[time-nuts] Re: Backup DC power with current battery technology?

[Poul-Henning Kamp]

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John Ackermann N8UR via time-nuts writes:

> I haven't explored LiFePo4 batteries until now, and I'm having trouble 
> finding a charger that can provide significant continuous load current 
> while maintaining a battery floated across the line.

LiOn is a weird battery chemistry:  Strictly speaking it is only a
~3.7V cell, but for strange reasons you can overcharge them to ~4.1V,
and get another 20% capacity, which is how nameplate capacity is
specified.

In theory you can float LiOn in the range 2.7V to 3.7V, but you
cannot trust the cells to balance themselves, you have to regulate
the voltage over each individual cell, and that complicates things.

But if you already have all the infrastructure and dont need a particular
long runtime:  Buy two new AGM batteries and spend your time and money
on something else.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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Never attribute to malice what can adequately be explained by incompetence.