[RE-wrenches] Switching to LiFePO4

Wed Sep 18 06:22:42 PDT 2024

Hi David,

This upgrade comes up a lot.  You are at a point where you have to decide;
do I match my old equipment with a new 24V Lithium battery bank (thus
limiting my battery bank options), or do I upgrade my equipment to 48V
which opens up the brands available?

I have had good success matching older equipment with new batteries but my
preference is always to try to get these systems to 48V if it's financially
viable.  Ray describes a solution to get the LBCO high enough to shut off
the inverter before the BMS shuts down and this works.  You can also
hardwire a power supply to wake up the BMS directly from the generator.

Remote monitoring is very useful too, especially in a rental scenario like
this.  It may be time for a full upgrade.

Very hard to know which companies will make it through...

On Tue, Sep 17, 2024 at 4:01 PM Jason Szumlanski via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> 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.
>> >
>> > _______________________________________________
>> > List sponsored by Redwood Alliance
>> >
>> > Pay optional member dues here: http://re-wrenches.org
>> >
>> > List Address: RE-wrenches at lists.re-wrenches.org
>> >
>> > Change listserver email address & settings:
>> > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>> >
>> > There are two list archives for searching. When one doesn't work, try
>> > the other:
>> > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
>> > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>> >
>> > List rules & etiquette:
>> > http://www.re-wrenches.org/etiquette.htm
>> >
>> > Check out or update participant bios:
>> > http://www.members.re-wrenches.org
>> >
>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> Pay optional member dues here: http://re-wrenches.org
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> There are two list archives for searching. When one doesn't work, try the
>> other:
>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> http://www.re-wrenches.org/etiquette.htm
>>
>> Check out or update participant bios:
>> http://www.members.re-wrenches.org
>>
>> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
>

-- 

Mac Lewis

*"Yo solo sé que no sé nada." -Sócrates*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20240918/a34de5d1/attachment.htm>