BEP Battery Monitor Dead

[jamiepyoung]

The BEP Battery monitor has stopped working on our boat.

BEP have said they can't repair and the replacement model is pretty expensive.

I'm considering replacing it with the NASA Battery Monitor. If I do replace it, can I just reuse the existing shunt and wiring etc, or do I need to replace it all?

Failing that, anyone got a used BEP DC Monitor for sale??

 

[VicS]

Different max continous current ratings ITYWF therefore different shunts

Nasa BM1 and BM2 monitor one bank with voltage input from one other. BEP monitor has I believe capability of indicating volts on two others.

Have not found an instruction manual on line for the BEP monitor so do not know if the wiring is the same or not. The instructions are on line for the BM1 and BM2 so you can compare them with those for your BEP monitor

If you fit a BM1 or BM2 be sure to wire it exactly as described in the installation instructions

 

[David2452]

They are both 50mv out shunts so it may well be possible, if it is then so much the better as you can keep the 450a shunt instead of the 100a standard NASA one. The NASA has a seperate fused supply at the battery which may cause some problems. Should you need to use the small NASA 100a then be careful that the current 450a one is not cabled up so that it can get over what the NASA shunt can cope with. Personally I would just get a NASA with the larger shunt and replace the lot.

 

[VicS]

They are both 50mv out shunts so it may well be possible,

but BEP shunt is 50mv at 450 amps. BM1 and BM2 50 mV at 100 and 200 amps repectively.

 

[David2452]

but wont they be 50mV at different currents ?

Yes, that's why I said may and not will, frankly it really isn't worth bothering as I said in the last sentence as some fiddling may be required.

 

[jamiepyoung]

To be honest, I haven't figured out what shunts are all about yet, so I think I'll just change it all....

 

[David2452]

To be honest, I haven't figured out what shunts are all about yet, so I think I'll just change it all....

The sensible route, just make sure the NASA shunt can cope with the current that is currently going through the BEP higher capacity shunt otherwise you may have problems.

 

[jamiepyoung]

I'll get the BM2 with the larger shunt.

I don't think our power use is that large - 35ft sailing boat with large chartplotter, autopilot (broken!), lights and fridge. That's about it!

I assume that would be OK?

 

[VicS]

I'll get the BM2 with the larger shunt.

I don't think our power use is that large - 35ft sailing boat with large chartplotter, autopilot (broken!), lights and fridge. That's about it!

I assume that would be OK?

Highest current most probably will be the alternator output when charging a well discharged battery, unless you have bow thrusters electric winches etc, apart from the starter motor current which will also pass through the shunt if you use the domestic bank for emergency engine starts.

The shunt will stand a significant overload and the BM2 will measure it although not be able to display it. Nasa have not, AFAIK, indicated the max safe current that can be put through a BM2 200 amp shunt

 

[jamiepyoung]

So, I bought the NASA BM2. Just before fitting, I had one last look at the BEP Battery Monitor. It turns out it was disconnected at the battery.....

So, good news, the BEP Monitor now works.
Bad news, I have a spare NASA BM2, opened, but unused...

The BEP Monitor has been on for a few days now. The domestic battery is showing 80% capacity. It is on constant charge (through a Victron Phoenix charger connected to shore power). The battery I guess is a good few years old. Is this to be expected?

 

[galeus]

Don't you set the parameters of the BEP monitor when you first set it up and possibly now needs reviewing as batteries get older.