It's cheaper but is it as good as a Victron?

[acropolis22]

This baby, <Broken link removed> is significantly cheaper than any of the the Victrons. Does anyone have any experience of these?

 

[Lenny HB]

Just how technical do I need to be? I have an IT background, and can follow instructions, but know very little about electrics.

Just how technical do I need to be? I have an IT background, and can follow instructions, but know very little about electrics.

Just need to know a bit about your batteries to set it up you can get all the info on this forum, and to keep it accurate you need to adjust the battery capacity annually to take account of natural degradation.

Here's my settings for my 3 x 78ah Gels, took a week or two playing about to get it accurate .

 

[acropolis22]

I am no electrical genius but have managed just fine. The instructions give the different values needed for LiFePO4 and fortunately there are other Funsters who can answer any difficult questions.

Just looked at the manual, which is mostly over my head. I assume most of the adjustments can be left at default?

 

[acropolis22]

Just need to know a bit about your batteries to set it up you can get all the info on this forum, and to keep it accurate you need to adjust the battery capacity annually to take account of natural degradation.

Here's my settings for my 3 x 78ah Gels, took a week or two playing about to get it accurate .

Thanks Lenny HB that's useful stuff. Your last comment is interesting. How does one know when it is accurate? (How basic a question is that?)

 

[Gromett]

I think the impossible 104% is because it makes no allowance for battery efficiency. It simply can’t cope with having to put more amps back into the battery than went out. If it starts at 104% does this mean the subsequent readings are also all 4% out? Does the impossible 4% accumulate over time and render the the readings even more inaccurate? Without an answer to these questions I put the NASA into the “chocolate teapot” category and bought the Victron BM.

I think it is because of Peukert's calculations not being accurate and the quick cheat is to allow the coulomb count to get to 104%. Basically it takes more to charge the battery than you get out.

If the ratio is not set correctly in the software it will either undershoot or overshoot. To ensure that no long term drift occurs I suspect they under-estimate to ensure you never have a lower battery state than the reading shows. But then the hacky fix at the top end is required.
I have no problems with this quick and easy method of battery monitoring. What I objected to mainly was that once the battery was full I had no way of telling the BM-1 this and for it to return to 100% reading. The victron is more accurate to start with, but ALSO has a two button shortcut to tell it that it the battery is at 100% and to start the coulomb counting process from scratch.

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[Pausim]

Just looked at the manual, which is mostly over my head. I assume most of the adjustments can be left at default?

I believe the defaults are for standard lead acid. Just need to set the AH.

 

[Lenny HB]

Thanks Lenny HB that's useful stuff. Your last comment is interesting. How does one know when it is accurate? (How basic a question is that?)

By discharging the battery and checking the current used against the full capacity and comparing to the percentage reading.

 

[acropolis22]

Thanks to all for your comments. Incredibly helpful. Have just ordered the Victron BMV-712 which I found at £155, a good discount I think and less than some places are selling the 702. Hoping I can find my way through the setup.

 

[WildBunch]

I had a NASA speed & depth log on my Pedro boat. It was fine until the display unit became faulty. It was working but the display was going blank intermittently. But to be fair it must have been 15 years old. I am not sure if that really helps acropolis22

 

[autorouter]

The NASA BM-1 and the Victron BMV/Smartshunt are constructed slightly differently.

The BM-1 has a shunt, which is a small but accurate resistor that all the amps is channelled through. There are two thin voltage sensing wires, that connect all the way to the display unit, which also contains the voltage measuring chip.

The Victron devices also have a shunt, and very short voltage sensing wires, but the voltage measurement chip is on a small PCB fixed to the shunt. The results are sent to the display by a data cable, or transmitted by Bluetooth in the Smartshunt. The Victron shunt needs a small positive feed from the battery to power the measurement chip, but the BM-1 doesn't need that.

Both methods work fine technically.

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[acropolis22]

By discharging the battery and checking the current used against the full capacity and comparing to the percentage reading.

You may have picked up from one of my other threads that I can't identify my battery so I don't know whether it is Type 1 or Type 2 AGM. I may well end up replacing the battery, but for the time being, will the volts and amps readings from a BMV 712 be accurate enough to tell me whether the battery is holding charge or not without me having done any clever setting up like wot you did.....

 

[Lenny HB]

You may have picked up from one of my other threads that I can't identify my battery so I don't know whether it is Type 1 or Type 2 AGM. I may well end up replacing the battery, but for the time being, will the volts and amps readings from a BMV 712 be accurate enough to tell me whether the battery is holding charge or not without me having done any clever setting up like wot you did.....

The volts & amps will be accurate the percentage takes a bit of tweaking to get it right.
When setting the battery capacity allow for the age of battery, 2.5% loss per year.

 

[tanex]

i have a victron 2000 watt inverter in my Hymer It is happy to work with Fangpusun

https://www.fangpusun.com/mppt-solar-charge-controller

All are made in China and are blue.

 

[msyd]

Nobody's mentioned the Votronic (German built) battery monitor which has a 400A shunt option. I've had three now (on different vans!) and they've done everything I needed.

 

[Clive Mott]

I would not put Victron on a pedestal, especially when it comes to LiFeP04 batteries,

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[Peppadog]

I hope the Victron unit proves good. It should do.
Roadpro are only an agent for Nasa. Who sell primarily to the boat chandlers. Nearly every boat owner that has ‘house’ (leisure) batteries installed will have, or had a BM1 onboard. I have had two boats with them fitted. They work as well as any shunt based monitor I think. But they do need resetting as the batteries slowly decline.
I fitted one of these to my current boat. It shows only the voltage and percentage of charge left in the house batteries, and voltage only of the starter battery. It does not use a shunt.
Link Removed
In my Hymer, I rely on the panel information. Its good enough. When its not, I’ll fit a Merlin smart guage.