Requested Features for Wizbang Jr.

[pechan]

Please post your realistic feature requests in this thread.
Then I will add them to a poll and let Midnite know what to concentrate on.

[pechan]

I will start it off.
I would like the classic to be able to add up the data from multiple wb jrs monitoring different shunts.

[boB]

Battery SOC  State Of Charge

[Halfcrazy]

Dishwasher

No really a SOC meter and system amp limit

[RossW]

Please post your realistic feature requests in this thread.

Adjustable gain so it can be used with other shunts.

For example: I currently have existing moving-coil meters with internal shunts. They seem to be "about" 7mV/A
Alternatively, and I know I will get shot down for this... but I'm not a fan of adding additional points of voltage drop and interconnects. I have 1m long x 35 sq mm cables between batteries and inverter which should produce 50mV drop at 104A. It seems silly to me to add another shunt if I could "calibrate" the WBjr to use an existing battery cable!

[boB]

Please post your realistic feature requests in this thread.

Adjustable gain so it can be used with other shunts.

For example: I currently have existing moving-coil meters with internal shunts. They seem to be "about" 7mV/A
Alternatively, and I know I will get shot down for this... but I'm not a fan of adding additional points of voltage drop and interconnects. I have 1m long x 35 sq mm cables between batteries and inverter which should produce 50mV drop at 104A. It seems silly to me to add another shunt if I could "calibrate" the WBjr to use an existing battery cable!

Well, you're sort of in luck on the gain.  The gain of the preamp is presently set to 8.  It can be set for
1,2,4 or 8.  With 7 mV per Amp, you need to reduce the gain by 70 from what we have presently.
That's quite a bit less. 

After this, the gain is also adjustable via modbus register in addition to the 8:1 reduction.
So, if that register can give another reduction of 8 to 9 times, it should work OK for you.

As far as a piece of wire for a shunt, they don't work very well because the resistance
changes with temperature.  A real shunt like a 50 mV at 500 amp that we typically use
is only 100 micro-Ohms so it isn't much to worry about in comparison to your
wire resistance.

Food for thought anyway.

boB

[RossW]

As far as a piece of wire for a shunt, they don't work very well because the resistance
changes with temperature.

The resistance doesn't change very much with small delta-T, and in my case it gets down to about 19 degrees in the battery room in mid-winter, and up to about 25 degrees in summer. (Remember, it's basically 5 metres underground)

Being one metre in length, and being fairly heavy (welding cable), the change in resistance by 6 degrees is virtually negligible IMHO. Temperature coefficient is 0.003862/degK, so I think over the range in question isn't an issue, do you?

A real shunt like a 50 mV at 500 amp that we typically use
is only 100 micro-Ohms so it isn't much to worry about in comparison to your
wire resistance.

50mV is 50mV, regardless how it's obtained, surely?  I mean, a 50mV shunt will make 50mV at its rated current.
While my battery leads may drop 50mV @ 104A (compared to your shunt only dropping 10mV @ 100A), that's an *EXTRA* 10mV, plus the extra two connections (only mV each, but more places to have problems, over time).

Additionally, if I get 50mV @ 100A, we can divide that by 5 (or turn down the gain) to get your 500A FSD - and unless I'm missing my mark, that will also reduce the effect of thermal variation (it'll still be the same percentage of full scale, obviously)...

Am I missing something obvious?

[boB]

As far as a piece of wire for a shunt, they don't work very well because the resistance
changes with temperature.

The resistance doesn't change very much with small delta-T, and in my case it gets down to about 19 degrees in the battery room in mid-winter, and up to about 25 degrees in summer. (Remember, it's basically 5 metres underground)

Being one metre in length, and being fairly heavy (welding cable), the change in resistance by 6 degrees is virtually negligible IMHO. Temperature coefficient is 0.003862/degK, so I think over the range in question isn't an issue, do you?

A real shunt like a 50 mV at 500 amp that we typically use
is only 100 micro-Ohms so it isn't much to worry about in comparison to your
wire resistance.

50mV is 50mV, regardless how it's obtained, surely?  I mean, a 50mV shunt will make 50mV at its rated current.
While my battery leads may drop 50mV @ 104A (compared to your shunt only dropping 10mV @ 100A), that's an *EXTRA* 10mV, plus the extra two connections (only mV each, but more places to have problems, over time).

Additionally, if I get 50mV @ 100A, we can divide that by 5 (or turn down the gain) to get your 500A FSD - and unless I'm missing my mark, that will also reduce the effect of thermal variation (it'll still be the same percentage of full scale, obviously)...

Am I missing something obvious?

No, as long as the gain of the amp is low enough, it ~should~ work OK I think as long as the amp doesn't saturate (clip)

what is your peak current ?

boB

[RossW]

what is your peak current ?

It's a 5KW inverter, 10KW peak (but I never ask that from it).
Assuming a "worst case" battery voltage of only 48V, 5KW is 104 amps (there it is again!)
(Slightly higher, given inverter losses I suppose).

Most of the time it runs around 1500W, down to about 600W overnight (so around 10-30A)

[MikeD]

Hi everyone, I am a new forum member. Have been fooling with solar for many years, and finally got my system installed late last year.

It has been fun and quite a learning curve getting it all built and installed, and now I am trying to get my 16 - 3 year old Trojan T105 batteries back in shape.
One bank was in my EV telephone truck, and the other bank was in an EV yard maintenance buggy. Both banks had little actual cycling and were sulphated, so I have been carefully using a pulse desulphater the Hydrovolt hydrometer and many EQ cycles to get them back in shape. They seem to be  responding well.
The system includes a Whizbang JR that is able to tell me the net AH, and total battery current and direction .
Since the batteries are the only source of power at night, it would be great if the  total AH drawn from the batteries and the time could give us a battery capacity value .
The other thing that seems to be missing is a way for the local app to have a way to graph the combined output of the  classics that are communicating via the follow me system, and to have the whizbang data be available in the graphs. Maybe have a system mode in the local app, where the display is the combined data for the whole system of classics. I only have 2 classics, and find my self switching between the two to get a better picture of the total output.
What whizbang jr enabled features do you guys have planned?

I am faced with spending a bunch of money to get the outback hub, Flexnet DC to enable better battery condition monitoring, and it would seem that the classics interfaced with the whizbang JR could provide the same information if fully utilized.
Update.
Installed your latest classic firmware, and see that you have provided a lot of new support for the whizbang jr.
Thanks for the continuing support.