On Monday, 9 January 2023 at 10:46:23 UTC+1, Fredxx wrote:
> On 09/01/2023 04:37, Commander Kinsey wrote:
> > I have 8 computers with 15 graphics cards running science projects. The
> > graphics cards run from 12 volts, adding up to a lot of current between
> > them. I have three 1kW power supplies connected to a big bus bar and
> > have set those power supplies to 12.6 volts, as the graphics cards
> > expect 11.4 to 12.6 volts, so I'm playing safe and allowing the biggest
> > voltage drop not to make it fall outside that range. Currently I'm
> > close to the limit of the power supplies, and since the current draw of
> > the graphics cards is uneven, I thought it would be a good idea to add a
> > car battery (actually a 130 Ah leisure battery) to the bus bars, to help
> > out if there was too much current draw momentarily. The power supplies
> > are current limited so don't mind if I try to draw too much, they will
> > just limit the current.
> >
> > My question is, is it ok to have the battery sat at 12.6 volts? This is
> > the voltage the battery sits at with nothing connected to it when it's
> > 95% full. If the battery were to supply a fair amount of current for a
> > while and become a little discharged, would it manage to charge back up
> > with only 12.6 volts supplied to it? Or does it require a float voltage
> > of 13.2 volts or more?
> If you do your homework, you will discover that 13.6-13.8V is considered
> a float charging voltage.
>
> A voltage of 13V is considered a charge maintenance voltage.
>
> Anything less than 13V won't supply any charge.
>
> You might like to rethink this.
you are wrong
read caption at battery:

Charging voltage

Standby use: 13.5V - 13.8 V
Cycle use: 14.4V - 15.0V
Charging current 5,40 A max ( 18Ah gel battery)

On Monday, January 9, 2023 at 1:20:04 PM UTC-5, a a wrote:
> On Monday, 9 January 2023 at 10:46:23 UTC+1, Fredxx wrote:
> > On 09/01/2023 04:37, Commander Kinsey wrote:
> > > I have 8 computers with 15 graphics cards running science projects. The
> > > graphics cards run from 12 volts, adding up to a lot of current between
> > > them. I have three 1kW power supplies connected to a big bus bar and
> > > have set those power supplies to 12.6 volts, as the graphics cards
> > > expect 11.4 to 12.6 volts, so I'm playing safe and allowing the biggest
> > > voltage drop not to make it fall outside that range. Currently I'm
> > > close to the limit of the power supplies, and since the current draw of
> > > the graphics cards is uneven, I thought it would be a good idea to add a
> > > car battery (actually a 130 Ah leisure battery) to the bus bars, to help
> > > out if there was too much current draw momentarily. The power supplies
> > > are current limited so don't mind if I try to draw too much, they will
> > > just limit the current.
> > >
> > > My question is, is it ok to have the battery sat at 12.6 volts? This is
> > > the voltage the battery sits at with nothing connected to it when it's
> > > 95% full. If the battery were to supply a fair amount of current for a
> > > while and become a little discharged, would it manage to charge back up
> > > with only 12.6 volts supplied to it? Or does it require a float voltage
> > > of 13.2 volts or more?
> > If you do your homework, you will discover that 13.6-13.8V is considered
> > a float charging voltage.
> >
> > A voltage of 13V is considered a charge maintenance voltage.
> >
> > Anything less than 13V won't supply any charge.
> >
> > You might like to rethink this.
> you are wrong
> read caption at battery:
>
> Charging voltage
>
> Standby use: 13.5V - 13.8 V
> Cycle use: 14.4V - 15.0V
> Charging current 5,40 A max ( 18Ah gel battery)

So if you connect a battery with low charge to a 12.6V supply, it will not charge at all? I'm pretty sure it will.

--

Rick C.

-- Get 1,000 miles of free Supercharging
-- Tesla referral code - https://ts.la/richard11209

On Monday, January 9, 2023 at 1:20:04 PM UTC-5, a a wrote:
> On Monday, 9 January 2023 at 10:46:23 UTC+1, Fredxx wrote:
> > On 09/01/2023 04:37, Commander Kinsey wrote:
> > > I have 8 computers with 15 graphics cards running science projects. The
> > > graphics cards run from 12 volts, adding up to a lot of current between
> > > them. I have three 1kW power supplies connected to a big bus bar and
> > > have set those power supplies to 12.6 volts, as the graphics cards
> > > expect 11.4 to 12.6 volts, so I'm playing safe and allowing the biggest
> > > voltage drop not to make it fall outside that range. Currently I'm
> > > close to the limit of the power supplies, and since the current draw of
> > > the graphics cards is uneven, I thought it would be a good idea to add a
> > > car battery (actually a 130 Ah leisure battery) to the bus bars, to help
> > > out if there was too much current draw momentarily. The power supplies
> > > are current limited so don't mind if I try to draw too much, they will
> > > just limit the current.
> > >
> > > My question is, is it ok to have the battery sat at 12.6 volts? This is
> > > the voltage the battery sits at with nothing connected to it when it's
> > > 95% full. If the battery were to supply a fair amount of current for a
> > > while and become a little discharged, would it manage to charge back up
> > > with only 12.6 volts supplied to it? Or does it require a float voltage
> > > of 13.2 volts or more?
> > If you do your homework, you will discover that 13.6-13.8V is considered
> > a float charging voltage.
> >
> > A voltage of 13V is considered a charge maintenance voltage.
> >
> > Anything less than 13V won't supply any charge.
> >
> > You might like to rethink this.
> you are wrong
> read caption at battery:
>
> Charging voltage
>
> Standby use: 13.5V - 13.8 V
> Cycle use: 14.4V - 15.0V
> Charging current 5,40 A max ( 18Ah gel battery)

It's not that simple. There are a bunch of lead acid battery types and the 12.6/6= 2.1 V cell voltage can indicate state of charge of between 75% through 95% depending on the type. So what you're reading is charging voltage for above 95% rated capacity. A 2.1 V for a gel cell is about 75% capacity, for a flooded lead acid it is about 95%.

On Monday, 9 January 2023 at 19:20:04 UTC+1, a a wrote:
> On Monday, 9 January 2023 at 10:46:23 UTC+1, Fredxx wrote:
> > On 09/01/2023 04:37, Commander Kinsey wrote:
> > > I have 8 computers with 15 graphics cards running science projects. The
> > > graphics cards run from 12 volts, adding up to a lot of current between
> > > them. I have three 1kW power supplies connected to a big bus bar and
> > > have set those power supplies to 12.6 volts, as the graphics cards
> > > expect 11.4 to 12.6 volts, so I'm playing safe and allowing the biggest
> > > voltage drop not to make it fall outside that range. Currently I'm
> > > close to the limit of the power supplies, and since the current draw of
> > > the graphics cards is uneven, I thought it would be a good idea to add a
> > > car battery (actually a 130 Ah leisure battery) to the bus bars, to help
> > > out if there was too much current draw momentarily. The power supplies
> > > are current limited so don't mind if I try to draw too much, they will
> > > just limit the current.
> > >
> > > My question is, is it ok to have the battery sat at 12.6 volts? This is
> > > the voltage the battery sits at with nothing connected to it when it's
> > > 95% full. If the battery were to supply a fair amount of current for a
> > > while and become a little discharged, would it manage to charge back up
> > > with only 12.6 volts supplied to it? Or does it require a float voltage
> > > of 13.2 volts or more?
> > If you do your homework, you will discover that 13.6-13.8V is considered
> > a float charging voltage.
> >
> > A voltage of 13V is considered a charge maintenance voltage.
> >
> > Anything less than 13V won't supply any charge.
> >
> > You might like to rethink this.
> you are wrong
> read caption at battery:
>
> Charging voltage
>
> Standby use: 13.5V - 13.8 V
> Cycle use: 14.4V - 15.0V
> Charging current 5,40 A max ( 18Ah gel battery)
--you are wrong
---read caption at battery:

--Charging voltage

--Standby use: 13.5V - 13.8 V
--Cycle use: 14.4V - 15.0V
--Charging current 5,40 A max ( 18Ah gel battery)

never delete the right answer