Dam blast and botheration

[Tubbyengineer]

I've been using un-fused lipo's for awhile Steve, this is for me, only me and nobody else so I'll know there are no fuses, the charging will be done via balance charger, connected via JST plug/socket that only fits one way, the box lid doesn't need removing once I have the Raptor installed and working so could you explain why I'd need install fuses please?

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It's not to protect the batteries it's to prevent the Raptor board from getting fried!

 

[Chegs]

How though, surely the raptor will only be at risk from incorrect polarity when changing cells and they won't be getting changed?

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[Tubbyengineer]

How though, surely the raptor will only be at risk from incorrect polarity when changing cells and they won't be getting changed?

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Really? You want to build this and you are not sure what a fuse does?

I'm choosing to believe you've just made a minor mistake - the two fuses are to prevent the Raptor from being destroyed by an overcurrent event such as a hard short on the Atty. The Raptor board itself can only handle 20A, it says so right there in the title...

 

[RicModMaker]

Really? You want to build this and you are not sure what a fuse does?

I'm choosing to believe you've just made a minor mistake - the two fuses are to prevent the Raptor from being destroyed by an overcurrent event such as a hard short on the Atty. The Raptor board itself can only handle 20A, it says so right there in the title...

Slapped legs Chegs now do what you're told and be a good vaper. ;-)
Some sound advice Tubbyengineer delivered headmaster style ;-)

 

[blademansw]

Really? You want to build this and you are not sure what a fuse does?

I'm choosing to believe you've just made a minor mistake - the two fuses are to prevent the Raptor from being destroyed by an overcurrent event such as a hard short on the Atty. The Raptor board itself can only handle 20A, it says so right there in the title...

I think a sealed box with a lipo battery inside without fuses in a dead short is an excellent idea. Goes BOOM

 

[sparkyjuice]

Don't see the need for the ripple smoothing caps TBH source is battery fets are used as switches ripple can only come from raptor switching circuit itself
And buck only....... Mmmm.
Still a 20A regulator is pretty good I suppose


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[blademansw]

Don't see the need for the ripple smoothing caps TBH source is battery fets are used as switches ripple can only come from raptor switching circuit itself
And buck only....... Mmmm.
Still a 20A regulator is pretty good I suppose


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I seem to recall ripple contributing to switching instability when I did my HND in Electronics. That was 20 years ago though and I have forgotten most of it.

 

[sparkyjuice]

I seem to recall ripple contributing to switching instability when I did my HND in Electronics. That was 20 years ago though and I have forgotten most of it.

Yes my point is that there is no ripple on a battery circuit unless it's reflected back from the raptor


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[blademansw]

Yes my point is that there is no ripple on a battery circuit unless it's reflected back from the raptor


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Quite possibly where its coming from then. It is showing output ripple on the datasheet after a quick scan through though

 

[blademansw]

From the datasheet:

Design Considerations
Input Filtering
The Naos Raptor 20A module should be connected to
a low-impedance source. A highly inductive source
can affect the stability of the module. An input
capacitance must be placed directly adjacent to the
input pin of the module, to minimize input ripple voltage
and ensure module stability.
To minimize input voltage ripple, low-ESR ceramic or
polymer capacitors are recommended at the input of the
module. Figure 46 shows the input ripple voltage for
various output voltages at 20A of load current with 2x22
µF or 4x22 µF ceramic capacitors and an input of 12V.

Output Filtering
The Naos Raptor 20A modules are designed for low
output ripple voltage and will meet the maximum output
ripple specification with no external capacitors. However,
additional output filtering may be required by the system
designer for a number of reasons. First, there may be a
need to further reduce the output ripple and noise of the
module. Second, the dynamic response characteristics
may need to be customized to a particular load step
change.
To reduce the output ripple and improve the dynamic
response to a step load change, additional capacitance at
the output can be used. Low ESR ceramic and polymer
are recommended to improve the dynamic response of
the module. For stable operation of the module, limit the
capacitance to less than the maximum output
capacitance as specified in the electrical specification
table. Optimal performance of the module can be
achieved by using the Tunable LoopTM feature described
later in this data sheet.