12/24 volt AC ( air conditioning )

[dzl_]

Originally Posted by john61ct

Only if you actually do get the extra long lifespan. That may not be "that difficult" but risks do exist.

Yes this is true. You've got to actually be planning for the long term and take care of your batteries (but you have to take care of your lead acid batteries as well). If longevity, weight, or charge rate aren't as important as other factors for your application, lead acid may still make the most sense. Its certainly cheaper to replace them if you screw something up.


And the potential risks are one of the reasons I'm hesitant about lithium. Not because its anymore difficult necessarily, but because its a lot more costly if I screw it up, and I've been known to screw a thing or two up here and there

At $1/Ah for Duracell / Deka GCs, the ROI payback minimum is at maybe 15 years.

$50 for 100ah, 12 volt deep cycle batteries? That's a great price.

[john61ct]

The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

But starting point is 200+AH @12V nominal, 2x6V at around $200 per pair

[john61ct]

Originally Posted by dzl_

You've got to actually be planning for the long term and take care of your batteries (but you have to take care of your lead acid batteries as well)
…
And the potential risks are one of the reasons I'm hesitant about lithium. Not because its anymore difficult necessarily, but because its a lot more costly if I screw it up, and I've been known to screw a thing or two up here and there

Unfortunately it isn't just human error at fault, plenty of expensive banks get wiped out by BMS failure - or rather, poor systems design, over-reliance on just one layer of protection for each danger factor, or buying important infrastructure based on price.

Lots of knowledge involved, and with many topics, no consensus among the experts.

Buying into the "drop-in" koolaid is no panacea either

[dzl_]

Originally Posted by john61ct

Unfortunately it isn't just human error at fault, plenty of expensive banks get wiped out by BMS failure - or rather, poor systems design, over-reliance on just one layer of protection for each danger factor, or buying important infrastructure based on price.

True, though I would argue the last 2 or 3 points you made there are in fact types of human error (poor system design being the one I'm most worried about). But BMS failure is a valid concern too (multiple layers of protection can mitigate this I believe, as a BMS isn't strictly necessary).

Buying into the "drop-in" koolaid is no panacea either

Can you qualify what you mean by this? I haven't heard anyone complaining about the quality of Battleborn for instance or being denied a warranty claim. But I also haven't really dug into it. Why do you think its "koolaid"

But starting point is 200+AH @12V nominal, 2x6V at around $200 per pair

So that is still quite cheap, but its misleading to think of it as "$1 per AH" when comparing to lithium.


This is what I meant about trying to make apples to apples comparisons. With 200AH of lead acid, you have only 100AH available. Unless you are only comparing between the same battery type LA to LA or LiFePO4 to LiFePO4, nominal amp hours is rather irrelevant unless you are trying to make one or the other look better or worse.

This is why I like the video I posted above. It accounts for depth of discharge, and frames cost per usable kw/hr over a uniform number of cycles. This is as close to an apples to apples comparison as I have seen.

If you didn't watch the video here is a price comparison between various batteries per usable kilowatt-hour for 1000 cycles.

(Prices are dollars per kwh per 1000 cycles)
Sealed Lead Acid (V-max)
$388
Flooded Lead Acid (Trojan 105) (not accouning for 15% in/ 15% out efficiency loss)
$240
LiFePO4 Drop-in (Battlerborn)
$150-250
LiFePO4 (DIY)
$100-166
Tesla
$49


https://youtu.be/3VU8Ks8RHSc

[john61ct]

I wouldn't pay too much attention to anyone making a living as a YouTuber, other than general noob-info orientation. Will used to come around arguing in the forums without a clue, but yes he's learned a lot since then but not actually an expert.

Price per thousand cycles? Might as well throw darts. . .

Drop-in mythology is you can keep your charge sources, just one layer BMS is OK but no access to what's going on,

too high voltage required for balancing, no way to tell when finished,

limited (crippled) current rates.

And who knows where the cells come from?

I would not rely on a warranty, over-paying for it anyway.

Sure if you're OK with only 10 years and a few thousand cycles, BB is prolly fine, but not for me.

[dzl_]

Originally Posted by john61ct

I wouldn't pay too much attention to anyone making a living as a YouTuber, other than general noob-info orientation. Will used to come around arguing in the forums without a clue, but yes he's learned a lot since then but not actually an expert.

There is nothing subjective in the comparison. You don't have to like or trust the creator. The same data is available a million different places. Its simply a comparison video using objective datapoints that have nothing to do with the video creator. Ad hominems are rather irrelevant here.

Price per thousand cycles? Might as well throw darts...

That seems like a pretty unscientific approach.. Lead acid has been around forever, and lithium has been around a decent amount of time now. Using the companies datasheets will give somewhat 'optimistic' results, but its still more useful for comparisons sake than just shrugging and choosing to ignore one of the most important factors in cost over time.

Sure if you're OK with only 10 years and a few thousand cycles, BB is prolly fine, but not for me.

I don't understand your argument here. Your arguing for Lead Acid which has a drastically shorter life cycle than Lithium, but then criticizing Battleborn for "only lasting 10 years and a few thousand life cycles"? Top of the line lead acids only claim 1000 cycles (1/3 to 1/5th of Battleborn).




Regarding BMS and drop in LiFePO4, some of your points are quite valid, though some are somewhat trivial to mitigate or are not a concern for many peoples use case.

[john61ct]

My point is that with no catastrophic accidents,

and proper care, which the industry actively discourages, the first few thousand cycles are barely breaking in the (non drop-in) LFP bank.

The datasheets assume EV's violent C-rates, grossly **under-estimates** potential lifespan.

And completely pulled out of thin air when it comes to much gentler House cycling, so absolutely useless as a point of "scientific" comparison.

Also pretty much true for lead chemistries, the cycle vs DoD stats and graphs are really only valid for comparing batts from the **same** maker, not comparing different brands.

And I am not at all "arguing for" either choice.

Just pointing out that attempts at so-called "scientific" or purely economic rational are pretty much irrelevant once you get past say 7+ years required to justify a potential ROI equation.

I 100% believe personally that **for me** LFP is by far the better choice, and am happy putting $5-10,000 into a solid system.

But I enjoy learning and messing about with this sorta stuff for the fun of it, am not kidding myself that I'm "saving money" with any sense of certainty,

if that was the buyer's concern I'd reco the GCs every time, seen them last well over 8 years.

I reckon I'll be long gone before my kids and grandkids are done with the LFP batteries anyway, so irrelevant to me.

But maybe (more likely?) not. . .

Others desperately need to save the weight and space, or need portability between camping, a boat and off-grid home,

now those can be much more compelling reasons to go from lead to LFP.

[dzl_]

Thanks for explaining your perspective in a little more detail. It looks like we are not as far apart in our perspectives as it initially seemed.

My point is that with no catastrophic accidents,

and proper care, which the industry actively discourages, the first few thousand cycles are barely breaking in the (non drop-in) LFP bank.

The datasheets assume EV's violent C-rates, grossly **under-estimates** potential lifespan.

And completely pulled out of thin air when it comes to much gentler House cycling, so absolutely useless as a point of "scientific" comparison.

I somewhat agree with you until you say its absolutely useless. It isn't a perfect metric, or perfectly applicable to how we use our solar systems. But it is a good ballpark 'baseline' figure. If you assume LiFePO4 are tested in harsher EV models, you can assume that a well designed solar system should do significantly better. Therefore if lithium can compete economically even with the harsher model, it becomes even more cost competitive in a gentler application. Its not precise, but its still useful.

100% believe personally that **for me** LFP is by far the better choice, and am happy putting $5-10,000 into a solid system.

But I enjoy learning and messing about with this sorta stuff for the fun of it, am not kidding myself that I'm "saving money" with any sense of certainty,

if that was the buyer's concern I'd reco the GCs every time, seen them last well over 8 years.

I agree with you, but I would point out that I haven't been arguing you would "save money." My argument is that they are cost competitive over a longer time frame. When you account for the advantages of lithium batteries, this for me, tips the scale towards LiFePO4 for mobile applications.


That said, I definitely agree with your caveat that you should at least have an interest in learning about the system and the details, and a comfort with DIY, before you decide on lithium storage.


Its good that you are hesitant to recommend lifepo4 without highlighting the risks/disadvantages. But I feel you are maybe overstating and overstressing the dangers/lack of information.

Others desperately need to save the weight and space, or need portability between camping, a boat and off-grid home,

now those can be much more compelling reasons to go from lead to LFP.

This is basically my argument.
1. Lithium offers significant advantages (weight savings, space savings, charge rates)
2. It also has some disadvantages, or extra precautions you must take
3. The cost per usable kwh over time is cost competitive with sla/fla
4. Because of the advantages for my application (mobile) and the relatively competitive costs over time, lifepo4 makes sense for my application.
4a. This would be true for me whether lithium worked out to be a bit more expensive over time or a bit cheaper over time. I wouldn't pay 2x-3x as much for lithium. But I would probably pay 1.5x for the advantages it provides me.

[john61ct]

Originally Posted by dzl_

I wouldn't pay 2x-3x as much for lithium. But I would probably pay 1.5x for the advantages it provides me.

What market?

In NA I can't see how

doing it right (optimizing the odds of getting decades longevity far linger than mfg ratings)

could cost any less than 7-10x acquisition investment putting in an FLA bank, and that is conservative taking usable Ah into account.

And not fully counting

> It also has some disadvantages, or extra precautions you must take

And that means no ROI on the delta until 25+ years out.

Which IMO makes this spurious
> The cost per usable kwh over time is cost competitive with sla/fla

Which leaves only this:

> Lithium offers significant advantages (weight savings, space savings, charge rates)

Don't forget "no need to get to ever get back to Full"

Plus the fun, hobby / learning element

and maybe status, bragging rights

[dzl_]

Originally Posted by john61ct

What market?

In NA I can't see how

doing it right (optimizing the odds of getting decades longevity far longer than mfg ratings)

could cost any less than 7-10x acquisition investment putting in an FLA bank, and that is conservative taking usable Ah into account.

In my opinion you are shifting the goalposts/looking at it wrong. First off, stubbornly sticking to 'acquisition cost' is a distraction in the big picture when the more important and more relevant factor (and all I've ever referred to) is long term cost per kwh over time. If you are looking at the longer term, initial investment cost is misleading if you will have to replace your FLA/SLA batteries 2-3+ times.



There are obvious reasons to want to do better than manufacturer ratings and 'do it right.' I certainly want to. But its misleading to make this assumption with lithium batteries when comparing economically to SLA/FLA. Lithium becomes cost competitive when the extra usable life outpaces its extra cost. So if lithium costs 3x more it needs to last 3x longer (without considering other benefits) to be cost competitive. Anything beyond that just tips the scales further in the direction of lithium. So yes, you will have a high initial investment if you want to build a lithium battery bank that significantly outdoes manufacturer ratings, but like you said earlier, that battery bank would have a 'decades long' life and might well outlive you.

> It also has some disadvantages, or extra precautions you must take

And that means no ROI on the delta until 25+ years out.

I can't help but feel you are being unfair, in dismissing all the data in the comparison I linked to which was based on manufacturer provided data, simple math, and testing as "throwing darts" but then throw out your own numbers without providing the least bit of explanation or source material. I have no idea how you arrive at the conclusion that needing to take extra precautions with lithium leads to a 25+ year ROI.

> The cost per usable kwh over time is cost competitive with sla/fla

Which leaves only this:

> Lithium offers significant advantages (weight savings, space savings, charge rates)

These points are meant to be taken together. If (A) its cost competitive over time, and (B) has inherent advantages (for my application), it seems like the right chemistry for the job.

Don't forget "no need to get to ever get back to Full"

Plus the fun, hobby / learning element

and maybe status, bragging rights

Yes not ever needing to get back to full is an important advantage, and might also lead to cost savings in other parts of your system.

I think your position that Lithium isn't right for everybody, especially if you want a system that 'just works' (SLA is probably the correct choice in that case) is a very reasonable position.

You are clearly smart and well informed regarding batteries, but I would ask you to consider whether biases you have formed over the years might be getting in the way of your ability to compare objectively. Maybe part of this is a reaction the 'lithium evangelism' that has become common, which is reasonable. But if feels like you are overstating some of the problems and ignoring/dismissing some of the advantages of lithium. But again maybe I am misinterpreting your perspective.

I do appreciate this dialogue, its helpful to have my assumptions (and my own biases) challenged, and I can see from other posts you have made that you do have a pretty clear understanding of the pros and cons of sla, fla, and lithium.

In the end it comes down to individual needs/preferences (I would think a lot harder about lead acid if weight/space weren't important), and the overall economics of the entire system (for me not needing to charge to full is important because I have limited roof space for solar and won't have a generator--foregoing a generator and not needing extra panels also saves me money which helps offset the cost of lithium). I would like to not discount SLA, and keep an open mind and keep learning (I admit I've never really seriously considered or researched FLA, maybe I should) but as of now I feel that lithium makes more sense in the long term if you are willing to learn how to properly use them (or pay the extra money for an engineered system with a warranty)

[john61ct]

Originally Posted by dzl_

sticking to 'acquisition cost' is a distraction in the big picture when the more important and more relevant factor (and all I've ever referred to) is long term cost per kwh over time.

And I **very** strongly feel, as outlined in detail, that promising an economic benefit from long lifetime is so risky as to be a scam.

The added gear and/or skills+knowledge to make that lifetime promise more likely (still far from certain) increases the real up-front investment far beyond the 7-10x delta.

> no idea how you arrive at the conclusion that needing to take extra precautions with lithium leads to a 25+ year ROI.

Because with infrastructure already in place, and minimal expertise and attention, no BMS, no fancy regulators, chargers etc the FLA bank - at $1/Ah - will last at least 5yrs, likely 8+

Now spend (minimum) 7x that on the same usable LFP Ah. No ROI until 35 years (minimum!)

> > that battery bank would have a 'decades long' life and might well outlive you.

"would" "might"

I can replace the the FLA bank every other year and still not get a payoff untill well after a decade. No objective investor would take such a risk.

> So if lithium costs 3x more

Again, you're dreaming, or in a different market. Maybe in Australia or Europe? Not North America, if you can find me good cells delivered at under $4 per 12V Ah please post a link. And the cells alone are a fraction of the real cost overall.

As stated, I am a complete fan of LFP, and think everyone relying on their banks **who can really afford it** should convert.

> I feel that lithium makes more sense in the long term if you are willing to learn how to properly use them (or pay the extra money for an engineered system with a warranty)

Absolutely, and I agree. I just reject the economic calculation as a rationale.

Like buying a killer stereo or big screen TV, or fancier house, a sports car or a fancy 4WD setup that strictly speaking you don't need, we don't need to economically justify these.

[dzl_]

Because with infrastructure already in place, and minimal expertise and attention, no BMS, no fancy regulators, chargers etc the FLA bank - at $1/Ah - will last at least 5yrs, likely 8+

Its frustrating to me that you keep referring back to the misleading $1/Ah figure, based on 100% DoD, which nobody would dream of doing with Lead Acid.



If you use a more reasonable 50% Dod, the ~215 Ah Duracell GC2 ($90 at Sam's Club) is $1.7/Ah if bought through Sam's Club.


Compare this to the Lion UT1200 (90 Ah, warrantied for 80% capacity after 3500 cycles @ 100% DoD) sold through Costco for $650 (sold out). This works out to $7.2/Ah or 4.2X the cost of per usable Ah (without accounting for any of the factors that skew things in favor of lifepo4).



Taking this one step further, the Duracell GC2 (an admittedly amazing deal) costs $170 per 100 Ah per 1000 cycles.



The Lion UT1200 costs $206 per 100 Ah per 1000 cycles.


That means over a 10 year period, considering batteries alone, (and assuming you baby the lead acids while abusing the lithiums), the cost of middlle of the road off the shelf lifepo4 batteries cost 21% more than the cheapest lead acid available.


This is a simplified comparison obviously, but I believe its a decent approximation, without accounting for whole system cost (which is obviously a better comparison but is much more complicated to do in the abstract).



Regarding charge cycles, I know you don't trust manufacturer ratings or warranties but Lion Energy is a Utah based company and Costco has a reputation for standing behind everything they sell and having an amazing return policy. I am skeptical of company claims and warranties too, but in this case I would have moderate trust in it. The 1000 cycle life assumption for the Duracell, is based on the stated cycle life for the more expensive Trojan 105 6v FLA batteries (I could not find any useful datasheet for duracell/deka)


I would be curious to discuss the external expenses/savings (i.e. beyond the batteries themselves) of lifepo4 vs fla vs sla.



As a general observation, I could see extra costs associated with fla/sla due to needing to oversize your charge system or buy a generator to make sure you can reliably charge your batteries until full. And extra costs associated with lithium (especially when building your own batteries) because you will probably spend more on battery protection. What specific costs are you alluding to when you refer to lifepo4 being more expensive apart from battery cost?

[john61ct]

Originally Posted by dzl_

Its frustrating to me that you keep referring back to the misleading $1/Ah figure, based on 100% DoD, which nobody would dream of doing with Lead Acid.

Sigh. Shouldn't be done with LFP either. Straw man, the price per Ah is what it is, and the FLA Deka GC2s are $1 per. If you mean the sealed ones, those are not suited to deep cycling, suck in fact.

The 7x minimum delta is where usable amps gets factored in, as I've stated many times.

I've also already stated that I don't consider drop-ins, only known good top quality cells like:
Winston/Thundersky/Voltronix, CALB, GBS, Sinopoly and A123 (now Lithium Werks / Valence / Super B)

They are cheaper anyway. Costco? you must be joking?

Or packaged systems designed for large House banks: OPE-Li3 (Lithionics/Ocean Planet), Victron, MasterVolt, Redarc (Oz specific?)

You can't use examples that just won't do the job. Maybe for a fan, a light, recharging phones, but completely dreaming if you're talking a normal rig with appliances living off grid.

You have to choose the tools that will do the job.

Yes we hijacked the thread, but it was about running **aircon** direct off DC storage fer crissakes, 100Ah will barely get you maybe an hour for one tiny section closed off, you're talking bringing a pea shooter to a cartel gun battle.

I'm tired, 'nuff for now

[dzl_]

And as an aside. The Duracell GC2's at $90 per 6v / 200Ah (100ah usable) is an enticingly good deal and has definitely piqued my interest in FLA. As the upfront cost (and cost of screwing up) is so low. 2600 usable watt hours (4 x 215Ah 6v) would only cost $360 if I did my math right. That is about 1/3 of the cost of the slightly larger diy lifepo4 battery bank I am planning to use (if I don't factor in life cycle).

[john61ct]

To be specific, I was talking about Duracell (actually Deka/East Penn) **FLA** deep cycle golf cart batteries, 2x6V

around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

Deka's AGM as I said are not recommended for deep cycling.

[dzl_]

Originally Posted by john61ct

Sigh. Shouldn't be done with LFP either.

John, you are either not listening or I'm not being clear (probably the latter). This is what the Lion warranty is based on, I am not advocating it be done, neither are they. (And my suspicion based on the fact that its a "90ah" battery that they say can handle 3500 cycles at 100% DoD is that its truly a 100Ah battery that they derated to reflect BMS cutoff limits). Treat the battery better and you will achieve a longer lifespan. But according their specs and their warranty @ 100% DoD you can expect 80% after 3500 cycles. Its not a straw man.

Straw man, the price per Ah is what it is, and the FLA Deka GC2s are $1 per. If you mean the sealed ones, those are not suited to deep cycling, suck in fact.

Again, it seems you won't differentiate between usable Ah, and nominal Ah. Its quite frustrating that you seem to not want to make this distinction for whatever reason. As its clear you've used both lithium and lead acid, I'm sure you are quite aware why its pointless to compare Ah without factoring in DoD (For my own comparisons I assume 80% for lithium, 50% for lead acid). It feels like you are being deliberately obtuse or misleading (unless I'm the one that is being obtuse and I'm missing your point).

And no, I believe we are talking about the same battery (Duracell GC2 deep cycle, $90 at Sam's Club). The price per usable ah @ 50 DoD = ( $90x2 ) / (215Ah x .5) = $1.70 / usable Ah. Maybe you can clarify what battery you are talking about.

I've also already stated that I don't consider drop-ins, only known good top quality cells like:
Winston/Thundersky/Voltronix, CALB, GBS, Sinopoly and A123 (now Lithium Werks / Valence / Super B)

This is your personal preference. You have good reasons for having this preference, many of which I agree with. But it skews the comparison when you are only willing to compare top of the line custom built lithium battery with rock bottom cheapest consumer SLA. But I think its a much more legitimate comparison to compare consumer oriented cheap SLA vs consumer oriented drop in lithium. Closest to an apples to apples comparison that you can get in my opinion. You don't trust a drop in and don't want a 'black box' bms, many people would much prefer a 3500 cycle warranty to a customizable bms and known cell specs.

They are cheaper anyway. Costco? you must be joking?

The battery you mentioned is sold through Sam's Club seems a little silly to get all high and mighty about a battery being sold through Costco unless you are just a diehard Wal-Mart shopper. And its worth noting that in both cases the store is the seller not the manufacturer.

I chose to use that battery for comparison because it was similar to the Duracell in that it was targeting mainstream consumers, hitting a low price point, and sold at a comparable retailer.

You can't convince me that it makes more sense to compare a top of the line custom lithium setup against a bargain basement SLA.

But even if you were, what do you ballpark the cost of those cells are? CALB and Sino are what, about $400-600+/- for 100ah@12v, plus the cost of a decent BMS. Victron is more expensive at about $1250 for 90ah, but even then, assuming an 80% DoD and 3-5k cycle life the Victron costs $350-580 per 100Ah per 1000 cycles.

I'm tired, 'nuff for now

Agreed, I think the exchange is becoming unproductive, we are talking past each other at this point. I believe we are both engaging in good faith, just misunderstanding each other.

[brokedown]

Just for clarity is this the battery you're referring to at Sam's Club?

I'm going to be building a new bank and the last few times I moved my 12v 4D AGM batteries I promised my back that the next set would be 6v cells.


https://www.samsclub.com/p/duracell-...c2/prod3590228

[joeblack5]

Does anyone else here has tried to run the original Ac compressor with an external electric motor. Although a mini split is cheap these days two to five horse motor is a lot cheaper.
I did some experiments with Dory and a 24 volt DC motor.
Our electric car ..a 1996 solectria ( geo metro) has a the original Ac system driven with a timing belt from a 1/2 HP DC brushed motor at 168 volt.

Regarding the batteries. Lead is simple and cheap and good if you are in a bind and have small usage.
A 100 ah rated battery is only 50 ah. After 2 years only 30ah is left over. Wat more cost effective to go to used vehicle batteries. The original 25kwh of an Nissan leaf can be bought for $3000 with 18 kWh effective left over. With that much extra capacity you are not often running in full depletion. The currents in stationary use are so much lower relative to automotive use that a BMS is not very useful. If you manually check with a voltmeter every month or so and manually add charge to cells that could use it the all will be fine.
Most of the safety stuff in automotive lithium batteries is there because the high discharge currents. High charge currents and max discharge requirements.
a 16 kWh chevy volt battery can be had for $1500.

Oh and forgot.. Lead batteries in hot climates do need more maintenance and do not last very long and batteries in cold climates suck completely. If you need to store your lead inside then you need to vent ... Altogether yes it is cheap in the short run and expensive in the long run. Heavy.. Acidic. Smell bad..take up a lot of space and very inefficient.. With lead you need at least 20% additional solar to correct for the ccharge / discharge inefficiencies. Not even talking about equalizing of lead cells which is nothing more then overcharging the battery and boiling of water and gas for the unbalanced cells.
Since skoolies have a limited solar capacity lead will be rarely charged properly for getting a long life out of them that is unless you have a minimal capacity.

Johan

[john61ct]

Originally Posted by brokedown

Just for clarity is this the battery you're referring to at Sam's Club?

https://www.samsclub.com/p/duracell-...c2/prod3590228

yes, black one is the GC2
equivalent to 215AH Deka Pro-Master GC10

gray one is the EGC2 - 230AH , called the GC15

> last few times I moved my 12v 4D AGM batteries I promised my back that the next set would be 6v cells.

Almost impossible to find true deep cycling FLA in 12V anyway, especially using automotive BCI Group sizes.

And yes much easier to manage, I think 65lbs?

[john61ct]

LI chemistries other than LFP or LTO should not be used, risk of thermal runaway far too dangerous in a mobile living use case IMO.

Especially secondhand from scrapped EVs, now orphaned from their engineered TMS, even if the BMS has been reverse engineered.

Maybe for a science project, in a back yard shed far from where humans live.

Never charged without constant manually monitoring.

The lower discharge rates of House bank usage helps a bit, but more with longevity than safety.

Yes lead's lower CAR as SoC climbs makes it slower, but say 3kW of panels should take care of a 1200-1800Ah bank just fine in decent insolation conditions.

Of course running the genset is required for aircon anyway, so a morning run can help in cloudy weather and in winter.