Cheap Little Battery MONITOR - But How Good Is it ?

Nabsim

Full Member
Yes that's true, I looked at data sheets for the Bosch Batteries and the AGM to see if they would be compatible together and it looks to me like they will be. See this post for more info: https://motorhomebuilder.com/threads/mixing-agm-and-wet-cell-battery-types.66890/ and you commented on that one already. :cool:
I didnt mean any incompatibility by using the manufacturers figures, more use the chart to see exactly what a certain voltage indicates. In the screen shot you posted earlier it showed 12.2V as 50% whereas they say the PowerFrame is only 25%SOC at 12.2V with 50% being 12.5V. They will take charge quicker than normal LA and their fully charged state is slightly under 13V so I would say a fair match for your AGM.

I am stopping now cos I am confusing myself lol
 

MarkJ

Full Member
Not sure how new this is, but I only saw the announcement today.


Does away with the need for a BMV? And so, I presume, can be a cheaper but full functionality solution?
 

wildebus

Full Member
Not sure how new this is, but I only saw the announcement today.


Does away with the need for a BMV? And so, I presume, can be a cheaper but full functionality solution?
It is very new and only revealed in the last month.
That is essentially a headless BMV. It will be cheaper, but won't offer the same functionality.
1) no physical display. That is an obvious one, but it does means it is impossible to check info without a smartphone
2) no relay functionality. Probably won't matter to most, but it can be a useful feature. I actually use the relay on the BMV-712 to control a water heater, for example.

Personally, I think for a campervan/Motorhome, choosing the Smart Shunt over the BMV-712 will save you money but the loss of functionality, especially 1) is too much of a disadvantage to make it a worthwhile alternative.
I think the SmartShunt is designed for remote monitoring setups where the manager of those locations connects via the Victron Remote Management console to monitor the system and in those cases, a physical display would be little value.
 
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Nabsim

Full Member
I don’t tend to use the physical monitor much myself, nearly always use phone or tablet. I think if I were to be buying now I would probably be happy with just the smart shunt. You do still have the head unit though if Bluetooth failed I suppose
 

MarkJ

Full Member
That is an obvious one, but it does means it is impossible to check info without a smartphone
I have this crazy idea to use an old phone as a built in control panel. You know they sometimes slow down as they age? Well, we have several of those in the drawer and I’m thinking they’ll be man enough to run Connect.
 

Nabsim

Full Member
I have this crazy idea to use an old phone as a built in control panel. You know they sometimes slow down as they age? Well, we have several of those in the drawer and I’m thinking they’ll be man enough to run Connect.
Just make sure you can download the Victron Connect app on whatever phone it is. Once they are no longer supported you can struggle with Apple devices on some things, not sure about Android.
Just an idea, what do you use for sat Nav? If it’s Android based you may have the option to run the app on that, think I could with mine (Aguri 720)
 

wildebus

Full Member
I don’t tend to use the physical monitor much myself, nearly always use phone or tablet. I think if I were to be buying now I would probably be happy with just the smart shunt. You do still have the head unit though if Bluetooth failed I suppose
I don't tend to use the display OR the phone, but the PC via the VRM. However, got data issues at the moment (O2 mast down for weeks!) and the van has not been talking to the internet for 13 days now. So it is easier for me to just nip over and look at the display to check the battery SOC rather than running the app, connecting to the BMV, etc (battery dropped from 87% to 67% in 12 days with fridge running and no real solar. Not too bad :) ). Having that quick visual check for me is worth the extra maybe £50, especially when spread over the years (extra £1 a month or less?)


In terms of in-van monitoring, I can also use my in-dash 'infotainment' system ...

IMG_20190914_183818
by David, on Flickr
 

Nabsim

Full Member
I sit on the sofa opposite the head unit but rather than get up and press a button for the backlight I use the app lol

horses for courses and it’s good to have more choices 👍
 

mistericeman

Full Member
Brilliant. Thanks. For once Mr Google let me down.
In fairness supplies look limited atm....
There were a couple of folks selling on ebay that, are now showing out of stock....
Ive definitely got one on my shopping list for the Moho.
 

MarkJ

Full Member
Just noticed that Jacksons Leisure say:

"Expected release date is 31st Aug 2020"

And no doubt that'll get corona-ed too.
 

RAW

Full Member
I spoke to Big Clive about this and he looked at the thread, this is the conversation:
Big Clive on Youtube here:- https://www.youtube.com/channel/UCtM5z2gkrGRuWd0JQMx76qA
Big Clive Live (a seperate channel) here:- https://www.youtube.com/channel/UClIzWmVzGPm2zhNT2XZ-Rkw
Big Clive on Patreon (pre release videos and other benefits) here:- https://www.patreon.com/bigclive/


  1. Robert

    1w
    Good Morning Clive :) Hope you are well Robert here in what was Flooded again Hebden Bridge (maybe wetter than the IoM !!) I have created this post about a cheap battery monitor I purchased on BangGood, I wonder if you could test it at some point. Product details are in the post motorhomebuilder.com/threads/cheap-little-battery-monitor-but-how-good-is-it.66896 Many thanks Robert

  2. Big Clive

    6d
    Hi Robert. I think I've got a similar device for solar power batteries. It uses a simple voltage range.

  3. Robert

    6d
    Hi Clive, any previous YT video's of you disassembling it and tearing down. If you read the thread on Motorhome Builder that i started then you can see that it is a bit of a mystery as to how the device can determine 12V battery capacity especially when there are multiple capacities and types in the 12V arena. So it is it actually being clever and have some sort of intelligent circuitry in it or is it just a simple voltmeter as David (wildebus) states and you also said above, so really the capacity the device shows is inaccurate? David is an electrician and similar age to us I think. Hope all is well with you Robert

  4. Robert

    6d
    Oh and thanks for getting back to me...

  5. Big Clive

    2d
    I think the capacity thing is just giving an indication of the remaining charge capacity based on a simple voltage level indicating the percentage left. You'd have to gauge it based on the stated battery size and allow for loss of capacity with time.
 

RAW

Full Member
So back to this thread on the Battery Monitor, I have created this thread on a cheap 50W Semi Flexible Solar Panel I am testing

Whilst testing I looked at Voltage on three devices, the Victron Battery Monitor directly connected, the cheap Battery Monitor and the pretty awful PWM controller delivered with the panel, for more on PWM vs MPPT then look at @wildebus Post testing those devices here:

This is the result of looking at Voltage
Screenshot_20200316-135805.jpgCheapVM_Voltage.jpgCC_Voltage.jpg

As you can see both the Victron and the Cheap Battery monitor are seeing the battery as having 12.8Volt whereas the Cheap PWM that was delivered with the Solar panel is showing a 0.2V drop.
Pretty sure this Solar Controller is working but very poorly. Anyway it's no real bother as I consider it a throw in with the price I paid for the 50Watt Panel.
 

wildebus

Full Member
I'll be trying to do some "real-world" testing with actual Solar Panels and the various controllers (including the model you have there) to see how they compare (won't have a lot else to do :( )
As an aside, I usually park on edge of my drive, reversed in. Currently driven in head-first at a bit of an angle. That maybe just 2 foot difference is actually giving me much better harvesting so a very small difference can be very important.
Voltmeters are a tricky thing. 0.2V reading difference at 12.8V is actually under a 2% variance which is very small in reality but with a 12V leisure system, we are only interested in such a small range of numbers, we need a quality calibrated device to give an accurate figure (so 2% variance needs to be more like 0.2%!)
 

RAW

Full Member
I'll be trying to do some "real-world" testing with actual Solar Panels and the various controllers (including the model you have there) to see how they compare
Sounds like a Plan, I am not that impressed by that particular PWM - the one I got from you seemed far better build quality. I might take it apart in Big Clive style but not a fan of my own voice played back to me.....
 
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