Weird Issue Sterling Error Light, Solar Stops Charging

[Ex-Calif]

Hmmm... Got me curious. The absorb time can be very low and even 0. If the battery voltage is above 12.6 the absorption phase could be skipped. Read the manual to understand the controller set points for various battery types and to confirm DIP switch settings if curious.

"

1.9.2. Absorption stage

When the battery voltage reaches the absorption voltage setting,

the controller switches to constant voltage mode.

When only shallow discharges occur the absorption time is kept

short in order to prevent overcharging of the battery. After a deep

discharge the absorption time is automatically increased to make

sure that the battery is completely recharged. Additionally, the

absorption period is also ended"

Manual is here -

http://www.victronenergy.com/upload/...E-ES-SE_A6.pdf

[simonpickard]

The volts were 13.7v I just checked. I think the solar is now putting in enough to keep things charged.

If you could please bear with me while I ask what I'm sure is a dumb question.

The volts I'm seeing are charge to the battery is that right?
That's not showing how 'full' the battery is? For that I need a battery monitor?

I think that's the thing I haven't been able to get my head around yet. I see the volts slowly dropping sometimes (if we're using a lot of power) and then that's the battery draining but from what I'm reading that might not be the case?

[Ex-Calif]

So basically a battery can be "charged" meaning full and it is temperature dependent and a few twists but basically to determine the state of charge - battery voltage can be used. See the attached chart for a sample.

To get amps into a battery any charging source must raise voltage above the current battery voltage level. So let's say that's 14 volts. This energy transfer creates heat due to resistance and that heat creates more resistance. Therein lies the need to taper off the charge to get the last amps in.

When removed from charge the battery takes awhile for the voltage to stabilize and drop down to what is considered a "full" charge.

Now here is the confusing part. Over repeated cycles the battery plate material falls off and collects on the bottom of the battery and the battery just can't hold as many amps (it is wearing out) - the voltage still comes up to "full charge" but if we use the water jug analogy - the jug has sediment in the bottom and can't hold as much water as it used to.

A battery monitor will measure voltage and "state of charge" but there are some very complex things going on inside the battery which in essence is a little chemical reactor. So the battery monitor needs to be "programmed" and if not programmed and periodically calibrated it can have great error.

There is a new monitor called SmartGauge - our resident and respected expert MaineSail has independently tested the SmartGauge and it basically handles all the errors correctly and automatically and can tell you the state of charge!

I would readily recommend you get this gauge. What it does not do unfortunately is measure amps in and amps out like a "traditional" battery monitor. I think it is a big miss on this monitor. While essentially amps in and out don't matter in this new gauge (prior monitors used amp counting as the SOC measure) I like to know what's going in or out to monitor the charging system.

What no monitor yet made can really tell you is how much of your capacity has been lost. As you live with a bank you will get a sense of how long it should last before charging. Eventually you will notice they "don't hold a charge" or "discharge quickly" - this is just saying that the capacity is worn out.

Batteries can last anywhere from a year (poorly treated batteries) to 10 years plus.

[simonpickard]

That makes more sense, thanks.

I wish these boats just came with a smartphone style % bar showing the battery life left and when to recharge!

Talking of which what level (volts) do you never let the batteries go below?

Regards.
Simon



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www.sailing-interlude.com

[nigel1]

Originally Posted by simonpickard

There are three LEDs on the solar controller so I think you're right that it's a three phase but I've only ever seen it in float or bulk mode.

Also this little bit of water is worrying me, or is that what batteries do? Should I just clean it up?



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www.sailing-interlude.com

Could be a spill from topping up the battery.
Wipe it clean and dry, and then keep an eye on it.

[Ex-Calif]

Originally Posted by simonpickard

That makes more sense, thanks.

I wish these boats just came with a smartphone style % bar showing the battery life left and when to recharge!

Talking of which what level (volts) do you never let the batteries go below?

Regards.
Simon



Please visit my blog:
www.sailing-interlude.com

That's basically what the Smartgauge does.

Very simple and accurate.

BTW - the smartphone has the same issue. As it gets old you will notice the battery dies sooner and sooner - came problem. It charges full but the capacity is gone.

You never want to go below 50% and it is "healthier" for the batteries to have shallower discharges - in reality the batteries are likely to "live" between 60% and 90% - I try to target mine to stay above 70% most of the time.

[simonpickard]

So when you say no lower than 50% how does that relate to volts? Or doesn't it? Do you need a battery monitor to be able to tell this?



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www.sailing-interlude.com

[nigel1]

I think 50% equates to about 12.2V, but that's with a battery at rest.
A battery with load may show 12.2V, but after the load is removed, the voltage will return to say 12.4 or 12.5.

I think a battery monitor is a good bit of kit to have, you will see in an instance if the charging sources are working, and what loads are on the system.
After a while, you will know what to expect, so a unusual reading can help you to sort out a potential problem sooner.

I sort of know what battery voltage I would expect on a sunny day with fridge, AP, plotter running, and what sort of voltage I would expect at night if the battery is at rest.

Go on, treat yourself, you know you want to

[simonpickard]

Been looking at that smart gauge. Looks good.



Please visit my blog:
www.sailing-interlude.com

[Ex-Calif]

What Nigel said - If I had a "moderate" load on the bank and saw 12.2-12.1 on the gauge I would be looking for a charging source.

[simonpickard]

I'm still not exactly sure about all this stuff so maybe I'm worrying about nothing here..

So after a solid two days on shore power we unplugged and needed to motor for the best part of 9 hours today where we are now on anchor.

90mins after turning everything off the volts are:

House (service) bank: 13.4v
Engine bank: 13.1v

I have the fridge on.

Is that normal or do I have an issue still?



Please visit my blog:
www.sailing-interlude.com

[Ex-Calif]

I presume it is sunny and the solar is putting out?

You have potential (voltage) on the bus greater than full battery charge. That's a good thing IMO.

To understand the batts better you'd probably want to see the voltage at the battery with the solar isolated to read the batt voltage but I don't think you have any issue.

[simonpickard]

Since keeping an eye on things the solar seems to take the batteries from around 12.6ish overnight to 13.6ish by mid-afternoon and then enter float mode. I think as long as I can keep things in this range I should be pretty good.

I'd still love a simple way to see how much is coming in via solar vs going out via the systems on board.

[monte]

The simplest solution is a victron BMV 600 battery monitor. Cheap, easy install ( look on Maine sails how to web page) and gives exactly the info you need. Using it you can see exactly the amps going in and going out and check exactly how much the solar is putting in or a light or nav gear is consuming.

[FlyingCloud1937]

Sounds like you are running in deficit mode.. If your bats never see 14-4 to 14.8 for LFA's, for 2-3 hours, you are not reaching full absorption.

So likely you will hard-sulphate your bank, and it will die an erly death.

A healthy charge cycle will take it all the way up, then after a few to eight hours it will drop back down to float voltages.

Lloyd

Originally Posted by simonpickard

Since keeping an eye on things the solar seems to take the batteries from around 12.6ish overnight to 13.6ish by mid-afternoon and then enter float mode. I think as long as I can keep things in this range I should be pretty good.

I'd still love a simple way to see how much is coming in via solar vs going out via the systems on board.