Merlin Battery monitor

[eddystone]

Chose this over types that require all battery connections to be relocated to a bus bar. Having connected it up and set battery type I get Er 04 message. This says battery voltage outside safe limits either above 17V or below 9V. As I thought I had selected wrong type of battery I reset to factory defaults and put in correct battery type. Still get same error message. When I press battery 2, which is the engine battery, it shows 12.89 under voltage but 45% charged. Release the button for battery 2 and it reverts to ER04, but also that voltage too low. I tested the battery voltage with a multimeter and the engine battery was 12.9 ish and the leisure bank (same type of battery) shows just under 12.8V. I have one positive wire (1mm which is nearest to AWG 18) connected to positive terminal of one of the leisure batteries via a fuse and one ditto to the engine battery and and one ground wire to one of the negative terminals on the leisure bank. The negative terminals of the engine and leisure bank are connected.

Any thoughts on what could be the problem?

 

[Mistroma]

I've had a Smartgauge for years and am puzzled by the fact you say the engine battery is 45% charged. Smartgauge only monitors SOC on one battery and voltage on two. I don't know if the design has changed but I only see either voltage or SOC, not both. Selecting battery 2 gives voltage on battery 2 with no way to see SOC.

Perhaps the 45% refers to the domestic bank with voltage outside normal range and E04 showing. That might make some sense and perhaps a very dodgy connection somewhere.

I assume you followed instructions to the letter regarding wiring directly to the battery and order of connecting things together. I seem to remember mine defaulting to 75% or so when first connected but I adjusted it to read 100% because I knew they were fully charged. I could have waited for a few cycles and it would have corrected itself without adjustment.

Mine is slightly more complex as I also have a Smartbank system plus mods. for variable ventilation via Smartgauge. I think a Smartgauge by itself is pretty simple to connect (direct to battery, 3A fuse on +ve side, don't short things).

Have you checked the battery type (doubt it would produce symptoms you mention) and factory reset (always worth a try)?

I would be tempted to connect it to a single standalone battery to see if it shows the correct voltage and starts at 75% charge. It would confirm that the basics are working as expected. The instructions just indicate connection of B1 to the +ve post and Gnd to the -ve post. You should not connect B1 to the engine battery and it will not monitor SOC on that battery.

I know that both engine and domestic must share a common -ve. Perhaps the fault lies in that area as I imagine that would cause issues with measurement and voltage differential.


Sorry not to be much help.

 

[PaulRainbow]

Sounds like it's set for 24V.

 

[halcyon]

Chose this over types that require all battery connections to be relocated to a bus bar. Having connected it up and set battery type I get Er 04 message. This says battery voltage outside safe limits either above 17V or below 9V. As I thought I had selected wrong type of battery I reset to factory defaults and put in correct battery type. Still get same error message. When I press battery 2, which is the engine battery, it shows 12.89 under voltage but 45% charged. Release the button for battery 2 and it reverts to ER04, but also that voltage too low. I tested the battery voltage with a multimeter and the engine battery was 12.9 ish and the leisure bank (same type of battery) shows just under 12.8V. I have one positive wire (1mm which is nearest to AWG 18) connected to positive terminal of one of the leisure batteries via a fuse and one ditto to the engine battery and and one ground wire to one of the negative terminals on the leisure bank. The negative terminals of the engine and leisure bank are connected.

Any thoughts on what could be the problem?

Check voltage on input terminal block clamp screw on Merlin gauge, i.e. service and engine voltage.

Brian

 

[eddystone]

Sorry didn't realise that only shows voltage, not status, for battery 2 (engine); therefore its its probably in the right ballpark when I press the B2 button. According to the instructions it automatically detects 12V or 24V, there isn't a user setting for that. Thought I was quite careful to get B1 and B2 positive wires to correct terminals, but if I had inadvertently swapped them could that explain it?