Would This Work?

[USAEBIKECO]

I have a 36 volt lifepo4 battery and i want to trickle charge the battery while im riding with 3 10 watt solar panels. The panels are 12 volts each.

I have Anderson connectors connecting the battery to the controller. Is it possible to wire the three solar panels in a series and connect it to the battery?

Would this work, or would it cause an electrical problem?

 

[dogman dan]

I can't see why it wouldn't be fine. 10 watts going in vs 500-700 going out. As long as the panels don't exceed the bms charger in amperage you should be ok. But other than looking cool, carrying a brick would be just about as effective. Wouldn't it work better to carry a charger and plug in for about 10 minuites, vs an hour of charging with tiny solar panels. Do the calculations, it's going to extend your range about 200 yards.

We've beaten this solar charge on the fly idea to death on this forum for quite a while. The general conclusion has been that carrying an effective size panel costs too much weight and wind resistance to be worthwhile compared to a 5 amp charger used for a few minuites. It's a cool idea, and for PR purposes, a great conversation starter. But carrying enough solar panels to effectively extend range doesn't work near as well as carrying a similar weight in more lithium battery.

Of course, the solar racing cars do exactly what I just said doesn't work. But if they just carried a similar weight in lithium batteries, they could be much smaller and lower drag, and go much faster or slowly, much farther. Generally the most practical way to solar charge is not so efficient, but having the panels at home charging a battery while you ride around on another is possibly the best approach. It could be a spare pack, or a 12v storage bank you plug a charger into.

 

[Drunkskunk]

Also, you can't trickle charge Lithium batteries. Near full charge, the low power steady input will start to plate the lithium onto the cathode and oxidize the anode.

 

[USAEBIKECO]

I was planninng that on a sunny summer day i could park the bike in the back yard and let the battery charge up. It would need to sit for a few days to fully charge. I know its cheaper to just use the home outlet but its interesting to try using solar.

 

[lifepo4ever]

look at this its so funny the bike can run for 20 second on solar panel and ultracap

he have to wait until the caps are recharge its just funny but so useless

 

[dogman dan]

Experiments are fun. I doubt your battery will be harmed by a bit of charging solar. We are talking about 6 hours of insolation x .27 amps of 36v. So yeah, lots of time to get a full charge. So it's unlikely that the battery will be trickling while fully charged much if you check it daily. Sorry if I came on a bit hard there, but a lot of guys think a small solar panel is going to extend their range for miles when actually the drag from it cuts thier range.

But like Drunkskunk says, if you used solar panels hooked straight to the battery for long, battery damage could happen. You'd need a charge controller, which mostly is avaliable in 12v or 24v sla variety. This is one of the reasons to set up 200 watts at home, use a charge controller to charge a lead battery, then plug in a charger to an inverter. Lots of losses along the way, but then the bike battery charges right, and you don't carry stuff around. If not used on the bike charger, then you can tap it to do other tasks instead of the grid.

If going green is the aim, it all depends on how you think about it. Any one of the energy efficiency remodels I've done to the house cut my energy use enough to ride several years on the annual savings. So in a way, you can just switch to compact flourescents and consider yourself riding on eco power. Or consider the difference between using a car or even the bus and an ebike. 5000 miles of riding only costs about $20 in power at my outrageous rates. That takes me about 200 miles in the car. That kind of savings really makes up for a few kwh from the grid.

 

[lifepo4ever]

sorry I talk about this video : http://www.youtube.com/watch?v=6h_XPz-GKS4

 

[Chalo]

Sorry if I came on a bit hard there, but a lot of guys think a small solar panel is going to extend their range for miles when actually the drag from it cuts thier range.
[...]
But like Drunkskunk says, if you used solar panels hooked straight to the battery for long, battery damage could happen. You'd need a charge controller, which mostly is avaliable in 12v or 24v sla variety. This is one of the reasons to set up 200 watts at home, use a charge controller to charge a lead battery, then plug in a charger to an inverter. Lots of losses along the way, but then the bike battery charges right, and you don't carry stuff around. If not used on the bike charger, then you can tap it to do other tasks instead of the grid.

If you have a smart electric meter (and these are more common every day), you can skip the battery and inverter part and just charge to the grid directly, getting full credit from the utility for your contribution. That's really the best arrangement-- fewer efficiency losses, make power while the sun shines, use it whenever you like.

If going green is the aim, it all depends on how you think about it. Any one of the energy efficiency remodels I've done to the house cut my energy use enough to ride several years on the annual savings. So in a way, you can just switch to compact flourescents and consider yourself riding on eco power. Or consider the difference between using a car or even the bus and an ebike. 5000 miles of riding only costs about $20 in power at my outrageous rates. That takes me about 200 miles in the car. That kind of savings really makes up for a few kwh from the grid.

There are lots of places where the average household can save more power with little effort or expense. Use an electronic thermostat that "hibernates" your climate control during the day when you're away. Turn off your insecurity lights, or any other lights that run when nobody is there to see them. Upgrade your water heater and hot water pipe insulation. Bunch up all the small chargers and power supplies that use wall warts into one place, put them on a switched outlet or a switched power strip, and get the habit of turning them off when you're not using them. Put the TV or stereo system on a master switch-- if it stays warm when it's turned off, then it's not really turned off, is it?

Compact fluorescent lamps constitute the low-hanging fruit of energy savings, which most concerned folks have already adopted. But the next easiest energy savings are still pretty darned easy. Ferreting out and shutting down all those small wattage sinks that run 24/7 makes a lot more difference than you'd think-- simply because the other part of watt-hours is hours.

I bet most households could realistically conserve enough energy to feed an electric car with the savings. But an e-bike? That's cake.

Chalo

 

[dnmun]

the easiest way is to just junk the clothes dryer. just like the automatic transmission, dryers were introduced in the 50's as an easy way to be like betty furness. until then people used a clothesline.

people just cannot do it. easy enuff to hang them on the line or clothes rack, but it is just like the soda pop crack heads. its legal so there is no reason to not use the dryer.

they should be made illegal. that would save enuff to replace 1/2 the cars on the road. turning off all the useless stupid night lighting would save enuff for the rest.

there is so much waste people don't even think about it. it is not just the standby power used by switchmode power supplies, but the huge cloud of lights that pollute the night sky so much that most people have never seen the stars.

 

[amberwolf]

Ferreting out and shutting down all those small wattage sinks that run 24/7 makes a lot more difference than you'd think-- simply because the other part of watt-hours is hours.

Also, for those folks using cooling as part of their climate control, the added heat produced by power usage inside the house will at least slightly raise the costs to cool it. Removing all of those sources when they are not actually in use will save some, too (which is one of the "hidden" cost savings of switching to non-incandescent lighting).

Of course, in places where heating is the only climate control needed, then costs for heating may go up a tiny bit.

EDIT (ADDED): I'd agree about the dryer vs clothesline. I dry my stuff on a line even though I have a dryer. The only time I use the dryer is when it is pouring rain and is humid inside the house as well, and I must dry stuff *right now* for whatever reason. Otherwise, I just put it out on the line. Even at night, it's dry enough here most of the time the clothes or even heavy blankets'll be dry by morning.

 

[docnjoj]

Good luck drying stuff on a line in Lower Alabama. I vent indoors in the winter to salvage the heat (filter and water trap) but trying to use a line in 100% humidity is just plain wet!
otherDoc