Ideas with some hypothetical numbers for extended boon docking in RV

[Old_Man]

Why? Why do I have to do that? I did my energy audit and the battery I'm buying is (at least on paper, for now) is up to the task.

I like using newer technology. I was an early-adopter of Mac computers. Lifepo4 has been around a long time, so I don't feel like an early-adopter in this case.

I like the light weight of Lifepo4, I like the small size of the Lifepo4 battery I'm buying (fits in the palm of my hand), I like the ease of using one battery. And later on, I may buy a larger battery if this battery proves woefully inadequate. But only one. Time will tell. But I'm going Lifepo4 right away. Only lead-acid I'm interested works the starter on the truck. And I have a small solar panel to charge the truck battery when it's sitting.

I just hope the water clears soon enough that there will be some good trout fishing in California.

[SunEagle]

You appear to be missing the fact, lifepo4 batteries let you take them down to 10 percent SoC without damage. Try that with any flavor of lead-acid. Those batteries die quick anyway, even faster when damaged.

I still think you have to do the math concerning how many watt hours you can get out of the battery's life and what it cost per kWh. Li chemistry does allow for deeper discharges but the initial cost may be very high and in the end the cost per kWh is also higher then FLA type batteries.

Do the math and not be fooled into thinking one battery chemistry is better then others.

[Old_Man]

Mike - I have seen a couple of threads that talk of the LFP batteries but when I search on google the batteries cost more than AGM and that is not including the BMS. Unless I am missing something?

You appear to be missing the fact, lifepo4 batteries let you take them down to 10 percent SoC without damage. Try that with any flavor of lead-acid. Those batteries die quick anyway, even faster when damaged.

[Old_Man]

many are full of Gasoline, which is QUITE explosive. FORD found that an expensive lesson, using a gas tank as a bumper.
Treated properly, over 30 years, gasoline tanks are much safer now. Cars mostly blow up in movies only.

I have no doubt as the Li battery tech matures, they will become safer, but currently, they are not recognized as safe as AGM batteries.

Disagree but that's ok. My problems with lead-acid, aside from the weight, are the lead and the acid, and the gases they produce. I'll use lithium. 12v, 30AH in a camper shell. Lead-acid is *ancient.* Not for me. at least not in the shell.

[Old_Man]

flexible psanels

b) Lithium batteries (much lighter weight, and less mature tech)

I'll be using a 30AH lithium battery in my camper shell. Two flexible 100-watt panels.

[Sunking]

Tree Johnny the issue is you cannot work around Pb batteries charge-discharge efficiency. It is a moving target hour by hour. There is no algorithm anyone can write to take into account all the variables, especially if they change hour by hour. It would require calibration and changes in algorithm every stinking day. Yes you bought a very expensive $10 volt meter.

[Treejohnny]

I have been reading a bunch from the off grid section about AGM batteries and it appears as though my battery monitor is very expensive voltmeter....I had much higher hopes of with the addition of a shunt.

Should I start new post there?

So I have read Lifeline's Technical papers on their battery, Victron's manuals about setting up their solar charger and battery monitor. Maybe my issues is from when I was in IL and clouds interfering with Absorption and Float cycles and not charging my battery to '100%' SOC. After all that I have read so far, I believe that I should set my solar charger to equalize/condition the lifeline batteries every 2-4 weeks for about 4 hours, this seems weird for AGM to me.

We are living in the trailer now. I bought a Honda 2200 inverter generator for cloudy days but I have only used it for testing after leaving the midwest. I pull trailer with Chevy Duramax, it has 12V system with 2 batteries and the ability to easily add second alternator. Maybe someone sells 24V alternator to just charge house batteries? The house batteries are 24V but I could make 12V leads to connect to truck, this would bypass the shunt for battery monitor, not sure if that matters now. This would allow me to sell the generator and free up a little room and stop carying gas can. With 2/0 wire from truck to house battery I could start truck from trailer battery or bulk charge trailer from truck. I also have a good jump pack to start truck if everything is dead. Of course I could just wait for solar to charge battery as well since I am already home.

[Sunking]

I am not happy with the battery monitor as the voltage and the SOC is wrong.

Of course it is wrong and will never be right. It is not possible to determine battery SOC from voltage. You wasted your money. Get rid of and sell it to a Sucker.

[Treejohnny]

I am back again for an update!
The system is up and running. 1600 watts of non tiltable solar, 3 strings of 3 180 watt 12 panels. Victron Solar charger(150/85) to 300AH 24 volt bank of 4 Lifeline 6v 300AH batteries. Victron 3000 multiplus hybrid inverter into trailer panel. There is a Victron Venus GX and 712 battery monitor.

I am not happy with the battery monitor as the voltage and the SOC is wrong. It will say 84% SOC and voltage is 24.94V. I am pretty sure that the battery bank is not getting completely charged. There is no draw without going through the shunt so I am sure it is on of the settings. I did not notice a problem until I am completely reliant on solar for battery charging.

The solar charger settings were:
Absorption - 28.6
Float - 26.6
temp compensation - 20mV/degree C

I change to generic AGM settings:
Absorption - 28.8
Float 27.6
Temp compensation 32.4mV/degree C
And now the absorption charging looks closer to what Lifeline wants it to be.

Is 'tail current' for battery monitor settings = in absorbtion when the current drops below 0.5% of the battery

[Mike90250]

Do you drive a car?

many are full of Gasoline, which is QUITE explosive. FORD found that an expensive lesson, using a gas tank as a bumper.
Treated properly, over 30 years, gasoline tanks are much safer now. Cars mostly blow up in movies only.

I have no doubt as the Li battery tech matures, they will become safer, but currently, they are not recognized as safe as AGM batteries.

[zamboni]

Catch up, man, the technology is a lot more stable.

Old_Man, i'm afraid you are in the position of having to justify where your "expertise" on LFP comes from. You are telling one of the most helpful, knowledgeable, and safety-oriented members of this forum (and a mod, no less) that he doesn't know what he's talking about. Why don't you tell us about /your/ LFP bank?

Do you drive a car? Because i hear they have these explosive batteries located in a hot compartment full of fuel and fire...


- Jerud
------------------------------------------------------------
1220W array / 1000Ah LFP house bank
MidniteSolar Classic, Magnum MS2812
ME-RC, Trimetric, and JLD404
2001 Fleetwood Prowler 5th wheel 25 foot, self-rebuilt
Full-time 100% electric boondocking (no propane, no genny) since 2015

https://www.livesmallridefree.com

[SunEagle]

You are wrong. You didn't see LifeP04 batteries do that. Catch up, man, the technology is a lot more stable. #smh

While LifeP04 may not have created large fires and are more stable then LiPo's the documentation I got with the ones I use with my RC transmitter suggested caution and to use a thermal bag when I charge them. To me that warning suggests there is still the potential for them to create a fire.

[Old_Man]

Lead Acid batteries are in common use, and much well respected gear exists to be able to charge and use them safely
Following a few ventilation precautions, jsut about completely eliminates explosion worries.

Lithium batteries are newer, little gear exists to reliably use (charging and discharging) them, and they are prone to catch fire and burn uncontrollably.
LFP versions of Li batteries are less prone to spontaneously self ignite, and no Li batteries are allowed in baggage compartments of airlines, SLA batteries are allowed.


There are many benefits to Li batteries, but I believe they are not ready for mainstream use yet. 2 or 3 more years might do it.

I would not sleep in a room with, or adjoining, a Li battery bank, I've personally seen 2 burned out shells of commercial Li household battery banks.

You are wrong. You didn't see LifeP04 batteries do that. Catch up, man, the technology is a lot more stable. #smh

[Old_Man]

I believe max2K meant that My choice of AGM will cost more than flooded lead acid.

Do you believe that lithium is safer than lead acid?

The reason why I ruled out lithium was the added $5000 cost and the expected term of this project being 1-3 years.

My batteries be in different room than the bedroom, even though I am not sure of the benefits.

1. AGM costs more than Trojans, yes (who named a battery after a rubber, anyway?) but I believe they suffer from the same drawback as any other lead-acid battery. Can't use much of the charge and what you do get createss explosive gases in your rig.

2. Lithium Iron Phosphate (LifePO4) is unlike the exploding phone and laptop batteries. It's stable. Lithium's detractors are legion and with the exception of very cold weather, there is no reason to use lead acid. I think lead-acid batteries should be banned as house batteries for RVs. They're dangerous, dirty, toxic and give a crappy ROI. I have no use for a lead-acid battery outside the starter battery for the engine. Antiquated, dangerous things.

[Mike90250]

Lead Acid batteries are in common use, and much well respected gear exists to be able to charge and use them safely
Following a few ventilation precautions, jsut about completely eliminates explosion worries.

Lithium batteries are newer, little gear exists to reliably use (charging and discharging) them, and they are prone to catch fire and burn uncontrollably.
LFP versions of Li batteries are less prone to spontaneously self ignite, and no Li batteries are allowed in baggage compartments of airlines, SLA batteries are allowed.


There are many benefits to Li batteries, but I believe they are not ready for mainstream use yet. 2 or 3 more years might do it.

I would not sleep in a room with, or adjoining, a Li battery bank, I've personally seen 2 burned out shells of commercial Li household battery banks.