[RE-wrenches] Switching to LiFePO4

Jason Szumlanski jason at floridasolardesigngroup.com
Tue Sep 17 15:01:01 PDT 2024


I don’t want to stray too far off track, but it’s worth discussing how
challenging it is to predict which manufacturers will be around in a few
years.

I know this might be a touchy subject, but Enphase is beginning to offer
full off-grid support. While I’m fully aware of the drawbacks of their
system architecture for off-grid setups, it’s also important to acknowledge
that no manufacturer is “too big to fail”—but Enphase is about as close as
we have right now. If something were to happen to them, the reliance on
remote access for the system functioning is concerning. It could
essentially become a big brick if a service issue arises and there’s no
support. On the other hand, Enphase may be a safe bet for certain off-grid
systems if you think they will come out on top.

But the reason I bring Enphase up is modularity. Building systems with
interconnected components from various brands can spread the risk. Sol-Ark,
with its “battery agnostic” approach, is a reasonable choice, as long as
there’s a replacement all-in-one option if they were to go out of business.
EG4 and Midnite seem to offer alternatives in that space now. As long as
LiFePO manufacturers stick with 48V/51.2V standards, complete battery
replacements should be straightforward. However, I do think that large
battery sizes like 5 kWh (or even 13.5 and 14.3 kWh) could be problematic.
Personally, I prefer the concept of smaller, 1 kWh chunks. In the case of a
40 kWh battery bank, for example, if one module fails and the manufacturer
is no longer around, it’s a lot easier to deal with. That's similar to how
we can drop one faulty 2V cell in a series of 24 lead acid batteries
sometimes. Enphase, if you think about it, is the least modular approach in
some ways, since it relies on a single manufacturer with a proprietary
system. So the whole concept of modularity is not straightforward, either.
It's a fantasy at this point to hope for a truly modular and
manufacturer-agnostic system.

What I find interesting is that most of my clients who went off-grid 7-15
years ago are pretty understanding when I tell them it’s time to replace
their systems. Realistically, fast-forward another decade, and we’ll
probably see significant advances that make a complete system replacement
worth it once again. I’m not saying we should be designing disposable
systems, but that might be where we’re headed, just like so many other
industries. Think of what Tesla is doing with the Powewall 3. They are
making solar and batteries as cheap as possible (while maintaining high
quality standards and keeping fuel in Elon's jet). However, when the PW4
comes out, the PW3 will be deprecated, and those systems will become
essentially disposable. The warranty is only 10 years. So when the inverter
insude the PW3 dies in year 11, guess what – the entire PW3, battery and
all, may be rendered useless. But, people still flock to Tesla for backup
systems. And for good reasons.

The days of keeping systems running on old components while upgrading just
parts of the system are probably behind us. The rapid evolution of
technology, equipment, codes, safety, and consumer needs will make whatever
we install today obsolete soon after it's up and running.


--end rant--

Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956
Florida Certified Electrical Contractor EC13013208


On Tue, Sep 17, 2024 at 5:20 PM Ray Walters via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Honestly, that advice would seem to  be true, but the reality is: It is
> not valid.  Just look at Blue Planet, that was supposed to be a top tier
> offering.  Solar World?  AEE? Magnum has had serious issues, Outback
> doesn't answer the phone, SImpliphi takes an attorney to honor their
> warranty. Even long standing companies are not sure bets, at all.  They
> do cost much more, so I'm not sure who to turn to anymore.  I'm about to
> install Rubix LiPO4, which comes in a 24 v offering, BTW for Dave.
>
> The biggest issue I've seen with old VFX inverters, is the LVD set point
> can't go high enough for LiPO4.  I use the aux out on a charge
> controller, to switch on and off the remote switch on the VFX.
>
> I like the Fortress with Solark combo, but its not without its troubles
> either.  If the Solark shuts off due to low voltage, so does your PV
> input.  Then the no load draw on the Fortress eventually shuts down the
> battery.  You really need some (at least 1 kW) of DC coupled PV to keep
> that death spiral from happening.
>
> Ray Walters
> Remote Solar
>
> On 9/17/2024 12:23 PM, Sindelar Solar via RE-wrenches wrote:
> > Jerry,
> > Re your advice to never get startups or small manufacturers as so many
> > disappear and now you are stuck, I guess we should stick with the big
> > well-established manufacturers, like Outback, Magnum and Blue Planet,
> > right?
> > As you would say, fun times...
> > Allan
> >
> > On 9/17/2024 10:58 AM, Jerry Shafer via RE-wrenches wrote:
> >> Dave,
> >> I would suggest stepping up to 48 nominal, fortress 18.5, battery 12
> >> or 15 k solark inverter, re-wire the array to single or dual string,
> >> make the wiring in the home capable of 240, this usually requires
> >> main panel re-work and set up the monitoring.
> >> Batteries are like replacement heart valves, never get startups or
> >> small manufacturers as so many disappear and now you are stuck.
> >> Fun times.
> >
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