bogomips Posted September 29, 2021 Share Posted September 29, 2021 I have installed a Nasa Marine Clipper BM2 battery monitor. All is well and it shows an accurate battery level and the amps being consumed/charged. However, the charge/discharge notice is the wrong way around. So when I put the lights on it says charge and when the solar panels working it says discharge. The obvious is that the shunt is wired the wrong way around but this is all correct and all negative wires go to the shunt and then onto the battery so I am puzzled. Attached is a basic diagram showing my electric set up if anyone can see anything that maybe wrong or worth checking? Link to comment Share on other sites More sharing options...
Tracker Posted September 29, 2021 Share Posted September 29, 2021 Surely the best people to answer this would be the manufacturers or their local agents? Link to comment Share on other sites More sharing options...
bogomips Posted September 29, 2021 Author Share Posted September 29, 2021 You would think so, I emailed them and only get told that my wiring is wrong. Thankfully the monitor is accurate and I am getting used to it. Link to comment Share on other sites More sharing options...
Alanb Posted September 29, 2021 Share Posted September 29, 2021 Hi, You could just swap the yellow and white connecting wires. Alan Link to comment Share on other sites More sharing options...
ian81 Posted September 30, 2021 Share Posted September 30, 2021 We have a BM!1 that works ok. The black and white go to the battery negative end of the shunt and to their respective terminals on the monitor. The yellow is on the other side of the shunt. Can you confirm that the wires are correctly connected to the monitor? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 30, 2021 Share Posted September 30, 2021 This 2015 YBW forum discussed a similar ‘backwards readout’ issue https://forums.ybw.com/index.php?threads/nasa-bm2-problem.438281/ BM2 installation instructions here https://www.nasamarine.com/wp-content/uploads/2015/12/Clipper-BM1BM2.pdf This 2018 O&ALive forum thread mentioned the NASA monitors https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Nasa-Battery-Monitor/48563/ Link to comment Share on other sites More sharing options...
Alanb Posted September 30, 2021 Share Posted September 30, 2021 Alanb - 2021-09-29 10:55 PM Hi, You could just swap the yellow and white connecting wires. Alan It was past my retiring time when I made the above post. Perhaps to be more precise, I should have added the words "at one end only" In my opinion there are three possible causes to the problem. 1. There is an error in the installation, but the OP says that this has been thoroughly checked. 2. There is a manufacturing error in that the yellow and white wire connections have been reversed inside the monitor. The manufacturers will naturally discount this. I advise against breaking any seals to confirm this possibility. 3. There is an alternative reversal inside the monitor, but it is hard to visualise how this could occur. My suggestion to reverse the connections of the yellow and white wires, which could be done at the connector block, will provide a quick fix. Alan Link to comment Share on other sites More sharing options...
bogomips Posted September 30, 2021 Author Share Posted September 30, 2021 I will try a bit of wire swapping, this will provide a quick and easy test. Failing all else the monitor otherwise is accurate and I will live with its quirks. Link to comment Share on other sites More sharing options...
bogomips Posted October 3, 2021 Author Share Posted October 3, 2021 Swapping the yellow and white wires around on the connector block resolved the problem, seems like a simple change but clearly the supplied wiring diagram or the unit is incorrect. Not to worry, the battery monitor now works fully. Link to comment Share on other sites More sharing options...
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