Why are battery Monitors So Expensive ?

nigtomdaw · September 2007

If a model airplane manufacturer can supply a lightweight battery monitor rated to 100 amps retail for $40 why cant the re sector produce a unit even without display but a USB interface for PCs 4 about $150 .I have a Xantrex XBM with PC interface and its great but so ex......pensive,,,,,,,,, battery monitoring is so crucial for off grid dwellers they are poorly served by the off grid re suppliers thus manufacturers and designers . Come on some one set a new bar for affordable battery monitors !

I know Midnight Solar is developing a new unit,,,, will it come with a price break through as well as a to be expected technology breakthrough !

bob Robin over 2 u and the re world manufacturers out there or do we go to China for a solution yet again !

Robin Gudgel · October 2007

Re: Why are battery Monitors So Expensive ?

I'm not sure what a model airplane company gives you for a status monitor. It may be little more than a volt meter, so it is difficult to compare the two. I have contemplated making a voltmeter with lots of computer smarts to make a guess at battery status. It just sounds too sleezy. The Trimetric has been an industry standard for many years and Ralph has done an excellent job of keeping costs down. I did the mechanical design of Trace Meter which was based on the Trimetric. There are a bunch of parts inside!!. Magnum Energy has been working on their monitor for two years and it is about ready to pop. It will retail for about $160.00. The $389.00 OutBack is meant for techies that don't care about cost. boB and I have discussed a monitor for years and figure we will need something in the future. Heck, it may even be the Magnum incorporated into our network?
In order for a product to retail for $40, the bill of materials can cost no more than about $8- $10.00. It is difficult to make something that has to have tha accuracy of a real battery status monitor for that price. All the off-grid monitors must also work to 500 amps rather than 100. That is not free either. As far as hooking up to a computer, well it comes down to quantities. USB does not go very far either, so you would need to have your computer within 20 feet or so of your batteries. The off-grid market is so small in the scope of being an electronics manufacturer, it is just not possible to get costs much lower. I'm not sure why all of us manufacturers keep trying to out do the others for products that will never turn enough profit to pay the R&D expenses? Sometimes it is a good thing for our industry that engineers are not the wisest business people. That said, I am very curious what the airplane manufacturer is actually doing for circuitry? Do you have one of these units and if so, what is inside?
It may be possible to make something for $125 or so in the future, but I don't see it going any lower than that due to small quantities. Let's review costs a bit. Let's say a monitor is available for $125.00. Knowing that the retail price is 4 to 5 times the price of parts, that leaves about $30.00 for parts. Hmmmmm.... That sounds like a lot of parts to me. Maybe you are right, maybe they can cost less? The small quantity is a big issue though. Nobody is selling thousands of these things. It is more like a few hundred per month total for everybody combined. If it takes an engineer two years to develop one of these gizmos as it has for OutBack and Magnum, then it just doesn't pay at these quantities. The profit for each unit would be in the $10.00 range. Even if a manufacturer received sales of 200 units a month, at $10 each, it would take 10 years to pay off the engineers expenses. Add another $20 retail to the price and it would cut the payback in half.
I'm not sure this helps much, but you can start to see some of the issues at hand. Companies like ours are certainly not doing this to get rich. We do it because we love beating our head against the wall.
Robin Gudgel
MidNite Solar

niel · October 2007

Re: Why are battery Monitors So Expensive ?

robin,
i hope you have a good supply of bandages and aspirins.

:p

nigtomdaw · October 2007

Re: Why are battery Monitors So Expensive ?

Robin thankyou for your time and effort in such a comprehensive answer to my question.

Question answered ! No further comment !

System2 · October 2007

Re: Why are battery Monitors So Expensive ?

The airplane one works very well and measures voltage and current draw.

I uses very little power. I was tempted on using them between my small string and CC before I up sized the system.

here are some of them

http://radicalrc.secure-mall.com/shop/?shop=1&cat=85

crewzer · October 2007

Re: Why are battery Monitors So Expensive ?

Skywlkr,

Here are some links to "inexpensive" meters:

http://store.solar-electric.com/didcvoampme.html
http://store.solar-electric.com/didcvome.html

I have a Xantrex Link-10 battery monitor. It's pretty sophisticated compared to a DVM or DAM. Take a look at the functions and features described in the owner's manual... they're not trivial!

HTH,
Jim / crewzer

Windsun · October 2007

Re: Why are battery Monitors So Expensive ?

nigtomdaw wrote: »

If a model airplane manufacturer can supply a lightweight battery monitor rated to 100 amps retail for $40....

I looked around at several of those types, and I see nothing in the $40 range that does anything like what units like the TriMetric do.

How about a link?

nigtomdaw · October 2007

Re: Why are battery Monitors So Expensive ?

Simple meters are not battery monitors I can source LED LCD digital volt and ammeters, panel meter style for less than $10 each. As I said I own a Xantrex XBM with the windows software interface and its fantastic but this retails as a package price around $400. I am more aware now from Robins reply on the economy of scale being a limiting factor and indeed in my web search for a economically price unit found 2 other European inverter manufacturers who use an identical unit as the Xantrex XBM badged under there own manufacturers name. Whether Xantrex was the creator or simply rebranded somebody elses design work in the XBM merely adds weight to Robins original reply ! As you would expect the Euro versions of the XBM are just as expensive !

With regards to the $40 model airplane monitor I threw this in as what appears possible at low cost and could possibly be expanded on . When I posed a similar question on pv trackers several comments were made that the electronics side of things were the least of the cost worries , well the battery monitor is only electronics and they seem able to punch big $ $$
Robins answer on economy of supply demand seems to answer the question best!

niel · October 2007

Re: Why are battery Monitors So Expensive ?

just kicking thoughts around i said to myself that yes a regular meter only measures at that time what the current or power would be and that adding time to that for the overall in relation to a battery state does increase the complexity and costs involved. then i thought about my kill-a-watt meter with its ability of measuring over time and many more features than any battery monitor would require. it might measure ac, but its electronics should be adaptable to the dc applications involved in battery monitoring and that blows that theory that it can't be done cheaply.

Solar Guppy · October 2007

Re: Why are battery Monitors So Expensive ?

Kill-a-watt is probably made in the millions of units and it also doesn't do 100 amps

niel · October 2007

Re: Why are battery Monitors So Expensive ?

i'm sure the quantity made and sold helps. the need of a shunt to have operation for the higher currents on dc will add to it, but i said it could be done cheaply and i did not say it will be as cheap as a kill-a-watt for clarity. as it is the trimetric is charged big bucks for the meter and then you have to buy the shunt seperately anyway so why not apply it to a kill-a-watt style meter? speaking as somebody who has a trimetric there just isn't any justification for the cost based on parts, looks, and labor imo. the backcase is optional, the interconnecting wires are optional, and of course the shunt is optional. i guess i paid for the extra labor costs for the bad instruction manual that came with it?:roll:

SolarJohn · October 2007

Re: Why are battery Monitors So Expensive ?

I've done some product development, including machine-language programming of microprocessor-based devices, but I wouldn't consider developing a battery monitor unless I thought I could come up with something way better than what is already available. And even if I did, I would then have to convince people of it's superiorority, a costly undertaking. Then, maybee it would start to catch on, about the time someone else builds and markets an even better one.

John

System2 · October 2007

Re: Why are battery Monitors So Expensive ?

I wanted to chime in here to clear up an inaccuracy.

The OutBack Power Systems FLEXnet DC advanced DC system monitor has a list price of $379 and is available for order now.

We spent a lot of time working hard to create a product which offers a high level of functionality for a fair price.

Though I think its mean spirited to say disparaging things about competitors products. The other battery monitoring options that are currently available are older technology or didn't benefit from communications between power electronics like what we can do with our proprietary network.

In my time in the industry (albeit not nearly as long as many of you) I have seen companies come out talking about not-yet-released products with exceptional functionality. In the end the product ships with a scaled back list of features. Ultimately, there is a disconnect between enthusiasm to create a ground breaking product and reality.

I encourage you all to take a look at the FLEXnet DC and make up your own mind if it is something you find worth your money,

You can find more information at our website by following this link:
Here

You also contact any of us with any questions by phone or e-mail.

Bryan

boB · October 2007

Re: Why are battery Monitors So Expensive ?

nigtomdaw wrote: »

why cant the re sector produce a unit even without display but a USB interface for PCs 4 about $150 .!

The Magnum BMK battery monitor/SOC meter is trickling out the door at the moment while we make some last minute adjustments to the software before the dam breaks... However, it just occurred to me that one might just be able to get pretty close to this request (solution?). Now, this would require a motivated chap like Intellact, Sakoman, Greener-Power or Right-Hand-Engineering to come up with PC/Mac/Linux software with the addition of a RS485 to RS232 or USB converter, cable or dongle to convert our network communications signals to something a PC can read/write.

The Magnum Energy network protocol is open and documented on the magnumenergy.com web site. The BMK info will get on the site too but is not there quite yet. At least our communications uses standard 8 bit data, 1 stop/start bit etc, so it can communicate with PC ports fairly easily.

I haven't tried yet, but a cable with a resistor-capacitor-diode might even make it work with RS232.

Anyway, I'm just kinda thinking out loud here, but the BMK will retail for $159.00 so this might not be too far off if somebody wants to do a bit of work. The data I've seen from the BMK looks very good so far.

Otherwise, the BMK works with the Magnum network... "Mag-Net" I've heard it called.

boB

mike95490 · October 2007

Re: Why are battery Monitors So Expensive ?

Bryan Thomas wrote: »

We spent a lot of time working hard to create a product which offers a high level of functionality for a fair price.

Uh.. at first glance, it looks like it requires a Mate ($$) to display anything ?

It doesn't look like it can connect to a PC to log data, to evaluate batteries over a period of years, or is that a function a Mate provides ?
(I don't own any OB equipment, no do I sell any RE equipment)
Does it come with the precision current shunts ?

nigtomdaw · October 2007

Re: Why are battery Monitors So Expensive ?

Ths was a slow start topic question Im glad to see a bit of input now, off grid an informative Battery Monitor is an absolute requiement, but becuse of the high cost, Im the only guy (yes an u not an a) UK joke sorry...... in my area that has any battery monitoring...... even the handfull of suppliers in the region dont stock any. Taking Robins supply demand factor into account, if Im the only daft lad to shell out $400 on the gear whilst the other 200 people in my area spend it on vino and cigs in my humble opinion maybe the market could be expanded by lowering costs. My lights never go out but my neighbours probably do, whos having the most fun ?

nigtomdaw · October 2007

Re: Why are battery Monitors So Expensive ?

Bryan from OB since youve posted and stated yourself on product claims and shipping realities when will the new fully featured 80 amp OB Charge Controller ship ?.....................................................................................................................................................................................................................................................tomorrow.............................................................next week................................next month......2008 ?;)

GreenerPower · October 2007

Re: Why are battery Monitors So Expensive ?

Just throw in my 2 cents, I agree that those devices could be much less expensive. Those devices are a must for each company - OutBack, Xantrex, Fronius, Magnum ... et al to operate with their product hence they have to make them. The current pricing is just supply/demand driven. IMHO, development of those might not in their best expertise (i.e. using up-to-date out-of-trade technologies) and therefore more overheads, development costs .... If these companies are open to a third party to produce the device (of course with proper NDA ... for their proprietary and potentially IP'ed "buss" protocol like the Outback hub, the Xanbus ...), I bet more creation can be done, you would probably see similar products with USB, cel, bluetooth ... capabilities at half current MSRP. A third party can leverage the overheads, component volume and cross-brand SW development for a lower-cost product. Who knows, some smart alec outthere could come up with a single device for all brands ... add a small A/D chip into a basic PDA design and you are there.

GP

boB · October 2007

Re: Why are battery Monitors So Expensive ?

>>add a small A/D chip into a basic PDA design and you are there.

From what I hear, PDAs change too often to assume you will be able to keep getting a product that will work with your/my/their software for a long enough time...

I would be very interested in your thoughts on what PDAs would be a good candidate for something like this, Greener (and others).
I'd love to be able to get an off the shelf handheld "solution" for these things. I really don't like that word, "solutioin", but I guess it applies here.

boB

westbranch · October 2007

Re: Why are battery Monitors So Expensive ?

see the entry on inverter monitoring via PDA on the Grid tie board.

Not any kind of a PDA expert , dont even own one, but once you have a PDA (/computer)that works why would you have to get a new one...unless it broke down... or were you thinking about CC software upgrades boB? Lots of cheap used ones out there...

Cheers
Eric

Roderick · October 2007

Re: Why are battery Monitors So Expensive ?

boB wrote: »

>>add a small A/D chip into a basic PDA design and you are there.

From what I hear, PDAs change too often to assume you will be able to keep getting a product that will work with your/my/their software for a long enough time...

I would be very interested in your thoughts on what PDAs would be a good candidate for something like this, Greener (and others).
I'd love to be able to get an off the shelf handheld "solution" for these things. I really don't like that word, "solutioin", but I guess it applies here.

boB

If you're an experimenter, then there are lots of ways to attack the problem. There are multi-port A/D chips made to monitor the power supply voltages in PC's. There are very cheap because of the enormous volume, or could even be harvested from junked PC's. They use the i2c bus - don't worry about what this is, but suffice it to say it's a low speed bus that you could communicate with using a PC or PDA. And once you know how to take a voltage or current reading, the rest is all software.

For a controller, I favor the older Palm devices like the Palm III, V, or Handspring Visors. These can be obtained for $5-10 (in working order!) at garage sales, flea markets, and CraigsList. Like any other PDA, phone, or computer today, these devices are not intended for programming by the casual user. But someone that's had programming 101 could do it. It might interest you to see my post in the Grid-Tied forum, about monitoring an inverter with a PDA. That program took about 3 days to write, not counting reverse-engineering the language of the inverter. I say that not to brag, but to illustrate that it's not a superhuman task, and it would be realistic for a technical hobbyist to program even if it weren't going to be a product.

The real difficulty is commercializing a product. For that, you need volume, and can't rely on bargain used parts.

mike95490 · October 2007

Re: Why are battery Monitors So Expensive ?

boB wrote: »

>>

I would be very interested in your thoughts on what PDAs would be a good candidate for something like this, Greener (and others).
I'd love to be able to get an off the shelf handheld "solution" for these things. I really don't like that word, "solutioin", but I guess it applies here.

boB

I live out of my Treo 600 (palm OS) and I think R. also uses a PDA, wrote PV Log for it. The question is, which PDA will still be in use 5 or 15 years from now ? Connectors for it ??

boB · October 2007

Re: Why are battery Monitors So Expensive ?

mike90045 wrote: »

The question is, which PDA will still be in use 5 or 15 years from now ? Connectors for it ??

Yes, that's the question I'm asking about.... Maybe not 15 years, but 5 years at least.

Greener Power... What do you use for programming tools ?? Or do you write your code in Java or what ?? Does your PDA have USB ?? I have an old Palm now that was gotten from Ebay for $20. Not sure what to use to program it with. Also need info on the hardware and/or architecture, system calls, etc. (??)

Thanks,
boB

GreenerPower · October 2007

Re: Why are battery Monitors So Expensive ?

boB wrote:

Greener Power... What do you use for programming tools ?? Or do you write your code in Java or what ?? Does your PDA have USB ?? I have an old Palm now that was gotten from Ebay for $20. Not sure what to use to program it with. Also need info on the hardware and/or architecture, system calls, etc. (??)

Personally, I have a Palm IIIe, with just a serial port and irDA. The development tools for its native PalmOS is free (available from access-company.com, Eclipse C/C++ development tools on Windows for PalmOS, what a hybrid but effective development platform). Newer Palm models probably have a USB port. My concern is SW protection from piracy and hackers on this platform. Something using uCLinux, nanoX, GTK ... like this PDA is probably best (note: that news release was in 2002 meaning ... very cheap now). The USB would provide expansion capability and common interface module creation to bridge cross-brand systems. Plenty of free development tools, open sources for Embedded Linux.

Yes, that's the question I'm asking about.... Maybe not 15 years, but 5 years at least.

In term of parts (even the whole unit assembly), for a few hundred quantity, probably Google around the net, eBay ... For a few thousands to 10s K quantity, going to far east manufacturers, they still make parts for PCs that are 10 years obsolete for prices better than eBay or garage sale. There are always a slightly "out-of-date" production lines somewhere sitting idle and they would make deals to keep it running.

From what I hear, PDAs change too often to assume you will be able to keep getting a product that will work with your/my/their software for a long enough time...

I agree with WestBranch, investing in an RE system is for likely 20 years or more. If the system doesn't change, why need the upgrade. I'm for something like USB, smartcard capability in the system for modular expansion (incremental cost) and security.

boB, in "up-to-date out-of-trade technologies", I also mean things like MPPT algorithms. The algorithms on the MX60 and FLEXmax80 or the Classic sound like breaking ground in this industry. In other trades, "optimization methods" such as "simplex method", "operation research" are well established with proven codes and are well applicable to this. I wonder any has been looked at.

GP

Why are battery Monitors So Expensive ?

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