Battery monitors ?

[Ka_sea_ta]

I disagree, the Magnum BMK has a sophisticated way of measuring SOC. As my bank aged, it recalibrated. It takes all outflow into account, and it is not a simple amps-in amps-out algorithm by the way. Whenever I used other methods to double check it, like a good old hydrometer or a measured time draw down, it was always spot on.

We used the hell out out of our inverter bank as we spent months at a time living on a mooring or on the hook, so all this was very important to me. It was also nice to know where we were in the charge cycle and the attendant amp draw. Another nice feature (with additional expenditure to be sure) is that we had the option in the right circumstances, to have the generator turn on automatically at prescribed state of charge. And if you liked turned off likewise.

Anyway, I know the unit you decided on is a good piece of kit, but personally I never saw a reason to install it in our system.

I just took this photo as You can see the SG shows a discharge of 5 amps while the Magnum remote shows 0 amps.... I assume the majority of this amp draw is parasitic loss in the inverter itself. there are a couple of 3 watt leds being used but that is it as far as 12 v loads go when I took this Pict.


This parasitic loss goes up substantially when it's inverting.... The SG takes these losses in to account when determining SOC and time left The magnum remote has a lot of good information just not as complete as the SG.

 

[FlyWright]

RC is always knowledgable and helpful.
I've donated and purchased stuff from him as a token appreciation for his willingness to help educate others.

Rodd Collins was a great help this summer when I fried my Balmar 621 alternator. His familiarity with the alternator and regulator allowed a fast and accurate diagnosis that was verified during rebuild locally. He could have sold me a replacement for similar $$ but steered me toward a local rebuild with Balmar parts as a better alternative for my needs.

He also came to my rescue when I had a question about the alternator temp sensor mount on the ground lug and had Belt Manager setting tips when reprogramming the MC-614 regulator.

My hat's off to Rod Collins of Compass Marine. I hope everyone here patronizes men like this who go to great lengths to share their knowledge and help others. If I was buying a Balmar SG-200 today, tomorrow or a year from now, I'd but it from Compass Marine.

Here's a great video on the SG-200.

Rodd Collins with Compass Marine Reviews SG200 Testing

 

[sunchaser]

I just took this photo as You can see the SG shows a discharge of 5 amps while the Magnum remote shows 0 amps.... I assume the majority of this amp draw is parasitic loss in the inverter itself. there are a couple of 3 watt leds being used but that is it as far as 12 v loads go when I took this Pict.


This parasitic loss goes up substantially when it's inverting.... The SG takes these losses in to account when determining SOC and time left The magnum remote has a lot of good information just not as complete as the SG.

Turn your remote to port 3 and you'll get the amps out. Have you compared with charger off? I just did mine and can see port 1 at 0 amps and 3 at 2 amps. Also, are the two gauges measuring at the same point?

To the OP, even though my two Magnum BM Ks are decent enough, if to do over I'd likely go Victron. In either case match up with same brand inverter charger.

 

[meridian]

I use the Victron with Bluetooth interface. I can walk around to any 12v device and see the amp draw by turning them on and off.

 

[Moonfish]

I just took this photo as You can see the SG shows a discharge of 5 amps while the Magnum remote shows 0 amps.... I assume the majority of this amp draw is parasitic loss in the inverter itself. there are a couple of 3 watt leds being used but that is it as far as 12 v loads go when I took this Pict.


This parasitic loss goes up substantially when it's inverting.... The SG takes these losses in to account when determining SOC and time left The magnum remote has a lot of good information just not as complete as the SG.

Do you have the Magnum BMK battery monitor in addition to the Magnum remote? We currently only have the remote and are going to add the BMK monitor for more accurate information.

 

[dhays]

I use the Victron with Bluetooth interface. I can walk around to any 12v device and see the amp draw by turning them on and off.

That would be handy.

 

[dhays]

I disagree, the Magnum BMK has a sophisticated way of measuring SOC. As my bank aged, it recalibrated. It takes all outflow into account, and it is not a simple amps-in amps-out algorithm by the way. Whenever I used other methods to double check it, like a good old hydrometer or a measured time draw down, it was always spot on.

I’m not sure I understand. Unless I’m mistaken, the Magnum BMK is still dependent on the Ah capacity of the battery bank that you enter in the setup menu. It will calculate a charge efficiency over time but can’t determine total bank capacity. SOC is based on total Ah in the bank and how many Ah have been removed and added.

IIRC, the BMK uses three criterion to determine 100% SOC. Charge current less than 2% of bank capacity, stable voltage, and the amount of amps returned to the bank is within 1% of the amps that were removed since the last 100% SOC. Once those three criterion have been met, the BMK considers the battery bank to be 100%.

I think that the 100% point is probably pretty accurate. However any other percentage is based on the amps removed compared to the total Ah available. If the total bank size is off, then the SOC will be off. Bank capacity for most of us is simply a WAG, and that that is what we input into the Magnum system during setup.

Maybe the BMK is doing something entirely different but I certainly don’t know what that is.

 

[gsholz]

https://www.amazon.com/BUNKER-INDUST-Bluetooth-Wireless-Automotive/dp/B07GP1RXYZ/ref=sr_1_31?keywords=battery+monitor&qid=1568651120&sr=8-31

I wanted to know our service battery status from anywhere on the boat (e.g. stateroom, fly bridge etc) without having to run wires. I found a Bluetooth enabled battery monitor that displays via an app on your phone. Just measures voltage but keeps a log. Very simple to install. it is only $30, works great for us.

 

[Ka_sea_ta]

Do you have the Magnum BMK battery monitor in addition to the Magnum remote? We currently only have the remote and are going to add the BMK monitor for more accurate information.

No just the remote for the Magnum.... I have no issues with the smart gauge. The original post was just a off handed comment on the long learning period for the SG200. Because the shunts for the SG and the Magnum are in series my second comment was directed at the differences in the current displayed which I assume is parasitic loss in the I/C which is ignored by the Magnum but picked up by the SG. The other option is that the current measurement on one of the shunts is bad.... I have seen as much as a 30% delta between the 2 displays...

 

[Jeff F]

I have the Balmar SG200 on my sailboat. It worked flawlessly until I got rid of the dedicated starting battery for my little Yanmar 1gm10 in favour of a beefed up single bank for house and starting. Then the SoC numbers started getting a bit wonky.

To be fair, Balmar does specify that the shunt is for house loads only. In that capacity the unit worked very well for me. I may put in a very small starting battery just to get back to accurate monitoring of the house bank.