Argus Battery Bug - opinions

[javaprog]

I can't believe no one on these forums has asked about these battery bugs. If they have I can't find the post. Is there an archive search? :neutral:

Anyway, this thing looks like it does a 1 second load test once a minute to monitor a battery. It doesn't need a shunt so it's not so expensive.

http://www.argusanalyzers.com/index.php?id=31

Has anyone tried one of these?

 

[Stu Jackson]

I've briefly reviewed their literature.

State of health information is simply not available from available common monitoring methods such as voltmeters or current counting meters.

That's simply not true. We have had detailed discussions here about the algorithms of the Link series battery monitors. Battery health has a lot to do with the healthy complete recharging of batteries. This unit seems to be designed to tell you when it's failing and little to tell you what condition they're in as state of charge.and amp hours (really KwHr). After all these years, one would think that a digital readout could provide actual numbers and not another analog "meter."

The BB-DCM must be installed directly to the battery terminals, and failure to do so will cause the BB-DCM to operate incorrectly. If the battery is located in an inconvenient location, audible alarms will inform you that further investigation is necessary.

The location requirement for this unit makes it highly impractical for sailboats. We have what I consider one of the best battery box locations on ANY sailboat I've EVER seen, and it's right in the saloon, forward of the galley. The C30s and C36s do, too. But I'd much rather look at my Link 2000 instrument right there in my nav station than have to pick up the saloon cushion and the battery box cover to look at this little puppy.

Since "it doesn't need a shunt" it is NOT measuring amperage draw or input, and thus is worthless in terms of battery charge state or condition in terms of what I've used (say, daily) or what I've replenished (i.e., alternator or other charging source). It also doesn't tell me what my instantaneous or averaged period amp draw is, so I can't tell if I inadvertently left something on.

If their claims of these issues are correct, I would consider one only in combination with the coulomb reading meters (i.e., Links-series) they so blithely trash in their website:

• How full is the battery?
• How much energy is available now?
• How much energy could the battery hold now if fully charged?
• How much storage capability has been lost since the battery was new?
• How much battery life remains?
• When to recharge the battery?
• When to replace the battery?

They claim the Links need to be reset and don't work in the range most of us use our battery banks. Hogwash! We've figured out the algorithms and Rich Stidger has penned the quintessential "Gothca" explanation for how to adjust Links properly so they work. See: http://c34.org/bbs/index.php/topic,4922.0.html (Thanks again, Rich!) These instructions work for Links 10, 20, 1000, 2000 and the Link Lites and Pros.

I've learned a lot about the proper care and feeding of batteries from reading, experience, this website and others. This simple little thingie doesn't answer half of the questions skippers need to know about their electrical systems, and could create more indifference to battery care on the part of un-knowledgeable skippers who would use and depend on it.

It does look like a handy tool for fleet managers who care little about daily battery use and recharge levels, and who could use it to schedule battery replacement programs and identify prematurely bad batteries

Thanks for bringing it up. How'd you find it?

 

[tsmwebb]

I've briefly reviewed their literature.

State of health information is simply not available from available common monitoring methods such as voltmeters or current counting meters.

That's simply not true....

Actually it is generally true. This thing may well be snake oil. Their system is far from completely described on their web site. But, they're not too far out in their critique of existing "energy" monitoring methods. http://www.argusanalyzers.com/battery-monitors/technology/competing-technologies-dcm.html And, the theory that they propose for their system is plausible. The devil is in the details, though, and they don't address them at all.

And, FWIW, it has a digital display as well as several analogue ones. So "after all these years" they are providing "actual" numbers.

--Tom.

 

[Maine Sail]

Stu made some good..

Stu made some good points. Here are a few more issues I can see with it.

They make three models. Two units that will max out at a 90 amp hour bank and one that will go only to a 300ah bank.

Seeing as most sailors have a bank larger than 90ah we would require at least the 300ah model which costs $169.99.

For an extra $25.00 you can have a true battery monitor that tells you much, much more information and will do a 1000+ah bank with no problem.

The Victon BMV-600 is $195.50 (LINK)at Jamestown Distributors and is one heck of a great little battery monitor that is very easy to hook up.

 

[tsmwebb]

Stu made some good points. Here are a few more issues I can see with it.

...
For an extra $25.00 you can have a true battery monitor that tells you much, much more information and will do a 1000+ah bank with no problem.
...

Good points.

But, as Stu's link points out, you have to tell the battery monitor how big your bank is and then it has to reset itself to that level when certain trip points are met. The monitor itself can not determine the size of your bank, nor can it tell when your bank is failing. Indeed, as your bank looses capacity the monitor settings should be changed. The user has to make these changes, they can't be determined simply by counting amps. Moreover, counting amps is hard. The reason batteries have different ratings for differing draws is that the efficiency of the battery changes significantly and exponentially with rate of charge. So 1 amp x 20 hours <> 20 amps x 1 hour. The exponential relationship between these two varies with age, battery construction, temperature at least. It is important to understand that amp counters don't measure the battery at all. Not ever. They look at a derivative function and try to work backwards from there. This is a difficult task and the very need to have built in reset functions proves that in practice it is not exact.

In theory, a load tester that can integrate tests over time could overcome some of these problems. But, I can imagine many practical problems implementing such a system.

--Tom.

 

[javaprog]

Stu made some good points. Here are a few more issues I can see with it.

They make three models. Two units that will max out at a 90 amp hour bank and one that will go only to a 300ah bank.

Seeing as most sailors have a bank larger than 90ah we would require at least the 300ah model which costs $169.99.

For an extra $25.00 you can have a true battery monitor that tells you much, much more information and will do a 1000+ah bank with no problem.

The Victon BMV-600 is $195.50 (LINK)at Jamestown Distributors and is one heck of a great little battery monitor that is very easy to hook up.

The 3 models are 90, 150 and 300Ah
The 150Ah model sells for $99
I wonder what percent of boaters have more that 150Ah in their house bank.

If it does what it says it does it is a "true battery monitor" in the sence that it will tell you your state-of-charge while under load. Additionally it will estimate battery's state of health. So it's both a short term and long term "monitor."

The location requirement for this unit makes it highly impractical for sailboats.

Agreed.

I wonder if it has to lie on top of the battery to sense the temperature or something.

Since "it doesn't need a shunt" it is NOT measuring amperage draw or input, and thus is worthless in terms of battery charge state or condition in terms of what I've used (say, daily) or what I've replenished (i.e., alternator or other charging source). It also doesn't tell me what my instantaneous or averaged period amp draw is, so I can't tell if I inadvertently left something on.

I didn't read it that way. The way I read it it can absolutly tell you your state-of-charge minute by minute.

You are correct about the instantanious draw however; and while that is nice I think most sailors could get along without it. I'm not too worried about leaving something on. I guess I could hit the DC main to be sure.

I wonder if it will work on a bank of batteries tied in paralell or if each battery has to have a seperate "bug."

 

[Stu Jackson]

Argus -- more opinions

Tom, you have described those issues quite well. However, the instantaneous draw that will whack out the standard Peukert's equation are quite rare in sailboats, even with inverters and microwaves.

I think what we have here is a gizmo that "simplifies" things for those poeple who, well, like to be simplified.

As I mentioned earlier, what I've learned by the shunt methodology has been extremely helpful. I know how to treat my batteries, and from the Gotcha thread have learned how the machine works and how I can make it work FOR ME.

I have mentioned, here, many times, that while I KNEW my energy budget, until I learned more about battery acceptance (which I'd read about over and over) I didn't understand how it affecte me and how much longer it actually takes to recharge until I installed and learned how to use my Link. And I've been passing that on to anyone who'd like to hear it, and some, who, perhaps, have not!

This gizmo ain't gonna help those folks, but they probably leave their boats plugged in all the time anyway...

Those who like to keep it simple and think they can buy a fuel gauge for their battery banks, let 'em have at it!

Oh, and does it tell you hours remaining with either the instantaneous or averaged time draw?

 

[tsmwebb]

...
Oh, and does it tell you hours remaining with either the instantaneous or averaged time draw?

No, I don't believe it does. And, I'm treating it with a big dose of skepticism.

However, the idea is interesting. I do eyeball load-testing all the time to get a feel for the accumulated error of my energy monitor. So, if I see a 20 amp load and the voltage is 12.75 and the monitor says I'm down to 50% SOC I know the monitor is goofy. It would be cool if the monitor did this automatically and either corrected itself or had a confidence display. IME, the errors in energy monitors are cumulative so the period of time you spend before hitting your reset condition makes a big difference in the accuracy of the system independent of the frequency and amplitude of the loads.

A load tester that also counted amps could measure the current health of the battery and give an independent SOC approximation(like the bug) and also predict time remaining and so on (like our monitors). Seems like a great match with a potential for a marked benefit and a cheap addition to existing technology.

--Tom.

 

[walt]

I really like having a charge monitor to tell what is going in and out of the batteries and would prefer the charge monitor over Battery Bug.

However.. one point to make. My batteries are on there last leg and I havent measured this directly but it seems to me that the battery impedance has increased from when they were new (exactly what the battery bug measures). Ill get some screwy readings from the battery and monitor such as Ive only used 10% of the capacity and am currently using only 1 amp but the battery voltage has dropped to in the very low 12 volt range. According to battery monitor, I have used only 10% of the battery and have 40% more to use. But when I also look at voltage, I know this is likely not true and I may actually have much less than 40% left to use because the batteries need replacing. According to the claim on the Bug web site (which I have no reason to question), since the Bug is measuring battery output resistance, it would actually give me a better indication of how much capacity I have left than the battery monitor.

I tried to find some specs on the battery bug but could not find any. I was looking for two things. First, battery impedance is temperature dependent so does the battery bug have temperature compensation? Second, it draws current to just operate but it also measures battery impedance by a short duration current pulse (it probably looks for voltage change from the known current pulse to determine resistance). So what is the total current drain (combination of powering the device and the short duration current bursts) of the battery bug? The charge monitors draw very little, I think my Linklite uses less than 10 ma and the Victron even less.

 

[walt]

Looking at the spec a little more, it says the current pulse is 100 amps for 1 msec. I could not find the "once per minute" sampling but assuming that is correct, the average current consumed by battery resistance measurement by this method would be:

100 amps / (60*1000) = 1.6 ma "on average"

So it looks like it doesnt really use much current from the battery at all to do the resistance measurement.

 

[Stu Jackson]

Walt, when was the last time you equalized your batteries?

 

[javaprog]

Looking at the spec a little more, it says the current pulse is 100 amps for 1 msec. I could not find the "once per minute" sampling but assuming that is correct, the average current consumed by battery resistance measurement by this method would be:

100 amps / (60*1000) = 1.6 ma "on average"

So it looks like it doesnt really use much current from the battery at all to do the resistance measurement.

http://www.argusanalyzers.com/battery-monitors/technology/competing-technologies-dcm.html

"By actively measuring DC internal resistance every 60 seconds, the DCM continuosly and directly tracks available energy in the battery providing actual state of charge, , and absolute capacity information at all times, most importantly, while the battery is in use. "

 

[javaprog]

For the cranking battery version model BB-SBM12, under features it says:

"Battery temperature is constantly measured and the cranking state of health alarm is adjusted for extreme low temperatures"

From the troubleshooting FAQ for the deep cycle version:

"Cause: The battery is operating in a very cold environment compared to when BB-DCM was first installed, and the BB-DCM has detected a significant decrease in effective capacity. A very cold battery will have a significantly decreased capacity compared to when the battery is warm. Under most conditions the BB-DCM can distinguish decreases in capacity due to cold temperatures and will not indicate a low battery health as a result of low temperature. A 'temperature icon' will be indicated on the display if the BB believes the measured capacity is the result of cold temperatures.
"

So, it would appear that the battery bug has a temperature sensor in it.