Solar to charge 2013 Prius Plugin

[Cambridgebiker]

Hi,

I just bought a Prius plug in with a 4.4kw battery that gets me to work perfectly in one charge. The charger takes 1kw to charge the batt charging takes about 3 hours (I guess it isnt a perfect 1kw in my mind after all must be a bit more...) but I don't think it takes much more since it can plug into a standard outlet. I was wondering can I ride around with 4 250 watt solar panels in my trunk and spread them out on my roof/windshield to be able to charge the car during the day at work?

I figure I get 4 hours of good sunlight (10-2pm+) where I could charge and since there are no plugs anywhere it would be great. I am wondering what is the typical loss or power expected if I have a 1kw system? I am in boston and only plan on charging on sunny days as I have a regular motor if there is no way to charge. Should I aim for 1.5kw array or would 1kw be enough? I see this one for around $1k for 1kw and I am figuring over 2 years it would be cheaper then gas which is great for me: http://www.ebay.com/itm/1KW-Solar-Panel-Complete-Kit-4-260W-Mono-Solar-Cell-Home-Boat-Off-Grid-System/381416155702?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D33747%26meid%3Db6f88615f8a9425f953b91aba568fa5e%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D271114188718

I am just unsure if it will be enough power to run the charger. Also wondering if it could severally damage my battery...

Thanks!

 

[Nobuo]

How much voltage your 4.4kW battery has?

The efficiency is not bad, you must be putting near 90% of the power that generates your panels into your battery after all conversion losses.

For this you have to configure the right final Vmp of your panels at full sun and use the right solar controller charger, in order to automatically close and open charge depending on battery SOC.

Although you could put all the panels in series you will need a step-up converter in order to get the right max charging voltage, this is not easy to achieve and avoid charging losses. The ideal would be having the panels at a Vmp a 30% more than your battery Vmax.

I charge a 72V (84Vmax) li-ion battery with a 180s of monocrystalline solar cells (90Vmp) and a very simple configurable solar controller, so I can adjust every parameter, for example:

Stop charging voltage (HVC) = 84V
Float Charge = deactivated
Under-voltage recovery voltage (LVC release) = 64V
Under-voltage protection voltage (LVC) = 60V
Temperature compensation voltage = deactivated

The efficiency is really high, the same as with an DC charger, but i don't need to use any other electronics than solar controller and solar panel

 

[Punx0r]

You may find the panel ratings are for equatorial midday sun while aligned at the optimum angle. You want to check actual output for solar users in your area and don't be too surprised if your proposed setup yield only half the panel rating.

Other considerations might include whether the panels would be secure against theft, vandalism and strong winds?

 

[icerider]

I charge a 72V (84Vmax) li-ion battery with a 180s of monocrystalline solar cells (90Vmp) and a very simple configurable solar controller, so I can adjust every parameter, for example:

Stop charging voltage (HVC) = 84V
Float Charge = deactivated
Under-voltage recovery voltage (LVC release) = 64V
Under-voltage protection voltage (LVC) = 60V
Temperature compensation voltage = deactivated

The efficiency is really high, the same as with an DC charger, but i don't need to use any other electronics than solar controller and solar panel

If you don't mind my asking, what brand of controller and where did you manage to buy it.

 

[Cambridgebiker]

Thanks everyone. My plan was to get enough charge to run the 110vac charger to then charge the battery. The battery itself is like 300v so dont really want to connect to that directly. Thanks for the advice about the 50% as advertised if I factor that in plus the loss to convert it to 110vac and 1000 watts (whatever amps that is) then I think this is sort of out of the range of feasibility. I am not too concerned about vandalism or wind I figure I can solve those problems with my 3d printer and where I work that isn't really an issue. It looks like my only option is a 2kw system and that is too big. I might try to see if I can get a deal and try it but probably not anytime soon because too much headache. Thanks everyone!

 

[Nobuo]

If you don't mind my asking, what brand of controller and where did you manage to buy it.

I'm using now this simple one, it only can be adjusted to charge a maximum of 78V, but enough for my use. All the parameters are configurable

http://www.aliexpress.com/item/10A-...804.html?adminSeq=119861048&shopNumber=319525

 

[Punx0r]

Maybe you can suggest your workplace installs a basic EV charging point as part of its environmental policy?

 

[Cambridgebiker]

Tried didn't work lame as hell. They even have plugs outside their building and won't let me charge they unplug me and put the building managers card on my windshield. They probably pay $.1 a kwh too so lame there are probably 5k people that work in this office park too. I'll keep trying but it is looking like I am going to have to run on gas for now