hypothetical: solar charging with icharger

[whatever]

Just thinking about solar charging small vehicle with solar cells as a roof.
Would there be any advantage using say for example an icharger ( or two) to charge the battery bank while vehicle is moving and wondering if it would work.
I'm thinking having a low volt pack ( or two) to accept the solar charge ( 12v ( 4s) a123 20ah with mppt) then using rc chargers to put the stored power into the
actual pack that drives the motor ( probably around 86v so would require 2 rc chargers).
Since the rc chargers require different source would require two lots 12v banks.
One issue might be regen braking current going into the driving pack interfering with rc chargers.
So idea is there are two different battery banks: one for storage of solar charge and one for driving the motor.

 

[dogman dan]

Sounds about right to me. You'd need a battery of some kind between the panels and the I charger so the current would be nice and stable and the i charger would not shut down from voltage fluctuations every time you got into a shadow.

But the big problem is the size panel it takes to charge an EV size battery of say 1000 wh. The vehicle often is not really big enough to carry much more than 150w of panel. In general, it's always going to work out better to have a much bigger panel at a stationary charging station, which can really gather significant quantities of energy. Not cheap, but better than trying to lug around 400w of panel.

It depends on what your goal is, collecting a lot of power, or just carrying a small collector to supplement your power. The small panel may not extend range much, but it will be a good way to get people interested in your EV if being an ambassador for clean transportation is your main focus.

 

[neptronix]

What dogman said

the voltage of a panel is going to vary widely. You want a marine battery and solar charge controller acting as the buffer.

 

[ddk]

tested the 1010B+on my stationary panels with good results. But they're stationary.
My trike is getting the roof supports fitted for a 150w panel and I'll be constructing a trailer to haul an additional 150w panel
and 'stuff'.
I have the option of using an mppt controller with or without batteries between the icharger and the panels, but I'm not to that point where I can make reasonable practical tests.

 

[whatever]

excellent advice
I agree its not practical to have a large area on a small ev, maybe 2sqmetres or slightly larger max,
My intention is to make a panel ( cells are on the way) or two, one or more of which can be used on the ev
for demo days etc, the panels will be used most of the time for stationary use for ebike/household lighting etc.
The small ev is running its 3 wheeler with bike wheels it will be used as farm vehicle most of the time and the odd
demo day here and there.
I ran two rc chargers to charge a 48v a123 20ah pack, but both chargers were running off the same power supply,
( charging it as two 24v packs) but the chargers interfered with each other, so had to put a high amp switch to separate
the two 24v packs. So when using with solar panels pretty sure you wont be able to charge with two rc chargers in series
on a pack over 36v unless you have separate intermediate storage batteries....hope makes sense.
( something to do with common earth on the rc chargers I think)

 

[Sancho's Horse]

I have been in contact with several solar producers for some business interests. There are some good CIGS (copper indium galium selenide) panels which are printed onto plastic substrate. The military is using them for remote charging of electronics in theater. They have the added benefit of being rollable into a small package, they are lightweight, operate in low light conditions and they are rugged (allowing even for pucture without dramatically reducing effectiveness...although low light effectiveness gets compromised with too much of this).

They will, however, require some suppport if having it made in the shade is your intention.

The military has also been pursuing several micro-generators, including a ruggedized Sterling engine which (being the army) can run off of several fuel sources (I will be using propane on occasion) or fresnel lenses (alternative solar). They may even be interesting to couple with heat loss off of the motor. The benefit to these is that you can use a wide variety of fuel sources because they operate on temperature differences of air (even the ice in you cooler could produce energy), they produce energy at an even and predictable rate, and they can be made very lightweight.

 

[dogman dan]

Dang military gets all the good stuff first. Those rollable panels sound cool. There is a good size 48v solar panel that folds down small for charging ebike batteries on the market, but the price is something like $700 or so.

But on a budget, we are stuck with what's on sale at harbor freight for now. They have 20w panels in a 60w kit. 120w or so could be trailered, but the main thing is that you could have 60w on a roof, then open up more when parked. I keep looking for that kit much cheaper at a garage sale, but so far no luck.

Stuff like that's possible once you have three wheels or tow a trailer with some area on the lid.

 

[ddk]

The Harbor Freight panels are expensive. large and heavy compared to these:
http://www.dmsolar.com/solar-module-1141.html
http://www.solarblvd.com/Solar-Pane...00-Watt-12-Volt-Solar-Panel/product_info.html
http://www.solarblvd.com/p2668/Sola....html?osCsid=9ccde2fe50ea927ceb5978f0a5e2925f

how do I know?
because I use 16 of the HF panels on my motorhome purchased because they have excellent performance under cloudy/foggy conditions and they were, at the time of purchase, the least expensive alternative.

Everything about solar panels has changed in the last few years.

 

[Sancho's Horse]

The problem isn't really the price. Some of the printed CIGS are sub $1/watt. The problem is that many will only sell to utility/utility scale projects. It seems in speaking with some of the American solar companies, getting government money somehow equates with utility purchaser or bust. Another example of American anti-ingenuity. The Chinese don't seem to have the same hang-ups...so...HF it is, or the ddk improved choices.