High Power Cycles Solar panels

Joined
Sep 26, 2013
Messages
69
Hi,
Have any of you bought a folding panel setup from HPC High Power Cycles? http://www.hi-powercycles.com/portable-solar-chargers-1/
They seem to be a very good system and they build a converter to match your battery voltage. I have a Bosch mid drive with 2 500 watt 36 volt batteries and Bosch says you can only use their chargers. But if the panels are the same output as the charger (voltage/amps) you should be fine right?

Thanks in advance...
 
I'm sure those folding panels are not very popular. They are probably the most expensive solar panel you could ever buy, on a watts per dollar basis.

For $1100, you can get a 120 watt panel that is portable. Whereas i can find a stationary 120 watt solar panel kit for around $125-$200 fairly easy.. why not, for the same price, install 500-700 watts of solar at your home, including battery storage, charge controller etc for the same price, and charge your bike much faster at home?

Versus.. a very expensive solar panel that can get you 120 watt hours into your battery over a period of 1 hour at the very best. How often are you leaving your bike + a $1100 solar panel outside? This makes sense if you are camping and have long stretches of time where you can just hang out and wait for a charge... otherwise, i don't see where it would be very useful to have one of these things.

Don't know about your bosch question, but there is probably a way to hack that.
 
If they were reasonably priced I would like having them. Super light, folds up small enough to carry without too much fuss. Would be great to have on ebike touring trips. If you got stuck too far from an outlet, worst case scenario you spend a day or two camping to charge up enough to get to back to civilization. I think within another 2 years there should be some reasonable options similar.
 
I want to use it to charge while camping and would be at the campsite for days at a time. This would be a cross-country trip, and so the home thing is not applicable. I want to charge an ebike, which uses 36 volt batteries. I have looked into all kinds of solar panels but there just does not seem to be anything that will do what High Power Cycles says their panels can do. The dealer that sells ebikes had the following comment.

The idea of charging your batteries with a solar panel isn't really a viable solution with any quality E-Bike battery, These batteries are high capacity and have been designed to charge most effectively when using the provided charger witch requires 120v at 15amps (standard home outlet). This amount of power would require an extremely large Solar panel set up. Solar panels can not be hooked up directly to any E-Bike battery, you would have need to store the energy via capacitors and have it converted to a 120v 15amp AC so that you could use the charger provided. Bear in mind all Quality E-Bikes use batteries and chargers that work together exclusively using battery management systems.

I don't know who is right...
 
Electro-Fox said:
The dealer that sells ebikes had the following comment.

The idea of charging your batteries with a solar panel isn't really a viable solution with any quality E-Bike battery, These batteries are high capacity and have been designed to charge most effectively when using the provided charger witch requires 120v at 15amps (standard home outlet). This amount of power would require an extremely large Solar panel set up. Solar panels can not be hooked up directly to any E-Bike battery, you would have need to store the energy via capacitors and have it converted to a 120v 15amp AC so that you could use the charger provided. Bear in mind all Quality E-Bikes use batteries and chargers that work together exclusively using battery management systems.

I don't know who is right...

LOL.. that kind of response is just blowing smoke up your ass from someone who does not understand what they are selling or dealing with. If i were you, i would not be buying anything from that dealer in the future.

120v x 15 amps = 1800 watts. He's saying that the minimum power requirement for a "quality ebike" ( what's the definition of that? ) is 1800 watts at the power source.. now tell me, have you ever seen a production ebike ship with a 1000w or higher charger?

I can't say i have seen such a thing.. 95% of OEM chargers i've seen are in the 100-500w range.

So, obviously you don't need a bare minimum of 1800w of solar panel output.

Also, the bike's batteries' BMS operates independently of the charger 99% of the time, so you just need a component that can convert the solar panel voltage to your bike battery voltage and limit the current, skipping the bike charger that wants 120v AC current altogether. There are some power supplies on the market that can do this. Capacitors are not necessarily required to buffer the charge, but would be helpful.


In my opinion, if you will be carrying solar panels on your bike, i would skip out on this idea entirely because the weight of the panels is going to require more energy under the bike's motion than they will produce. This is because the power density of solar panels is extremely low. We are talking 15-20lbs for a 100w panel that will create 100 watt hours per hour at absolute best if aimed optimally.

For 15lbs of weight, you could have 1.5kw-hrs of lithium battery.. you could build such a battery for around $1000 yourself. charge it up.. bring it to camp, and swap out your battery rather than even bother carrying a solar panel. Because the HPC solar panel is so wildly expensive ( a standard 100w solar panel can be had for $100 easily ), the battery is actually the more economical choice.. :lol:
 
Otherwise a cost effective rig for camping looks like this.. assuming you had a 600 watt hour battery and you had a 400 watt charger from your ebike that you wanted to use rather than a DC-DC that goes from the 12V of the lead acid battery straight to your ebike battery....
100w of solar panels ( $100-$150 )
100w charge controller ( ~$75 )
60 big marine lead acid battery for storing the charge ( $100 )
600w 12V to 120v inverter ( ~$100 )
+ your charger ( Free )

Total cost: about $400.

All this stuff would probably weigh 40-60lbs though.

You'd slowly collect energy from the sun into the marine battery, which would hold 600 watt hours and would take about 6-8 hours to charge to full from the panel. You'd hook the bike up to the AC inverter, which would mostly get it's power from the battery.. drain that battery to charge the bike battery, and the battery and solar panel combined could produce 700 watts for about an hour until the 12v battery is dead. This would work well, but is gonna be heavy to carry around.

The HPC charger works if you're willing to leave your bike plus the panel out in the sun for many hours to recharge. I'd rather let a solar panel and battery accumulate energy so that my charge time off the sun is very short.. ideally 30 minutes, rather than the 6-ish hours you're probably looking at for the HPC panel ( i have no idea how big your battery is, but you can do the calcs )
 
Electro-Fox said:
provided charger witch requires 120v at 15amps
Must be one big heavy charger, at 1800W. I have Meanwells that are the size of a trade paperback and a lot heavier (7-8lbs each?), that take in about 840w at 120vac 7a, and output up to 11a at 58vdc (638w), about 75% efficient I think.

Must also be a heck of a battery, being able to be charged at such high current: assuming even just 75% charger efficiency, that would still be 1367w at the dc side. Say it's 58v output (to compare with the 14s EIG packs I charge with the MWs), then that's a 23A output into the battery.

Not a lot of ebike batteries would like to be charged at 23A, "quality" or not. ;)

In some of them the BMS would cook at a quarter that charge current.

If it was a 36v pack (like 42v full), then it would be more like 32A charge current.

Those are just maximums the charger *could* put out, not that it necessarily would for teh whole charge...but if the pack was empty and the charger was limted only to that level, it would start the charge at that current, until the pack was full enough to lower the current draw from the charger.


So I think that whatever seller it is you're quoting there doesn't really have much idea what they've got, how it works, or how good or bad their stuff is compared to anyone else. ;)


Edit: neptronix replied while I was typing with basically what I was trying to say. :lol:
 
BTW, if you ignore all the extraneous posts in it, there are a lot of good posts abotu how to do what you want in teh Solar Charging an Ebike thread, along with a few others if you just look up "solar" in titles and display by thread.
 
Electro-Fox said:
The idea of charging your batteries with a solar panel isn't really a viable solution with any quality E-Bike battery, These batteries are high capacity and have been designed to charge most effectively when using the provided charger witch requires 120v at 15amps (standard home outlet). This amount of power would require an extremely large Solar panel set up. Solar panels can not be hooked up directly to any E-Bike battery, you would have need to store the energy via capacitors and have it converted to a 120v 15amp AC so that you could use the charger provided. Bear in mind all Quality E-Bikes use batteries and chargers that work together exclusively using battery management systems.

I don't know who is right...

If you apply a filter to this dealer's statement it's almost right. Sales people usually get the gist of something technical but don't have a full understanding. Many lay people think a solar charge is something the size a sheet of A4 paper and greatly underestimate the capacity of a decent ebike battery. I'd guess the 120V/15A refers to "wall outlet", meaning 120V AC and capable of supporting a high inrush current. Even a 300 or 500W charger does require a "very large" (perhaps up to 1000W-rated) solar panel by many people's reckoning. It is true you can't connect the battery charger direct to the solar panel, nor the panel directly to the battery/BMS. The part about capacitors is odd, but I've found some DC-input SMPS wouldn't start when powered by a solar panel due to the inrush current requirement. It was only a ~5W load and 20W of panel wouldn't do it, but a 10W panel and a small electrolytic capacitor did the trick.
 
A suitably specced PV array makes a pretty good battery charger, wired straight to the battery; it inherently current limits during the bulk phase and if you put a series voltage regulator in line it would stop when it got to the right voltage (easy to do with e.g. LM317). Not totally ideal but reasonable.
The problem with this incredibly simple arrangement is that goodness only knows what's going on in the BMS in your battery box.....
And, of course, the many numpty ways of getting something slightly wrong and setting fire to the batteries or at least voiding yr warranty.
But a PV array is the quintessential "current controlled power source"!

PS note the sun is getting brighter, but not very fast :)
 
Recently I read that Lithium Ion batteries require a specific algorithm. I say this when communicating with High Power Cycles and although I got basic quick responses to questions I finally got his answer (after 6 emails) when I emailed them the bike shops statement I posted here. Here is what he said;
They simply are not informed. Charging with a solar panel is not much different than charging with a solar panel/charge converter. You are simply pumping DC voltage into the battery using a specified lithium charging algorithm. Most chargers for a 36V battery would be 42V/3A output which would equate to roughly 126 watt output. The 150W solar panel would charge roughly at the same rate.
Bosch might have a proprietary protocal for charging which I do not have experience with.


So what is that mean? Sorry for the questions, just trying to figure this out and I am not very technical. I was really close to pulling the trigger on a Riese & Mueller bike, which is a really nice bike albeit expensive. I liked that bike because you can get two batteries, which is according to them is 1000 Watt Hours, which depending on terrain could get me some decent range. Recharging would be easy when near any business that would allow you to charge. The problem is I plan on being in remote areas, and unless I am near a current bush :wink: then I would be without power. The solar aspect works here, if you can do it at all. I bailed on buying that bike until I work out the details of this.
However, I thought about something else on a different bike and setup. It is easy to find panels that are relatively light panels in 12 volts as they are used for charging lead acid batteries in RV's and boats. I wonder since these are 12 volts why you could not get 4 of these panels and wire them in series to get them to 48 volts, and then use a 48 volt battery. It would make it easier to source the panels, but what kind of controller would be needed based on the algorithm. :?: I wonder what HPC is doing for their controller? They say that they can make the controller to match any batteries voltage. So how could I get a controller like that and use it in a setup like I mentioned above...the panels in series.

Thanks
 
I sympathize. In my opinion what you want to do is reasonable and probably quite possible (it might not be quite as effective as you hope, but that's another story..) But as soon as you move away from the supplied mains charger your sales channel will withdraw their warranty, and if you get things wrong you can do quite a bit of damage which can be quite expensive.
What you need is either a better technical education, or a friend you trust, who has the required technical education, who is willing to spend many hours making your bike work for you.
On here you'll get as many different pieces of advice as there are posters, you have no idea who to believe. You should have stuck with the physics classes.... :)
 
bobc said:
I sympathize. In my opinion what you want to do is reasonable and probably quite possible (it might not be quite as effective as you hope, but that's another story..) But as soon as you move away from the supplied mains charger your sales channel will withdraw their warranty, and if you get things wrong you can do quite a bit of damage which can be quite expensive.
What you need is either a better technical education, or a friend you trust, who has the required technical education, who is willing to spend many hours making your bike work for you.
On here you'll get as many different pieces of advice as there are posters, you have no idea who to believe. You should have stuck with the physics classes.... :)
You may be right....but then what is Endless-sphere for? I think I will forget the solar idea. I did email Bosch and put in a suggestion for them to make a panel specific to charging their batteries as an accessory. I recently met someone that is on the US advisory panel for Bosch, or something like that, and he said that he liked the idea and will be putting the suggestion in the next meeting.
 
FWIW, the "controller" for a solar panel is usually an MPPT unit, which basically just outputs a converted voltage and current that pulls the maximum possible power from the panels without loading them too much.


If the unit is set to output a constant voltage, and just limit the current to the max the pack could be charged with, then it would work as a DC-DC charger (rather than going thru the inefficient conversion from dc-ac then back to dc, if using an inverter).


If you look thru the solar charging an ebike thread, and ignore the many extraneous posts, it'll help with your understanding. ;) There are a number of ways to use solar that are discussed in that thread.

There are also a number of other solar projects on ES that you can look up and read thru that will help, too.
 
It is do-able.

People might find it easier to advise if given specifics: particular bike/battery, how much you want to recharge by and how quickly.

Also, being able to carry your solar charging kit on the bike is more challenging than if it's going to be kept in a vehicle that you will use as a base for your riding.
 
To back up what Amberwolf said, an MPPT unit would have all the controls and hardware in it to do exactly what you want, in an optimally efficient way, and needs sufficient intelligence to make it possible to be "lithium friendly" e.g. by backing off the charging voltage when the battery is full.
Unfortunately you can't buy one with the firmware in to do what you want.
I'm actually doing a home made version of this this for my home based solar powered scooter charging system, and I'm using an arduino nano as the intelligence in there - let me point you to the thread
https://endless-sphere.com/forums/viewtopic.php?f=41&t=84427
There's a schematic in that thread + a short description, when I get further with it arduino code will go on there. But this is for charging SLAs at 12V and with 500 to 600W - it would need quite a few changes for your needs.
 
Solar Converters Inc. can supply you a turn key solution to about anything you can Invision . No use re inventing the wheel. When I wanted a way to charge my 52 volt battery off my airplanes 12 v system while flying, I supplied them with the pertinent specs and 2 weeks and 200 bucks later order, problem solved. Great service from them, they are old timers in all things solar. The company name says it all!
 
craneplaneguy said:
Solar Converters Inc. can supply you a turn key solution to about anything you can Invision . No use re inventing the wheel. When I wanted a way to charge my 52 volt battery off my airplanes 12 v system while flying, I supplied them with the pertinent specs and 2 weeks and 200 bucks later order, problem solved. Great service from them, they are old timers in all things solar. The company name says it all!

Thanks for the post...
I think that what I would need from them is a step up DC-DC transformer. I would use a total of four smaller 12 volt panels (so I could store them easier and because they are easier to find.) I would wire two of them together in parallel (=12 volts) and then wire each set together in series (=24 volts) and finally connecting that to the 36 volt DC-DC step up transformer.

Does that make sense?
 
yep makes sense. Just bear in mind.....

[1] a 12V panel (one described as such) is likely to be a panel sized to charge a 12V lead acid battery. These are charged at up to 14.5V. All such PV panels I've dealt with output their maximum power at ~18V but have an open circuit output voltage up around 22 to 24V.

[2] A boost converter includes a series diode between the input and output - it can't switch itself off to terminate the charging if the open circuit array voltage is higher than the "full" battery voltage (regardless of the control electronics) so there might be a danger of overcharging (oooh - smoke & flames....)

I'm sure Solar converters inc will know all this stuff & be able to offer sensible recommendations :)

PS what you call a DC/DC step up transformer, I call a boost converter
 
Back
Top