That is my understanding too. But one point I would make is that the
discharge from the BMS is pretty low compared to the size of the
batteries we are talking about. I was told by a techy at signature
solar that for a rack mount battery to go into storage, it should be
charged between 1/2 and 2/3 full and it would be good for 2 years
without discharging too much. That is with the switches in the off
position, which does shut down most of the BMS functions but is not a
disabled bms.
On 1/5/24 3:13 PM, Peter Kranz via AF wrote:
If you want to do lifepo4 right, here are the key points (In my opinion).
1. After a discharge, a boost charge at a voltage of around
3.5-3.65V/cell should be applied to recharge the battery, until
you reach termination charge current.
2. After boost charge is complete, you may want to hold voltage for a
period of time to allow the BMS to top balance the cells. Your BMS
will likely be programmed to top balance above 3.4V/cell. I like
to hold the pack voltage at just above 3.4V/cell for as long as it
takes for this top balance to complete.
3. After the top balance is complete you should switch to a float
charge of 3.375V/cell for maximum lifespan. Holding voltage higher
in float can lead to pack swelling and lower lifespan.
4. Batteries should not be charged in any way at or below freezing
temperatures, discharging is ok.
5. Batteries not being used (spares) should have the BMS disabled to
avoid BMS induced self discharging.
Peter Kranz
www.UnwiredLtd.com <http://www.unwiredltd.com/>
Desk: 510-868-1614 x100
Mobile: 510-207-0000
pkr...@unwiredltd.com <mailto:pkr...@unwiredltd.com>
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