Victron BMV700 Help needed.

[davedindubai]

Here’s our setup:
Lagoon 450 with standard LA batteries, 1 year old. 840ah
1000w solar
Victron Quattro 5000/200/12v
Victron MPPT 150/85
Victron BMV700
Victron Color Control
2000a shunt wired correctly with all loads coming from this.

My problem since the full electrical install was done has been the SOC does not read correctly. I actually have been using the battery voltage for the last year to monitor the battery state of charge. I know this is incorrect but we’ve been too busy enjoying ourselves and travelling to stop and get it sorted. I’d like to get it sorted finally! Electricity is magic to me so I went for the most simple and easy to use system there is. Everything works great apart from the SOC.

I’ve asked local (Fort Lauderdale) Victron specialists to come out and have a look but nobody is very interested in a small job like this.

My BMV settings are:
1. Battery capacity. 0840
2. Charged voltage. 14.1
3. Tail current. 04.0
4. Charged detection time. 03
5. Peuhert. 1.25
6. Charge efficiency. 095%
7. Current threshold. 0.10
8. Time to go. 03
9. Zero current. Zero
65. Shunt current. 2000
66. Shunt voltage. 0050

These are mostly from the Victron website and recommendations for lead acid batts.

I have had the charged voltage set to 13.5 since the install but after reading yesterday, it says that as we have solar to set it higher, 0.3v below fully charged voltage of 14.4v. I’m assuming that I’ve in fact not been charging the batteries fully until now.

I plugged in shore power for 10hrs yesterday and did a full charge to float then unplugged for the night 9pm, so I was obviously expecting some drain over night. I did a ‘synchronise’ at 100%.
It’s 9am the next day and the BMV says:
Consumed Amp Hours: 24.9 (???????)(this cant be correct?)
Battery voltage: 13.0v
SOC: 98%. (?????) this can’t be correct, can it?

Over night we have 4 fans running, the inverter turned OFF, 1x stainless fridge, 1x stainless freezer, the toilet pump run a few times and some LED lights on for a short period.

We have had a few hours of bulk charging this morning from the solar and the MPPT 150/85 says:
Battery Vmin / Vmax / Imax = 12.31v / 13.38v / 35.5a

Also, the SOC on the Quattro says: 100% (?????)

Can anyone help please?

[john61ct]

IMO get a SmartGauge

But here are some valuable details

https://www.google.com/search?q=site...ery+monitor%22

[sailormed]

Are you sure you have the correct shunt value? Mine came supplied with a 500A/50mV shunt.

[sailorboy1]

Change the charge effiency to 85-89

Increase the absorption charge voltage to 14.6-14.8 (this alone is probably 5% soc error for you)


Make the time at charge, with the higher voltage, be a lot longer. In fact if the BMW never thinks you are at100% and resets there is nothing wrong with that.

[john61ct]

Will work with any shunt with the same mV rating.

I've seen big 1000A ones

[sailormed]

Yeah, the OP programmed a 2000A shunt. But the value of installed shunt must be programmed correctly, otherwise you get strange results.

[Stu Jackson]

It's not only your solar:


For everyone installing a battery monitor: The "Gotcha Algorithm" thread, a "MUST READ"

Link-series Charging Algorithms -- The "Gotcha" Factor!

DEFAULTS are factory settings that are made to be modified to suit your setup.

Also read this one:

Programming a Battery Monitor (by Maine Sail)

Keeping Your Battery Monitor More Accurate Photo Gallery by Compass Marine How To at pbase.com

and his newer 'site

https://marinehowto.com/programming-a-battery-monitor/

[john61ct]

Pretty sure all the old articles have been migrated by now?

But google prolly won't show the new URLs until the old ones have been gone a while

[travellerw]

Something is definately wrong. If you were indeed running a fridge, freezer and 2 fans then there is no way you only drew 25(ish) AH. It would be more like 90AH with what you listed.

1. As already suggested, I would ensure you have the right shunt value.

2. Ensure that the shunt is installed on the NEGATIVE side of the bus. IT MUST BE ON THE NEGATIVE RAIL.

3. Double, tripple and quadrouple check that %100 of the loads are running through the shunt (yes, both in and out need to go through the shunt).

4. Bump the "Charged Voltage" to the same value as the "Absorbtion Voltage" on your Victron MPPT 150/85 (can be found in the manual if you are using the rotary switch)

On our boat all the loads and charge sources goto 2 buss bars. One positive bar, and one negative bar. The negative buss bar is bolted directly to the shunt. A wire runs from the shunt to a DC breaker. Then a wire runs from the breaker to the battery terminal. There is absolutely nothing that goes directly to the batteries.

Finally, I recommend that you contact Victron directly. I have had really good results through the "Victron Live"
https://www.victronenergy.com/live/

However, sometimes live doesn't work as you need to send pictures. In that case, I would contact them directly and ask for technical support. My experience is they will give you an e-mail address of an actual engineer to help you out.

https://www.victronenergy.com/contact

[BruceS]

Yep! Negative side for the Victron shunt! All Neg leads connected thru that shunt.