Upgrading charging system with Lithium option 34ft sailing boat

[Zigzag]

Hi I've been considering this for some time now, I would really appreciate the forum members thoughts on this proposal, all feedback is welcome. Rough drawings below. Thanks in advance..

Each end of the season (Mediterranean) not generating enough power and barely generating enough during high season. More power would enhance living comfort audio/visual use, fans etc. Main draw is refrigerator, Power demand for charging phones/laptops etc is increasing,

Present setup =

160w solar, Rutland 913 wind generator, dual pwm solar and wind controller, 60amp alternator and split charge relay, smart battery monitor, 75ah lead acid engine start battery,

230ah lead acid service battery charges to about 80% then goes to float charge and overnight will drop to around 60% this is using only 20% capacity = 46ah out of only 69ah max available ie discharge to 50%

Proposed setup =

260w solar, CTEK D250SE Dual Input DC-DC Charger & MPPT Solar Controller, Rutland 913 wind generator, dual pwm solar and wind controller (now used solely for wind to charge start battery), 60amp alternator, smart battery monitor (now solely for engine battery), Victron Battery Protect BP100, 75ah lead acid engine start battery,

190ah lithium battery with Bluetooth monitor app, (conservative charge regime) will charge to 90% and discharge down to 20% (70%) = 133ah available


Benefits of proposed upgrade

Moving to a MPPT charger with 5 stage charging from either solar or alternator to charge Lead Acid start battery and LifePO4 service battery (improved battery charging). Utilise more solar energy generated, at present some is being wasted and dumped when battery reaches float stage.

Upgrade can be done in stages, to include the new CETEK solar charger will be a minimal wiring change, will allow future use of increased solar capacity (current solar charger max is 160w), and provide pathway for lithium install. Current Lead Acid service battery 4yrs old so will need replacing soon (Replacement Lead Acid Around £250-300) Lithium option Approx. £600. (Aluminium cased raw cells 190ah)

Features of the CTEK D250SE Dual Input DC-DC Charger & MPPT Solar Controller

• Can be used with Lead Acid and Lithium
• max output 20A so will not overstress 60A alternator (improved 5 Stage charging)
• max charging 14.2V floating at 13.3V so will not overcharge (LifePO4 setting)
• small size, IP65 (splash proof important for a marine environment)
• Trickle charging of the starter battery from a solar panel
• Can be charged with current 230v charger (through starter battery)

LifePO4 Battery protection

High voltage - max charging 14.2V floating at 13.3V so will not overcharge (LifePO4 setting)
Low voltage / battery drain – Victron battery protect will cut load before depleting the battery and before reaching BMS low failsafe settings

Present setup



Proposed Setup

 

[snoobler]

Before I can get past it, I need to know why your lead acid battery is only charging to 80%.

 

[Zigzag]

Before I can get past it, I need to know why your lead acid battery is only charging to 80%.

Hi thanks for your interest, it charges well until about 80% then the controller goes to float mode which takes forever to increase and normally just dumps the charge.

 

[snoobler]

Okay, if you're reporting 80% based on some gauge that reports battery charge, the issue is likely with the gauge. You should determine what the issue is there. The good news is that had you actually been running your battery in 60-80% range, it would deteriorate notably faster than typical as Lead acid batteries MUST be charged to 100% and used as little as possible to maintain float. You also need to charge them at a high enough rate to ensure they don't degrade from low current charging.

Your PWM controller might also be malfunctioning. If you're seeing voltage raise after float mode, then that's not normal UNLESS it's because the wind turbine is still pushing enough current to raise the battery voltage.

You should see the voltage run to something around 14.4-14.7V, hold for a few hours and then drop to float and hold. The wind turbine may also affect this as well.

The 913 you mention provides very little power unless you're routinely in 30 kt wind.

https://sbo.sailboatowners.com/downloads/Hunter_gen_49719243.pdf

With full solar and 30 kt wind (150W of wind power), you are probably providing enough current to properly charge your existing battery. However, your low usage likely means it is getting fully charged by solar alone even if the current is lower than desired.

OKAY... now that I've gotten all of THAT out of my system.

The only issue I see is undersized panels. If you limit your daily usage to about 108Ah of the available, and you get the typical "5 hours rule" of sunshine, then you should be good with that panel. This of course assumes that you're only charging the service battery with solar.

Otherwise, that looks like a great upgrade, particularly for the improved quality of life you seek!

 

[Zigzag]

Okay, if you're reporting 80% based on some gauge that reports battery charge, the issue is likely with the gauge. You should determine what the issue is there. The good news is that had you actually been running your battery in 60-80% range, it would deteriorate notably faster than typical as Lead acid batteries MUST be charged to 100% and used as little as possible to maintain float. You also need to charge them at a high enough rate to ensure they don't degrade from low current charging.

Your PWM controller might also be malfunctioning. If you're seeing voltage raise after float mode, then that's not normal UNLESS it's because the wind turbine is still pushing enough current to raise the battery voltage.

You should see the voltage run to something around 14.4-14.7V, hold for a few hours and then drop to float and hold. The wind turbine may also affect this as well.

The 913 you mention provides very little power unless you're routinely in 30 kt wind.

https://sbo.sailboatowners.com/downloads/Hunter_gen_49719243.pdf

With full solar and 30 kt wind (150W of wind power), you are probably providing enough current to properly charge your existing battery. However, your low usage likely means it is getting fully charged by solar alone even if the current is lower than desired.

OKAY... now that I've gotten all of THAT out of my system.

The only issue I see is undersized panels. If you limit your daily usage to about 108Ah of the available, and you get the typical "5 hours rule" of sunshine, then you should be good with that panel. This of course assumes that you're only charging the service battery with solar.

Otherwise, that looks like a great upgrade, particularly for the improved quality of life you seek!

Thanks again for your reply, perhaps I've not explained the current situation clearly.
The battery monitor is the respected merlin smart gauge it will register 100% after full 230v charge and automatically adjusts itself to stay in calibration, I'm unable to reach 100% just using solar and wind during normal use. The Marlec pwm controller handles both wind and solar and charges both starter and service batteries, it enters float when the service battery soc reaches about 80% which is the normal max soc I'll achieve. The 913 will produce about 5ah with 20knts of wind but they are normally short lived. If I were to increase just the solar panels I feel it would just hit float mode sooner and still not achieve 100%.
Many thanks again I do appreciate your views.

 

[snoobler]

I have no knowledge of the gauge, but the description isn't consistent with standard 12V charging. Most "smart" gauges need to be programmed with certain criteria to establish behavior. The best gauge in the world may not be reliable if it's not properly setup.

Here's an example of a proper 12V charge:

230Ah battery charged at 23A (1/10 of capacity is standard)
When the bulk/absorption voltage of 14.4-14.7 is reached. The battery is at approximately 80% SoC.
For the next 3-5 hours, the charger holds the 14.4-14.7V and tapers the current off.
When the charge current drops below 2-3% of the start current (around 5A), the charge terminates.
Charger enters float mode and supplies only enough current to maintain a typical 13.2V float.

What may be happening in your situation is that the 230V charger is sending substantially more than 23A to the battery hitting the absorption voltage much sooner. Then it would hold voltage and taper current. It may cut off charging at something like 20A after holding absorption. This would put the battery at a true charge of somewhere around 80%.

Regardless, this should all go away with your new setup. You might investigate how the Merlin needs to be reprogrammed to better reflect your new setup.

Actually, you definitely will:

https://jgtech.com/index.php?route=product/product/download&product_id=384&download_id=18

Section 5.1. You will need to specify a different battery. Since there is no option for non-lead batteries, you will need a custom program. If you already have a custom program active, it may not match your existing battery type and could explain the disparity.

 

[Zigzag]

I have no knowledge of the gauge, but the description isn't consistent with standard 12V charging. Most "smart" gauges need to be programmed with certain criteria to establish behavior. The best gauge in the world may not be reliable if it's not properly setup.

Here's an example of a proper 12V charge:

230Ah battery charged at 23A (1/10 of capacity is standard)
When the bulk/absorption voltage of 14.4-14.7 is reached. The battery is at approximately 80% SoC.
For the next 3-5 hours, the charger holds the 14.4-14.7V and tapers the current off.
When the charge current drops below 2-3% of the start current (around 5A), the charge terminates.
Charger enters float mode and supplies only enough current to maintain a typical 13.2V float.

What may be happening in your situation is that the 230V charger is sending substantially more than 23A to the battery hitting the absorption voltage much sooner. Then it would hold voltage and taper current. It may cut off charging at something like 20A after holding absorption. This would put the battery at a true charge of somewhere around 80%.

Regardless, this should all go away with your new setup. You might investigate how the Merlin needs to be reprogrammed to better reflect your new setup.

Actually, you definitely will:

https://jgtech.com/index.php?route=product/product/download&product_id=384&download_id=18

Section 5.1. You will need to specify a different battery. Since there is no option for non-lead batteries, you will need a custom program. If you already have a custom program active, it may not match your existing battery type and could explain the disparity.

Yes you are correct in the proposed setup the smart gauge will only be connected to the lead acid start battery option 6

 

[snoobler]

And there we have it. Calcium-calcium batteries are rare beasts. If your charger is set for lead acid, and your monitor is looking for Calcium-Calcium (which are NOT lead acid batteries), then the charge voltage never gets high enough for the monitor to see a fully charged calcium-calcium battery.

Once removed from the service battery circuit, it should be programmed for the appropriate battery:
If yours is a sealed lead acid battery, it's likely a type 4 lead-antimony or high calcium.

Even something identified as "marine calcium" is type 4 unless it's specifically marketed for electric propulsion and states that it requires a special charger.

 

[Zigzag]

And there we have it. Calcium-calcium batteries are rare beasts. If your charger is set for lead acid, and your monitor is looking for Calcium-Calcium (which are NOT lead acid batteries), then the charge voltage never gets high enough for the monitor to see a fully charged calcium-calcium battery.

Once removed from the service battery circuit, it should be programmed for the appropriate battery:
If yours is a sealed lead acid battery, it's likely a type 4 lead-antimony or high calcium.

Even something identified as "marine calcium" is type 4 unless it's specifically marketed for electric propulsion and states that it requires a special charger.

Thank you I appreciate your comments and yes in the proposed new setup the monitor for the start battery will be set to type 4.

What I would really like is the forums opinion / critique of my proposed new setup.

 

[Zigzag]

Hi Guys
I need to start ordering soon, is there anyone willing to offer opinions / critique of my proposed new setup?

Also what's the forums thoughts on the Victron battery protect vs their smart battery protect? Is the fixed 12v low voltage cut out too low on the battery protect?

 

[snoobler]

The only issue I see is undersized panels. If you limit your daily usage to about 108Ah of the available, and you get the typical "5 hours rule" of sunshine, then you should be good with that panel. This of course assumes that you're only charging the service battery with solar.

Otherwise, that looks like a great upgrade, particularly for the improved quality of life you seek!

You might have missed it, but I did have a critique of your proposed setup.

12V isn't too low. If anything, you might find it a bit too high if you're using a lot of your capacity at lower currents.