Lithium Battery

[mikec557]

Originally Posted by Old_Stevenick

Great post. I'm hoping the Hot Water Heater electronics don't draw much. That's my next test. Right now I'm on day 2 of just the fridge and that other 3watts. See how much power I'll have left after 2 days. Then drain the battery, charge, it (I'm returning my 20Amp charger and getting a 45Amp charger to charge faster.)

Then I run it with the hot water heater on propane to see what it draws from the DC.

Phones I'll charge from portable charging bricks, so it's just lights and the water pump. We won't take showers or use a lot of water in the camper. Oh and rolling down and up the Canopy.

2 days is my goal, then charge with my portable 2200 dual fuel generator.

3 watts is so miniscule (aka 1/4 of 1Ah), how are you measuring that? In 24hr period, that's 6Ah. With 100Ah battery bank, that would not concern me. Maybe I missed it earlier, do you know what is using that 3 watts?

By the way, with lithium you don't need to drain it down before recharging. Lithium has no memory. I'm guessing you'll have more Ah than you'll need for 2 days.

[Old_Stevenick]

Originally Posted by mikec557

3 watts is so miniscule (aka 1/4 of 1Ah), how are you measuring that? In 24hr period, that's 6Ah. With 100Ah battery bank, that would not concern me. Maybe I missed it earlier, do you know what is using that 3 watts?

By the way, with lithium you don't need to drain it down before recharging. Lithium has no memory. I'm guessing you'll have more Ah than you'll need for 2 days.

I'm draining it just to see how much I get out of it!

Yes the 3 watts is small, but as you say it's still 72 watts over a 24 hour period.
The way I figure it I have 90% of that 100 ah, which is 1,200 watts X .9 = 1,080 watts. 540 watts per day.

Fridge and those 3 watts are a steady 20 watts, that's 480 watts, leaving me with 60 watts for lights, water pump and hot water heater.

Seems close to me, we could go without hot water if necessary. Just nice for washing your hands. We'll take showers at the campgrounds.

[Old_Stevenick]

Oh I didn't answer your question "how are you measuring that?" I bought a Victron Smart Shunt and connected it to the battery in a waterproof box next to it. It transmits usage to my iPhone.

[mikec557]

Originally Posted by Old_Stevenick

Oh I didn't answer your question "how are you measuring that?" I bought a Victron Smart Shunt and connected it to the battery in a waterproof box next to it. It transmits usage to my iPhone.

Gotta love that Victron equipment.
Your real world test of usage will be interesting to follow. Keep us posted on your analysis.

I don't remember the exact number but I think we have 2A per hour parasitic draw at night. Then I run a fan or two in hotter weather, or the electric mattress pad in colder weather, and the cpap regardless of weather. But with two batteries and 300 watts of solar, it simply doesn't matter.

When you're done with your usage test it will be interesting to see if a 100 watt solar suitcase giving you 5Ah for say 4 or 5 hours per day would be worth your while. Maybe if it eliminated the need to start the genny it would be worth it, or maybe not. Get your usage data, then let's see.

[mikec557]

PS at the end of the 2 day boondock test, before you start the genny, tell us what the Victron battery monitor says the SOC is.

[Old_Stevenick]

I'll be noting what the monitor says after 2 days, but then will continue to run it until the fridge won't start up. I'll start the generator after the third day, then run another test with the hot water heater on.

I'll definitely keep you posted. I've looked into solar and sure I will go that route at some point. It doesn't seem like it would give me a 3rd day of boondocking though, so not worth it - yet. We camp in the woods a lot too, not much sun.

[mikec557]

Originally Posted by Old_Stevenick

I'll be noting what the monitor says after 2 days, but then will continue to run it until the fridge won't start up. I'll start the generator after the third day, then run another test with the hot water heater on.

I'll definitely keep you posted. I've looked into solar and sure I will go that route at some point. It doesn't seem like it would give me a 3rd day of boondocking though, so not worth it - yet. We camp in the woods a lot too, not much sun.

I'm going to send you a PM with a link to another manufacturer's forum... because I'm not sure it's proper to post a link like that here. The long and short of it, he's doing a bunch of upgrades to his camper which included two Battleborn 100Ah batteries. He camped 4 days. The nights were in the upper teens or lower 20s and he ran his inefficient (as we all have) propane furnace at night. Somewhere he mentions that it cycled every 10 minutes because of how cold it was and the 200Ah lasted all 4 days with no recharging. So I'm thinking your goal of 2 day on one battery is truly doable...

[Old_Stevenick]

Refrigerator bulb circuit draws power even with the light off.

Strange results this morning. The refrigerator light seems to draw power even when the door is closed. With the door closed 20wh draw from the camper. Open door, the same. Open door, push the lever to turn the light off - down to 11wh! Put my phone inside and took a video, light does go off when you close the door.

Took the bulb out. Draw stays at 11wh, door open or closed!

Something in that fridge draws 8wh with the door closed and the light off, only when there's a bulb in the fixture.

[Old_Stevenick]

Was going to edit my post, but instead will post this correction.

I just went out and did all my tests again and the draw did go down with the door closed this time. It seems that maybe the light-off door switch wasn't working well.

I'm drawing 11 watts now between the fridge and other parasitic draws. Instead of the 20 I was drawing. I did take the bulb out anyway.

Add the hot water heater to that and I think I may be good!

[mikec557]

Interesting. Before you posted the edit I was going to ask about the light switch. We have a model 2020, built in Oct-2019, and our fridge is the first one that does not have a mechanical lever to turn the light off and on. Ours has a motion sensor. Open the door and a second or two later the light comes on. I don't know what the motion sensor draws.

[Old_Stevenick]

So i'm running the hot water heater, pump is on (but not being called upon right now) fridge on with bulb removed. Radio still lit up when off.

17 watts! I was at 20 without the water heater yesterday. Going to run things for a while to see at what point the battery stops putting out enough power to light the fridge.

Than will charge up and do a full boondocking test. 17 watts is about 1.5 ah X 24 hours is 36 ah per day. Add lights and other things and 2 days will be easy. With solar could probably get to 3 days. For now I'll stick with a 2 day recharge cycle.

[flybouy]

Originally Posted by Old_Stevenick

So i'm running the hot water heater, pump is on (but not being called upon right now) fridge on with bulb removed. Radio still lit up when off.

17 watts! I was at 20 without the water heater yesterday. Going to run things for a while to see at what point the battery stops putting out enough power to light the fridge.

Than will charge up and do a full boondocking test. 17 watts is about 1.5 ah X 24 hours is 36 ah per day. Add lights and other things and 2 days will be easy. With solar could probably get to 3 days. For now I'll stick with a 2 day recharge cycle.

If you want a true indication of how long you can "boondock" just go out and live in it for a day or two. The only way to tell is to use the fridge as you normallt would, wash dishes, wash hands, take showers as normally would, otherwise running tests while appliances are idle will not reflect "real world" results.

I'd also be mindful of just how low you are running your battery down during your experimemnting. You can do damage to a flooded battery by discharging them too far.

[Old_Stevenick]

flybouy I completely agree with you, this is just giving me a baseline. The way I look at it is if I can't even barely get 2 days this way, no way I will in the real world. If I can get 2 days with 20 ah to spare, I feel like I have a shot at it!

This is a Lithium Iron Phosphate battery, which supposedly are allowed to be drained down all the way with no damage. I won't go below 10% in my tests.

[flybouy]

Originally Posted by Old_Stevenick

flybouy I completely agree with you, this is just giving me a baseline. The way I look at it is if I can't even barely get 2 days this way, no way I will in the real world. If I can get 2 days with 20 ah to spare, I feel like I have a shot at it!

This is a Lithium Iron Phosphate battery, which supposedly are allowed to be drained down all the way with no damage. I won't go below 10% in my tests.

I got distracted when typing this and forgot the battery change. The garage called me and told me my steering gearbox is bad, $2K to replace.

Anyway, you should have no ptoblem making it 2 days.

[Old_Stevenick]

Sorry about your steering gearbox flybouy, ouch!

[JRTJH]

I have a pair of GC2 golf cart batteries. They are rated at 200-225 A/H and should not be discharged below about 50%. So, if we consider the pair at a 12 volt 100 A/H source, it's "somewhat comparable to your battery if being discharged to around 50%.

We routinely dry camp for a week at a time. During the winter I recharge the battery bank with a generator (midnight furnace issues are not pleasant). During the spring/summer, we regularly go 3 days between charging the battery. That's using no more than 50% of the charge from the battery bank. Our consumption is based entirely on how WE USE the trailer, not on "how the trailer systems consume power when not being used by humans"...

I don't see any reason to believe that your battery, if it's rated at 100 A/H, should not perform in a similar fashion.

So, depending on what YOU and YOUR FAMILY do when camping, how much TV, radio, how many LED lights, how often you open the refrigerator or how much water you use will dramatically affect the battery consumption. A "stagnant RV will not consume anywhere near what an RV being used will consume".... It's sort of like measuring the amount of propane used to heat water in the water heater for a week. The amount of propane will vary dramatically from "heating it with no water use" and "heating it while taking 6 showers and washing dishes twice daily"...

It's difficult at best, unscientific at best, to rely on"stagnant use data" to calculate "active use requirements"... The only way I know to obtain the data you're trying to determine is to actually "live in the trailer" not "calculate it by subjective information"....

That's like determining GCWR by using a bathroom scale to weigh everything you put in the trailer, so the "hitch weight must be XX because 13% of that weight is "supposed to be on the tongue"... Real world seldom follows "hypothetical use"...

[Old_Stevenick]

JRTJH, thanks for that post. Our usage will be low and we'll be monitoring it, so upping my hopes to 3 days is now on the table again!

We do a lot of 4 day trips. So if we could get to an easy 3, than I think a small solar setup might easily get us to 4 days, no charging would be awesome.

For many years it's been us and a pop-up. We'd go a week on the battery which was just a standard lead acid battery, so we go easy.

[JRTJH]

I'd recommend this:

The best laid plans often don't consider an "overlooked part that totally spoils the plans"....

At this point, you have the generator, you have the battery, you have the RV. Go on the trip, you're prepared to recharge if needed and can skip recharging if not needed. Either way, you'll learn "real world usage" not "hypothetical, might be usage"...

I'd recommend that you stop the worrying and overthinking about what "might be" and just go do the "will be"... If it works, and you get 3 or 4 days, great... If it doesn't work, then you'll need to make some changes either to electrical consumption or increase the battery power supply... Either way, you'll still have the generator as backup during the "learning phase"....

I guess what I'm saying is "no matter what your calculations today might be, the test isn't with the pencil, but with the actual battery performance when you're out camping".... If your DW is like mine, all the "pencil work" goes out the window when she isn't sleepy and decides to stay up after bedtime, burning lights while reading a book.... So, real world doesn't match pencil world... What do you do, argue with her to turn the light off or ignore the "hard work with the pencil that you spent days trying to calculate" ????

[Old_Stevenick]

Yup, the time is to relax. Until now, looking at that darn 20 amps of parasitic usage was very troublesome. Just fridge at idle. Once I got the fridge power down by so much by taking that bulb out now if it's 2 days, 3 days or maybe even more someday, doesn't matter.

I was worried I wouldn't even get to 2 days and that would have really sucked to have to run the generator almost every day. So I put a lot of time and energy into getting to this point. Anything more than 2 is gravy and I'm not going to spend any energy (so to speak) planning for gravy.

[JRTJH]

IMO, the reason for having a "glamper" is to go "glamping"... That means you have a light in the refrigerator (not a cold hand from digging in the ice chest) and you have a light to read a book at night (not a flashlight held in place by your teeth) and a water pump to flush the toilet after using it (not a trip in the rain to the outhouse)....

The best learning occurs with experience and that big investment has all the features to make life better than the "old popup"... Disabling them to try to get a few extra hours without recharging ??? Defeating the conveniences is almost as "primitave" as keeping the popup would have been. In that case, just keep using the popup and avoid even needing a new battery ?????

You'll be fine with what you have and on that first trip, you'll probably be "delighted" that you can enjoy the comfort of both a refrigerator light and a flush toilet without having to count the difference in 8 watts vs 12 watts of battery consumption....

Use what you paid for and enjoy the "glamping"... It's much nicer "with lights and a refrigerator"