Battery Monitor Panels

robavery

robavery

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Am looking for a battery monitor panel that will also give info on accumlative amps used. Sterling do one with an amp counter but not sure how accurate that might be. Mastervolt also but expensive. Any one know of any alternative good products???
 
We bought a BEP Marine one at the boat show from Merlin. £170 - but includes a 500amp shunt. Looks very good indeed, and will monitor 2 banks.

We looked at the NASA one, but it only monitors one bank (so you can't check you engine battery), also, the shunt is only 100 amps - so if you need to parrallel your battery banks in an emergency to start the engine off your domestics you would very likely blow the shunt.

Haven't installed the BEP one yet - but looks very well made.

Jonny
 
I went for a simple approach so SWMBO would be able to tell at a glance if she could use her hairdryer http://www.smartgauge.co.uk/smartgauge.html
Tells me volts for the starter battery and volts and whats left % in the main battery.
Having said simple I also have the advanced one of these
http://www.smartgauge.co.uk/smartbank.html
to control the split charging of the batteries.

Of all the devices I have tried ( sterling, link etc) it is by far and away the most accurate and easy to fit.

Julian
 
Get one that takes your battery's charging efficiency (Peukert's coefficient) into account. Some can estimate it themselves some you can enter it. I have a Sterling battery monitor which is fixed to the charging efficiency of a 'standard' lead acid. Which is great except I have AGM's so its sums are always wrong. As soon as I find a new gadget big enough to fill the hole it's going on Ebay and I'm getting a Xantrex Link 20 which is my current favourite (although the BEP one also looks good).
 
I have a BEP and have set it up as carefully as I can. It gives a fair idea of the state of charge but it isn't perfect by a long way. While it is able to compensate for the charge characteristics (Peukert's coefficient) it does NOT seem to compensate for the difference between discharging at different rates.

For example, your battery has an Ah capacity quoted at a specified discharge rate (usually given in 'hours'). A '10 hour rate' discharges the battery fully over 10 hours, and a '20 hour rate' discharges it over 20 hours, etc. If you take a battery with, say, 100Ah quoted at a 20 hour rate, then the specified discharge rate is 100/20 = 5A In other words, if you fully charge the battery and discharge it at exactly 5A (not easy as the volts will normally fall, but that's another story) then at the end of 20 hours the battery will be flat. Now, with that same battery, if you double the discharge rate from 5A to 10A, you will not get anything like 10 hours life before it discharges fully. It might be about 2/3 or that, or less.

So, as you can see, these meters are hugely inaccurate if most of your discharge is not at the specified discharge rate (which is usually the case). They will still correctly show the Ah used but what one doesn't realise is that the battery capacity is incorrect - it can go either way, if the actual discharge is lower than the specified rate then the meter will be pessimistic, if higher, it will be optimistic. Since nobody ever knows exactly what is actually left in the batteries few will ever be aware of this discrepancy and might be discharging to a lower level than they had intended. That's why I only use my BEP as a rough guide however the BEP volt and ammeter function is brilliant and from that I can see almost exactly what is happening.

In summary, the BEP is excellent when used intelligently having understood the nature of the problem.
 
It looks very good and easy to install but I am more keen to see how many amps/hr my equipment uses over certain periods and think the Smart gauge will not give that info - am I right!!
 
I have a sterling one, monitors 4 banks at diffrent voltages, handy for genny start batteries etc, only monitors one bank for AH, but thats all I need, domestic bank, excellent unit and very accurate. I wouldnt be without it now!
 
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