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<p>I think once you compare the cost of 24v battery options ( Rubix,
Simpliphi) to the 48v (Midnite) it will be worth replacing the
inverters. 2500 Ah @ 24 vdc is 60 kwh; that's a good sized
battery bank even for full time off grid, I think over kill for a
backup system. Just pencil it both ways, my last 24 v system I
noticed that LFP was almost double $$/ kwh compared to 48v. </p>
<p>Also, I Will reiterate that many on the list, including me, have
had XWs throw the programming and start charging at maximum DC
voltage (32vdc!) Many a battery bank has been cooked with fire
danger a real possibility. Just another reason to consider going
48v. I just did a 24 v LFP upgrade for a client with an Outback
24v inverter. We too decided to keep the inverter, but many
lessons learned during install, would change that choice next
time:</p>
<p>1) Inverter age (10 to 15 years is getting long in the tooth,
even if its worked perfectly)<br>
2) Battery cost/ kwh (48v much cheaper)<br>
3) Battery options (more options)<br>
4) Half amperage on battery cables<br>
5) Inverter can accept full 240 vac charge amps from generator
(using a newer 120/240 inverter)<br>
6) Charge controllers can operate at double their 24 v capacity<br>
7) More Charge Controller choices, (such as the Midnite Hawke's
Bay, which very unfortunately do not operate at 24 v)<br>
8) Less parallel batteries for larger banks<br>
9) Everything is wired to your spec, and you're not taking on
somebody else's workmanship. </p>
<p>I too saw a working system that I didn't want to redo, but I kept
uncovering crappy wiring that eliminated any cost savings from not
replacing the inverter.....<br>
</p>
<p>You need to look at the full project economics, long term
reliability, and future expandability.</p>
<p>Ray Walters<br>
Remote Solar<br>
303 505-8760</p>
<div class="moz-cite-prefix">On 12/22/2025 1:32 PM, Chris Daum via
RE-wrenches wrote:<br>
</div>
<blockquote type="cite"
cite="mid:011b01dc7382$28f91ef0$7aeb5cd0$@OasisMontana.com">
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<p class="MsoNormal">RE: Closed loop communications… I have a
customer who needs to replace his old AGMs; he’s looking at
getting something like 2500ah @ 24V and wants LFPs. This is a
battery based, grid tie system. His equipment is a pair of
XW4024s (Schneider – and he has NO interest in replacing his
inverters) and three Classic (Midnite) charge controllers.
I’m concerned with integrating the LFPs with his old inverter,
but his Classics, I believe, can be reprogrammed to
accommodate the LFPs. This system was installed around 2015
so the equipment is not new – but it’s basically been humming
along until a couple of weeks ago, when there was a week of 60
to 90 MPH winds that killed the power for a while. This is
near Boulder, CO (at 9000 ft elevation). His system worked
fine til his old AGMs gave out. Their power was out for ~3
days, then came on for 2 days, then went out again for a
couple of days. So he realized how undersized and old his
batteries were.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">If he gets some new LFPs, do you think
they’ll work with this vintage equipment? Any of your
wonderful advice to pass along!? I’m thinking the Classics
can dial in the settings he needs.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks, y’all!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoAutoSig">Chris Daum<o:p></o:p></p>
<p class="MsoAutoSig">Oasis Montana Inc.<o:p></o:p></p>
<p class="MsoAutoSig">406-777-4309 or 4321<o:p></o:p></p>
<p class="MsoAutoSig">406-777-4309 fax<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<br>
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