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Makes And Models => Zero Motorcycles Forum | 2012 and older => Topic started by: kcoplan on August 30, 2012, 06:12:37 AM

Title: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on August 30, 2012, 06:12:37 AM
I really like the idea of going "full solar" for my commute . . . once I finally get my Zero S.  I already ordered a standalone backup solar power system from Northern Tool, and was reading the manual for the power hub (inverter) which has a warning that the output of the power hub is a "modified sine wave" that might cause problems with certain kinds of battery chargers.

I have sent this question to the service e-mail at Zero - but I wonder if  any of the techno geeks on this forum know the answer - will a modified sine wave AC Source be a problem for the sort of charger the Zero system uses?

PS - the power hub is 1800 watts, so it should cover the 1kw draw of the charger, and I figure that four 150w solar panels and a 440 amp hour battery bank should basically allow for a 50% charge every day or so - which would cover half of my 30 mile RT commute ( the other half I hope to cover at my office, which recently installed a solar array on the roof).
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: frodus on August 30, 2012, 09:36:06 PM
Contact DeltaQ, they make the charger on the Zero AFAIK
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: trikester on August 31, 2012, 12:06:26 AM
What I wish we had on our ZERO chargers was a way to reduce the charging rate. I would like to camp out with my DS without having to take a 1600 watt generator and gas (which I have done). I would like to be able to turn down the rate so that it could charge all day from a reasonably sized solar panel without the need for the large LA batteries that Frodus uses. I could alternate between hiking one day and riding the next day, hiking the next, riding the next, and etc.

We should be given a choice to reduce our charging rate if desired, which could be for several reasons.  Even if I was still taking a gas generator I could carry a much smaller one if I could choose to take longer to charge at a lower power setting. 8)

Trikester
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: Lipo423 on August 31, 2012, 12:35:40 AM
Kcoplan,

Please take a look at the picture (apologize as it is not a nice one). Some inverters deliver the signal as shown above, while some more "sophisticated-expensive" ones deliver a pure "sinusoidal" signal, more suitable for any charger...1800W at 1110/120V should be more than enough

I also suggest you to re-check with DeltaQ
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on August 31, 2012, 01:06:48 AM
Thanks for the advice -- I have e-mail inquiries into both Zero service, and DeltaQ customer support.  Haven't heard back from either one yet.  Lipo423 -- your graph looks more like a square wave than a modified sine wave, in my understanding -- I think the modified sine wave inverters are somewhere in between a true sine wave and a square wave.  Something about the modified sine wave may confuse some kinds of chargers, apparently.

I'll post whatever response I get from Zero and/or DeltaQ.  I suspect it is OK, since the DeltaQ charger seems to be designed to work with a wide range of input voltages (85-265) and frequencies (40-65 hz).  But it would be nice to get confirmation.

Meanwhile  . . . my bike is supposed to arrive at the dealer's today  . . . but I wont be able to pick it up until next week.
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: Lipo423 on August 31, 2012, 01:28:49 AM
No problem...Correct, it looks like a kind of "multiple" square signal, but I made it that way, so you could see it easily.
For sine waves the RMS voltage is 70% of the peak voltage. For square waves, it's 100%. For a "modified sine wave", it could be anything... Some battery chargers that derive their charge voltage from this RMS input voltage will only work properly with a pure sine wave AC input.

You should be fine, but I would definitely get confirmation from them.

What a shame, about your bike...you must be fired up!!!
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: frodus on August 31, 2012, 03:23:10 AM
Trikester, I didn't end up using SLA's, I was theorizing if I did have a solar panel system, I'd use some 12V bats i had laying around and an inverter.... but I've since sold the SLA's. I never did buy anything solar, it was just a concept when we were discussing solar.

I doubt I'd do anything that runs completely on solar, as my bike is a comuter and only charges at night. Grid tie is a better idea. For camping and such, solar is a good idea if you have enough power coming from the panels to make it worthwhile.

To the OP, let us know about the DeltaQ and modified sine inverters.... good stuff to know.

Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: trikester on August 31, 2012, 08:24:36 AM
Oops! Sorry frodus,  :-[ I intended the original poster kcoplan. For his solar panels he had the 440 ah battery which I assumed was lead acid.

Trikester
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on August 31, 2012, 08:33:37 AM
Got a very prompt and helpful response from DeltaQ as follows:

Thank you for your email.  A modified sine wave produced by the inverter should not be a problem for powering the QuiQ.  However, generators with active voltage regulation circuitry may interfere with the power factor correction (PFC) stage of the charger.  I looked up the specifications on the internet in regards to the Xantrex PH1800 and it doesn't state anything about active voltage regulation.  The rated continuous output of the charger being 1.8 kW should be enough, but we usually do recommend having a 2 kW source.

Best regards,

Gilbert Lee


So it looks like a go.  I'll keep you guys posted on how the solar thing works out.

Can't wait to get my bike!
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: Jiminy on August 31, 2012, 09:28:28 AM
Something you might not have considered is to figure out how to feed the charger with DC voltage to charge directly from DC to DC. From rectifier research that I have done I have been told by several sources that rectifiers will allow a DC input to bypass the diode bridge and go right into the battery. I don't know how to do this yet but that's where I'd research if you want to use the least amount of solar panel to charge your bike. Why turn the solar DC to AC only to turn it into DC again? Getting two or possibly three 30VDC 240W panels in series might give you plenty of voltage and amperage to charge the Zero S battery in a decent amount of time. You will need battery storage if you charge at night.

I have a 72vdc electric bicycle that uses 32 wh/mile and I charge solely on solar power. I have a 20V solar panel feeding an MPPT charge controller that charges a deep cycle 12V battery. I then use a 10S charger connected to the 12v battery to charge the two 36v battery packs in parallel to run the bike. I hook up the two packs in series to get the 72vdc. I haven't used any grid power in a few months doing this but I only ride 9.2 miles per day for just under 300 watt hours. The charging equipment isn't free, of course, but the power provided is pretty much free.

Anybody here with a 12 Zero S know how many wh/mile they use?
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: protomech on August 31, 2012, 10:50:16 AM
Jiminy,

I use the following for steady-state power estimation:

35 mph 65 Wh/mile 2.3 kW
40 mph 80 Wh/mile 3.2 kW
45 mph 95 Wh/mile 4.3 kW
50 mph 110 Wh/mile 5.5 kW
55 mph 120 Wh/mile 6.6 kW
60 mph 140 Wh/mile 8.4 kW
65 mph 160 Wh/mile 10.4 kW
70 mph 180 Wh/mile 12.6 kW

Take them with a grain of salt, they'll vary with rider position, rider weight, prevailing winds, etc.
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: Electric Terry on August 31, 2012, 08:22:58 PM
I have been charging the zero off solar from day 1, but I do have a pure sine wave inverter as other things like CFL's and microwaves buzzed and ran funny.  All you need is a 1000-1500 watt continuous inverter.  You'll see draw in the rance of 750-950 watts. 

Frodus's suggestion to grid tie is best.  I'm "Off The Grid" see here: www.facebook.com/lifeoffthegrid (http://www.facebook.com/lifeoffthegrid)

So any power I use I have to make myself.  I literally called the power company last year and told them to turn off the power.  They asked where I was moving, and I explained that I was staying there and said to call back closer to my move date to schedule the disconnection of service.  I had to talk to 2 supervisors before I could get them to understand I did not want their power because I was making my own.

Anyway, the one difficulty in being off the grid and having an electric vehicle, is for it to work properly you need a huge amount of solar batteries.  At least an extra 12kwh worth to charge a 9kwh motorcycle as there are losses to heat coming out of the lead batteries, losses in the DC/AC inverter, losses in the AC to DC charger and losses going into the EIG batteries as well. 

What I have found is to charge during the peak sun days I am there to load balance the system, goes directly into the inverter to charge the bike versus the losses to heat in and out of the deep cycle SLA pack.  Your solar wattage goes a lot further.  But from experience I will tell you, If you have 1000 watts of rated solar, expect 250-500 watts out of the panels.  With all the losses to batteries, inverters etc, expect 200-300 usable watts.   To operate the delta Q you will either need a lot of SLA batteries to store charge over a few days with just a few panels and then use it all at once to charge the bike for an hour or so, or to get 4000-5000 watts of solar, and run it almost directly with a few batteries just as a buffer for when clouds go by etc to prevent the inverter from shutting down. 

Sorry I just responded to this thread now, this is right up my alley.  Check out the FB page and click "like'for me if you're interested in this stuff.  Although lots of my posts recently have been about the bike, lol.
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: protomech on August 31, 2012, 10:41:25 PM
DC to DC charging for the Zero is the way to go. I've been eyeballing the MidNite Solar MPPTs for a bit.
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: Vertigo1 on August 31, 2012, 10:43:38 PM
I wonder how something like the forty2 would work for charging a Zero? I also wonder how it manages loss and if the ~180-200 watts solar is effective through the outlets or if the same losses as discussed here bring it down to a much lower number?

http://www.kickstarter.com/projects/1408708524/the-forty2?ref=live (http://www.kickstarter.com/projects/1408708524/the-forty2?ref=live)
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on September 01, 2012, 07:56:39 AM
Thanks for the additional advice.

Yeah, Imnow DC-DC charging would be a hell of a lot more efficient, but I thing that would mean bypassing the Zero charging system and voiding my warranty.  Also, the Zero batteries have to be much more than 12v, so that means series connecting the solar panels and batteries and having lots of dangerouse DC voltages around. No thanks.

I am not counting on getting a full 9kw charge out of my system.  I am getting the ZF6, so full charge is 6kw.  I hope to get a half charge every two days out of four 150 watt solar panels - 3 kwh every two days, so I only counting on about 50% of the panel output for 5 hours each day - less in the winter -that seems conservative to me.

I agree about it being more efficient to charge during the day, bypassing the battery losses.  But apparently it is better to charge the Li Ion batteries right away rather than leave them semi-discharged overnight.

We'll see how it all works out!
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: BSDThw on September 01, 2012, 02:17:05 PM
DC/DC Converter mean you change your voltage it would be possible to make 12VDC to 74VDC but as closer both voltages are the better the efficiency (if using the right technology).

You don't need to bypass the charger. You have the connector at the right of your battery pack for the additional charger.

As much as I know you can feed it from 0-24A (2* DeltaQ => 2*12A) DC.

The Delta will work current delimited till you reach the top voltage than it will reduce current to stop over-voltage.

A correct adjusted DC/DC Converter could feed the battery with the maximum your Solar module is able to deliver(e.q 3ADC and 50-74,7VDC).

By the way a "modified sine wave" is a square like Lipo423 painted but between the negative and the positive square there is a time when the voltage remains zero. So the the peak voltage is 325V/ 155V
and the RMS area of the power is the same as for a sinusoidal.
 

 
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: ed5000 on September 05, 2012, 12:11:41 AM
I have a 12 VDC system at home with a 300 watt pure sign wave inverter that I use to charge my electric bicycle.  For the bicycle I have a 300 watt charger that changes 120 VAC to 60 VDC so it's not very efficient but, interestingly the bike charges faster on the inverter than my standard wall outlet.  The bike charges in 3/4 of the time on the inverter over the wall outlet.  I'm not sure what's going on except it must be a power factor issue.

I've been very tempted to buy a Samlex 1500W pure sign wave inverter to charge my 2010 DS.  It would only cost about $500 and I already have everything else but, I would really rather go with a dc to dc converter.  I would need one that converts 12vdc to 60vdc for a '10 DS.  Anyone know a good one? 
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on September 05, 2012, 12:39:12 AM
BSDthw -- Thanks for the advice, but I am not sure a "DC-DC" converter ends up being that much more efficient.  As far as I know, the only way to step up DC voltages (what a DC-DC converter would have to do) is to convert the DC to AC and run it through a transformer, then rectify it back to DC.  That is, essentially what an inverter combined with a charger will do, with one additional (and not strictly necessary) voltage step down involved.

Inverter plus charger:

12v DC converted to 12v AC stepped up through transformer to 120VAC --> charger steps 120VAC down with transformer and rectifies to a voltage and current regulated 72VDC (???)

DC-DC Converter:

12v DC converted to 12v AC stepped up through transformer to 72VAC then rectified and voltage controlled to 72v DC

So a DC-DC converter will probably be more efficient than a DC-AC inverter connected to a charger (AC-DC), but not dramatically more efficient.

But my knowledge on this subject is somewhat dated.  If there is a DC-DC converter that works without making AC as an intermediate step, I suppose it could be much more efficient  . . .
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: ColoPaul on September 05, 2012, 01:43:20 AM
As far as I know, the only way to step up DC voltages (what a DC-DC converter would have to do) is to convert the DC to AC and run it through a transformer, then rectify it back to DC.

Charge pumps can work to 90+% efficiency, but I've only seen low power implementations.
http://en.wikipedia.org/wiki/Charge_pump (http://en.wikipedia.org/wiki/Charge_pump)

A type of switching supply called a "boost" also works without a transformer:
http://en.wikipedia.org/wiki/Boost_converter (http://en.wikipedia.org/wiki/Boost_converter)
They are used in high power situations, and can be very efficient if they don't have to be built to tolerate wide voltage/current ranges.
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: RickSteeb on September 07, 2012, 10:25:32 AM
"Got a very prompt and helpful response from DeltaQ as follows:

Thank you for your email.  A modified sine wave produced by the inverter should not be a problem for powering the QuiQ.  However, generators with active voltage regulation circuitry may interfere with the power factor correction (PFC) stage of the charger. ..."

Power factor correction would seem likely to have serious issues with the "modified sine wave", as keeping current "in phase" with near instantaneous voltage swings is not possible.  Just sayin'...
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: trikester on September 07, 2012, 08:35:59 PM

From a career of designing switchmode power supplies (AC - DC & DC-DC & a few modified sine inverters) plus power factor correctors (I have a patent for one of those), I agree with RickSteeb. The power factor correction built into the front end of the battery chargers could (most likely would) have a problem with the modified sine wave source. However, it may still work but put an unusual load waveform (possibly stressful) on the power supply. I never looked at that combination.  :-\

Trikester
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on September 08, 2012, 06:32:46 PM
Trimester, when you say "unusual load waveform on the power supply" do you mean the inverter in the power hub, or the "power supply" in the QinQ charger?  Do I risk frying the charger?
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: trikester on September 08, 2012, 08:07:50 PM
I was referring to the modified sine inverter supplying the charger input. The power factor corrector in the front end of the charger could create high current spikes in the source as it tries to do its normally sine wave job. However, without knowing the design, I'm just guessing about its behavior. It would be a good thing if someone on this forum had that combination and could monitor the output current, and voltage, waveform of the inverter with a scope, while it was powering the charger, and post the waveform.  ???

Trikester
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on September 09, 2012, 01:50:44 AM
That's good, Trikester.  If I have to choose between frying my 12k bike and my $800 inverter . . . I choose the inverter.

- Karl
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on September 12, 2012, 08:03:26 AM
Success!  After receiving further assurances from the DeltaQ techie, I used the Xantrex inverter and the battery bank to recharge my Zero S ZF6 this evening without any problems.

Today was the first day I rode the Zero to work and it was also the first day with the solar panels connected.

The 15 mile trip to work was a typical commuting day  -  probably averaged 35 mph, with a couple of 65 mph stretches.  Only used 3 of 12 "bars" to get in, and I plugged the bike in all day at my office.

The trip home was a little faster. - probably averaged 55 mph.  Used 4 bars.

So with the ZF6 about 30% discharged, and with the solar battery bank showing 13.1v (probably about 90% charged) I plugged the Zero in and watched for fireworkks.  The charger worked normally, and the Powerhub showed 960 watts coming out of the batteries and 880 watts going into the Zero.  After two hours, the Zero indicated a full charge (about the right amount of time for a 30% recharge) and the PowerHub draw dropped to 10 watts, with 0 watts going out to the Zero.  My solar battery bank is at 12.2v, which should be about halfway discharged, which is just about as much as I want to discharge it.

It's a 440 amp hour battery bank, so 2 kwh at 12v should work out to 160 amp hours, well under 50% of the battery bank capacity, the sweet spot for maintaining the longevity of the solar battery bank.

So -  tomorrow, we'll see how fast the solar panels recharge tha battery bank, but at least as far as the battery bank and the inverter goes, looks like I have a fairly sustainable solar powered commute (my office just installed a solar array on the entire roof )

Thanks again for all your advice!
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: manlytom on September 12, 2012, 03:03:08 PM
Lucky u can charge at work. Only way 4 me is to wheel into the lift and navigate it into my office.

So u charge it carbon neutral at home - what about the power at work?
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: kcoplan on September 12, 2012, 07:53:23 PM

Lucky u can charge at work. Only way 4 me is to wheel into the lift and navigate it into my office.

So u charge it carbon neutral at home - what about the power at work?

I teach environmental law at Pace Law School in White Plains, NY.  My building is very green -- it houses our Energy Project -- and we just covered the entire south facing roof with solar panels this year in a grid-tied system.  I think I can take credit for solar power when I charge my bike at work!  (I am running a cord out the window of my first-floor office).

Also, I pay a couple of cents extra at home for what Con Ed claims is 100% wind power, so even without the solar panels at home, I have some claim to being zero carbon (though electrons are very fungible, of course).

There's something really cool about having a second way to get to work now that is completely independent of oil companies and only partly dependent on electric utilities!  (My other carbon free way of getting to work involves two bicycles and a kayak, but that is a longer story).
Title: Re: Solar Charging and Modified Sine Wave Inverters
Post by: protomech on September 12, 2012, 10:26:49 PM
Also, I pay a couple of cents extra at home for what Con Ed claims is 100% wind power, so even without the solar panels at home, I have some claim to being zero carbon (though electrons are very fungible, of course).

The utility that servers northern Alabama, TVA, has a renewable energy program which I subscribe to. It's almost entirely landfill methane, though they're adding more wind recently.

Anyhow, the fungible electrons bit really bugs me.