Lithium for replacement house? Easy?

[arctictraveller]

[QUOTE=jony101;195594]
Even with generator or house current it will require overnight charging. . One thing I notice is if you drain your battery all the way down, with solar it will take several days to get it back to 90 percent. My 240 solar panel barely keeps up with it. QUOTE]

I thought one of the advantages to lithium batteries was their high acceptance rate of nearly 100% until fully charged. Is that not the case?

[ctb]

OH YES!!! That is all great information from just the experts I was hoping would give some advice! Jony, excellent presentation!! Wonderboy,always above and beyond...though I have to read it once or twice to get it all, daveb, you are the champ! Bhauler and Flux, you two too ..Thank you all for the replies and knowledge! Yes the abuse was from various ways...or at least I was seriously damaging it with discharge/use practices, recharging, not checking water levels....things like that...

[ShuttlePilot]

Greetings ctb, It's great of you to be thinking of an upgrade at the time of replacement of your battery. I think we all do that thought process regarding most things on our vans. Regarding lithium battery banks I believe it's going to become the standard in the near future. However at the moment in the RV world with the current equipment available(batteries, monitors, etc) and the knowledge/experience of the public, the folks that are using it successfully fall into two categories. First, those that can afford to have a company design, fully automate/make idiot proof, test, install, and warranty a wonderfully working system. And those who chose to build their own as a hobby with the side benefit of successful/usable power storage. When I say chose a hobby I mean, study in depth, take lots of time, accept the risks, listen to others who have succeeded/failed, hone your skills, you get the idea. In your case I would say if you don't want to chose either of those options, a quality, lead acid/AGM battery that you take care of would probably serve you very well. It sounds like your in tune to the knowledge base hear on the forum regarding batteries and if you wanted to dive deeper into lead acid science I recommend handybobsolar.com, which I think has been shared on here before.

jony101 Thanks for sharing your home built system. I've shown a few people my home built setup and been flamed by some folks with,"your going to blow yourself up, Samsung note 7, don't park that thing close to me, ect". Don't let the doubters get to you. Thanks again for your in depth tour.

Here is my set up for those that are interested. I chose to keep my 200ah 4D AGM battery as my primary source of storage and add the lithium as a Tesla Power-wall type auxiliary battery. All "house" equipment (fridge, water heater,freezer, solar, lights, etc,) uses the Lead battery all the time. But I can move up to 30 amps of power into the lithium from the lead/house side at times of abundance, ie driving or lots of solar, or move up to 30 amps from lithium to lead/house when needed, ie cloudy day or movie night. This allows me to keep my AGM battery from getting to low or wasting alternator amps. It's a very hands on setup with lots of button pushes but that's Ok because my van is a very manual set up. More Apollo era than Space X.


240 18650 batteries from used laptop batteries in a 60P, 4S configuration. So 60 batteries in a group X 4 groups. 27lbs including the wood case. 1.4 killowatts of usable storage. So roughly simmilar to a 130 lbs, 200Ah 4D Lifeline if discharged down to 40% remaining. Boywonder could probably check that math. One thing I would mention if someone was to go down this road is that, I tested over 500 18650 batteries for capacity, voltage, temperature to find these 240. Which were the best out of the group and then matched up by capacity. When using 18650 batteries it's not just put a bunch together and go. There is a lot of work at the test bench before assembly.



Here I'm using a Revlectrix PowerLab 8 (slightly modified and reprogramed though the PC interface) as the controller to move up to 30 amps in either direction and as a type of BMS. To the left is the disconnects for the lithium bank.

Anyway I hope I haven't hijacked your thread in a negative way. ctb please let us know if you go the way of the future and how it's works out for ya.

-Eric

[Flux]

I think they do boywonder. They charge at 14.4 and float at 13.6 so most 2 stage should work fine. They have protection built in there.

Maybe down the road when my 4D needs replacing these things will have come down in price a bit......maybe.

So I guess you somewhat need to limit the Amps going to and fro here??

I am fascinated with these DIY setups.

[ShuttlePilot]

Originally Posted by Flux

So I guess you somewhat need to limit the Amps going to and fro here??

Flux, short answer is yes. Simply, Lithium batteries don't have the internal resistance a lead acid battery dose. You know how in lead acid as the battery nears the full state it will only accept a few amps compared to the beginning(increasing resistance). A lithium battery will accept near the same amps through full charge, and beyond full charge which is where trouble will happen(thermal run away). So a controller to limit amps if the source will exceed the batteries rated amount and stop charge when full is much, much more important in lithium. I choose to not float charge my lithium at this time based on what others have told me.

Also, don't confuse the different Lithium chemistry batteries. The 18650 cells are a higher voltage, 3.3 - 4.2 volts per cell, than the Lithium Iron Phosphate ,2.7 - 3.5 volts per cell, used in most "lithium" RV packs. So in my packs design being 18650s my charged voltage is 16.4v ( I choose a 0.1 volt under) and discharged is 13.2v which is higher and not as compatible with the lower volts of the lead acid. So I'm using the controller like a transmission to change the voltage as well as a tight charge algorithm. At the cost of some efficiency.

Just like lead acid batteries have specialized chargers/ support equipment to support the chemistry each lithium type has it's specialized equipment to support it's type. Lithium Iron Phosphate is closest to lead acid but not interchangeable. Some equipment is usable for both if reconfigured. And lastly you have to kind of forget some of what you know about lead acid as it will destroy your lithium bank.

- Eric

[Scalf77]

jony101, thanks for sharing, nicely done.

Eric, I really like your hybrid approach.

-greg

[boywonder]

Shuttlepilot: very cool!! one question....

where did you get 500 used 18650's?

[Flux]

Thanks for all the info!!

So it's best to just not fully charge I take it. So do you stop charging when the batteries reach a certain voltage then??

[1der]

All great info and well written up.

One of the factors, I believe, with Lithium battery banks is they are not very tolerant of charging at temperatures below 32* F. Right now, sitting here in Beastie3 in Mammoth, it is 27*F, it got down to 5*F this morning.

Our AGM batteries are mounted below and behind the differential, so they see whatever the temp is outside. If I dedicated some room inside, I could have the batteries above 32* while we have the heater on, but I would not be inclined to often leave the heater running while away from the van.

How are you guys dealing with this supposed Li temperature constraint?

[Wrinkledpants]

Originally Posted by ctb

I am at the point I think we need new house batteries for Sporty...I have abused them..mainly through ignorance of how to use/what to expect/do's n don'ts etc...fortunately running into a thread a year or so ago to help get what I could out of or 1st set (original from SMB North 2-small)...reading other posts from users going with lithium systems from the start and others retrofitting current rigs...and being on the "other side" of the bell curve on here (a lot of you members are so smart and knowing about all operating systems etc...it makes me feel lucky I can log in lol)is it possible to just 'simply' install new lithium batteries/battery to replace the old lead-acid batteries? My house batteries are in a box behind drivers seat/under Goucho...thanks in advance for the thoughts/education...

That depends on what else would be plugged into the lithium battery. What charger do you have? Solar? Inverter? Battery Monitor? Do you have one or two alternators?

We're doing a lithium build from the start, so I'd be happy to share what I've learned so far. Will need some more info from you as the range of convenience and cost varies wildly depending on what your current setup is.

I think you have the most difficult step already taken care of by having the batteries mounted inside. The big environmental factor with lithiums is that they can't be charged below freezing temp. So having them in a climate controlled interior is required, unless you build a special heated box under the van for them.