Cheap Electrical Monitoring

[Alan de Enfield]

At the price may be worth a 'dabble', but you do need 2 'screens' to monitor both charge & discharge.

 

Hmmmmmm……..

 

https://www.ebay.com/itm/DC-Panel-Meter-Voltage-Current-Power-Energy-Combo-Monitor-for-Car-Battery-Solar-/361349810094

 

or

 

https://www.ebay.co.uk/itm/LCD-DC-Combo-Meter-12V-24V-36V-48V-72V-Voltage-Current-Power-Car-Battery-Monitor/262869262834?_trkparms=aid%3D333200%26algo%3DCOMP.MBE%26ao%3D1%26asc%3D20140728113935%26meid%3D01ba005235414f91a0271961c46754a1%26pid%3D100148%26rk%3D1%26rkt%3D4%26sd%3D183261275390%26itm%3D262869262834&_trksid=p2059210.c100148.m2813

 

Edited October 6, 2018 by Alan de Enfield

[MoominPapa]

Have they never heard of negative numbers?

 

MP.

 

[Alan de Enfield]

1 minute ago, MoominPapa said:

Have they never heard of negative numbers?

 

MP.

 

Probably not - but at £9 each, ………………………………………….

[WotEver]

Yes, it’s typical of these cheap monitors that they can only read in one direction. I bought a couple a year or two ago to play with and did exactly what they show in the diagram, one monitor wired with the shunt ‘backwards’. They work well for what they are. Maximum 100A from this supplier. 

[jonesthenuke]

I have just bought one of the Hall effect sensor versions, these are bi-directional. A bit flimsy but seems to do what it is supposed to; but with no instructions I am still working out how to set all the functions. If anyone has instructions I would appreciate a copy?

 

https://www.ebay.co.uk/itm/Battery-Monitor-Digital-DC-90V-300A-Voltmeter-Ammeter-Power-Capacity-Time-Meter/292548114150?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

 

 

[WotEver]

14 minutes ago, jonesthenuke said:

If anyone has instructions I would appreciate a copy?

They’re all much the same in operation. PM me and I’ll send you some generic instructions. 

[Matt&Jo]

Any suggestions for a more reliable all in one unit around say £50 and under? 

[David Mack]

I have fitted an EBay meter which measures positive and negative currents. It seems to work fine, and the display unit has even survived a trip into the bilge water. Cost about £23  including postage from China. But I did replace the supplied USB cable which connects the shunt unit to the display with a longer one.

[Matt&Jo]

10 minutes ago, David Mack said:

I have fitted an EBay meter which measures positive and negative currents. It seems to work fine, and the display unit has even survived a trip into the bilge water. Cost about £23  including postage from China. But I did replace the supplied USB cable which connects the shunt unit to the display with a longer one.

Any links to these units? Id like to see voltage state of the batteries and current draw, 

[David Mack]

1 hour ago, Matt&Jo said:

Any links to these units? Id like to see voltage state of the batteries and current draw, 

 

Not exactly the item I bought but similar. This one comes with a temperature probe.

 

https://www.ebay.co.uk/itm/Wireless-Color-LCD-Screen-DC-0-400V-0-300A-Volt-Ammeter-Power-Meter-Watt-Tester-/302951447595?skus=Model:VAT-1300, 0-300A 0-100V&varId=601873972984

 

Edited January 13, 2019 by David Mack

[WotEver]

1 hour ago, David Mack said:

 

Not exactly the item I bought but similar. This one comes with a temperature probe.

 

https://www.ebay.co.uk/itm/Wireless-Color-LCD-Screen-DC-0-400V-0-300A-Volt-Ammeter-Power-Meter-Watt-Tester-/302951447595?skus=Model:VAT-1300, 0-300A 0-100V&varId=601873972984

 

Yeah, there are loads of these around. You just ignore the SoC readings because they bear no relation to reality but for the rest they’re pretty good. 

Edited January 13, 2019 by WotEver

[Wiltshire Moonraker]

I have fitted one of the Hall Effect meters, details & instructions here on Aliexpress I successfully extended the Hall Effect cables to reach the batteries.  

[WotEver]

12 minutes ago, Wiltshire Moonraker said:

I have fitted one of the Hall Effect meters, details & instructions here on Aliexpress I successfully extended the Hall Effect cables to reach the batteries.  

Yeah, loads of those available. £25 from eBay for instance: https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F223163181707

[TheBiscuits]

9 hours ago, Wiltshire Moonraker said:

I have fitted one of the Hall Effect meters

 

9 hours ago, WotEver said:

Yeah, loads of those available.

@WotEver (or anyone else who might know!)

 

What is the accuracy of these Hall Effect sensors compared to a wired shunt meter?  Close enough? Bob on?

 

I am idly wondering about the pros and cons of the (small) voltage drop on the extra two connections when adding a wired shunt versus the accuracy of an induction coil.

[Wiltshire Moonraker]

10 hours ago, WotEver said:

Yeah, loads of those available. £25 from eBay for instance: https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F223163181707

Just responding to @jonesthenuke's request  for instructions.

 

[WotEver]

2 hours ago, TheBiscuits said:

What is the accuracy of these Hall Effect sensors compared to a wired shunt meter?  Close enough? Bob on?

Close enough. As I said previously you can ignore any SoC figures because they don’t have any settings for charge efficiency, so they’re even worse than a BMV, but current in and out and voltage are all near enough for you to know what your battery system is doing with a bit of experience. 

[Steve_C]

Would the 100amp meters need to go through the suppliers 100amp shunt or could i run them through my existing 200amp shunt? I have found a supplier who does meters only.

[WotEver]

1 hour ago, Steve_C said:

Would the 100amp meters need to go through the suppliers 100amp shunt or could i run them through my existing 200amp shunt? I have found a supplier who does meters only.

You’d need to check the shunt specs. The meter docs will (should) tell you what shunt to get. 

 

50mV, 75mV, and 100mV are all common. 

[Steve_C]

26 minutes ago, WotEver said:

You’d need to check the shunt specs. The meter docs will (should) tell you what shunt to get. 

 

50mV, 75mV, and 100mV are all common. 

Back to the drawing board then. Meter = 75mV, my shunt 50mV.

[Dr Bob]

14 hours ago, TheBiscuits said:

Close enough? Bob on?

No. He's gone to bed.

[TheBiscuits]

2 hours ago, Dr Bob said:

No. He's gone to bed.

Ah. Bob off then