[RE-wrenches] Switching to LiFePO4

Thu Jan 9 08:28:10 PST 2025

Hi Dave,
I had a lengthy response to one of your wrenches requests but failed to
send it .  As it might be of interest to others, I am sending it now.
Since I wrote it, I have completed the repairs of the two e-flex 5.4’s. The
one with on off switch on when received had drifted down to total shutdown
at way below the recovery voltage in the low 40’s.  Charging initially with
a 2 amp power supply overnight brought it back to 44 volts then my iota
topped it off.  Works good now.  The other one with lights but no output
had a bad battery fuse which Fortress replaced and it also is fine.  Most
other brands without access to the BMS would have created a problem with no
easy resolution.  Below is the original email:

    I have upgraded systems in various ways but my choice has been to
upgrade to 48v for more battery options if your input voltages from the
solar allow.  I prefer Fortress e-flex 5.4 batteries as they are manageable
in size and weight, field replaceable BMS, good tech support and a
company that is well managed and should be here for the long haul,  They
are not the least expensive but from what I have seen with several
customers having bought the cheaper ones only to find out that the
companies do not respond to tech support calls or they are out of business.
I hook up the other brand batteries they have purchased elsewhere but tell
them I can't support them. I have a single VFXR3648 at my house and 2
fortress e-flex 5.4 The only problem I saw with the VFX and Fortress
batteries was the low battery cut off setting not going high enough.  I
have the Fortress Guardian that gives me remote SOC on each battery,
battery voltage and charge and discharge amps, and combined battery info
with one click on the app. When I updated my inverter to the VFXR I now
have a good low battery cutout setting but otherwise notice no difference.
I have had one e-flex hit by lightning and yes, I was negligent and did not
have SPD's on the system.  Fortress sent me a new BMS board and I had it
installed in a half hour.  I have two e-flex's here at my shop now with
issues and their tech support has been great,  They even email me to see
how I am doing with the troubleshooting. I,ve just been too busy to pull
the covers. One battery had the on /off switch in the on position right out
of the box so that one will need a direct recharge to the batteries
bypassing the bms. The other one lights up but tech support says it is
probably in low battery voltage mode and also will need an internal charge.
I have confidence that they will both be working soon as soon as I can get
back to it. I also use an IOTA  charger with my single outback inverter for
faster generator charge using the L 2 off my generator for the IOTA and L 1
through the inverter, This also gives me the jump start feature for the
lithium batteries in the event that the batteries shut themselves off in a
low voltage situation.

John Blittersdorf

On Tue, Sep 17, 2024 at 6:02 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.
>> >
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