Charge Controller for Kaneka 60W 48v Thinfilm Solar Panel

2 Posts
Jun 3, 2010 11:09 pm
Charge Controller for Kaneka 60W 48v Thinfilm Solar Panel

I have a off grid cabin with 4 golf cart batteries powering a 12VDC to 120VAC Xantrex 2kW inverter.  The main load is CF lighting with occasional use of a power tool, microwave or small appliance. 

We currently use the cabin 2 weekends a month and recharge the batteries using a generator and the inverter's 100A charger.

My next step is to add solar panels to charge the batteries in our absence.  The Kaneka 60W 48v Thinfilm Solar Panels look like a good deal until I look for a charge controller that will accept the panels 48VDC nominal & 96VDC open circuit voltage to charge the 12V battery bank. I was looking at 2 panels.  The charge controllers I'm looking at that can do the voltage conversion are 3-4 times the current I need and hundreds of dollars.  Any suggestions on a charge controller that could handle 10 amps and 48VDC panels to a 12V battery bank?

Thank you,


8 Posts
Jun 4, 2010 09:36 am
Re: Charge Controller for Kaneka 60W 48v Thinfilm Solar Panel

Hello Jerry,

The short answer to your question is "No".  Unfortunately, at this time there is not an inexpensive charge controller that can step down solar array voltage to a lower battery bank voltage, while maximizing the energy harvest from the array.  A more sophisticated charge controller is simply going to cost more than one that has less capability.

That said, given the size of the system you are considering, perhaps a different combination of PV module and charge controller would be a more economical solution.  Using cost as the guideline, a more powerful single solar module that operates at a nominal voltage of 12V, coupled with a PWM type charge controller may cost less and still get the job done. 

There are several PV module and charge controller options that could work, but if you really prefer to use the Kaneka 60W PV modules to charge a 12V battery bank, an MPPT controller will be required.

If we can be of any help identifying other options, please me know.

Eric Pedersen
AltE Staff

877-878-4060 x141
eric @
"Making Renewable Do-able"
578 Posts
Jun 4, 2010 10:40 am
Re: Charge Controller for Kaneka 60W 48v Thinfilm Solar Panel

hi jerry,

the siren song of the kaneka thin film pricing is irresistible to some, but for many smaller systems they dont make the most sense.

you said you were looking for around 120 W @STC. here are some rough numbers to break it down.  this is just basic stuff, and much of the necessary balance of system equipment required for a code compliant installation is not included for sake of simplicity and brevity.

2 kanekas - $270
combiner box - $100
shipping by truck - 150
mppt controller (tristar 45) -$445

total - 965

or as eric said, you can go with 12v gear and get more power for less dough.

1 kyo 135 - $390
combiner box - $100
shipping by ground service $ 75
pwm controller (xantrex c35) $105

total 670 and bonus 15W at STC

of course the possibilities are endless, but if cost is an important variable in your system design, the modules are not the only piece to that puzzle to be considered.


altE staff

"Making Renewable Do-able"

Tel: 877.878.4060 x107  or +1.978.562.5858 x107
Fax: 877.242.6718  or +1.978.562.5854
2 Posts
Jun 4, 2010 06:23 pm
Re: Charge Controller for Kaneka 60W 48v Thinfilm Solar Panel

Thank you for the valuable input.  One other factor, its going to be hard for me to avoid occasional shading by trees.  Would 48V panels work better because they could still see a lot of voltage drop off before they get below 14 or 15 volts.  Whereas 12 volt panels may quickly drop below a voltage that could push any power to the batteries.

Granted the power in the shade would be less but might the 48V panels still manage a trickle charge in the shade where as 12v panels couldn't?

Thank you.

Jun 5, 2010 07:07 am
Re: Charge Controller for Kaneka 60W 48v Thinfilm Solar Panel

Two weekends a month or, 4 days out of 30?
If only half of those days are sunny enough that would leave 13 days total. So if we take *the amount of power to be used for two days at the retreat and divide it by 6.5, that would approximate the amount of power that would need to go into the batteries while the retreat is not occupied so that hopfully the batteries would be recharged to 100% when someone arrived on the preceding hiatus.

*This factor needs to be known, as close as possible to realworld conditions, in kiloWatthours or, kWh's.
One other factor would be helpful to know in advance and that is the number of hours of equivalent full rated charge at the prospective PV location.

I once saw an article, in a Mother Earth News magazine, where this person made a "homemade solar time clock" from collected bits and pieces of electronic gadgetry and placed it in the PV array's prospective location. Of course he had to record the location of the hands of the analog clock each day but I am sure there are accumulative digital clocks the would do just as well. I am supprised no one has put such a (inexpensive) device on the market by now. For site analysis.
I think a Bogart Tri-Metric monitor might do the trick and it can become a perminate part of the system later. Just have to come up the right size, very small, very inexpensive PV module. Or, just go for broke and put a 100 watt PV module up there and see what happens. As long as the charge controller is sized for such a possible future, you can always add more PV! Right?

As Mr. Cormican stated, "the possibilities are endless."
1 Posts
Jun 9, 2010 12:56 pm
Re: Charge Controller for Kaneka 60W 48v Thinfilm Solar Panel

I also have a remote cabin & a much similar setup. What I have found is the BV MPPT250HV controller will handle these panels well. BV confirmed this via email to me, as I was a little unclear as to whether it would handle the Input voltage satisfactorily. I found that the combination of these panels & controller where a much more economical way to go for me, as the panel location is 110' away.
just my 2cents. - jeff

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