My two 6 volt batteries are brand new, and connected in series.The TT was at the dealer for warranty work, for about a month. When I picked it up and tested the batteries they were at about 30%, despite being 100% when I dropped it off. I was a little miffed, but came home and hooked up to 110 from my garage, thinking that over several days the onboard inverter would boost me back up. Much to my dismay, after two days hooked up, the batteries still read about 30%. I now have them isolated and connected to a smart charger, which has been feeding them 25.8 amps for several hours. Why were these batteries not charged up by the onboard inverter/charger? I know that dropping them down to 30% is not ideal, but it shouldn't wreck them, should it?

Hate to say it but from past experience of what others have reported it probably has done your batteries in. You may be able to get them back again but they will most likely not be at the same new performance before they was discharged below the 50% charge state.I have never returned any of my trailers back for warranty work but if I did I would most definitely remove my large expensive battery bank and let them deal without a 12VDC battery source. I might connect up a Lawn Mower 12VDC battery to get me to the dealership and be legal with DOT safety regulations.We have alot of money invested in our battery banks and you know the dealership is not going to replace them if they were discharged during the time the trailers set in their shop. Just my thoughts hereRoy Ken

What is the voltage at the converter output?

30% of 12.6 volts is approximately 3.78 volts. Is this what you are measuring?In any case, you're correct in assuming your on-board charger should have kept the batteries at a full charge or better...typically a float to absorb charge is 13.2 to 13.6. So, it seems either you have the batteries disconnected from the system, or your charger isn't working properly. With the TT plugged into shore power, what is the voltage measurement on the batteries? If Charger is working, you will not measure less than 13.2 volts. If the batteries are very low to begin with, the charger will be putting out over 14 volts.Make sure your battery disconnect switch is in the on position. Measure and let us know what you find.Ron

quote:. If the batteries are very low to begin with, the charger will be putting out over 14 volts.----------------------------------------------------------------------------Not true.Very low batteries could start as low as 12.8 to 13.2, at maximum amperage.As the voltage comes up, the amps taper down. You will not see 14+ volts till batts are 70-80% ??

6 volt battery problem | Good Sam Community

17 Replies

time2roll
Nomad
Oct 04, 2014
Yes WFCO normal mode is 13.6 volts and WFCO has a float mode at 13.2 volts. I think your WFCO is just in float mode. 13.2 at converter and 13.04 at the battery is pointing to an open circuit between the two. Probably a fuse, switch or bad connection from WFCO to the battery.
wa8yxm
Explorer III
Oct 04, 2014
13.2 is a bit low but you also have to take the meter into account (13.2 might really be 14 volts)

Seriously I would give it a bit of time to charge before I hollered.

SOME smart chargers (I do not know about the WFCO) will sense very low batteries and adjust so they start them back up slow.. My Progressive Dynamics 9180 with wizard is not so sensitive, It will kick into bulk mode and do it's best to bring 'em up fast. (Providing the circuit breaker holds, at that kind of current draw it has been known to trip those)
67Tony
Explorer
Oct 04, 2014
MrWizard wrote:
You still have not told us.. how you arrived at 30%
What was the battery voltage reading, when got the trailer beck from the dealer

Yes. The batteries read 11.8 with my volt meter, which I interpreted to be about 30%.
Also, the battery status blinky lights in the camper (1/3, 1/2, 3/4, Full) read 1/3.
67Tony
Explorer
Oct 04, 2014
Addendum:

Using the manual, I checked the WFCO converter output voltage and it reads 13.2 Vdc.
This was on shore power with the batteries disconnected.
The manual claims it should be 13.6 (+/-.2)...is my reading close enough?
MrWizard
Moderator
Oct 04, 2014
You still have not told us.. how you arrived at 30%
What was the battery voltage reading, when got the trailer beck from the dealer
67Tony
Explorer
Oct 04, 2014
I got them back up to 13.04, as read with my Gardner Bender digital volt meter.
I'm still puzzled as to why the onboard unit could not budge them off 30% after two days.
I understand that my WFCO (WF-8900) is nothing to write home about....but is it really that crappy?
RJsfishin
Explorer
Oct 04, 2014
Well, if you have one of those 9620's, then anything is possible,....I guess.
ScottG
Nomad
Oct 03, 2014
RJsfishin wrote:
quote:
. If the batteries are very low to begin with, the charger will be putting out over 14 volts.
----------------------------------------------------------------------------
Not true.
Very low batteries could start as low as 12.8 to 13.2, at maximum amperage.
As the voltage comes up, the amps taper down. You will not see 14+ volts till batts are 70-80% ??

That's not accurate either, The voltage should jump up to the bulk rate within a few seconds. My PDI 9620 is at 14.X and 55 amps to the batteries after a deep discharge within 30 seconds.
I would suspect the battery is shorted if it wont allow 14V.
Dakota98
Explorer
Oct 03, 2014
The batteries are probably just fine. I won't go into the "why" the converter will not bring them back up at this point. Assuming the water level was adequate at the point you put them on the Smart Charger, the charger should roughly be in the vicinity of 13.2 volts in the very beginning. It should increase by a tenth of a volt over an extended period of time reaching a maximum of about 16.0 volts near the end of the process, doing this equalizes the cells. This will take the batteries to approx. 85-90 % capacity, at which point the charger will probably back off. Remove the charger. Put a load on them using a 12 volt utility light for a couple hours or a load tester for about 10 seconds & let the batteries "rest" afterwards for a few hours. This will remove any existing surface charge present. Afterwards, put them back on the charger & it should bring them to 100% in a short period of time.
wa8yxm
Explorer III
Oct 03, 2014
Why did the batteries not re-charge suspect list:
ONE: On some inverter/chargers you can disable the charger (IE: MINE)
Two: Which side of the battery disconnect switch does the INVERTER connect to, if the HOUSE side... and they are disconnected....
Three: Blown fuse, tripped breaker (Including the 120 volt to the inverter)

And finally: As someone else ask... How are you measuring?