Need a quick answer from the battery guru's

Hi KATOOM,

Your WFO will outperform a 6 amp charger by a country mile. A forty amp Vector stand alone would be a good choice. Or simply replace the WFO with one from Iota, PD, or Powermax.

KATOOM wrote:
I have a WFO 55 amp Power Convertor and the trailer is a 2005. Does that help? I was told through other threads that most convertors dont go into boost mode and wont charge the batteries more than a trickle when using the generator. Thats when I was also told that forgoing the power convertor and just using a separate battery charger would work better to bring the batteries up to a more reasonable charge in a short amount of time.

hershey wrote:
The RV's converter will normally be your best, most efficient charging system.
But: Whatever you do, don't get tempted to try to use both the onboard converter and a battery charger. You'll just be shooting yourself in the foot and slow the charge process down to a snails pace.

What strange advice! You can use both and they will add their amps so long as both chargers have their voltages above battery voltage.

Whether, while adding, the total is higher than one charger could do depends on the battery acceptance rate. eg, two 40s make 80, but to get that 80 you need the batteries accepting 80 or more amps. No point putting two 40s on when acceptance rate is 40. Each will just do 20 to make the 40 total.

As battery voltage rises under charging, the charger with the lower voltage will be taken out of play first (its amps taper before that) then the one charger finishes the job.

You can have lots of chargers all charging away on the same battery bank.

KATOOM wrote:
I have a WFO 55 amp Power Convertor and the trailer is a 2005. Does that help? I was told through other threads that most convertors dont go into boost mode and wont charge the batteries more than a trickle when using the generator. Thats when I was also told that forgoing the power convertor and just using a separate battery charger would work better to bring the batteries up to a more reasonable charge in a short amount of time.

Only works if you have a high enough amp portable charger, not a 6 amp job.

http://www.boatandrvaccessories.com/black--decker-vec1093dbd-12-volt-40-amp-battery-charger.html

Even 40 amps on 220AH is fairly slow as you can see in the graph posted earlier. You could get two of these 40ampers and use both at once to get 80 amps. That would be about the same as the 70amp graph shown.

It is all down to how much of a hurry you are in and how much you want to spend. As you can see in the graphs, there is not much point going above a 30% charging rate as it goes vertical and time saved by going to higher amps becomes very little.

Don't forget your generator may have a watts (VA) limit as to how many amps of charger it will run. That may be the real limit you face. A PF corrected charger can do more amps on that gen , but PF correction is rare among chargers.

The RV's converter will normally be your best, most efficient charging system.
But: Whatever you do, don't get tempted to try to use both the onboard converter and a battery charger. You'll just be shooting yourself in the foot and slow the charge process down to a snails pace.

The converter(s) in my motor home can fill up my batteries fairly quickly even if they are over low when I fire up ye old generator.

But then I have 180 amps worth of converter, Normally only use the 80 amp job, leave the "up to 100" one turned off.

I have a WFO 55 amp Power Convertor and the trailer is a 2005. Does that help? I was told through other threads that most convertors dont go into boost mode and wont charge the batteries more than a trickle when using the generator. Thats when I was also told that forgoing the power convertor and just using a separate battery charger would work better to bring the batteries up to a more reasonable charge in a short amount of time.

From my previous HTT I had an IOTA-55 deck-mount converter. It's now mounted to the roof of the pass-through, 3' from the batteries. It does a better job of charging off a generator than the factory WFCO.

The real answer depends on your specific equipment and use but a good ball park is going to be something like 2 hours to get from 50% to 90% charged with a charger that does properly go into boost mode (14.4+ volts), if doesn't go into boast mode it could be 8 hours or more to get to 90%. I'm one of the furtunite ones my WFCO actually does go into boost mode straight from the factory but I also have solar so I rarely use the converter when away from full hookups.

I was not one of those people. The WFCO in my "old" 5er never went into boost mode no matter what I did to improve its chances. I ended up buying a Paramode converter which worked much better (cause it actually worked). My MH came with an IOTA which I used after the Paramode (moved it to the MH) crapped out. The IOTA works well although I have yet to see 55 amps for more than a second from it (it's more like a 53 amp converter).

Wayne Dohnal wrote:

If you have a RV manufactured within the last 10 yrs you most likely will have a more modern converter which uses a switching power supply. These converters can supply the FULL rated amperage into the battery.

Unless it's a WFCO converter, then odds are it will never go into boost mode.

Actually there has been some folk that simply upgraded the wire size and or shortened the distance between the WFCO converter and battery and were successful at attaining boost mode. But with stock wire and or distance you are most likely correct.

I myself have a PD9160 with charge wizard and have no issues with all three modes.