Will you miss the car?

[adam2]

I've heard lots of very bad things about electric scooters, mostly battery issues, and I suppose a trike could a lot more batteries.

A friend has a home made electric trike.
The batteries are housed in a box under the rear axle, thus keeping the center of gravity very low.
Two 12 volt 70A/H batteries are used in series, with the motor driving the rear wheels.
The pedals drive the front wheel.
Speed under electric power alone can reach 45MPH (which is in excess of that permitted, without registering it as a motor vehicle)
Range is from 20 to 50 miles, it varies that much depending on conditions.
Whilst the machine can be pedaled, it is hard work as it weighs about 100KG with batteries.

LED lights are fitted, including brake lights and turn indicators.

Two PV modules are fitted, the charging from these is very limited, but can by useful when camping, which the owner does.
A week or so of camping at least partialy charges the battery for the return trip.

[DominicJ]

I've been trying to work out of the additional weight/drag of a solar panel would outweigh the extra energy generated.
Not for an electric scooter, but for a car.

I suppose it depends on wether a 20mile round trip is useful really, for me a trike with that range and decent cargo space would be useful for shopping, but not a lot else.
But then, a self build could happily have as big a bettery bank as you required.

[JohnB]

I've been trying to work out of the additional weight/drag of a solar panel would outweigh the extra energy generated.
Not for an electric scooter, but for a car.

I have 60 watts of PV flat on my van roof, and if it wasn't for all the vents and things, could probably get 6 times that up there. My van just fits in a car parking space, so the roof is bigger than a very large estate car. 360 watts maximum (at mid day on a sunny summer day, and not very much in winter) would provide plenty of power for living in it, but would do nothing useful as far as going anywhere is concerned. Lots of PV needs a big vehicle that needs loads of power to move it.

[adam2]

I've been trying to work out of the additional weight/drag of a solar panel would outweigh the extra energy generated.
Not for an electric scooter, but for a car.

I suppose it depends on wether a 20mile round trip is useful really, for me a trike with that range and decent cargo space would be useful for shopping, but not a lot else.
But then, a self build could happily have as big a bettery bank as you required.

Fitting PV modules to an electric car is not normaly worth it, the out put is very small indeed compared to the load.
As an example consider a mid size EV with a battery bank of perhaps 40KWH.
It is unlikely that more than 200 watts of PV would fit on the roof, and that might only produce 100 watts since it would not be correctly angled (unlike a fixed installation).
Therefore the solar input is unlikely to exceed 1 or 2% of the requirement, and is not normaly considered worth while.

There are however exceptions.
If the owner of the EV regularly leaves it unused, perhaps in an airport car park, then a PV array will charge the battery, only very slowly, but better than the self discharge and possible battery damage that would otherwise result.
Likewise low performance EVs such as golf carts often have a large flat roof to protect the occupants from the sun. PV modules can be worthwhile in that case, especialy if the vehicle spends a lot of time stationery, in the sun.
Large vehicles such as buses could benifit from PV, since they have large flat roofs, and spend a lot of time stationery, at least on urban routes.

[JohnB]

I can't monitor it, but I suspect I get more out of my PV when stationery, than when on the move. Constant changes of direction, in and out of shade from buildings and trees, changing orientation going up and down hills etc. I can't read the display on my charge controller when driving though! Does a moving PV module work as effectively as a stationery one if all other factors are equal?

[DominicJ]

It was more for a car. Most of the time I drive at night, with lights and heaters on, not sure how the battery charger works, if its just a trickle or cuts out when the battery is peaked.
I thought maybe I could save a bit of fuel by charging the battery with solar during the day, rather than petrol during the night.

[adam2]

I can't monitor it, but I suspect I get more out of my PV when stationery, than when on the move. Constant changes of direction, in and out of shade from buildings and trees, changing orientation going up and down hills etc. I can't read the display on my charge controller when driving though! Does a moving PV module work as effectively as a stationery one if all other factors are equal?

If other factors are equal, I would expect a moving PV module to give slightly more output. Heat reduces the output of PV modules and movement would help to cool it.
In practice though other factors would probably not be equal, movement would most likely entail passing under trees and bridges or into shadows cast by tall buildings or other vehicles.
When stationary I presume that you park with the module unshaded, when possible.

[adam2]

It was more for a car. Most of the time I drive at night, with lights and heaters on, not sure how the battery charger works, if its just a trickle or cuts out when the battery is peaked.
I thought maybe I could save a bit of fuel by charging the battery with solar during the day, rather than petrol during the night.

The battery on a petrol engine driven car is maintained at full charge by the alternator, which automaticly regulates to provide this.
Therefore when a vehicle is stopped after all but the very shortest journey, the battery is already fully charged and nothing would be gained by connecting it to a PV module.

If however, for some reason the vehicle makes lots of extremly short trips, then the alternator may not have time to replace the current used for starting, and charging from a PV module would help. The petrol saving would be minute, the main gain would more reliable starting and a longer battery life.

Vehicles in infrequent use are sometimes fitted with a PV module, this counteracts the self discharge of the battery, and replaces any very small current used by a clock or alarm system.
The idea is to prolong the life of the battery, not to save petrol in such cases.

[goslow]

I had a similar idea to help our car's battery stay charged. We were only chugging round town most of the time and we got the impression it was getting too worn out by the too frequent engine starting (er...and its one of those MPVs with electric sliding doors which can't help!). Not sure the PV module made much difference, its very hard to tell without some kind of direct measurements on the battery.

[arabela]

yeah guys i really miss my car very much.
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