Recommend a Good Battery Monitor

[hzcruiser]

Originally Posted by Pelagic

My problem with ordering these Amp/volt displays sight unseen is that I have no idea how robust the connections are..especially for Amps!

This review shows the difference in quality

https://youtu.be/T4b1pg3nc50

In my book that guy in the video is just horrible... my comment to him is:

"Buying the cheapest device for the toy tractor, frying it, then complaining about it and comparing it to a more expensive device..."

[Pelagic]

While his "ugly american" bias certainly came thru....when an ampmeter starts to smoke within the parameters they are marketed for....my anger would come thru to.

That is why I'm looking for recommendations on units that are well made

[john61ct]

Or just buy a unit rated for 1000 amps if you know you need to accommodate 300. When you can buy a dozen cheap ones for the price if one good one, I just carry spares.

Otherwise, have you browsed marine supply catalogs?

Australian and European vendors are good, BEP / Marinco maybe

[missourisailor]

I've waited a bit to see if anyone would mention the Ah counter that I use. And since no one has yet, here is my favorite.



https://www.electriccarpartscompany....y-Pack-Monitor

It won't tell you SoC.
But it will tell you real time volts, amps, how much time has past since reset and how many total amps consumed in current time period.

Not fancy.
Not programmable.
Not WifI or Blue Tooth connectable.
No charting or graphing.

Just tells you how many amps in "X" time period.

[john61ct]

Have you had much dealings with the guy? He lists lots if interesting stuff via eBay, but some here have given mixed feedback.

[missourisailor]

Originally Posted by john61ct

Have you had much dealings with the guy? He lists lots if interesting stuff via eBay, but some here have given mixed feedback.

If you as talking to me, I have bought lots of stuff from Electric Car Co.
From their website. Don't know anything about their Ebay presence.

[wsmurdoch]

These things measure the refractive index of the battery acid in a flooded lead acid battery, if I read the information correctly. Since refractive index indicates sulfuric acid concentration (as does specific gravity), they should show state-of-charge. Perhaps they could be part of a "roll your own" state of charge meter.... I can't find a commercial product doing this.

digital-marketing-r

[john61ct]

Originally Posted by wsmurdoch

These things measure the refractive index of the battery acid in a flooded lead acid battery, if I read the information correctly. Since refractive index indicates sulfuric acid concentration (as does specific gravity), they should show state-of-charge. Perhaps they could be part of a "roll your own" state of charge meter.... I can't find a commercial product doing this.

digital-marketing-r

I'm calling scam, until I either test myself against the top SoC methodologies, or see such test reports by a source I trust.

Thanks much for bringing it to my attention.

[john61ct]

These only measure Specific gravity and temperature.

The actual SoC can only be loosely from this info, unless painstakingly calibrated under your specific battery and usage conditions.

And that relationship will change over time as the bank ages.

Useful only as a very involved science project, and even then only for FLA banks of course.

[missourisailor]

Originally Posted by wsmurdoch

These things measure the refractive index of the battery acid in a flooded lead acid battery, if I read the information correctly. Since refractive index indicates sulfuric acid concentration (as does specific gravity), they should show state-of-charge. Perhaps they could be part of a "roll your own" state of charge meter.... I can't find a commercial product doing this.

digital-marketing-r

I've seen things like this used on land based storage units.
But as John stated, only useful for flooded LA batteries.
Useless for AGM's, Gel's, Carbon Foam, LiFePo..etc.

[john61ct]

Originally Posted by john61ct

These only measure Specific gravity and temperature.

The actual SoC can only be loosely from this info, unless painstakingly calibrated under your specific battery and usage conditions.

Meant to say,

SoC can only be loosely guesstimated from SG, just like voltage correlation, resting period requirements are pretty impractical.

[CatNewBee]

look at the victron bmv 712 - really nice with bluetooth built in... I like it.

[CassidyNZ]

I know this is an old thread but it’s still relevant.

My Xantrex Link 10 has finally given up the ghost. It started some months ago when the one set of green LEDs went dead but the details were still available for both banks on the digital read-out. Yesterday, the digital read-out failed so all that’s left is one set of green LEDs. So reluctantly I have to call time on it.

So I’ve read through this thread and done a bit of research on the responses, discovered that some of the recommendations have been updated with new gear.

What I think I’ve also discovered is that if I use a Xantrex LinkPRO, the wiring looks pretty much exactly the same as what I already have so, if the assumption is correct, not only will that save a bit of money (+- $100) but also some work. So that makes it a lead contender.

This raises two questions. First, is my assumption regarding wiring correct? Second, does anyone have a compelling reason (preferably from personal experience) why this BM would be a bad choice?

What I will lose is the total monitoring on the “emergency” bank. The Link 10 sensed both banks with the same level of detail, the LinkPRO senses only voltage on the second bank. But that seems to be the standard feature on most later-model units. As someone said up-thread, that’s probably all that is needed.

If anyone can advise I would be well pleased. Since I am a retiree/pensioner, I’m not looking a “quality at any price” options so please don’t recommend top-of-the-market options, I can’t afford those.

[CatNewBee]

Originally Posted by CassidyNZ

I know this is an old thread but it’s still relevant.

My Xantrex Link 10 has finally given up the ghost. It started some months ago when the one set of green LEDs went dead but the details were still available for both banks on the digital read-out. Yesterday, the digital read-out failed so all that’s left is one set of green LEDs. So reluctantly I have to call time on it.

So I’ve read through this thread and done a bit of research on the responses, discovered that some of the recommendations have been updated with new gear.

What I think I’ve also discovered is that if I use a Xantrex LinkPRO, the wiring looks pretty much exactly the same as what I already have so, if the assumption is correct, not only will that save a bit of money (+- $100) but also some work. So that makes it a lead contender.

This raises two questions. First, is my assumption regarding wiring correct? Second, does anyone have a compelling reason (preferably from personal experience) why this BM would be a bad choice?

What I will lose is the total monitoring on the “emergency” bank. The Link 10 sensed both banks with the same level of detail, the LinkPRO senses only voltage on the second bank. But that seems to be the standard feature on most later-model units. As someone said up-thread, that’s probably all that is needed.

If anyone can advise I would be well pleased. Since I am a retiree/pensioner, I’m not looking a “quality at any price” options so please don’t recommend top-of-the-market options, I can’t afford those.

You may find a cheap used replacement unit on eBay, if you have been happy with it.

[Dockhead]

Originally Posted by CassidyNZ

I know this is an old thread but it’s still relevant.

My Xantrex Link 10 has finally given up the ghost. It started some months ago when the one set of green LEDs went dead but the details were still available for both banks on the digital read-out. Yesterday, the digital read-out failed so all that’s left is one set of green LEDs. So reluctantly I have to call time on it.

So I’ve read through this thread and done a bit of research on the responses, discovered that some of the recommendations have been updated with new gear.

What I think I’ve also discovered is that if I use a Xantrex LinkPRO, the wiring looks pretty much exactly the same as what I already have so, if the assumption is correct, not only will that save a bit of money (+- $100) but also some work. So that makes it a lead contender.

This raises two questions. First, is my assumption regarding wiring correct? Second, does anyone have a compelling reason (preferably from personal experience) why this BM would be a bad choice?

What I will lose is the total monitoring on the “emergency” bank. The Link 10 sensed both banks with the same level of detail, the LinkPRO senses only voltage on the second bank. But that seems to be the standard feature on most later-model units. As someone said up-thread, that’s probably all that is needed.

If anyone can advise I would be well pleased. Since I am a retiree/pensioner, I’m not looking a “quality at any price” options so please don’t recommend top-of-the-market options, I can’t afford those.

I don't find this type of battery monitor to be useful. If you read back through the thread you'll read a lot of explanations of the drawbacks of this approach to computing SOC. If you're on really tight budget, just read voltage. If you know what you're doing you will get better results from reading voltage, than from an amp-counting meter.


In my experience, much better results come from the old Merlin SmartGauge, which does not measure amps, but applies an algorithm to voltage. These are cheap and I think still available. The only drawback is that the SmartGauge is not accurate during the charging phase, which is not important to me, but could be important to someone using solar.



There is an updated version of the SmartGauge sold by Balmar, which I believe combines counting amps with the original voltage-based algorithm of the original SmartGauge. I haven't used it, so no direct information, but I would bet that this is going to be the best battery monitor you can buy. Albeit at a price.


On a tight budget, reading voltage is perfectly adequate in my experience. It depends on your exact use case and what charging sources you have, but for most of us, the really important thing to know is when we have to stop coasting on battery power and start up the generator. For me that happens when system voltage reaches 24.2v without any heavy consumers on. If that were a real open circuit voltage -- zero loads after hours of resting -- then that would be 50% SOC. When the system is in use, the voltage will be lower, for a given state of charge, depending on the loads. What that means is that the SOC will be something more than 50%, but depending on the size of the bank, so in my case, it's only a few percent, provided no really heavy loads (electric cooking etc.) have been used in the last hour.



Precision of greater than a few percent, and all the more when all error is on the conservative side, is just not needed for this application.


Likewise when charging, great precision is not needed. I try to keep charging until at least the charger's bulk phase is over, which gives 85% in my case. Every boat will differ depending on bank size and type, charger size, and charge profile, but I know (based on a lot of testing) that when the charging voltage reaches 30v during absorption charging, that I am at 97%, which I consider a full charge when I'm off grid.



So my advice on a budget would be the original SmartGauge (you can buy it here for £96 https://jgtech.com/Electrical/Batter...art-Gauge.html). Or you don't even have to spend that if you are willing to get to know your system well enough that you can manage it by reading voltage.