A Question on Charging

[Utahsailor]

This spring we installed a new battery bank with about 1,000 AHr of T105s. The solar panels have kept it fully charged during the summer and for short sails. We have left Belfast ME for the south and find the shorter days, more masking by sails and rigging and higher power consumption during sailing don’t allow full charge from solar alone. During day long powering the dual 300A output alternators used to fully charge the bank but now the charging has plateaued at 89% (from Balmar Smart Meter). I ran the engine this morning at anchor and was still putting in 180 A after 45 minutes. The solar setup is 840 W with dual Morningstar controllers. All charging inputs lead to a common bus. So a few questions:

Could the Balmar controller see the competing controllers and cut back its output?
How can I safely shut off the solar panel output to just use Balmars for long powering days?

Thank you for the answers

[a64pilot]

Couple of ways, a simple breaker can disconnect the Solar, or change the set point for float on one of them so the Balmar's is higher.
I assume the set points are adjustable on at least one, either the Morningstar or the Balmar?


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[smac999]

Cutting back at 90% is normal. Generally you don't run an engine or gen past 85% for battery charging (unless you are motoring or need AC loads anyways). Normal artery operations between 50-85% on a boat until you plug in. Solar will help and get you above this.

If you want to charge 100% with the engines this is where li batteries start to shine. and Agms might help.

But in short. If you are charging lead acid batteries over 85% with engines or gen (for sole purpose of charging) you are just wasting gas. As they will continue to take less and less charge from 85-100%

190a into a 1000ah battery at 90% seems pretty normal to me assuming they are flooded acid. (20%)

[exMaggieDrum]

I don't believe a Balmar smart alternator regulator, e.g. the 614, would care about the solar panel charging. It would go in to bulk/absorption charging quicker if the batteries were already at the bulk/absorption voltages. But it should follow the set times for bulk and absorption and then it overrides the end point of those phases based on its internal algorithms. It is important to set the right bulk/absorption voltage (14.8 for T-105 per Trojan specs) and 13.2 for float. You can set longer bulk and absorption times by programming the units.

You didn't say if 180A after 45 minutes is the same now as it was before but it doesn't seem out of line from what you could get, but it all depends on how charged the batteries were when you started. But 180A is a healthy rate of charge. What you really need to do is to log the charging noting the capacity when you start and then note the times and voltages you see. You also didn't say whether the solar panels were contributing to the 180A or not. Your 300A alternator potential will be limited by the battery acceptance of a charge. The acceptance of amps will decrease dramatically as the batteries begin to fill up - way before they get to 90%. AGMs can take a higher charge longer but they both stop accepting charge at some point.

If they were taking 180A I don't think they were near the 90% state right then, but you have a larger bank than usual I may be wrong on that. The time to 98% full is dramatically longer than the time to get to 90% though, at the absorption voltage. With your large solar panels you should be able to "top off" the batteries if your usage is not high, after the batteries are bulk charged by the alternators.

You also don't say if your solar regulator is a smart type or not. You need a very high quality programmable regulator for your panels. You should set the voltages the same as for the alternator regulator.

With such large charging sources it is important for you to not get the batteries too hot by charging them too fast. In the PNW that is not as critical as in warmer climes, but if you batteries are in the engine room it is critical. You do not want to overheat the batteries. Balmar has temperature sensors for their regulators.

The regulators for the alternators have nothing to do with the Balmar Smart Monitor. It only tells you what it thinks the capacity is. I don't have any experience with this Monitor but Maine Sail, who is widely respected on CF for his expertise, recommends them. You want to make sure it is giving you a correct reading though if you are making decisions based on what it says.

You should have a fuse (at a minimum) between your solar panel regulator and the batteries. You can pull the fuse (if convenient) if you want to turn off the solar panel charging. It should not hurt anything (for any controllers I have seen). But what works better is a switchable circuit breaker (like a Blue Sea 285-Series) at the correct amp rating, mounted where you can get at it easily. Then you can monitor the charging by the alternators, or monitor your actual usage without the alternators running, without the solar adding while you monitor it. You can also see the contribution direct to the batteries by switching it on and off. Or, if your controllers have an off/on switch you can use that too. Some do, some don't.

We had to push out our boom to unshade the solar panels all the time when at anchor. But the mast can also shade the panels depending on wind/current alignment to the sun.

I guess it is possible that your batteries have a capacity issue but you would want to verify that. That is a more complicated discussion you can find elsewhere here (with lots of opinions unfortunately). I posted something on that last week where I quoted the Balmar Smart Monitor owner/inventor.

Welcome to the many mysteries of DC battery systems. Good luck. If someone gives you different info you'll have to decide what to do. I'm sure someone will have something different to say. Unfortunately there is no free lunch with batteries. Until better batteries (that anyone can afford) come out we are stuck with technology that cannot be "insta-charged".

[smac999]

another comment, I have never used the smart meter, only battery monitors. But I can't see how it can work while charging?...


if you are at say %55 battery. and start your engine with a 300a alt (or both engines with 600a (not that you'd get that into a 1000ah bank). it's going to hit 14.x volts and stay there. after 10 mins, 20 mins, 4 hours. at 14.x I can't see how the smart meter, which is based on voltage. could show you a correct % while charging. so I don't know if you can trust that thing to watch while charging??? if a battery is sitting under charge at 14.5v it could be 0% or 100% full. a volt meter would be useless for this task.

[a64pilot]

Read Mainsails article ref the Smart Gauge, I believe he says in the article that it's not as accurate during charging, but it's pretty close.
With my smart gauge I notice once I go into float, it takes a long time to go from say 98% to 100%, but that is a long way from 89%

Of course if I understand the Smart Gauge, a simple loose or dirty connection will make it read low, but I believe the poster said the Alt's were still putting in lots of current after a long time, and if that's the case, then the bank is low


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[Maine Sail]

7-10 hours+ is what is needed to charge most used lead acid batteries to 100% SOC.... The last 10% is slow, the last 5% is excruciatingly slow and the last 2% ...

The Smart Gauge will only be at its best accuracy for SOC once it is dark, charging has stopped, and the banks is no longer being charged.

When you get down towards 10-15A of charge current, measured at absorption voltage, your bank is now "full"...

If you are still pumping 180A after 45 minutes you are unfortunately a long way from 100% SOC....

[Utahsailor]

Thanks everyone. I should have given more info: I started the charge this morning before the solar panels had started producing. The SOC from the Smart Meter was 80% and, after the 45 minute engine run, had increased to 85% and the current from Balmars had reduced to 170 A, a normal amount for the large battery bank. The alternators and batteries all have temperature sensors. My main question was about a relationship between the different controllers that might have changed the way the Balmar smart controller worked. The next day I run the engines a long time, I'll shut off the solar panels and see if the batteries charge differently (there are switches ahead of the controllers, I didn't know if anything would be damaged by shutting the panels off. My only wonder about the T105s, which I much prefer to the old AGMs, is that they are using more water than other members, maybe a pint in two weeks.

[btrayfors]

Use Hydrocaps or Water Miser caps on the T105's to help reduce water loss. I have used WM caps on all my golf carts (10) for many years.

You can cut off the solar panel output BEFORE the controller(s) without damage. You do not want to cut the connection between the controller(s) and the batteries unless the solar panels are already disconnected.

Bill

[svlamorocha]

Originally Posted by Utahsailor

This spring we installed a new battery bank with about 1,000 AHr of T105s. The solar panels have kept it fully charged during the summer and for short sails. We have left Belfast ME for the south and find the shorter days, more masking by sails and rigging and higher power consumption during sailing don’t allow full charge from solar alone. During day long powering the dual 300A output alternators used to fully charge the bank but now the charging has plateaued at 89% (from Balmar Smart Meter). I ran the engine this morning at anchor and was still putting in 180 A after 45 minutes. The solar setup is 840 W with dual Morningstar controllers. All charging inputs lead to a common bus. So a few questions:

Could the Balmar controller see the competing controllers and cut back its output?
How can I safely shut off the solar panel output to just use Balmars for long powering days?

Thank you for the answers

If the alternator is putting out 180A then the regulator is CLEARLY not cutting back.

Starting hypothesis is that the batteries are not fully charged, hence they take all the 180A that the alternator can produce. While the batteries are taking 180A you should keep track of voltage AT THE HOUSE BATTERY TERMINALS that should go up slowly but continuously while the alternator is charging. Ideally you should use a DC clamp meter to measure the current 8amps) in the fat negative wire from house bank to shunt, to make sure that the 180A are going that way and there is no installation of calibration problem in the battery monitor.

The two regulators (solar and Balmar) will only "interfere" with each other once the voltage goes up to the "absorption level" set in each of them. In other words, the two controllers/regulators will only interfere with each other when the batteries are about 3/4 full, and the rate of charge at tthat point is limited by the batteries, not by the chargers. When using Victron systems that let you program all the values at will I prefer to set the solar absorption voltage higher than the absorption voltages or the shore and alternator systems, because this saves energy without affecting the charge current.

What are the two absorption voltage settings in your system? They should be 14.8V (temp compensated) at the batteries. If they are lower then the batteries will not last as long as they should.

Do the regulators/controllers have a pair voltage sense wires (thin wires that are only used to measure battery voltage, separate from the fat wire used for charging)? If not then trying to fine tune the interaction between two controllers is a waste f time.

While you are troubleshooting disregard the % SOC reading in the monitor and look at amps going into teh house bank and voltage across house bank terminals.. Maine Sail explains this very well.

Once you understand what is happening to your batteries then you probably need to correct your "syncrhonization" settings (current, voltage and possibly time) in your battery monitor, which are the "recipe" that tells the monitor when the battery is 100% full. The usual "current 0 rated Ah capacity divided by 20 or multiplied by 5%" should in most cases be replaced by "divided by 100 or 200, or multiplied by 0.55 or 1%" and th evoltage should be set to the absorption (not float) voltage.

Also do not make th emistak eof believing that the regulator/controller´s "decision" to switch from absorption to float voltage (which is based on a very rudimentary algorithm that may be adequate for your boat and the way you use it) means that the batteries are full. There are many boats in which you have to restart the cycle once or twice to get the batteries close to fully charged (say acceptance current drops to rated Ah capacity divided by 100 or 200). It is OK to stop charging before 100% but if you do not reach 100% for more than say a week for AGMs and a few weeks for flooded, you end up with sulphate that "hardens" on the plates and takes away capacity.

[Maine Sail]

This is a chart I did for a customer a while ago who thought his AGM's should charge to "100%" in a couple of hours based on glossy marketing. Using one of his own used batteries, I capacity tested one then drew out 50% and recharged with the data logger recording.

I data logged, at 2:00 intervals, both current and voltage. Lifeline defines the battery full at 0.5% current acceptance at absorption voltage / 14.4V...

This battery took 7:06 minutes to get from 50% SOC to 100% SOC (as defined by the manufacturer) using a 25A charge rate and a 14.4V absorption limit.. A new AGM would be faster and flooded batteries, new or used, generally slower.....

[barnakiel]

Originally Posted by Utahsailor

The SOC from the Smart Meter was 80% and, after the 45 minute engine run, had increased to 85% and the current from Balmars had reduced to 170 A, a normal amount for the large battery bank.

;-)

I think you said your batts are 1000 Ah?

So how can a change from 80% to 85% (5% x 1000 Ah = 50 Ah) equal to 170 A (at the end of the 45' period) ???

One or another piece of your equipment is out of tune.

Think of it, if at the end of 45 minute period your A meter reads 170 A then you were putting in this amt or more in the 45' period. Then this is 0.75x170= 130Ah while your % meter reads out only 50Ah ...

Something is off and it sounds like it is either your A meter or your % meter. If they are one instrument then make sure the installation and calibration are fine.

BTW If you start your alt rig in the morning before the sun kicks in, you will have no problems with solars messing up the Balmar regulator.

BTW2 If you have T's in a big bank make sure you equalize them as per the sheet. I have seen them going way off if not equalized regularly. This does influence how well and how quick they charge.

b.

[svlamorocha]

Originally Posted by Maine Sail

This battery took 7:06 minutes to get from 50% SOC to 100% SOC (as defined by the manufacturer) using a 25A charge rate and a 14.4V absorption limit

When you say "7:06 minutes" you mean 7 hours and 6 minutes; right?

[svlamorocha]

Originally Posted by Maine Sail

This is a chart I did for a customer a while ago who thought his AGM's should charge to "100%" in a couple of hours based on glossy marketing. Using one of his own used batteries, I capacity tested one then drew out 50% and recharged with the data logger recording.

I data logged, at 2:00 intervals, both current and voltage. Lifeline defines the battery full at 0.5% current acceptance at absorption voltage / 14.4V...

This battery took 7:06 minutes to get from 50% SOC to 100% SOC (as defined by the manufacturer) using a 25A charge rate and a 14.4V absorption limit.. A new AGM would be faster and flooded batteries, new or used, generally slower.....

This is cool stuff.

The 7 hours and 6 minutes are based on a "proper" absorption voltage for Lifeline AGMs, which Maine Sail takes for granted becaue he installs and configures things properly. There are many boats in which the voltage at the terminals in the absorption stage is way lower than 14.4V (due to drop or "default" settings), hence absorption current is lower than in this chart and the batteries will never charge to 100%. Where I say 14.4V for Lifeline AGMs read 14.8V for Trojan FLAs

Mosts importanty this chart shows that solar is great to "finish" the charge but this means that you need to run genset/engine early in the morning when the batteries can take bulk current from both sources. Nobody will run engine or genset 7 hours to charge batteries, but the sun is up for more than 7 hours.....

[Maine Sail]

Originally Posted by svlamorocha

This is cool stuff.

The 7 hours and 6 minutes are based on a "proper" absorption voltage for Lifeline AGMs, which Maine Sail takes for granted becaue he installs and configures things properly. There are many boats in which the voltage at the terminals in the absorption stage is way lower than 14.4V (due to drop or "default" settings), hence absorption current is lower than in this chart and the batteries will never charge to 100%. Where I say 14.4V for Lifeline AGMs read 14.8V for Trojan FLAs

Yes if there is voltage drop the batteries will take even onger to reach 100% SOC. Batteries actually can attain 100% SOC when charging at less than their absorption voltage but it takes a LOT longer. Also doing this regularly will not be healthy for them over the long haul.

Mosts importanty this chart shows that solar is great to "finish" the charge but this means that you need to run genset/engine early in the morning when the batteries can take bulk current from both sources. Nobody will run engine or genset 7 hours to charge batteries, but the sun is up for more than 7 hours.....

Yes solar is great for the absorption stage and genset or alt for bulk and some early absorption.

P.S. That graph is really only representative of that battery at that state of health. Some will take longer and some will charge faster...