Boondocking power options

[david]

Merlin is absolutely correct, resting voltage needs to be just that, and to have any accuracy the battery needs to be resting for several hours with no charge and no load.

I too am surprised by how quickly your batteries seem to drop. Get a hydrometer at any autoparts store. That is the only real way to check state of charge.

And if you are using DC for the fridge, switch to propane as Merlin notes. The fridge will use a huge amount of DC.

David

[fasteddieb]

Thank you guys.

1) The Dometic refrigerator in our 21BHS is just dual-use - 120v or propane. I mentioned it running only because I assume some dc  current is used even when running on propane, which it was.

2) I had given passing thought to the battery voltage indicating lower with even a small load on it. After sitting for a while disconnected, the voltage on my spare did seem to increase.

3) I will purchase a decent hydrometer and attempt to monitor that way.

4) One other data point - for some reason our water pump seems to "spit" a lot, as if air gets into the system when not hooked to shore water. I assume it draws a fair bit of current, since the trailer LEDs dim a bit when it's activated. I'll start another thread on troubleshooting that.

5) I vaguely recall a "heater" in the refrigerator that draws current constantly and can be disconnected for boondocking.The only heater my Dometic manual refers to is 120v. Am I misremembering the details on this?

Finally, "ignorance is bliss" may have been our motto previously. If not constantly checking the voltage, my guess is things still keep running down to fairly low voltages. I know that's not supposed to be ideal for battery longevity, but in real life I've had car batteries run down to zilch repeatedly when sitting for an extended time or if a light was left on, and they still seem to bounce back and give decent life. Maybe my motto should be...

[charliem]

[font size="3"]Eddie,

Your method of connecting VM and measuring is OK, but the battery must be at rest. Your measurement of 12.85 volts indicates it had just been charging. Not a good SOC reading. A fully charged battery at rest should read 12.7V.

Minimal load and no charging for 60 minutes seems to work. The minimal load of the propane detector is almost unavoidable, but the fridge does have a 6 watt heater running continuously. That's 12 Ah per day lost. Dometic used to provide a switch but it "confused" the masses and cost 50 cents. Gone. You need to disable it if you plan on dry camping.

The water pump may pulse and/or sputter, but its total usage is minimal over a day unless you're washing the Flex. The biggest usage is the furnace, assuming the lights are LEDs and the TV is 12V.

Unless your Flex has been specifically modified it will not properly recharge, even in 5 hours. It's probably delivering 10 Amps or less, depending, and not constant at that. Most new cars drop back to 13.6V at the alternator when driving and that's not enough to recharge the CL battery. I carry a set of 20 foot #4AWG copper jumper cables for recharging. The work well, but are still limited by the 13.6V limit.

So in the end I think your highs were too high and your lows were too low. Looking forward to your next update.

Camp on!
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[whoofit]

[quote source="/post/20544/thread" timestamp="1460637566" author="@charliem"][font size="3"]Your measurement of 12.85 volts indicates it had just been charging. Not a good SOC reading. A fully charged battery at rest should read 12.7V.



So in the end I think your highs were too high and your lows were too low.
[/font][/quote]
Was just going to add the skin effect from charging. He was not starting with a fully charged battery. This coupled with testing the low end under load paints the right picture. Been there before myself.

[fasteddieb]

Thanks, Charlie.

Can you point me to a post on where to wire the 6w heater switch?

[charliem]

[quote source="/post/20546/thread" timestamp="1460638797" author="@fasteddieb"]Thanks, Charlie.

Can you point me to a post on where to wire the 6w heater switch?[/quote][font size="3"]Some details here: [/font][a href="http://livinlite-owners.com/thread/144/fridge-frame-heater-switch"]http://livinlite-owners.com/thread/144/fridge-frame-heater-switch[/a]

[font size="3"]Pay particular attention to the blue wire in TT's picture. DO NOT cut the lug off. The blue wire is spiral wound resistance wire and cannot be easily terminated with a lug. Been there and won't do that again!     Remove the lug from the ground stud, connect it to a SPST toggle switch, and connect the other terminal of the switch to ground. Mount the switch. [/font]

[fasteddieb]

Bought a hydrometer from O'Reilly's today - will play with it later.

Here's how my refrigerator is wired:


My color vision is a bit off - I'm looking at the light bluish wire on the post on the right, correct?

[charliem]

[quote timestamp="1460669318" author="@fasteddieb" source="/post/20559/thread"]
Here's how my [font size="3" color="e6193a"]air conditioner[/font] is wired:


My color vision is a bit off - I'm looking at the light bluish wire on the post on the right, correct?[/quote][font size="3"]I assume you meant refrigerator, not AC? Yes the light blue wire should be the heater. You can verify this by disconnecting CL from shore power, turning on the fridge, and measuring the current from the battery. Disconnecting the light blue wire should reduce the battery load by approx. 0.5 Amps. If it checks out, mount a SPST toggle switch nearby and run the blue wire through it to the ground stud. The heater does make some difference in condensation, particularly near the bottom of the freezer door, in soggy Florida. So you can run it when you have commercial power available. [/font]

[fasteddieb]

[quote timestamp="1460679264" source="/post/20566/thread" author="@charliem"][quote source="/post/20559/thread" author="@fasteddieb" timestamp="1460669318"]Here's how my [font color="e6193a" size="3"]air conditioner[/font] is wired:


My color vision is a bit off - I'm looking at the light bluish wire on the post on the right, correct?[/quote][font size="3"]I assume you meant refrigerator, not AC?[/font]
[/quote]Yes. Brain fart and fixed.

I'll play with that soon - thanks!

[tinkeringtechie]

I disconnected our frame heater with the intention of adding a relay to turn it on when shore power is present, but never got around to finishing it because it literally made no difference. We just turned off the fridge after 10 months of continuous use and never once had condensation or door sticking. We're up in the northwest though, so maybe our climate just doesn't need it.

[charliem]

[quote timestamp="1460729320" author="@tinkeringtechie" source="/post/20575/thread"]I disconnected our frame heater with the intention of adding a relay to turn it on when shore power is present, but never got around to finishing it because it literally made no difference. We just turned off the fridge after 10 months of continuous use and never once had condensation or door sticking. We're up in the northwest though, so maybe our climate just doesn't need it.[/quote][font size="3"]I've never had frost or ice buildup, but I THINK I've noted some condensation around the bottom of the freezer door. Admittedly not rigorously explored. I'll PM you some Florida wet to check yours out  8-) .[/font]

[fasteddieb]

After arriving home, I brought my original Interstate battery up to the house to charge, using an old Sears charger. It has a setting for "Deep Cycle", which I used. After two days, the "Full Charge" light never came on. It seemed like the voltage was maxing out at about 12.46v. Put it in Campy while plugged into 30A shore  power and it came up to 13.26v, still hooked up to the trailer:


[img style="max-width:100%;" src="https://farm2.staticflickr.com/1476/26492535995_bb805b4ef0_z.jpg"]

Has me questioning if it might be time for a new charger for the house.

As far as the new Walmart battery, after charging on the trailer for a couple days with 30A power, but with shore power disconnected, it showed 13.09v, though I have another voltmeter that shows about .1  v less:


[img style="max-width:100%;" src="https://farm2.staticflickr.com/1535/25887645914_454384cc04_z.jpg"]

Finally, checked the voltage with shore power attached:


[img style="max-width:100%;" src="https://farm2.staticflickr.com/1473/26426411471_bda1129b25_z.jpg"]

Finally, checked it disconnected from Campy:



[img style="max-width:100%;" src="https://farm2.staticflickr.com/1594/26426396811_80d53db6cc_z.jpg"]

Do these voltages make sense? charliem thought they were high. Hard to see how the charger in Campy would fail in that manner - and I don't think the output voltage is adjustable - is it?* And I recall that one symptom of overcharging is the boiling out of electrolyte, yet I've never had to add any.

And any recommendations on an all-around battery charger to replace my old Sears unit?

*From the manual:

[fasteddieb]

Back on point, I think our first step towards more efficient boondocking will be a portable 100w solar solution. We try to space out "extravagances", so that will probably be a May expense.

After that I my consider going with two 6v golf cart batteries on the rear bumper. Seems like voltage loss running up to the existing wiring could be reduced by just using a large enough gauge, or even several wires in a "bundle". One wire would be enough if I run a substantial ground strap right at the battery.

Now, can anyone explain why two 6v golf cart batteries in series would be more efficient than just a large marine deep cycle battery of the same amp/hours? It would certainly simplify the installation.

[charliem]

[font size="3"]fasteddieb said: "Do these voltages make sense? charliem thought they were high."

My comment was to your reading of 12.85v. A fully charged battery at rest should not read much above 12.7, assuming the voltmeter is accurate. Reference your forth picture: how long has that Wally World battery been off the charger? 13.1v is really high for a battery at rest.

I would agree the old homestead is due for a new charger. The present one should be relegated to wheel chock duty.

Two 6v golfers are better than two 12v marine batteries for two reasons: First, the marine batteries are not true deep cycle. They are a hybrid starting/lighting battery optimized for neither. Secondly, parallel connected batteries have current sharing issues that get worse with physical separation. Series connection assures every cell gets and gives the same current. FLA batteries are really current sensitive animals, not so much voltage sensitive. Even when looking past two 6v golfers the preferred solution would be two larger 6v batteries or even six 2v cells in series. That's what the Telcos use for their standby systems, but they're big, heavy, and expensive.
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[david]

What Charlie said. I don't think any 12V battery is a true deep cycle battery with heavy plates and more room above and below the plates for electrolyte and sulfate buildup. See
http://www.pbase.com/mainecruising/deep_cycle_battery. Everywhere you see "boat", read it as "RV".

David