Battery status or what are these displays really telling me?

[Klompen]

We had our SMB pre-wired for solar and we have a 100 watt suitcase panel and a 200 AH AGM battery.

As I read the display in this photo, the battery is above 85% charge and in the absorption charge phase. I'm confused by the status bar, which shows only 1 solid bar and 3 flashing. That indicates that I have only 25% charge, not 85%+. In addition, after having the panel out all day in solid sun and moving it to keep a good angle, I'll only show 12.7 or 12.8 volts when the sun goes down.

So what are these panels really telling me about what my solar charging system and the state of my battery?

[Scalf77]

From the picture I can tell the Magnum Charger is off and the voltage is at 12.8 volts, the zamp controller says that it is putting out 4.9 Amps. I believe that the indicators are telling you that the battery is above 12.5 volts which is the same as the absorption status ( whoops). I would go with the 12.5 volts as it is 12.8 volts, and which would not be correct absorption setting for a AGM battery. It is very possible that the 100 panel is not giving you enough current, to provide an adequate absorption phase. I assume that you got the 85% SOC by believing it is in absorption phase.

The Magnum Inverter/Charger Remote does support an actual battery monitor. It is an extra kit called the BMK. If you had a BMK you would access it by going to the meter button on the Remote. I would check your build, and see if had one included. If needed I could walk you through accessing it.

Unless you have a BMK none of these units actually tell you the state of the battery, you can glean that information from the voltage, but that can be in accurate when there is a load on battery. It is also difficult to tell you what your ending voltage of 12.7 or 12.8 means, as a voltage measurement at a point in time is just that, we really need to know more before and after.

I expect the bar LEDs are for what ever feature you are displaying, which I believe at this time is in current, and showing you it's 25% of controller capability. I would expect that to change as you switched the amp/volt button through it's outputs " voltage, current, amp-hours, and temperature". Note temperature will only be available if you have the temp sensor installed.


I first guess is that you have been undercharging your battery. I would plug in and go through a full charge with the shore-power charger. The Magnum remote should provide you data as it goes through it's charge cycle.

Hope I have answered your question, and probably prompted some new ones.

greg

[Klompen]

Thanks Greg for the quick response.

We do not have a BMK, although one can be added. As I understand it, a BMK would tell me a true state of charge as well as telling me how much power was going in/out over a 24 hour period.

I've attached images of the appropriate pages from the manual. Absorption rate (and therefore 85%+) comes from the LED indicators.

The %charge does not change when I cycle from amps to Ah to volts. As I read the book, it is only about state of charge.

I agree that it seems to be undercharging. I'll probably connect to my SiL's generator and see if I can get a full charge. Your post on solar/shadow was very helpful. I haven't looked yet to see if you have one on what effects charging most volts from the panel or amps. I managed to get as high as 5.4 amps and 13 volts on the Zamp controller.

[Scalf77]

I am not sure how they calculate SOC for their BAR meter, they inherently don't have enough information to make that projection, other than resting voltage and you can't get that when charging. They could make some calculation based on that voltage while charging, but it would be somewhat inaccurate. The best thing to do is record the 1 hour after you have lost solar charge, and one hour before you start charge.

If you are relying on the 100 watt panel to charge the battery while camped, you will be probably be unhappy with the results.

The Magnum BMK kit would be your easiest answer for a battery monitor, although I like the new Balmar SG200

This is a pretty good thread on battery charging, it currently covers shore power and alternator, I will be adding some solar data in the coming weeks.
http://www.sportsmobileforum.com/for...ing-23438.html

-greg

[Klompen]

I'll definitely review that thread.

We connected to a generator for 30 minutes. The photo shows the status after that. We went away to watch fireworks so nothing was on except our fridge. 6 hours later the Magnum shows 12.6V and the Zamp still shows 4 bars for battery state (no charging going on at 2230). It makes me suspect that we also have battery issues.

Is the Balmar SG200 compatible with the Magnum like their own BMK? (Nevermind... I see that it is an independent unit.)

[Scalf77]

So, I'm not sure what you are expecting to see out of the zamp controller. It does not really have the capability to give you an adequate SOC reading. It really only knows the battery voltage and the current that it generates (subsequently it could record Ahrs). It does not know the about the current that is being used by any loads, or by any current being supplied by the Magnum Charger. You might want to discuss with Zamp how accurate their display is, I don't have one, and can only go on my general knowledge.

It would have been good to have seen what your Magnum Remote said while you were on the generator. It would have told you if you were in bulk, absorption or float. I am pretty confident you did not make it to float. Charging a battery goes through two primary stages; Bulk, and the Absorption. In the bulk phase the charger will provide a constant current. If you have battery at 50% SOC it will take a while for the charger to get the battery to the absorption level voltage , this is generally above 14+ volts depending on the parameters of your charger and temperature if it has a supplied temperature sensor.

After reaching the Absorption voltage we will see the charger move into that phase. In this phase the charger will hold at that phase at a lower current, the current will continue to decrease in this phase, but the voltage will remain steady. There will generally be a current point that will cause the charger to believe that it has fully charged the battery, and it will transfer into the third phase "float".

Float is going to be in the 13+ range and again it will be determined on what parameters your charger is set to and again temperature if you have a sensor.

In my opinion your solar setup does not have the capabilities to fully charge a reasonably drained battery in a day. It can certainly extend your stay, but you will need to plug in at sometime to fully charge the vehicle. It is possible that driving doing the work of the bulk charge and if you have enough sunlight when you get to your destination that solar could then top it off. For my Magnum Charger it takes six hrs to get from 50% depth of charge to fully charged battery in float for my 210 amp-hr AGM battery. The charger is set to 60 amps.

So I suspect you have a charging problem, which of course will lead to a battery problem.

You would need to provide space for the SG200 display, other than that, both battery monitors require that you install a shunt. The SG200 has what they call a smart shunt, with active components in the shunt, while the BMK has the active components in a separate module, that then connects to Magnum Remote. I have the magnum BMK and have installed a few of the SG200's. It is refreshing to read the color display of the SG200, it is a one button wonder that takes a little bit of usage top feel comfortable going through the display.


-greg

[Klompen]

Thanks, Greg for all your insight. This has all confirmed what I already suspected - that I need a BMK and more solar. This just makes clear how blind you are without a BMK.

Sorry that I did not take a photo when on the generator. It showed Absorption Charge, 14.x V, and amps in the 40s. The generator showed a draw of 9.1 amps when we started and 6.5 after half an hour.

Ernie