Hi John,
Your very nice Orion BMS will balance your batteries in standard
manner ("top" balancing, so to speak.) Orion makes an outstanding (and
a bit pricey) battery management system, with all the bells and whistles
if you wish to use those features.
Attempting to perform some sort of manual "bottom" balancing will
simply confuse the Orion. It will see the "bottom" balanced pack as
completely unbalanced, and wok diligently to correct the situation. This
might take the system awhile to correct, perhaps several days. It will,
eventually, bring the pack into perfect balance. This is what the
battery companies all recommend, as do the OEMs.
>>>> "Bottom" "balancing" explained <<<<
The folks that advocate bottom balancing are trying to get by
without a BMS at all. It really only "works" for a short while, perhaps
only a few cycles. The batteries get out of "bottom" balance inevitably.
Think of a herd of cats. They might go in the same direction and
same speed for a short time. They will not march in sync because it is
simply not in their nature.Expecting them to stay in sync is foolish.
If you drive your car regularly, then you will ruin batteries with
some regularity, and are taking a very big chance on a battery pack
fire. I personally know several "anti-BMS" folks that drive their EVs
regularly, and ruin several batteries every year. They attribute their
ruined batteries to flawed manufacturing. A few anti-BMS folks have had
spectacular fires, often more than one spectacular fire. Some have lost
a garage.
If you ignore self-discharge (or actively dis-believe in self
discharge) then bottom balancing sounds enticing. Folks don't understand
why you really need a BMS. You _want_ to believe that you can get by
without a BMS, so this is what you convince yourself. It is very much
like the flat earth folks, or the climate change deniers, or cigarettes
are not addictive, or any other conspiracy theory that you might name
that is contrary to the mountain of scientific research that shows
otherwise.
Trust the science. Trust that the OEMs would not spend an extra
penny on a BMS if they did not have to. Believe that you will have a
fire that could very well burn down your house if you forgo a BMS.
Bill D.
On 3/13/2021 5:30 PM, John Titman via EV wrote:
Hello all: I am a newby so, bear with me . I have converted my 1965 Ford
Falcon to an all electric vehicle with an HPEVS AC51 motor with a Curtis
1239e controller,
an Orion2 BMS . I've fitted 48- 271 Ah 3.2 volt batteries and am
experiencing
battery balance problems . I am in the process of bottom balancing the
batteries but, I'm not sure how critical the bottom voltage should be after
discharging. Do they all need to be exactly 2.5 volts ?The battery voltage
keeps jumping up to about 2.51 to 2.54 volts after numerous discharging.
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