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Battery monitors - Smartguage?


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Has anyone used a smartguage battery monitor to keep an eye on % battery capacity used? I see many good reviews but just dont understand how it works.

 

https://www.smartgauge.co.uk/smartgauge.html

 

Seems a simpler cheaper alternative to the normal BEP battery monitor with shunt etc. (if it works of course)

 

Any feedback out there? Or wise words on battery monitoring in general.

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Battery monitors are essential, Ive got one of these on the VB, tells me anything I need to know about the state of the batteries, Voltage levels, % charge level, A/hr "left in the tank", Amps coming in from solar and going out via the kids idevices, plotters, stereo etc etc.

Also indicates when the system is charging (solar inputting more than is going out) or the opposite. 

This one can monitor two separate batteries or banks of batteries. 

 

Screen Shot 2017-05-03 at 2.49.54 PM.png

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Yes, my entire solar system is from them and its all been good since installed (other than a full meltdown of the MPPT controller) which they replaced. Also got their AGM batteries. HEAVY, but good. Im not sure how the monitor copes with the battery degradation over time, I don't know enough about it all in that respect. I just know the sun makes amps appear in the battery, the fridge/plotters/stereo/lights/kids etc use those amps that have found their way into the battery and Ive got a cool LCD screen thingy that tells me how many of them I've got left. 

Hauling out in the weekend of the 13th so come by and have a look if you like.

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I agree that batt monitors are the best way to get a decent lifespan from your batts. BUT they must be properly programmed for the SPECIFIC MODEL batts you have. Most are not, and give rubbish info. Get the purkets (sp?) factor from the manufacturer (NOT THE SALES REP!) for your batts and enter that, and the type and capacity, and make absolutely certain that your charging systems are providing the correct voltages, for the correct times, in their 3 step charging process. It you do that, and never discharge more than 50%, you should get over 10 years out of good batts.

Clipper, yes, batts do degrade over time, but capacity falls off quite rapidly - my last set lasted 14 years, incl 10's of 1000s of miles, and living aboard for over  3 years total, and only showed obvious signs of age in the last 2 years, then they were stuffed.

Most batteries that "fail early" haven't actually failed, they've been killed - often because of a poorly installed or programmed monitor. Or just a voltmeter.

Personally I'd steer clear of any battery monitor that does not include a shunt. I dont see how they can really KNOW what the batts are up to.

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The system I use plugs directly into the shunt and there is facility to switch it to suit any battery type AGM, Lithium, Pb, etc etc. Once connected it then measures/determines the battery capacity and works from there. Our house battery bank is only charged via solar, the engine start system is fully separate and maintained by the solar but also charged by the motor. I tried a DVSR in the system so the motor could charge both but it didn't get along with the solar so i took it out. I prefer the systems are independent anyway.

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hmm, if you don't input the size of the bank, nor its peukerts factor, I dont think the unit will be very accurate.... because it does not know how many AHs should be available, nor what the charge efficiency will be.

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One of the set up screens when first starting it up has you select battery type, closest Amp capacity to whats there and a few other parameters. 

Whats a peukerts factor anyway, sounds more like a measure of seasickness?

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peukerts factor is how efficiently that battery is charged - basically how much more power you have to put into it than you get out, so it can work out charge state. 

Most systems, when the charge current is reduced to a small percentage (5% roughly) the the counter should reset to full. This way they don't get out of sync.

However, some systems are "confused" by solar charging, as the current provided might be around the reset current, so they can reset early :-(

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It's pretty much a glorified Volt/current meter. Without being able to compute Purkets law and for that matter, Battery temperature, it can't do a thing other than be a Time over Voltage calculator.

Purkets Law was created by Wilhelm Purket way back in the late 1800's. A battery is a Chemical device and thus is not linear in both output current capacity and charge input capacity, to get it back to full charge. Neither input and output current curves relate to one another. Or in other words, the charge gradient does no look the same as the Discharge gradient. Nor are different battery chemistry types the same. And to make it even more complicated, the amount of overall capacity, varies depending on what the discharge current is. So you will get greater overall capacity if you draw say 10A/hr than you would if you drew down 50A/hr. The higher the Current drawn, the less capacity the battery will have. So Purket worked out a Formulae that could calculate a Batteries capacity over discharge rate, more accurately and there is a constant used in the Calculation for each battery type and make.. That Constant is usually given by the Battery manufacturer, although it can be difficult to obtain from the cheaper manufacturers. 
Not all Batteries, even if the same type, are the same. Mr Makesthebest builds an FLA 12V 100Ahr battery and Mr Notsogood also makes an FLA 12V 100Ahr battery. But the two most likely will have very different Capacities over discharge rates. That 100Ahr is usually shown by the time that 100Ahr was taken from the Battery. It may be given as 100Ahr(10 hr) or 100Ahr(20 hrs) and that difference in time can be a huge difference in actual Capacity.
Purkets Constant ranges from 1.2 to 1.6 for FLA, 1.1 to 1.25 for Gel and 1.05 to 1.15 for AGM.

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I've had a smart gauge for installed for a year now. I went the Smart Gauge way because I didn't want to install shunts.

 

Read about a good testing here..

 

http://www.pbase.com/mainecruising/smart_gauge

 

Mine is a Merlin version that I ordered direct from the UK... cheaper than Balmar.

 

It just confirmed to me that you can tell a lot from an accurate volt meter.

Thats what i wanted to hear! To be honest, it seems

too good to be true, so I appreciate the response.

 

What do you mean by merlin version? Do you mind me asking how much and where from?

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Yeh I think they are just distributors. I've read through quite a bit tonight in the tech section and it does seem quite a good setup. Gibbo seems to know his stuff!

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If you have shore power with good multistage Battery charger and spend little time living off the House bank, then a good Battery gauge is all you need. If you live a lot off grid and have a good expensive House bank, then you really need a proper Battery monitor. Being able to monitor and manage discharge and more importantly, Charge is essential to getting the most and the greatest life span from the Bank. Especially when Cruising and you may need to get more than just 24hrs from the bank and you may have to charge using a Generator or your engine ALT, where getting the Bank fully recharged summed over the time of running a Gen/Eng, is important. Failure to recharge the House Bank fully results in earlier death of the bank and simply not as much energy to be able to draw down on each day.
I must look up when we got our House bank, but I think it must be around 14yrs for ours as well. Yeah, yet another expense on the Horizon.

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Our Votronic is good so far have had it about 8 months, german made, they do compensate for Peukets law depending what battery type you have. 

Of course Lithium don't require this and some monitors don't have a specific Lithium Setting.

They are very simple to install as everything is pretty much pre wired just connect the shunt between the earth and the battery negative and plug in the single cable between the shunt and the monitor.

I was a bit suspicious of them initially because of the very reasonable price but pretty impressed so far. 

Nice to be able to check the current drain and work out very accurately where the power is going and how much certain devices use.

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