Is it okay to leave my trailer plugged in all the time?

[John in Santa Cruz]

FWIW, my understanding of the basic multi-stage charging goes like this...

0) setup: test the battery open circuit voltage, apply a short amount of elevated voltage, measure the current, a really smart charger will estimate the battery AH capacity and charge state and adjust the current levels of the following stages.

1) Buik Stage, constant maximum current, voltage ramps up until it hits a threshold around 13.8-14V, this gets you to about 80% charge

2) Absorption Phase, constant elevated voltage, with the current decreasing, typically around 14.2-14.4V, for about 4-8 hours, this charges the remaining 20%.

3) (flooded cell only) Equalization Stage: boosted voltage as high as 15.5V, with a constant low current of 2-5% of the bulk current, for 10-30 minutes, this equalizes the voltages of the cells (again, wet cell only, don't do this to AGM)

4) float: drop to around 13.5 to hold hte battery fully charged, maintenance level, keeps the battery from self discharging

[paulk]

Originally Posted by rubicon327

The PD Wildkat main board replacement has the exact same voltages on paper as the WFCO 8955. The issue is many never see the WFCO actually bulk charge at 14.4V. At any rate, I’m not aware of many 12V items that are extremely sensitive to a little higher voltage. The LED light issues lately are probably just bad circuitry because the lights are cheap. One exception might be the furnace. In old Atwood literature I found that they recommend no higher than 13.5V with a warning that “high voltage can cause unbalanced combustion and excessive motor wear”. So either way if you have a WFCO that indeed does go into “bulk” mode at 14.4V or a PD unit that goes into “boost” you could at times be at 14.4V and are exceeding furnace specs. Both units have a normal or absorption mode at 13.6V and a storage or float mode at 13.2V.

Supposedly, the MaxxFan doesn't like high voltages either:
http://www.escapeforum.org/forums/f9...ems-12314.html

When the battery is below 50%, it might make sense to trade off wear on the electronic components against wear on the battery, since lead acid batteries lose lifespan at those low voltages. That seems to be the calculation WFCO has made here.

Although there is certainly a high enough voltage which will cause instant damage, the more likely concern here is usage over an extended period of time at higher voltages might decrease the lifespan of electronic components. Operating at 14.4 volts for a short period of time in unusual circumstances is unlikely to cause much damage.

[paulk]

Originally Posted by John in Santa Cruz

FWIW, my understanding of the basic multi-stage charging goes like this...

0) setup: test the battery open circuit voltage, apply a short amount of elevated voltage, measure the current, a really smart charger will estimate the battery AH capacity and charge state and adjust the current levels of the following stages.

1) Buik Stage, constant maximum current, voltage ramps up until it hits a threshold around 13.8-14V, this gets you to about 80% charge

2) Absorption Phase, constant elevated voltage, with the current decreasing, typically around 14.2-14.4V, for about 4-8 hours, this charges the remaining 20%.

3) (flooded cell only) Equalization Stage: boosted voltage as high as 15.5V, with a constant low current of 2-5% of the bulk current, for 10-30 minutes, this equalizes the voltages of the cells (again, wet cell only, don't do this to AGM)

4) float: drop to around 13.5 to hold hte battery fully charged, maintenance level, keeps the battery from self discharging

WFCO follows this basic pattern, although they change the numbers a bit. Bulk is up to 50% instead of 80%, and they have a lower absorption voltage, and they don't have equalization. At 15.5 volts, equalization has 22% more voltage than a 100% charged lead acid battery, and this will increase the current over a resistive load by the same, so you'll see about a 50% increase in power on things like motors and fridge heating elements. That seems like a lot.

Float is 13.2 volts on both PD and WFCO.

[NCBill]

+10 Left plugged in when stored under the carport (100% of the time other than when we are camping).

Just pulled the battery and had it tested, as we have a big trip planned. Battery is five years old, which is on the old side for an OEM camper battery. Tested good. Battery in my truck did not fare as well (seven years old).

[WaltP]

Originally Posted by Iowa Dave

Hi Glenn
GREAT minds think alike.
Iowa Dave

And fools seldom differ.

Walt

[WaltP]

But yeah, I also leave mine plugged in. What's the evidence that periodically unplugging to let solar "exercise the battery" is a good practice?

Walt

[suncoastdancers]

Don't forget that propane and (wired) CO monitors have a shortened service life if they are continuously powered-up. And they are not cheap to replace.

I keep AC power to the unit for heat in the winter. Then I isolate the entire 12V circuit and throw the breaker for the converter as it is not needed. The batteries remained topped-up from the solar panel as the controller is ahead of the cutoff switch.