Adjustable 24V MPPT solar charge controller needed

[la7qz]

Good morning

One of my customers here in St Maarten has a Gunboat catamaran and are interested in replacing their bank of 8 x 225Ah AGM batteries wired for 24V with four of Mastervolt's new MLi 24/160 Lithium Ion batteries. The battery charger (run from a small genset) and the engine alternators are easy to reconfigure for the requirements of the batteries, but the Morning Star solar regulators can only be selected between wet, gel and AGM batteries, none of which use the same parameters as the Li-Ion batteries.

The yacht has 12 x 80W 12V Sharp solar panels wired for 24V with 2 x Morning Star ProStar 30 solar charge controllers. I am looking for a 24V, preferably MPPT solar regulator which can be adjusted to the voltage requirement of the Li-Ion batteries. The settings needed are:

Bulk / abs charge at 29.2V and float charge at 26.5V. Return to bulk on 26.3V.

The whole point of the project is of course to save weight. Gunboats are just about the fastest sailing catamarans around. the owner of Coco de Mer wants to own the fastest gunboat... I met Coco de Mer in the Anguilla channel a couple of weeks ago when we were on our way to Anguilla in Magic for our wedding anniversary. I'd say she's plenty fast already, but if you can afford a gunboat, then I suppose you can afford to install batteries costing more than I paid for my yacht...

To most of you (and me) this seems like a luxury problem, but maybe in 10 or 20 years, the development of large Li-ion storage batteries will have reached a point where us normal guys can afford them.

Owen, Donna, Sparky and Coco

Yacht "Magic"

St Maarten

Netherlands Antilles

[scottsAI]

I would contact Mastervolt, ask them to update their solar charge controller to charge their new MLi 24/160 Lithium Ion batteries.

Have fun,

Scott.

[Airstream]

The Lion web site spec sheet says 28.5V charge until cut out at something like .015C current (2.4A). That level of required precision is intimidating... : )

http://tinyurl.com/yh55nww

[Airstream]

Ah - The quick spec page lists one voltage and the PDF calls that voltage the minimum - internal temperature coefficient monitoring! Quite the layout with the MasterBus® product line!

[zap]

I too noticed the different voltages listed.

I'm with Scott... my first call would be to Mastervolt to see what they recommend.  Lithium Ion is too expensive to chance it.

[Bruce S]

In just reading the PDF for these batteries, I'd say NICE wish I could afford them too. Little heavy but with 160Ah that's pretty good.

The PDF also says to use their battery charger, those batts, like most all Li-ons have a BMS right at the batteries on the inside.

It also says you can connect it to a generator, which being that it came from the manufacture it probably means gense to battery charger to batteries.

I'm still playing around with Li-Ons and I've not really takem the plunge to building my own BMS system.

Perhaps Comanda will chime in here; she has hours of time with these.

Best of luck, but if he has the $$$ for the batteries a battery charger for them could be nothing more than pocket change.

Bruce S

[la7qz]

I have been in contact with Mastervolt from the start with this project. They only have the one line of solar charge controllers and yes, it would be a great idea if they updated them.

They say that we can use the existing Morning Star controllers quite safely since the bulk and absorbsion voltage are lower than the specs for the Li-Ion batteries, but with some loss of efficiency. However, it would be preferable to find charge controllers that can be adjusted to the exact specs wanted by the Li-Ion batteries. Mastervolt are not in the business of recommending products from their competitors which is why I am now looking for alternative controllers. It would be a shame to not be able to fully utilize all those nice panels.

Owen

[GWatPE]

I am using LiPo battery for a 24V battery inverter setup, with solar and wind and grid recharging.  I have been testing now for many months, cycling approx 2kWhr/day.

You need to keep within the battery manufactures maximum and minimum voltages.  If I could post a pic, here I could show some daily logs from my system.

On my setup, 8 LiPo cells straddles the voltage range of a normal 12 cell lead acid 24V system voltage range.

On the charge controller, I would just reduce all the boost, equalize, settings to the float voltage.  The boost and equalize times can be reduced to zero, if possible.  On my setup, I have the float voltage set to 27.6V  This is 3.45V/cell.  I set this from monitoring of the battery and observing the rate of change of the terminal voltage.  Individual batteries may be slightly different in actual voltage.

My LiPo battery bank has a useful operating voltage from 26.5V down to 25.5V.  

Normal inverter settings are not suitable for low volt cut off either.

Normal battery voltage measurements are not suitable for determining battery SOC.

The LiPo battery has a very flat charge, and discharge voltage curve.  

The problems with cell equalization over time still need to be adressed, but this is another aspect.  Cell SOC imbalance is amplified with overcharge, and overdischarge of the battery.  

Gordon.

[peter altas]

I'm using a (Schneider Elerctrics) Xantrex XW60 MPPT which is charge voltage configurable and multi-unit parallelable (if your power needs grow).  Be aware that the Bulk phase is not voltage controlled (it controls Amps and charges just slightly above the battery voltage).  Absorption and float stages are voltage controllable.  It also has a temperature sensor for compensated charge.

[peter altas]

... but even though it appears to have a great deal of adjustability and functions (has a excellent data logger too) it still may not be suitable for lithium.  I'm still learning about flooded cells and know nothing about Lithium's or their charge requirements.  

[scottsAI]

Owen,

Remind Mastervolt they sell systems, they are lacking a "system" for their new Li-on battery.

A good supplier will recommend a competitor when they do not have what they Need.

Look at Progressive insurance. Helped selling Semiconductors to large OEM automotive.

Cost of Li-on battery is 10x controller, state the Li-on battery will not be bought unless the system works to your satisfaction.

Have fun,

Scott.

[Boss]

Being landlocked in northern New Mexico I just had to google a gunboat. Indeed expensive toy

62' Gunboat Gunboat 62

    * Year: 2002

    * Current Price: US$ 1,590,000

    * Located in En Route to, St. Maarten/St. Martin

    * Hull Material: Composite

    * Engine/Fuel Type: Twin Diesel

    * YW# 75542-2079977

I dumbly gaped at that number for several minutes, and this was the least expensive boat listed, secondly what caught my eye was the location, coincidence?

[ghurd]

Looks like only 10 solar panels on that one.

For $1.6M, you'd think they could squeeze 2 more on it.  LOL.

G-

[la7qz]

Hi

That's Safari. I've done a bit of work on her. She's not the one that wants the Li-Ion batteries though. Several gunboats come through here on a regular basis.

PS. We just got the wind turbine back up a couple of weeks ago after rebuilding the masts. Now we can keep our batteries up without running the noisemaker (diesel engine) again. Bliss!

Owen