Which Battery Monitor ?

[PatrickS]

If one has a starter battery and a house bank wired up to an A-B-Both-Off switch, how do you connect e.g. a Link 20 or similar to both the starter battery and house bank without it getting confused when in Both position, even if only for a short period?

[Esprit Marine]

Originally Posted by Maine Sail

The algorithm is actually quite simple. It does nothing more than add the time and the amps being consumed over a given period to determine ah's used. This is not an over complicated concept and an easy one to program.

Hmm, not quite...

A battery monitor is "blind", it does not actually see what really goes in or out of the batteries. The only measure a battery monitor takes, is the actual amps passing through the battery cable via the shunt. To estimate the actual amps going in or out of the batteries, the monitor uses a complex algorithm taking into account data as varied as the battery charging efficiency coefficient, its Peukert exponent, the temperature compensation if temperature sensor available etc. A good battery monitor should also have a learning algorithm to adjust the initially entered charging efficiency factor and Peukert exponent with the cycles and age of the batteries.

With basic battery monitors, data will not be reliable and you will have to reset the monitor to zero regularly.

[Esprit Marine]

Originally Posted by PatrickS

If one has a starter battery and a house bank wired up to an A-B-Both-Off switch, how do you connect e.g. a Link 20 or similar to both the starter battery and house bank without it getting confused when in Both position, even if only for a short period?

PatrickS, it is just a question of installing each shunt between each bank and the battery switch.

That said, there is no real interest having a shunt / monitoring amps on the starter battery as it is normally always fully charged (starting the engine should take less than one Ah). More important is monitoring the voltage, to control e.g. voltage at rest, maximum voltage when charging, and how low the voltage will drop when starting the engine.

[Esprit Marine]

Originally Posted by Esprit Marine

PatrickS, it is just a question of installing each shunt between each bank and the battery switch.

Forgot to mention this supposes to have a 1, 2, Both, Off battery switch on the negative as well as on the positive circuits.

[Therapy]

Originally Posted by Esprit Marine

With basic battery monitors, data will not be reliable and you will have to reset the monitor to zero regularly.

So which are which?
Just go by price.......not!

[theonecalledtom]

So I now have my 602 installed and feel like a blind man who can now see. When I turn on a halogen vs an LED light I can see the difference and I can also now see that the house bank drops from 12.7v to about 12.2 right after charging and that the slightest load will knock it down further. Right now it won't give me an accurate percentage used because I have no idea how many Ahs the batteries really support (20? Less?) but it at least allows me to monitor the situation until we replace the batteries.

I can also see how the charging system is behaving.

Installing it was pretty straightforward though I had a make an extra west marine trip because the shunt has 3/8" bolts and some of my existing system uses 5/16" lugs.

As for accuracy of data the voltages agree with my multimeter pretty well. The amps I would hope to be relatively accurate and at least consistent.

PatrickS - The shunt across which the system measures current flow is only across hooked to a single bank, whichever batteries the switch is set to. The Link20 (which I returned two of due to manufacturing defects) has a double shunt. The shunt is between the ground and the batteries and when monitoring Ah on a single bank you just bypass it for the other bank. When set to "both" you do lose seperate voltage readings.

[Pblais]

So which are which?
Just go by price.......not!

Resetting them to zero is not usually the problem but it is possible it could read more in than out. What does happen is as the battery ages. The exponent changes and it won't ever get full no matter how much goes in. It's more of a problem when the batteries are just getting old and if you watch it regularly you'll start to know it. That is something you might never see without a monitor.

Knowing more is still worth the effort. It teaches you how you really use power instead of how you think you do.

[dkall]

You can easily; if you're at a dock, check the capacity of the batteries. Since you have a monitor, fully charge the batteries, let sit for a day with no load, then run 5 amps through them till they reach 10.5 volts. Calculate the total amp hours and that's where you're at. Ample Power gave me that tip. Of course charge immediately when you get your answer. Also from either Ample Power or Lifeline they say that if the total amp hours is less than 80% of original capacity then it's time to equalize or replace. Lifeline say's (I think) that you can equalize a couple of times consequtively if you're not getting back in the correct amp hour range and obviously if you're not getting back into, it is time to replace them.

[Extemporaneous]

Originally Posted by Esprit Marine

Hmm, not quite...

To estimate the actual amps going in or out of the batteries, the monitor uses a complex algorithm taking into account data as varied as the battery charging efficiency coefficient, its Peukert exponent, the temperature compensation if temperature sensor available etc. A good battery monitor should also have a learning algorithm to adjust the initially entered charging efficiency factor and Peukert exponent with the cycles and age of the batteries.

You mention a temperature sensor.
Do you know of a (any) Battery Monitor that actually uses a temperature sensor (as oppose to temperature range setting) and also gives you Watt-hours?
I'd be VERY interested.

Regards,
Extemp.

[Extemporaneous]

Link 10 (some) is the only one I can find.
And at that, I'm not sure how it uses the information.
Can you still get these?
Anyone know of another?

Regards,
Extemp.

(found Link 10 but Temp. Sensor is discontinued)

[dkall]

The EMON is a system from Ample Power and has battery sensors in it Energy Mangement System and sensors in it's Regulator.

Great solid products and I do like them. But the wiring everything up is quite a pain. I don't think anything else would be much better. They respond quite well to emails and I have spoken with them on the phone. Once in a great while their stuff comes up on eBay. Their Alternators I think are much better than anything out there. Period.

I have no affiliation with them.

[Extemporaneous]

Originally Posted by dkall

The EMON is a system from Ample Power and has battery sensors in it Energy Mangement System and sensors in it's Regulator.

Great solid products and I do like them. But the wiring everything up is quite a pain. I don't think anything else would be much better. They respond quite well to emails and I have spoken with them on the phone. Once in a great while their stuff comes up on eBay. Their Alternators I think are much better than anything out there. Period.

I have no affiliation with them.

Thanks dkall.
Too bad it doesn't monitor watt-hours.

It seams so strange that few (none?) of these companies that make product to monitor batteries (SPECIFICALLY BATTERY ENERGY), monitor all of the parameters that contribute to the Energy stored in a battery at any given temperature.
Weird!?

Any others, anyone?

Extemp.

[Esprit Marine]

You can link a battery temperature sensor to most of the big brand chargers (Xantrex, Victron, Mastervolt, Cristec, Sterling etc), but this generally comes as an option. The problem is that you will need a temperature sensor for all charging regulators (charger, alternator, large solar panel bank, wind generator...), and you can end up with quite a few sensors and cable runs. Hopefully in a few years time, multiplexed power bus will have proved themselves and will make such information as battery temperature from one sensor available to all regulators.

[Extemporaneous]

Originally Posted by Esprit Marine

You can link a battery temperature sensor to most of the big brand chargers (Xantrex, Victron, Mastervolt, Cristec, Sterling etc), but this generally comes as an option. The problem is that you will need a temperature sensor for all charging regulators (charger, alternator, large solar panel bank, wind generator...), and you can end up with quite a few sensors and cable runs. Hopefully in a few years time, multiplexed power bus will have proved themselves and will make such information as battery temperature from one sensor available to all regulators.

I've looked at Xantrex (only one I found was link 10 which is discontinued). Some others, nope.
I'm hoping 2 requirements can be fulfilled.

• Monitors watt-hours.
• Utilizes temperature (via actual sensor) to calculate energy input and output.

If you know one that does both, PLEASE let me know.

And Thanks,
Extemp.

[s/v Jedi]

Extemp,

Why the need for Wh's... isn't Ah, which will have an almost linear relation to Wh, okay? These monitors don't show how much energy you used; they show how much is left in the batteries and Ah is okay for that.

cheers,
Nick.