usage. Thanks to everyone for helping me sort this dilemma, enjoy the day!

[mnoland30]

If you're going to boondock a lot, it makes perfect sense to install a solar panel on your roof. Trimetrics makes a great battery charge indicator and charge controller. It is a little pricey, but it tells you exactly how many watts are going out or into your battery at all times. To get the most out of your batteries, you want to charge them fully. Short charge times with the generator won't really do that. You need high voltage (above 14 volts) and low current to get the last 10% or so of charge into your battery. A solar panel will do just that. Of course if you have enough panel, you won't need a generator. I quit carrying mine, because I found I never need it. For the $200 it would cost to change your converter, you could come close to installing a solar panel and charge controller. You'll save that in generator eventually. And solar is so much quieter.

[KyDan]

Not trying to beat his thread to death but....
on my previous rig I once used a little NOISY 2 cycle generator.
Only on one trip and the looks I got from folks spoke volumes! When we
got home momma told me to get a Honda!

Trying to get as much juice in my batteries as fast as possible I used
the on board charger plus a 25 amp stand alone charger.
My unscientific test indicated to me that I was getting a slightly faster
charge using both.
I put a clamp on ammeter on the extension cord going from the genny
and read amps with just the trailer plugged in
and amps with just the stand alone charger plugged in
and amps with both plugged in.
I got a higher amps reading when both were plugged in.
That's all I've got. I don't remember the numbers but the combined
load was higher than individual loads added on paper.
I gave the noisy little generator to my son who actually used it during
an ice storm. He was able to keep his freezer going and even watched
a little TV.
I always thought if a guy could cobble some sort of decent muffler on that
thing it would be an OK emergency power source.

My acid test will be 6 days off the grid in the Smokies.
IF I can get by with running the Honda for a couple hours ever other day
I'll keep what I have.
If I have to charge every day I'm gonna be looking at a new Progressive
power center.