Batteries: What is considered "low".

[mitiempo]

Originally Posted by coopec43

I've only just installed my Victron SmartSolar so I've got a thousand and one other things to think about at this stage. But in very broad terms how do I make adjustments? (I've downloaded relevant parts of the manual but have yet to study it at this stage)


Some people have said they use their smart phone so I assume the controller is blue tooth and I would have to download a package to interface with the controller?

Your controller may be Bluetooth.

Is it a Smartsolar or Bluesolar controller?

https://www.youtube.com/watch?v=aPB4NiOAZIo

[coopec43]

Originally Posted by mitiempo

Your controller may be Bluetooth.

Is it a Smartsolar or Bluesolar controller?

Thanks for your help. (I will look at the video clip this evening)

This is what I have. (There's reference to Bluetooth below)


Victron Energy SmartSolar MPPT 100/20 (Up to 48v-20A) Bluetooth Solar Charge Controller

SmartSolar MPPT 100/20

Solar charge controller
A solar charger gathers energy from your solar panels, and stores it in your batteries. Using the latest, fastest technology, SmartSolar maximises this energy-harvest, driving it intelligently to achieve full charge in the shortest possible time. SmartSolar maintains battery health, extending its life.
The SmartSolar charge controller will even recharge a severely depleted battery. It can operate with a battery voltage as low as 0 Volts, provided the cells are not permanently sulphated or otherwise damaged.

Models:12/24/48 Volt

MPPT: Ultra Fast Maximum Power Point Tracking
By constantly monitoring the voltage and current output of your solar (PV) panels, MPPT technology ensures that every drop of available power is rinsed out of your panels, and harvested for storage. The advantage of this is most noticeable when the sky is partially clouded, and light intensity is constantly changing.


Remote Monitoring and Control
Remotely control and monitor the extensive features of your SmartSolar MPPT charger with built-in Bluetooth by pairing it with your smartphone or other device via VictronConnect. If your installation is connected to the internet with a GX device, the Victron Remote Management Portal (VRM) provides access to the full power of your MPPT, anytime, anywhere; both VictronConnect and VRM are free to use. For remote installations - even when there is no internet connection nearby - you may be able to monitor your MPPT by connecting the GlobalLink 520.


Load output
The intelligent Load output function prevents damage causéd by running batteries 'flat'. You can configure the voltage at which SmartSolar disconnects a load - thereby preventing excessive drain on your batteries. And here's the clever bit: SmartSolar will attempt a 100% recharge every day. If it can't - during periods of poor weather - it raises the disconnect voltage, daily, until it achieves success. We call this feature BatteryLife because it maintains the health, and extends the life of your battery.


Bluetooth Smart built-in
The wireless solution to set-up, monitor, update and synchronise SmartSolar Charge Controllers


VE.Direct
For a wired data connection to a Color Control GX, other GX products, PC or other devices


Ultra-fast Maximum Power Point Tracking (MPPT)
Especially in case of a clouded sky, when light intensity is changing continuously, an ultra-fast MPPT controller will improve energy harvest by up to 30% compared to PWM charge controllers and by up to 10% compared to slower MPPT controllers.


Load output
Over-discharge of the battery can be prevented by connecting all loads to the load output. The load output will disconnect the load when the battery has been discharged to a pre-set voltage (48V model: interface with a relay).
Alternatively, an intelligent battery management algorithm can be chosen: see Battery Life.
The load output is short circuit proof.

Battery Life: intelligent battery management
When a solar charge controller is not able to recharge the battery to its full capacity within one day, the result is often that the battery will continually be cycled between a ‘partially charged’ state and the ‘end of discharge’ state. This mode of operation (no regular full recharge) will destroy a lead-acid battery within weeks or months.
The Battery Life algorithm will monitor the state of charge of the battery and, if needed, day by day slightly increase the load disconnect level (i.e. disconnect the load earlier) until the harvested solar energy is sufficient to recharge the battery to nearly the full 100%. From that point onwards, the load disconnect level will be modulated so that a nearly 100% recharge is achieved about once every week.

Programmable battery charge algorithm
See the software section on our website for details

Day/night timing and light dimming option
See the software section on our website for details

Internal temperature sensor
Compensates absorption and float charge voltage for temperature.

Optional external battery voltage and temperature sensing via Bluetooth
A Smart Battery Sense or a BMV-712 Smart Battery Monitor can be uséd to communicate battery voltage and temperature to one or more SmartSolar Charge Controllers.

Fully discharged battery recovery function
Will initiate charging even if the battery has been discharged to zero volts.
Will reconnect to a fully discharged Li-ion battery with integrated disconnect function

[mitiempo]

Originally Posted by coopec43

Thanks for your help. (I will look at the video clip this evening)

This is what I have. (There's reference to Bluetooth below)


Victron Energy SmartSolar MPPT 100/20 (Up to 48v-20A) Bluetooth Solar Charge Controller

SmartSolar MPPT 100/20

Solar charge controller
A solar charger gathers energy from your solar panels, and stores it in your batteries. Using the latest, fastest technology, SmartSolar maximises this energy-harvest, driving it intelligently to achieve full charge in the shortest possible time. SmartSolar maintains battery health, extending its life.
The SmartSolar charge controller will even recharge a severely depleted battery. It can operate with a battery voltage as low as 0 Volts, provided the cells are not permanently sulphated or otherwise damaged.

Models:12/24/48 Volt

MPPT: Ultra Fast Maximum Power Point Tracking
By constantly monitoring the voltage and current output of your solar (PV) panels, MPPT technology ensures that every drop of available power is rinsed out of your panels, and harvested for storage. The advantage of this is most noticeable when the sky is partially clouded, and light intensity is constantly changing.


Remote Monitoring and Control
Remotely control and monitor the extensive features of your SmartSolar MPPT charger with built-in Bluetooth by pairing it with your smartphone or other device via VictronConnect. If your installation is connected to the internet with a GX device, the Victron Remote Management Portal (VRM) provides access to the full power of your MPPT, anytime, anywhere; both VictronConnect and VRM are free to use. For remote installations - even when there is no internet connection nearby - you may be able to monitor your MPPT by connecting the GlobalLink 520.


Load output
The intelligent Load output function prevents damage causéd by running batteries 'flat'. You can configure the voltage at which SmartSolar disconnects a load - thereby preventing excessive drain on your batteries. And here's the clever bit: SmartSolar will attempt a 100% recharge every day. If it can't - during periods of poor weather - it raises the disconnect voltage, daily, until it achieves success. We call this feature BatteryLife because it maintains the health, and extends the life of your battery.


Bluetooth Smart built-in
The wireless solution to set-up, monitor, update and synchronise SmartSolar Charge Controllers


VE.Direct
For a wired data connection to a Color Control GX, other GX products, PC or other devices


Ultra-fast Maximum Power Point Tracking (MPPT)
Especially in case of a clouded sky, when light intensity is changing continuously, an ultra-fast MPPT controller will improve energy harvest by up to 30% compared to PWM charge controllers and by up to 10% compared to slower MPPT controllers.


Load output
Over-discharge of the battery can be prevented by connecting all loads to the load output. The load output will disconnect the load when the battery has been discharged to a pre-set voltage (48V model: interface with a relay).
Alternatively, an intelligent battery management algorithm can be chosen: see Battery Life.
The load output is short circuit proof.

Battery Life: intelligent battery management
When a solar charge controller is not able to recharge the battery to its full capacity within one day, the result is often that the battery will continually be cycled between a ‘partially charged’ state and the ‘end of discharge’ state. This mode of operation (no regular full recharge) will destroy a lead-acid battery within weeks or months.
The Battery Life algorithm will monitor the state of charge of the battery and, if needed, day by day slightly increase the load disconnect level (i.e. disconnect the load earlier) until the harvested solar energy is sufficient to recharge the battery to nearly the full 100%. From that point onwards, the load disconnect level will be modulated so that a nearly 100% recharge is achieved about once every week.

Programmable battery charge algorithm
See the software section on our website for details

Day/night timing and light dimming option
See the software section on our website for details

Internal temperature sensor
Compensates absorption and float charge voltage for temperature.

Optional external battery voltage and temperature sensing via Bluetooth
A Smart Battery Sense or a BMV-712 Smart Battery Monitor can be uséd to communicate battery voltage and temperature to one or more SmartSolar Charge Controllers.

Fully discharged battery recovery function
Will initiate charging even if the battery has been discharged to zero volts.
Will reconnect to a fully discharged Li-ion battery with integrated disconnect function

You can change any parameter with your smartphone.

[Rohan]

Originally Posted by torrmundi

No, this is no better than an inaccurate voltmeter.

I did 3 spot checks just now:
USB charger with voltage indication (fed with unknown length of unknown awg wire): 12.9
Magnum voltage monitor (mounted on current bridge with doubled 1/0awg cables): 12.96
Victron voltage monitor (mounted directly on house bank): 13.04

All for the same battery bank, but measuring at different points with differing currents going to those points, differing wire guages and differing display resolutions. In particular, the USB charger appears to truncate voltage readings, rather than round them.

Then you would have same problems with a dedicated voltmeter display. So what is your solution - keep checking with a multimeter? No thanks.

I use this product myself and it works fine. It's also less than 20 bucks so well worth the investment.

I also have a voltage gauge that came with the boat and this plug-in version has never disagreed with it.

[Stu Jackson]

If the wire size is appropriate for the load(s), then the voltage drop should be within the sizing you determined when you chose the wire size. 3%, 10%, bigger for min. VD but connections, as Maine Sail keeps reminding us, is always there.


Bigger question: mislead by more than one digit to the right of the decimal point?

[wingssail]

Originally Posted by Rockinar

Got a new auto pilot and Dometic fridge on my boat and doing a longer passage next week. Boat does not have a battery monitor. I was going to check the batteries (AGM) with a multimeter on occasion.

What would be considered "low"? I want to make sure I dont drain them to the point where it wont start. Is there a "safe" zone?

We monitor our batteries with a voltmeter (built in but a multi meter will of course work)

Charge until 14.4 volts (while refer or other load is also applied)

Monitor with normal load applied.

Recharge when voltage gets below 12.0

The house battery will start the engine even at 11.5, but we have a "start" battery in the case that the "house" battery won't do it.

ALL of this is manual, (no isolators, no combiner's, no nppt, no nada)

It's worked for 38 years.

[Dockhead]

Originally Posted by wingssail

. . .

It's worked for 38 years.

And you're full time liveaboard, full time off grid, right?



Just out of curiosity, what kind of batteries do you use, and how long do they last?

[Pizzazz]

Here are some basic rules.

1) You need at least 400 AHrs @ 12V for any reasonable usage, if you have a fridge. Plus, of course, separate bank to start your engine. If you have less, fix that.

2) You need a voltmeter and a ammeter at a minimum. When having light loads (less than 5A), you consult your voltmeter, 12.7 is full, 12.0 is empty or nearly empty. If you draw more than 4-5A, the voltage can be lower. Overtime you will develop a sense of how much lower is acceptable (i.e. if the fridge is on, the voltage could be 0.5V lower than the above, stop the fridge and it will bounce back.

3) If your voltage drops to 10V at some point, you most likely have a bad cell. If it drops to 8V you may have two bad cells. Or you may be severely discharged. In either case, you will need to replace batteries soon.

4) It is a good practice to discharge batteries all the way down at least once a month and to equalize them (if wet cells) at least every couple of months.

That's it. At some point, get a proper battery monitor but not essential initially.

[wingssail]

Originally Posted by Dockhead

And you're full time liveaboard, full time off grid, right?

Just out of curiosity, what kind of batteries do you use, and how long do they last?

Yes, Full time liveaboard, 12 mos/year.

No, not full time off the grid. We are off the grid about 3 months per year. The rest of the time we are based in a marina with shore power.

We used Trojan T-105 (6V x4) plus one 12V low maint start battery for many years. We got about 5 years for a set, sometimes more.

In Nambibia we needed Batts and bought what was available which were Silver Calcium 12 v deep cycle. They were exhausted within 3 months and would not take or hold a charge more than 3 hours.

We replaced them with Trojan T105's which lasted 7 years.

Then we went to LTH 6v golf cart batteries, same size, weight, and specs as Trojan, 1/2 the price. They lasted two years!

We bought them (LTH 6v golf cart batteries) again two years ago based on unavailability of Trojans and this set is doing very well at two plus years.

We are now more careful about keeping them from going below 12v while cruising, which requires daily recharge with the engine.

Note that we have 450 amp hour capacity yet daily usage of 125 amp hours brings these batteries down to 12v, However while cruising we cannot get them to 100%, more like 75-80% SOC. At the dock we achieve 100% SOC and they last four days without recharging.

We will look at Lithium next time but complete replacement of the entire charging/regulation system makes this an expensive change for us.

[wingssail]

More about Batteries

Our experience with LA has been average life is 4 years.

Our cost per year (estimated, at current prices):

Mexican LTH Golf cart LA 425AH capacity (est 4 year life)= 150/year
Trojan T105 Golf cart LA 450 AH Capacity (est 5 year life)= 280/year
AGM Optima blue top 400AH? Capacity (est 6 year life)=300/year
LifePo4 drop-in 360 AH capacity (est 10 year life) =300-500/year
LifePO4 Premium quality, unknown.

These are Mexico prices so they include shipping and duties to Mexico.

The LifePO4 cost does not include revisions to alternator, regulator, NPPT, DCDC or other required upgrades.