which battery monitor

[Jabamusic]

to address the economic aspect, you could consider the following shunted solutions to complement your existing volts panel gauge & battery selector switch (I'm assumming you have these already)?

http://www.ebay.co.uk/itm/Mini-Blue..._Measurement_Equipment_ET&hash=item2313e685f6

use two of above, one to measure alternator o/p and one to measure current draw, or alternatively the gauge below will give you net current flow. Combined with the volts gauge & slector switch, you'll have everything you need to monitor battery status. (offered simply as an alternative - I love the look of analog gauges).

http://www.ebay.co.uk/itm/Round-Ana..._Measurement_Equipment_ET&hash=item2562f23f6e

Reading with interest the whole battery monitoring story and interested in the above.

One question (maybe 2!): Will this solution provide sufficient monitoring as suggested? and how to wirie all in?

ps I like the round dials- would suit the boat !

 

[cimo]

Reading with interest the whole battery monitoring story and interested in the above.

One question (maybe 2!): Will this solution provide sufficient monitoring as suggested?

All comes down to what you would consider sufficient I suppose J. A bit of background as to where I'm coming from -

Personally, I'm content cycling my "maintenance free" Lead acid batteries anywhere between ~50% and ~85% during the season. Happy to replace the relatively low tech units once they give up the ghost (whenever that will be). I take the view point that the inefficiencies inherent in energy conversion & storage seldom justify additional expense - it's a game of diminishing returns to me. This approach can work, so long as you can live within a relatively modest power budget. Many take the alternative view, but personally, I like to keep it as simple as I can.

For me, a volts gauge and an ammeter will suffice.

Volts will approximate battery bank state of charge at rest, tell you if you alternator is working and, if you got a smart charger (I don't), it can tell you which part of it's cycle the charger is currently in.

An ammeter will allow you a real time approximation of the %discharge of you battery bank (current in), in addition to current draw (though not at the same time). It won't tell me amp-hours, but with the above information, I wouldn't feel the need to know.

That's alot of info from two low tech instruments. There's nothing new here mind you - this is the info that most bench battery chargers traditionally provided in the past. An additional advantage is that these dials are much better able to cope with the harshness of the small boat environment in my opinion.

and how to wirie all in?

ps I like the round dials- would suit the boat !

The volts meter you probably already have? (if not take it's i/p from the back of the ammeter - I wouldn't worry about voltage drop here, you'll eyes will re-calibrate to read it correctly).

My installation charges and draws via the common post on my 1-B-2-off selector switch. This would be the best location for the ammeter shunt for me. Failing that, at the battery terminal would be good (keeping you battery banks separate would require two ammeters in this case, if required). I have a 50amp alternator which is my largest current source, and the ammeter I link'd to was spec'd for that I think, although you'd get better resolution on the dial if you were to slightly under spec the ammeter (I don't imagine full scale deflection would harm the gauge as long as it wasn't too under-spec'd - but I'd verify that with the manufacturer).

A bit long winded, but come back if I missed anything. Others will be able to fill the gaps too (or indeed, shoot holes if its easier!).

I do have a thing for analog gauges I must admit - hopefully, I'll get around to fitting the ammeter soon.

I can recommend the following if you're interested. It covers analog instrumentation pretty well, in addition to being a pretty good generic reference for the engine. rgds. c.

http://www.amazon.co.uk/Troubleshooting-Engines-International-Sailboat-Library/dp/0070123543

ps - hope the op doesn't mind, I'm assuming we're beyond thread drift now.

 

[Cardo]

I have recently installed a Nasa BM-2. It seems working perfectly OK so far.

It was pretty straightforward to install although I'm happy I got the BM-2 with M8 screws on the shunt as it looks far more robust than the BM-1.

One question though. It seems the maximum Ah is supposed to be 600.
In fact I have two 700A.h batteries... Thus in theory (only) 1400 A.h. (it's a sailing boat, although nothing pulls out much, I like the idea of having a respectable autonomy).

Has anyone identified any reason why in theory the modules are limited to 600A.h ? Although I can integrate the flow of current OK, it wont let me go above the real capacities of the batteries.
Any idea welcome. Thanks

You have two 700Ah batteries? Flippin' 'eck, they must be huge!

On a more serious note, are you sure they're 700Ah each? Most boat batteries are in the range of 80Ah to 150Ah or so. I think you can get some 200Ah ones, but they're big buggers.
My boat has a pretty decent battery bank and that only has 500Ah total (from four batteries). 1400Ah, unless it's a particularly massive boat, is a lot.

 

[Richard10002]

You have two 700Ah batteries? Flippin' 'eck, they must be huge!

On a more serious note, are you sure they're 700Ah each? Most boat batteries are in the range of 80Ah to 150Ah or so. I think you can get some 200Ah ones, but they're big buggers.
My boat has a pretty decent battery bank and that only has 500Ah total (from four batteries). 1400Ah, unless it's a particularly massive boat, is a lot.

I wonder if he's reading the Cold Cranking Figure, rather than the 20hr figure? Easy mistake to make.

 

[john_morris_uk]

I appreciate the attraction of a monitor that just monitors battery voltage, but if you grit your teeth and find the time and space to fit shunts you do get more information. I don't know how much they are but we have used a Sterling Battery monitor like this: http://www.sterlingpowerproductsbam.co.uk/products-pmp.htm

It tells us the current consumption and voltage on each battery bank and Ah used which of course counts back as we are plugged in or the wind generator or engine produces charge.

 

[Zozo1202]

I wonder if he's reading the Cold Cranking Figure, rather than the 20hr figure? Easy mistake to make.

Well. I guess I made a mistake indeed then. Sorry.
It will solve my problem though.
True the batteries are really huge. But if standards are 100-150 ish, indeed I must have misread. I'll check.
Thanks

 

[Richard10002]

Well. I guess I made a mistake indeed then. Sorry.
It will solve my problem though.
True the batteries are really huge. But if standards are 100-150 ish, indeed I must have misread. I'll check.
Thanks

Maybe a mistake, maybe your right, but worth checking.

 

[pyrojames]

Well. I guess I made a mistake indeed then. Sorry.
It will solve my problem though.
True the batteries are really huge. But if standards are 100-150 ish, indeed I must have misread. I'll check.
Thanks

If that is an Ah rating they will be about 250 kgs each. Half a ton of batteries is going some!