Remote battery Voltage sensing?

[Mike W]

Hi boB,

Is there an easy way to create remote battery voltage sensing with the Classic 150? I was wondering if it couod be as simple as lifting a resitor lead and bringing an extra wire out? If possible, would a another resistor be fitted from the sense point to the batt V+ terminal in the classic so that in the event the remote batt sense lost voltage, the classic would still function as today?

We use the classic and 1000W of solar to power our sailboat down south in the winter. I’m looking at going to Lithium batteries and am interested in getting accurate voltage sensing at the battery.

Mike

[boB]

Actually, yeah there IS a resistor that senses the battery voltage at the terminal.  Moving that sense point would
only sense the positive lead though and you would still be left with the negative cable voltage drop.

I'm not sure how well this would work though because of the noise that would be picked up with that
wire being external.  Good question.

So, how much charge current and therefore voltage drop when the battery gets up to that finishing voltage ?

The current has usually dropped off enough that that point that it is minuscule.  But maybe not in your case ?

boB

[RossW]

Hi Bob, you'll recall we discussed this a couple of years back in IRC, and it was on the "wish list".
Voltage drop at the end of charge is, as you say, fairly small - but it's not the only time it's important.

Knowing the actual voltage while the pack is charging hard is highly beneficial too!

While eliminating the drop from the positive lead only isn't ideal, it does still halve the error, so it's worth having!

A proper differential input so we could have sense leads on + and - terminals would be wonderful, but that isn't just a simple "lift this resistor" field fix.

[boB]

I think what would be cool (and fairly simple) would be a new-ish Whizbang Junior
with that differential input just like it uses for the 500 amp shunt.

boB

[Vic]

I think what would be cool (and fairly simple) would be a new-ish Whizbang Junior
with that differential input just like it uses for the 500 amp shunt.

boB

YES !!   +1,000 !   Had been hoping for just such a solution.

Thanks,   FWIW,   Vic

[markinredding]

I have a Classic 150 at our cabin. No internet and the controller is in the basement.
I hooked up an old linksys router to it. On my smart phone and a tablet running Android I down loaded the "Classic Monitor" app from the Play store. It monitors every aspect of the Classic there is. (I have and would recommend installing the Wizbang for sure!!! In fact I think you must have it to get the battery voltage.)
First thing I do when I get there on the weekends is start the app and leave it running. It has an awesome multi page display you swipe through. My favorite is the watching the daily charge as it goes through the various charging phases.
I can open the phone or tablet any where in the cabin (three stories) and see everything. Coolest app I ever had and it is free. (You can only have one device connected at  time, I like the tablet but...) This is a 35 year old system I completely updated and had assorted issues. I drive up and look at the panels and know nothing - fire up this app and you can see everything. Has a calendar that show for one thing if the charging cycle made it to Float.

[Westbranch]

Mark, I believe you are referring to Grahams (personal ) Android version of the Local App.... YES it  is  a great clone , too bad the LA has to be run with Adobe AIR...

[boB]

Mark, I believe you are referring to Grahams (personal ) Android version of the Local App.... YES it  is  a great clone , too bad the LA has to be run with Adobe AIR...

What's wrong with AIR ?  Except that it will probably stop having updates which doesn't stop it from working, luckily...

At the time the LA was designed, AIR was going to be a good option because it was cross-platform compatible.
I think you can still download AIR for the 3 big formats ?

All formats have their problems though...  "Upgrades" like to windows 10 even screw things up for people.

Dang electronics and computers will ALWAYS break down at some point.  I hate that.

boB

[Westbranch]

Hi boB, I run W7 (held onto XP as long as possible, so stable!)  and since early March I have randomly been getting  an 'not available' type of message when I start the LA, so I close it and reopen and it finds my 1 active Classic...  Have also checked for AIR updates and none exist... I have auto notifications set for program updates and manual install...

When or if it doesn't work after a restart I'll post a note here.

Due to a request from my SWMBO we are running Graham's android app all day and all she worries about is the  SoC %....
I do still use the LA for Tweaking the value settings, but the graphics are hard to see with these old eyes...

ciao....

[ClassicCrazy]

yeah I use the Local Status App all the time - but it certainly has it's issues. Always have to click through a few errors - all the time - forget what they are but  consistently every day  to get the data. Also no way to resize the window to full screen.  One only has to use Grahams Classic Android monitoring app to see what a fantastic display of data could be. We ask Graham to make some change and he seems to be able to do it fairly easily. The Local Status app just doesn't seem so flexible for the programmers to make changes. But it works and like I said I use it despite the  annoyances.

Larry

[boB]

Yes, computer annoyances abound.

I did try Graham's app once on my Android and it was REALLY nice !  He did a great job on that.

I think it only works on Android at the moment ?  Which is fine with me.

I have so many annoyances with Android too though although I'm sure that Graham's app will
continue to function.

Android wasn't what it was when Andrew made the LA I don't think ?

Thanks for the updates on things.  It could all be worse !

boB

[Vic]

Like everything,   while the LA  might not be perfect,   it IS a huge benefit to many of us with Classics   ...

But just to try to be clear,   that the Remote Battery Voltage Sense  (leads)   being discussed  in the original post  would allow the Classic to measure the battery voltage with separate wires that have essentially NO current flow in them.   Presently the Classic measures battery voltage at its output terminals.   So,   there is a voltage drop in these leads,   that depends upon the amount of current flowing in the Classic's output leads,   and in the circuit breaker for that connection.

The bottom line,  as things are now,   the Classic and the LA and/or the Android app  work exceedingly well.   Most of us always want MORE functions,   features and  capabilities.   Thanks boB and the entire MidNite crew for all of the amazingly terrific products,   that work SO well,   as they are.

FWIW,   Vic