Minimize battery drain on Skylark 21FKV.

[Hasty1]

I have the Skylark 21FKV, which I am extremely happy with. Mostly, camping is without electrical hookup and a generator is used to recharge the battery. The large number of efficient LED lights in the ceiling really light up the interior when every one is turned on. The Skylark's Progressive PD4045 Power Control Center charges the battery quickly at 45 amps, needing 725 watts. This is well thought out to match the 750 watts continuous rating of my Honda EX1000 generator. I find that my battery lasts 4-5 days before discharging to 1/3, and wanted to know what is using the power, how can I increase the discharge time, and how can I minimize the generator run time.

In short, do not leave the switches for the tankless water heater or antenna amplifier on. Minimize using the only incandescent lights: the exterior amber light and the light built into the hood over the stove. The rest of the lights are LED and very efficient. Maybe these only two incandescent lights can be replaced with LEDs? If windows were left open or the trailer not occupied, consider removing fuse #7 to remove power from the LP/CO detector and radio.

In detail, an amp meter measured the battery draw from each electrical load and placed into a spreadsheet. How long it would take the battery to discharge to 1/3 was calculated under various scenarios. Awning operation and actual heating of water is infrequent and was not measured. The refrigerator is assumed to be cooling 1/3 of the time.

The battery capacity is assumed to be 90 ampere-hours (90000 mA-hours)
The refrigerator is a Norcold N52UL (5.5 cu ft)
The furnace is an Atwood 8525 IV (20,000 BTU)
The tankless water heater is a Girard GSWH-1-WH

__________________________________________________ _____
FUSE BATTERY DESCRIPTION
# LOAD
(mA)
__________________________________________________ _____
#3:
368 mA Two LED ceiling lights in the bathroom
368 mA Two LED ceiling lights over the bathroom sink
1270 mA Bathroom fan
#4:
1360 mA Kitchen hood light (over the stove)
1140 mA Kitchen hood fan (over the stove)
#5:
61 mA Refrigerator is turned on, but is not cooling
250 mA Refrigerator is turned on and is cooling
1700 mA Furnace fan is running.
2060 mA Furnace fan is running and heating.
#6:
9 mA Red LED that stays on in the under-cabinet light over bed
70 mA Under-cabinet light over the bed turned on
72 mA Under-cabinet reading light over the bed turned on
337 mA Two LED ceiling lights over the bed each turned on
#7:
15 mA Two Red LED that stays on in the lights over the dinette
70 mA LP/CO detector, Atwood LPCO
30 mA Radio while turned off. Jensen AWM970
679 mA Radio while turned on. Jensen AWM970
205 mA Antenna amplifier turned on.
153 mA Two under-cabinet lights over the dinette each turned on
#8:
1000 mA Exterior porch light at the door
558 mA Four ceiling lights in the living area
#9:
240 mA Tankless water heater switch is on, but not heating water.
? mA Tankless water heater switch is on and is heating water.
#10:
14 mA Two under-cabinet Red LEDs that stays on over the couch
110 mA Two under-cabinet lights each turned on over the couch
#11:
0 mA Power awning not operating
? mA Power awning operating

60000 Battery capacity, if allowed to discharge to 1/3. (mA hours)
138 mA current draw if refrigerator is turned off
124 Additional average mA current draw if refrigerator is running 33% of the time. =(250-61)/3
262 Typical average mA current draw if not occupying the trailer. (=138+262)

Typical number of days battery lasts if fuse #7 for the LP/Co detector and radio is installed operating the refrigerator (at setting that cools 1/3 of the time) and:
9.5 Nothing else is turned on.
5.0 Only tankless water heater is turned on, but not heating water.
5.4 Only antenna amplifier is turned on.
3.5 Antenna amplifier is turned on and tankless water heater is turned on, but not heating water
5.8 Only the exterior porch light is turned on 4 hours each night.
3.6 Only the bathroom fan is turned on for 8 hours each night.
17.0 Nothing else is turned on and Fuse #7 is removed, disabling the LP/Co detector and radio.
4.1 Furnace runs 4 hours/day.
5.1 Radio is turned on 8 hours/day.
5.1 Kitchen hood light is turned on 4 hours/night.
7.0 Four ceiling lights in the living area turned on 4 hours/night.

[mike837go]

There is not much you can do about any individual load. Just getting 4-5 days is utterly fantastic considering how many parasitic loads and electronic controls are in today's RV's


My last trailer only had lights and water pump load on the battery and we got 3 days before the water pump would start to run slow.


The new one, I gave up trying to carry 100% of the electricity needed to camp for 5 days. I now carry and genset are recharge (2-3 hours runtime) daily.

[MPH9]

Propane is best fuel for fridges

[jimp]

If you are truly discharging your battery down to 1/3 on a regular trip, you will kill it in short order

[Fire_Instructor]

If you are going to run your batteries down to ⅓, consider switching to a pair (or two pair) of 6v golf cart batteries wired in series to create one "big" 12v battery. These batteries have thicker plates, and are designed to be run down, then recharged.

[KiwiBruce]

One thing you did not mention, how old is the battery?

With age the plates get a build up of sulfate that reduces their capacity. You might do well putting on a solar battery charger/ de-sulfator like the Battery minder model SCC-005. In that it will not put a lot into the battery while you are using it will over time keep the battery in better shape.

[Mustang65]

Originally Posted by jimp

If you are truly discharging your battery down to 1/3 on a regular trip, you will kill it in short order

As jimp noted, discharging your batteries lower than the 50% level (around 12.0VDC) will shorten the life of the battery(s). If you move to (2) 6VDC batteries and do not change how low you discharge them it could become very expensive in the long run.

Here is a chart from Trojan regarding their "Deep Cycle" batteries. Hope it helps.

Don

[Hasty1]

The Jayco Skylark has a Progressive Dynamics PD4045KA Power Control Center for charging and maintaining the battery. From the products operation guide: "When the converter senses that there has been no significant battery usage for 30 hours the output voltage is reduced to 13.2 volts DC for minimal water usage. When in storage mode the microprocessor automatically increases the output voltage to 14.4 volts DC for 15 minutes every 21 hours to help reduce sulfation of the battery plates."

[Hasty1]

I agree about not discharging the battery too much. The KIB monitor drops below the battery "GOOD" indication when the battery voltage is below 12.1 volts. While the battery is discharged at less than 1 amp the monitor could indicate battery "GOOD" while the battery is actually less than 20% charged. It is best to run the generator sooner than later. Keeping the battery loads down does reduce the necessary generator run time.