Discover has been showing cell level since the beginning of LFP via
lynk, Dashboard, and spread sheets.
Much nicer now with Lynk2.
Dave Angelini Offgrid Solar
"we go where powerlines don't"
[2]https://offgridsolar1.com/ [3] [2]
e-mail [email protected]
text 209 813 0060
On 2025-05-17 8:47 am, jay via RE-wrenches wrote:
Thanks
This system uses a passive balancer which is only active at or above
some high voltage setting, bms specific which therefor needs enough
time at those voltages to balance.
I wish the OEM would state such things as which type active or passive
balancing and exactly how much it can balance and those specifics.
Since most closed loop systems have almost no time spent at the top
voltage, I am assuming they are using active balancing. And many people
are using lithium with legacy inverters/CC so better info would be
good.
Its why I like to use batteries that I can see the cell voltages ( EG4
for example) via the built in display or via their inverter coupled
with their battery.
Jay
On May 17, 2025, at 9:51 AM, Maverick Brown via RE-wrenches
<[email protected]> wrote:
Jay,
Over time I noticed that with lower voltage (say 54.4 [3.4vpc]) and
little to no absorb was causing a wider gap in the SOC of individual
batteries. I found that the solution was to charge to a higher voltage
and to absorb longer that 5 minutes, etc.
I could observe this spread of SOC on various Lithium battery brands
and I started editing the settings to get back to a more Lead Acid
style approach. It works.
I was typing an even longer explanation... This video says it all:
<hqdefault.jpg>
FAQ: Charging Cycle: what is absorption for, and is it needed? l Battle
Born Batteries [1]
youtu.be [1]
I chose 3.45V per cell for all LiFePO4 batteries (so 55.2 for 16s
batteries) and so far, all customers, all brands are fairly tight on
the SOC range per battery. I have to be onsite to measure that, of
course, but data looks good.
I set the Absorb time long enough to give the individual battery
entities time to internally balance and catch up on SOC. The higher SOC
batteries will naturally taper their charge current. But, 55.2 is not
high enough to trip a Charge Relay in any battery.
As a side note, Fortress sells the Guardian and that lets you see the
SOC of individual batteries from afar and then you an do something
about SOC remotely. I wish I could hack the Guardian for other brands,
I would install it everywhere. I wonder if Solar Assistant can see
individual CAN connected batteries??
All Y'all, Let me know what you think and if you have any feedback.
Thank you,
Maverick
Maverick Brown
Off-Grid Solar Commander since 2006
Maverick Solar Enterprises, Inc.
* Solar Commander Remote Power
* SunFlow Systems Cathodic Protection
[email protected]
512-460-9825
On May 17, 2025, at 10:21 AM, Jay <[email protected]> wrote:
Hi maverick
Can you explain the logic of 55v for 3 hrs?
Thx
Jay
On May 17, 2025, at 7:50 AM, Maverick Brown via RE-wrenches
<[email protected]> wrote:
Jason,
I think it is valuable to have SOC information available if you also
have an InsightHome device that can show the SOC data for reference
etc. For legacy inverters, voltage still makes the decisions.
I don't know of any battery that communicates together to balance
between individual battery entities. That still leaves the necessity to
charge via voltage high enough to get all batteries to high and similar
SOC.
The E-BOX says via Pylontech protocol that its battery voltage range is
46.5V to 56.8V, so I think 48V LBCO is fine and certainly 44 is too
low.
There is a ".8" version of battery firmware and a ".16" version. I can
send you the .16 version that I have (SPBMS16SRP2205V1.5.18.C16). I use
HyperTerminal to install the software and it is the absolute easiest
battery to view the details using the Pytes USB to Serial cable (other
cable brands could also work). HyperTerminal was provided free by
Pytes. I can send you that as well. A lot of this might still be on
their website.
I lieu of having a Pytes Hub to stack the existing bank as multiple
groups of 10 batteries, you could upgrade each battery to .16 firmware
and make two communicating stacks of 10 that don't communicate
together. If you have InsightHome, you can wire the CAN port of the
left 10 to Insight and the RS485 port of the right stack to Inight and
make "two battery banks" show up in Insight. On the Pytes, the CAN RJ45
Blue pair is CAN and the Orange Pair is RS485 (from the RS485 port). If
you have InsightFacity you can use both CAN ports. CAN devices show up
automatically and RS485 device need to be setup via InsightLocal /
Setup / Device Detection / Detect Device / RS-485: 1 to 10.
On the Charge Controllers, I would set Absorb to 55.2 for 3 hours.
I even started using EQ at 56.0 on some systems.
Good luck today!
Maverick Brown
Off-Grid Solar Commander since 2006
Maverick Solar Enterprises, Inc.
* Solar Commander Remote Power
* SunFlow Systems Cathodic Protection
[email protected]
512-460-9825
On May 16, 2025, at 6:22 PM, Jason Szumlanski via RE-wrenches
<[email protected]> wrote:
The advantages of closed loop communication between LFP batteries and
inverter systems are pretty obvious. But when you are operating in an
open loop because you are working with a legacy inverter that does not
support battery communication, how important is it for batteries to be
wired together?
I started contemplating this today when I ran into a Pytes stack of 20
E-Box 48100R (5kWh) batteries. Whoever installed them wired all 20 in a
single communication daisy chain. Come to find out, this version of the
battery only supports 8 or 16 in a communications network. The bank is
connected to a couple of XW+ inverters, so it is operating based on
voltage. The owner must have had to use an unconventional method to
turn the batteries on, because typically you would only press the
switch on the master battery. In this case, that doesn't work because
the communication chain is broken at some point.
The reason for my visit was the battery is sitting at 43 volts because
the generator didn't start and the low battery disconnect was set to 44
volts, well below the 49 volts recommended by Pytes. Side note: I
could not set the low battery cut out higher than 48V with these
inverters.
I was there to get these jump started with a Chargeverter. I rigged it
up and got things going, but various batteries were alarming out.
Ultimately I just disconnected the communication cables on all the
batteries and they all started charging from the Chargeverter which was
connected to the common bus. Awesome!
So back to the original question... Are the batteries really doing
anything in terms of balancing when they are connected in a
communications daisy chain when they are not enclosed loop
communications with an inverter? How important is the communication
anyway? And in this case, assuming that the maximum batteries in a
communication chain is eight, I would probably be better off setting up
four separate communications with four master batteries in groups of
five. Again, I'm not sure how important that is in terms of balancing.
What if I had different quantities per communication group? They're not
talking to each other anyway!
Not to muddy up this thread, but I will say that the Chargeverter saved
the day. Within 20 minutes, I was able to get the inverters turned on
and the SCP to help me identify what went wrong. Then I turned on the
inverters and got them charging the batteries simultaneously with the
Chargeverter and solar. It really just needed a jump start! I had
rigged it up in a way that I could easily do this and then safely
disconnect the Chargeverter while the rest of the system continued to
charge the batteries. It was my first experience with this little gem,
and I'm happy to have it in my toolbox now.
Tomorrow I am going back to restart the charging process and hopefully
get the batteries up to 100%. I also plan to check the firmware, which
I am almost positive is mismatched in this stack of batteries. All of
my off-grid systems are a boat ride away, so I'm going to pretend it's
a weekend and I'm not working. Haha.
Jason Szumlanski
Florida Solar Design Group
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