Hi JJ,
I think the comment I referenced said you can? run them flat and not to 'BMS' cutout. For what it's worth I have already cycled my SLAB batteries far more than 300 times and they were used when I got them. In dayes of olde I had two or three Ni-Cad battery packs that lasted more then 12 years of regular use simply by avoiding complete charge depletion and not using "fast charge". So no abuse. I replaced those with NiMH and those are performing even better (age unknown). If we use due care with any of the technologies they can give us excellent service. The lithium technology has high power density for light weight and has a useful voltage-discharge curve. The LiFePO batteries are the ones I am acquiring to replace my aging SLAB batteries. Thanks for the comments. I will look into getting the controllers and buying the cells to assemble my batteries.
73,
Bill KU8H
bark less - wag more
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On 11/2/22 01:44, JJ wrote:
Only speaking from personal experience...I have a 48v 200ah pack that has been going for 7 years, running it till bms cutoff every time about every 2 days...no measurable loss of capacity yet here...it's on my bike, and the range is the same as when it was new...NEVER run a pack w/o BMS...as for damage, I see if lead acid is run to 100% DOD, it is permanently damaged shortening it's lifetime and capacity...this is not nearly as much of a worry with LifePO4...run it down >4000 times (to BMS cutout)and the pack should still be at 80% capacity or better...watch for grade A cells..lesser cells will be unbalanced, and affect battery capacity, even with BMS...
Cons I've found:
You can damage a cell if it gets below 2.50v I think it is..permanent damage will result..
NEVER charge LifePO4 when below freezing (can discharge however)
BMS system is the weakest link...have seen failures...
NOT recommended to float-charge them..
EXPENSIVE EXPENSIVE EXPENSIVE
I have a feeling they will get even more expensive if I read the supply chain correctly...
On 2022-11-01 14:26, Max via groups.io wrote:
I don't agree with the "NO damage" statement. From looking at various brands they ALL show fewer cycles the deeper you discharge the battery. Is it as bad as a lead acid battery,no. But please don't misinform a new user to this type of battery.
I really like the LiFePo4 chemistry. I have 400Ah (4 x 100Ah) in a bank as well as some of the smaller ones. They are too expensive to not take good care of them.
Max KG4PID
On Tuesday, November 1, 2022, 11:41:52 AM CDT, JJ <ve1jot@...> wrote:
Consider getting a LifePO4 battery....less than half the weight, more
than twice the available power, non-flammable, not like explosive
lithium or gassy lead-acid..you can run these flat with NO damage plus
get <4000 cycles, whereas only about 500 cycles with lead-acid. Also my
ic-7300 likes the new batts better, as they do not sag in voltage under
load..check it out..better for the enviornment too!!
On 2022-11-01 11:16, Marty Hartwell wrote:
Hi Bill
I have and use my FT-817 sometimes in portable operations, currently
my only rig for either
V/U or HF opts, if I want to go digital I have my pi housed in a nice
case that has a 7" monitor.
Its specifications say it requires 5.1v at 3A, and so I use a buck
converter from the 12V. The
battery I am using is heavy from a lawn mower, so these days if I
can't drive to the op site I
don't go, but here in TN we have quite a few parks I can drive up to a
place to set up. Nice
for POTA.
Have a good day.
Marty kd8bj
On 10/31/22 15:47, Bill Cromwell wrote:
Hi Marty,
I looked at customer "questions" section and the manufacturer states
5V@2 amps and 12V@3 amps. I removed those batteries from my "shopping
cart" since they won't actually meet my use needs. At the moment I am
running 12V sealed lead-acid batteries (SLAB) at just over 7
Amp-hours. They are holding up well but are reaching end of life.
Some of my gear draws up to 7 amps in transmit. If I only wanted them
for QRP operation they would be suitable. Maybe I will buy *one* for
that purpose. However, when I buy more suitable (to me) batteries
those will certainly handle a QRP rig at the park. I run up to about
fifty watts when I feel evil :) Less than one watt sometimes too so
maybe there is some hope for me.
I will look at other offerings from this and other manufacturers.
73,
Bill KU8H
bark less - wag more
On 10/31/22 15:00, Marty Hartwell wrote:
Hi Bill
I looked at the pictures on the left side that shows the different
views. The
second one down showing the front with the switch and USB and 12V
input/output the USB shows 5v/2A (Max).
My pi is housed with a monitor and I know it says 5.1V/3A and it
does show
low voltage warning, because I used a Buck Converter that had screw
terminals
for the connections and had to remove the connectors and solder the
wires
in/out to overcome the voltage loss., Maybe if you pi in run
headless it
is ok with 2A at 12V, good luck.
Nice looking battery if it works good.
Marty kd8bj
On 10/31/22 12:19, Bill Cromwell wrote:
Hi,
I put two of them in my 'cart'. I didn't notice anything about a 2
amp limit on the 5 volts. And nothing on the 12 volts either. Where
did i fail to look?
73,
Bill KU8H
bark less - wag more
On 10/31/22 10:45, Marty Hartwell wrote:
Hi
I noticed the 5V is only rated at 2A, have you noticed any problem
with the pi which needs 3A
I believe?
Marty kd8bj
On 10/31/22 04:36, Vic WA4THR via groups.io wrote:
Roy, the battery I use is this:
<
< <>>
which is nice in that it also provides a 5v connection for the
RPi in addition to the 12v for the rig. Seems to run all day.
=Vic=
