[LiFeP04_RV]

Not quite $0.85 per amp hour but the cells we have are about $0.875 per amp hour now on eBay
https://www.ebay.com/itm/Lot-of-8-p...377409?hash=item2ab7fc1501:g:NAcAAOSwaB5Xtx0m

Any idea of the actual maker?

AliExpress link to compare?

I think CALB. The aluminum case is hot like the CALB CAM80, dimensions are identical.

 

[Sunking]

Sure, but we're discussing an RV, and one that is unlikely (I would guess) to have a massive solar installation and will almost certainly have a 12 volt automotive charging system.

Well you would be surprised how many folks use Solar as their primary power source. As long as you keep panel wattages to less than 1000 watts which is the vast majority, 12 volts works just fine. Kicker is and this is the big kicker, if you have an Electronic Battery Isolator and drive at least every 3-days, then solar is just a wasted expense. Most setups I recommend and design only use Solar as a Supplement in the 200 to 400 watt range into a pair of 6-volt batteries wired for 12 volts. If truth be known Solar in that case is just show and tell and actually does not do much. You see this type of setup a lot in RV Rentals and Factor designs.



Then you have that crowd of tree-huggers who hate anything that uses gas or diesel. They will require a huge system in excess of 1000 watts, and that requires 24 volts or higher. Funny thing is if truth be told off-grid solar is not only 5 to 10 more expensive than buying power, but is also a very heavy polluter and Li batteries make that even worse because they require so much energy to make you never get an EROI. However I could care less, just pay me.

 

[brian_]

Well you would be surprised how many folks use Solar as their primary power source.

In fact, I wouldn't be surprised. Lots of people use solar panels rated under 200 watts to meet their needs in travel trailers (when camping in conditions in which they are happy without air conditioning)... typically with about 200 amp-hours (nominal) at 12 volts (nominal) of flooded lead-acid battery capacity. Individual energy requirements and travel conditions vary, of course, and sportcoupe has chosen a higher capacity.

As long as you keep panel wattages to less than 1000 watts which is the vast majority, 12 volts works just fine. Kicker is and this is the big kicker, if you have an Electronic Battery Isolator and drive at least every 3-days, then solar is just a wasted expense. Most setups I recommend and design only use Solar as a Supplement in the 200 to 400 watt range into a pair of 6-volt batteries wired for 12 volts...

That's what I was saying. So it seems that we agree that higher-voltage systems appear to be unlikely to be an improvement over 12 volts for the subject of this discussion.

 

[john61ct]

And with lead off grid, solar is a necessity for longevity's long tail, no matter how many ICE amps you have available on demand.

 

[john61ct]

> a huge system in excess of 1000 watts, and that requires 24 volts or higher

Not "huge" and a 12V setup is fine.

My favorite setup is a ~250W / 40+Voc panel paired with a Victron 75/15, around $120. Super efficient and full-featured, custom setpoints and data logging from my phone.

Add as many such pairs as you like over time to fill the roof or on slideouts, portable folding, whatever.

No need for the panels to match, and each is MPPT optimized for azumith angle or partial shading conditions.

Maybe 80AH avg per day each into the bank, including some days less than ideal conditions. Get 5-6 pairs and run 16k btu aircon off it

Yes silly I know.

But going to 24V House setup just to save a bit of money on thick wiring or cheaper SCs is sillier.

 

[Duncan]

NOT what I have found

I have a 5,000 watt home system that runs on 400v - no battery as yet but it is saving me enough to pay for itself in about 7 years
In energy terns about 8 months to repay the energy needed

And this is South Island - not a hot place with ZERO subsidies of any kind

I am thinking about a battery - but it will do double duty as a range extender

 

[john61ct]

Just a reminder of the OP topic

I'm looking to make a storage battery for a camper

 

[Duncan]

I'm looking to make a storage battery for a camper

He has ignored the best advice of using some EV modules - you guys are all working on the "not worst"

 

[sportcoupe]

Just a reminder of the OP topic

Correction. Topic is:

400AH lithium cells? Best price per AH? $0.85/ AH?

Only a few posts addressed the topic.

 

[john61ct]

Because the distribution channels for good quality LFP are very limited, no way to get much below the 5-7x premium over lead.

Lower pricing without compromising quality is IMO a matter of luck with a once-off deal, very rare.

And taking chances with unknown makers or dodgy middlemen, again you may get lucky, but you may not really find out for many years.

 

[sportcoupe]

Because the distribution channels for good quality LFP are very limited, no way to get much below the 5-7x premium over lead.

Lower pricing without compromising quality is IMO a matter of luck with a once-off deal, very rare.

And taking chances with unknown makers or dodgy middlemen, again you may get lucky, but you may not really find out for many years.

I have seen the light, there isn't cheap high capacity lifepo4 cells available yet.

I have been looking at industrial 6V AGM's now for my camper van build.

 

[Sunking]

Sure, but we're discussing an RV, and one that is unlikely (I would guess) to have a massive solar installation and will almost certainly have a 12 volt automotive charging system. Carrying a generator just because the system wasn't properly set up to charge from the vehicle would be silly, and doing without power is not reasonable.

Brian I think you are overlooking some things. 24 and 48 volt super high efficiency air conditioners like Truckers, Off-Griders and Telecom use. I agree with your POV. If all you need is lighting, some entertainment like a TV/Radio/AV and low power devices 12 volts is just fine. But you have people who insist on electric cooking, refrigeration, and the impossible air conditioning requires a lot of power that a 12 volts is just not capable of doing safely, efficiently, and economically. How many 12 volt EV's do you see. Only a DIY would be that foolish. If the owner refuses to consider using propane for high energy requirements, you have limited your options and have to get creative.

I have built a many RV systems with both Solar and w/o Solar. Even rented several RV, and the factory units I have rented that have Air Conditioning all have a generator built-in using 24 volt batteries, and a 24 volt heat pump like Truckers use to cool their sleeper cabin. To do that demands higher voltage if solar is used. a 80-amp MPPT controller can only input 1000 watts and that is not enough power for heavy loads.

Besides anyone who is truly off-grid solar stationary requires a generator to perform routine maintenance and cover their your butt for cloudy spells. Otherwise you spend a lot of days in the dark and destroy your batteries prematurely.

I agree 12 volts makes the most sense sense for most applications. But when you throw electric cooking, electric refrigeration, and air conditioning into the mix, 12 volts is not going to cut it on solar. 250 MCM and larger copper wire is not practical or cheap. Let alone the experience and tooling to terminate such large cables and compound that with 1-hole Terminals or stabs expecting to have no issues loose connections and burning up with 200 to 400 amps flowing.

Do you wanna talk food trucks now? That is 240/120 territory and higher.

 

[sportcoupe]

But you have people who insist on electric cooking, refrigeration, and the impossible air conditioning requires a lot of power that a 12 volts is just not capable of doing safely, efficiently, and economically.

I agree 12 volts makes the most sense sense for most applications. But when you throw electric cooking, electric refrigeration, and air conditioning into the mix..........

Air conditioning is not impossible on batteries. You are limited in how long you can run it. A simple van doesn't need 16k BTU a/c unit, a 5k BTU cools a small van easily. That's 420 watts for a basic 5k BTU unit. It's a lot, but not impossible.

My 12v fridge runs on 40 watts and it only runs 20 mins an hour tops.

I still have to source an efficient microwave that will still pop popcorn.

 

[john61ct]

I have been looking at industrial 6V AGM's now for my camper van build.

in the US market, stick to Lifeline, Odyssey and Lifeline.

Maybe Firefly if PSOC abuse is unavoidable.

I've heard Trojan's getting out of AGM (again), Deka's are meh not really deep cycling, Rolls are outsourced.

But we do you think AGM is required?

Much higher cost per AH per year, much easier to murder, need more precise and higher-current charge sources for lingevity.

 

[sportcoupe]

in the US market, stick to Lifeline, Odyssey and Lifeline.

Maybe Firefly if PSOC abuse is unavoidable.

I've heard Trojan's getting out of AGM (again), Deka's are meh not really deep cycling, Rolls are outsourced.

But we do you think AGM is required?

Much higher cost per AH per year, much easier to murder, need more precise and higher-current charge sources for lingevity.

You said Lifeline twice. What about Full River?

I don't want to deal with messy FLA. I have 140 amps available to charge AGM.

 

[john61ct]

But you have people who insist on electric cooking, refrigeration, and the impossible air conditioning requires a lot of power that a 12 volts is just not capable of doing safely, efficiently, and economically.

I agree that aircon is very expensive, impractical, so set that aside.

But fridges & freezers, washing machines, dishwashers, induction cookers, microwaves, used judiciously are no problem on a properly sized and designed 12V system.

Of course the robust charge sources need to be there to replace AH used.

In a very high usage scenario, without a 30+' roof, solar is just there for lead's long tail, a genset or big alt is required in the morning for the first few hours.

I've already laid out how solar can be reasonably optimized, one SC per panel if desired.

No one is talking stationary, this is a mobile House supply use case.

Yes heavy wiring, properly crimped is required, par for the course.

200-400A is not going to happen often, obviously efficient versions of appliances need to be selected, 40-80A is normal and only for short times.

The marine world and expedition camping is where this type of setup is routine, the USian RV industry is slapstick / slipshod, Euro and Aussie standard usually much higher.

Yes an alternative is to just go mains current off a big inverter like Victron, but that is not conducive to minimizing AH per day consumption, and add its own expenses, complications and safety issues.

 

[john61ct]

Air conditioning is not impossible on batteries. You are limited in how long you can run it.

Figure an hour of time shifting your genny runtime for each 100AH (50 usable) of capacity dedicated to that function.

Then replacing the AH consumed, much bigger genset required if still running the aircon same time.

Not impossible, but very impractical for most, without a huge rig and spending many thousands extra.

Really tight thick insulation helps.

And of course super-efficient aircon tech, not consumer grade units.

Use propane for your popcorn.

 

[Sunking]

in the US market, stick to Lifeline, Odyssey and Lifeline.

All good batteries, but there are more of equal quality and better. You mentioned Lifeline made by Concorde but they make even a better AGM in a much wider range of capacities and voltages called Sun Extender. All those mentioned are on the same boat as lithium with a worthless 1 year warranty. Another manufacture of high quality AGM batteries is Fullriver and carry a 7-year warranty. You can hammer them with 80% DOD with no problems in an RV application.

 

[john61ct]

You said Lifeline twice. What about Full River?

I don't want to deal with messy FLA. I have 140 amps available to charge AGM.

Whoops, Northstar's #3, I try to mix the order up, all 3 are great.

Call them for local dealers, never find in big box, and you do not want to pay for shipping.

Full River is OK, not proven as long in the US as the top three, all the TPPL tech came out of Enersys research funded by US military, rest were spinoffs from that,

and IMO lots of the value eroded by shipping from China.

But fine, if you find it for say 30% cheaper including transportation costs.

 

[john61ct]

Sorry typo

But **why** do you think AGM is required?

Much higher cost per AH per year, much easier to murder, need more precise and higher-current charge sources for longevity.