I need more power Scotty!

Can't be sure but they look similar to the I2C connector on the sensor shield that is a 4 pin connctor.. It may be that the polarizing key is different but it's worth a look. Looks like Calgary has a few places that sell Arduino components. Perhaps, one of those places can definitely identify your connector.

Paul
 
Here is a good write up on using a battery monitor, and how NOT to just believe what it says. Written for sailors, so info is a little more critical halfway across the Pacific Ocean, but still applies. The author is a highly respected person in his field. Also links to a "new" kind of battery monitor that has just light gauge connections to pos and neg battery terminals, way more accurate, and no user input required. Interesting.

http://www.pbase.com/mainecruising/programming_a_battery_monitor
 
Unfortunately testing for capacity isn't really practical for most of us. Decline with age isn't something I'd thought of. Lots of info there and even though half of it went right over my head I still picked up a few useful tips. Trying to come to some conclusions there it seems like maybe it might even be better to shoot for max min of 65% SOC. Definitely need to look my charge profile over and see if I can use any of that info to tweak it a bit.
 
Given that what my battery claims is the ah rating is likely optimistic I could just lower the setting but, what if I go to far? Ex. my battery is rated at 220 and I set the meter at 200 but its really higher than that? Whats that do to my charging algorithm?
 
BrianW said:
Here is a good write up on using a battery monitor, and how NOT to just believe what it says. Written for sailors, so info is a little more critical halfway across the Pacific Ocean, but still applies. The author is a highly respected person in his field. Also links to a "new" kind of battery monitor that has just light gauge connections to pos and neg battery terminals, way more accurate, and no user input required. Interesting.

http://www.pbase.com/mainecruising/programming_a_battery_monitor
Click to expand...

craig333 said:
Given that what my battery claims is the ah rating is likely optimistic I could just lower the setting but, what if I go to far? Ex. my battery is rated at 220 and I set the meter at 200 but its really higher than that? Whats that do to my charging algorithm?
Click to expand...
Great info here BrianW!

Craig, instead of doing just relying on the SOC display, I think this article suggests that we keep an eye on the battery resting voltage too, to detect a discrepancy. For example, it is early in the evening after the sun is down and nothing is charging the batteries, and you can still turn off all the lights ... so you do that. If you see that the resting voltage is is now 12.2 or lower, and your SOC displays more than 50%, something is amiss, AND you are in deep doo doo. 12.2 is a 50% SOC battery, and you want your batteries to be higher than that first thing in the morning, when they will start charging up again, never mind last thing at night.
 
Vic,

That was pretty much my "take away" from the article. The battery voltage is the number to watch, not the SOC. I have an early Victron monitor in a boat and will be using it a little differently now. Just knowing that the SOC reading can be off is valuable.

The Balmar monitor looks interesting if you read the test report. Doesn't really give information on draw, or charging rate, but does give accurate SOC. Without all the capacity testing etc. Plug and play at its best. Just throw another $250 (US) or so at it... I would still want a Victron or similar for the info they do provide, nice to know what appliance draws are in real time, and what kind of charge from solar etc.

Gets all very complicated, no?

cheers
 
BrianW said:
Vic,

That was pretty much my "take away" from the article. The battery voltage is the number to watch, not the SOC. I have an early Victron monitor in a boat and will be using it a little differently now. Just knowing that the SOC reading can be off is valuable.


Gets all very complicated, no?

cheers
Click to expand...
Indeed it does. Or you can KISS and just buy new batteries more often. :oops:

I would NOT rely on battery voltage though. I would use it as a "sanity check" on the SOC. The Victron (and Trimetric) units are very good at self regulating and adjusting for the various factors that article says to keep in mind, so most of our community here can relax a bit if they are using the Trimetric....
 
We're not doing all that badly though at first he makes it seem as though the sky is falling (90% of the battery monitors are not programmed correctly) what he's getting is why are we settling for 4-5 years battery life out of our very expensive batteries (he's certainly a proponent of using expensive batteries (high quality) batteries ) when with the proper settings we could extend that out to 7-10 years.

He does, somewhat reluctantly have some advice for those of us what can't or just aren't going to do a 20 hour ah test and more. Read the smarter use of your battery monitor section. I'd still like to hear some advice for or a rule of thumb for estimating battery deterioration over time. Maybe that just varies way too much to even guesstimate.

Well now I've at least heard of Peukert compensation :)

Now I'll go out and see if I can turn off auto sync (or if I even have it).
 
What would you think of using voltage only for the guy who has very low electrical needs (no fridge) a single camper battery and doesn't mind replacing a cheapie every other year?

Many of us started that way. Volt meter, small solar panel, hoping the chinese controller does a decent job.
 
Please bear in mind as well that he is talking about boats. In a long voyage scenario where maintaining batteries correctly can be critical for navigation (gps) for example. I think that is where actually knowing the capacity would possibly be worth the effort.
He does say that using an amp/hr meter has raised the awareness of battery condition in general, which is a good thing. Knowing that it is *possible* to have an amp/hr meter show a 70% SOC with low voltage indicating less of a charge is a step further in the right direction, imo.
 
craig333 said:
What would you think of using voltage only for the guy who has very low electrical needs (no fridge) a single camper battery and doesn't mind replacing a cheapie every other year?

Many of us started that way. Volt meter, small solar panel, hoping the chinese controller does a decent job.
Click to expand...
Craig, are you using AGM batteries or flooded cell? If you are using FLA batteries, the BEST way to measure SOC is still measuring specific gravity.

Using voltage implies that you can measure resting voltage, when the batteries have not been charged or drained for more than just a few hours.

The idea of checking voltage in addition to reading the SOC on your meter is to catch gross mismatches.

How long do you head out for at one time? IF your are back at home base once a week you can charge up to full using a good charger like the Noco Genius and get a much better idea of what your resting voltage is at 100% SOC.
 
I wasn't referring to myself. I'm pretty confident in my own system.

I've sized my system so I'm very unlikely to ever draw it down too low even if my batteries were lower ah than I thought (age or manufacturer being a bit optimistic). I'm still a bit unclear how what that does to my charge profile if I have an incorrect number in there.

Of course I had to recheck Bogart Engineerings site to see if they had any updates and I noticed what they had to say regarding Peukert compensation. Much different. It'd be nice if the experts all agreed on this stuff.

And yes, boaters are a lot more likely to make the extra effort. Much like aircraft nerds aficionados.
 
Lol, "much like aircraft...aficionados". Ok, boats and planes... guilty as charged !
 
craig333 said:
Of course I had to recheck Bogart Engineerings site to see if they had any updates and I noticed what they had to say regarding Peukert compensation. Much different. It'd be nice if the experts all agreed on this stuff.
Click to expand...
Craig,

Thanks for the tip on the Bogart info - is this the article you read?

I'm not so sure that the experts are disagreeing so much as taking a different approach to how they think people will use their equipment. The Bogart stuff has an extremely practical feel to it.
 
The document referenced below totally misses the mark and shows a fundamental misunderstanding of battery electrochemistry.

From the document:
Simply put, the reason you get less amp hours out when the amps are higher is that the higher amps drag down the volts more than a lower amp load, so the 10.5 volts endpoint is reached sooner. It is not because some of the electrons in the battery get lost or wasted when you draw current out faster.
Click to expand...
This is fundamentally untrue. You actually get fewer joules out of a battery at higher discharge rates as the internal resistance of the battery is higher under high discharge rates. Anyone who has used a battery under high discharge rates will know that they get quite warm, that heat is wasted energy you won't get from the battery as electrical power. You can easily convince yourself of this by doing the same experiment but using electrolyte gravity as the 'end point' instead of cell voltage - Peukert will still apply.

There is a fine line between physics and marketing.



Vic Harder said:
Craig,

Thanks for the tip on the Bogart info - is this the article you read?

I'm not so sure that the experts are disagreeing so much as taking a different approach to how they think people will use their equipment. The Bogart stuff has an extremely practical feel to it.
Click to expand...
 
rando said:
There is a fine line between physics and marketing.
Click to expand...
Sometimes not so fine I guess. So the Bogart paper maybe be in error on the physics. Do you think that it is also misleading? From my read their point on the difficulties of trying to predict future loads that might be impacted by a Peukert exponent calculation is worth thinking about.
 
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