Since i'm nursing 36v, finding a single 40v+ 4 amp panel has been frustrating. So far, it looks like Sanyo's 50v 180-190w panel is the best option. But at $900 average, it's a difficult pill to swallow. I already found (I hope) a suitable MTTP charge controller.
** Solar Charging Your EV Batteries? **
- Thread starter Papa
- Start date
dnmun
1 PW
plug in, don't waste money on panels. especially when you live right next to all those dams and pay so low a rate for power.
use the money to buy lifepo4 instead, or the three GM minimotors. you might wanna contact westedge.com or whoever they call themselves in seattle and see if they will buy the minimotors for you and then you can get the rims and spokes, but they may be able to get 20" minimotors. but GM may already have a 20" hub motor for their scooter line.
use the money to buy lifepo4 instead, or the three GM minimotors. you might wanna contact westedge.com or whoever they call themselves in seattle and see if they will buy the minimotors for you and then you can get the rims and spokes, but they may be able to get 20" minimotors. but GM may already have a 20" hub motor for their scooter line.
torker
100 kW
Only way I would charge with solar is if I was setting it up to run other items also. But as you are finding out it is really too high cost to be practical. Now if you have rebates where you are in addition to the 30 % federal rebate it may start looking more cost effective.
dak664
1 kW
- Joined
- Aug 17, 2008
- Messages
- 317
The numbers are comparable if you put it together yourself. Single crystal PV panels can be had below $2 a watt so call that $2 for a kWh in a year (~3 full sun hours a day), $0.10/kWh over a 20 year life. DC-DC converters are getting cheaper, check out http://zahninc.com/specD.html for a 160 watt, 10-20 volt in, 36 volt out module for $100 (my 80 watt ATTiny85 hacks cost <$5 in parts plus toroids from cell phone charger cables, but I don't have to get UL approval 
).
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Lock
100 MW
And probably that 180-190W rating is only seen under optimum conditions... at the equator maybe? Do you intend to implement solar tracking as well? Then ya have yer cloudy daze... EVer get blanketed by snow? Autumn leaves? Chances are, real output will be something less. Watt are yer degrees of latitude BTW? Maybe just check the solar maps...Papa said:
tks
lOcK
I'm retired (and patient) so vehicle charge time is not a serious concern - providing I can see full or near full batteries within, say, 24 hrs. I haven't purchased vehicle batteries yet. I prefer to wait until I actually need'em, in hopes of securing 'fresh', in addition to putting them to work as soon as they are purchased so that all my usage falls under warranty. I know I can 'make do' with 36v @ 12ah.dak664 said:
Yes, that's makes perfect sense now, but I'm inclined to believe that 'cheap' power won't be with us much longer. There is just too much uncertainty in the economy right now and I'm not one to get caught with my pants down.dnmun said:
Yes, in fact, that is exactly what i'm doing.torker said:
torker
100 kW
http://sunelec.com/
Found this site. Haven't found anything cheaper yet. I'm using a small morningstar charge/lighting controller that I like. So far all I am running is yard lighting.
Found this site. Haven't found anything cheaper yet. I'm using a small morningstar charge/lighting controller that I like. So far all I am running is yard lighting.
dogman dan
1 PW
Yup, that's the place. Get the b grade panels and series connect to get the voltage you need, or charge a battery, and run a 110 v ac charger off an inverter.
Expect the power to cost about 50 cents a killowatt hour on a small setup though. A huge setup can get as cheap as 15-20 cents a killowatthour. Though there are losses from using an inverter, it makes the most sense, since you store all the power it's possible for the panels to gather. Expect to spend at least 2 thou.
Expect the power to cost about 50 cents a killowatt hour on a small setup though. A huge setup can get as cheap as 15-20 cents a killowatthour. Though there are losses from using an inverter, it makes the most sense, since you store all the power it's possible for the panels to gather. Expect to spend at least 2 thou.
spinningmagnets
100 TW
Even though the actual numbers show grid-charging is very cheap, it might be fun for ES to be a leader in finding out the best way to solar charge for those who are interested.
I'm wondering if a solar-PV panel and charge controller would be best set up to charge a 24V deep-cycle lead/acid marine (boat) battery, and the flooded lead acid battery could charge up a 22V LiPo bike battery? Same idea with 48V FLA charging 44V LiPo? If a set-up like this would work (and honestly, I don't know) what type of charge controller would be best suited to charge the big FLA, and should there be some smart circuitry between the FLA and the bike battery pack (whether LiPo or LiFePO4?)
Its my understanding that most PV panels are set up to provide 24V or 48V to the remote-cabin crowd...
I'm certain some part of that sounded really silly to someone who understands electronics better than me, and I'm not asking about a cost/benefit ratio...Just wondering if it could work and what configuration and chemistries were best suited for this?
I'm wondering if a solar-PV panel and charge controller would be best set up to charge a 24V deep-cycle lead/acid marine (boat) battery, and the flooded lead acid battery could charge up a 22V LiPo bike battery? Same idea with 48V FLA charging 44V LiPo? If a set-up like this would work (and honestly, I don't know) what type of charge controller would be best suited to charge the big FLA, and should there be some smart circuitry between the FLA and the bike battery pack (whether LiPo or LiFePO4?)
Its my understanding that most PV panels are set up to provide 24V or 48V to the remote-cabin crowd...
I'm certain some part of that sounded really silly to someone who understands electronics better than me, and I'm not asking about a cost/benefit ratio...Just wondering if it could work and what configuration and chemistries were best suited for this?
TPA
10 kW
I bought 10 of the sun 205 panels from there. They have pretty good service, but I have not had to call them about a problem. They are usually very busy.
Use the panels to charge a couple of basic large sla batts, and charge your bike off those.
Use the panels to charge a couple of basic large sla batts, and charge your bike off those.
torker
100 kW
Most pv panels and charge controllers are 12 to 24 volt. Once you get to the bigger/ more expensive setups you might find 48 volt panels. Of course it's easy enough to wire them in series for 48v but charge controllers and inverters are more expensive at the higher voltages. I think most charge controllers use PWM like our ebike controllers . Mine is 12 v 10 a and has a lighting control and lvc for 100 dollars.
dak664
1 kW
- Joined
- Aug 17, 2008
- Messages
- 317
The simplest and cheapest way is to use one or more 12 volt panels to charge a 12 volt deep-cycle battery, and use an automotive or UPS inverter to power the EV battery charger. No charge controller is needed if the panel is <100 watts, as flooded cell lead-acid batteries can be charged continuously at less than C/10 if you top up with water as needed, checking every 2-4 weeks or so. Used six volt golf cart batteries will last a long time in this application.
This is not very efficient (<50%) but most battery warranties are void if you don't use an approved mains charger. The efficiency is better (~75%) if the panels are producing power when the inverter is on, to avoid the loss in the lead-acid battery charge cycle. If the warranty is not an issue 12 to 36 volt DC-DC converters run directly from the panel could give 90+% efficiency.
Another option is to do the bulk of EV battery charging with the PV panel, perhaps through a relay that disconnects above a certain voltage, or a shunt regulator like a Trace C40. Either can switch to a diversion load to make use of excess power. Two panels in series would put out around 36 volts and perhaps could be connected directly or through one or more dropping diodes (0.2 volts each for Schottky) to avoid overvoltage at the end of the charge cycle. Panel voltages change with temperature though, being more in winter and less in summer, so that would involve a lot of monitoring and tweaking.
So PV charging need not cost much more than the panels. Consider buying 6 smaller 12 volt panels (I have Siemens SP75s getting on to 20 years old) as they can be easily reconfigured for different voltage and current outputs.
This is not very efficient (<50%) but most battery warranties are void if you don't use an approved mains charger. The efficiency is better (~75%) if the panels are producing power when the inverter is on, to avoid the loss in the lead-acid battery charge cycle. If the warranty is not an issue 12 to 36 volt DC-DC converters run directly from the panel could give 90+% efficiency.
Another option is to do the bulk of EV battery charging with the PV panel, perhaps through a relay that disconnects above a certain voltage, or a shunt regulator like a Trace C40. Either can switch to a diversion load to make use of excess power. Two panels in series would put out around 36 volts and perhaps could be connected directly or through one or more dropping diodes (0.2 volts each for Schottky) to avoid overvoltage at the end of the charge cycle. Panel voltages change with temperature though, being more in winter and less in summer, so that would involve a lot of monitoring and tweaking.
So PV charging need not cost much more than the panels. Consider buying 6 smaller 12 volt panels (I have Siemens SP75s getting on to 20 years old) as they can be easily reconfigured for different voltage and current outputs.
Yes. I currently have two 12v 40w cheapies feeding four golf cart batteries. The system has been essentially trouble free for 7 years now, but the batteries are beginning to show their age. With the need for 36v now, I just decided to upgrade to a single,40v+ panel and MTTP charge controller. The Sanyo HIP-190 touts a module Efficiency of 16.4% (most cheapies are 2-5% less) and is capable of producing an open circuit voltage (Voc) of 67.5. I have yet to find another PV manufacturer which produces that high of voltage from a single panel.torker said:
Actually, the current technology is MPPT (Maximum Power Point Tracking). http://en.wikipedia.org/wiki/Mppt However, not unlike higher voltage PVs, finding smaller <10a MPPT charge controllers that'll handle 40v+ is proving difficult. So far, it's looking like the Morningstar SunSaver MPPT is about the only suitable candidate: http://www.morningstarcorp.com/en/sunsavermppttorker said:
I did locate a smaller MPPT controller specifically designed for lithium, but max input voltage is only 28v and max output voltage is only 14.8.
dnmun
1 PW
if you still go this way, consider finding just the up converter, or inverter to go from the low output voltage DC of the panels up to you pack voltage directly. go look on ebay or google up the upconverters that would get you from low to high.
you don't need to clean up the power a lot either so you could even build one yourself, since it is gonna be pushing current into a battery which can absorb the voltage spikes or noise in the output. maybe reduce the power lost in the resistor that is across the schottky diode that absorbs all the high frequency AC noise from the transformer to the output in that RC snubber on top of the diode.
that high frequency AC stuff won't wreck your battery, except maybe the electronics in a fancy BMS would get nervous and try to shut down. but that would be simplest solution. except using the grid is simplest and cheapest. you will need backup for the panels anyway.
if you wanna invest in solar, then capitalize a hot water heating system that uses solar panels, the btus captured/capital cost is highest. 3 orders of magnitude better and the solar hot water storage is simpler than batteries too.
if they just eliminated electric hot water heaters, and electric heat, and electric dryers, and turned off the useless night lighting and street lights, and converted illumination to leds or flourescent then we would have enuff conserved to shut down all the gas turbine electric generation and then the CNG could drive 20% of the car fleet and the electricity saved would carry another 20% in plug in hybrids, or straight EVs.
use the grid for charging and not wasted on resistance heating. except where natural gas is not available, but most of the world uses propane for cooking, without a network of pipelines, jsut a guy that rides around on his bike delivering cooking gas in tanks.
we just went over the top here because energy has been free since the saudis started pumping oil to the max after we won the war. WW2 that is. now its almost over.
you don't need to clean up the power a lot either so you could even build one yourself, since it is gonna be pushing current into a battery which can absorb the voltage spikes or noise in the output. maybe reduce the power lost in the resistor that is across the schottky diode that absorbs all the high frequency AC noise from the transformer to the output in that RC snubber on top of the diode.
that high frequency AC stuff won't wreck your battery, except maybe the electronics in a fancy BMS would get nervous and try to shut down. but that would be simplest solution. except using the grid is simplest and cheapest. you will need backup for the panels anyway.
if you wanna invest in solar, then capitalize a hot water heating system that uses solar panels, the btus captured/capital cost is highest. 3 orders of magnitude better and the solar hot water storage is simpler than batteries too.
if they just eliminated electric hot water heaters, and electric heat, and electric dryers, and turned off the useless night lighting and street lights, and converted illumination to leds or flourescent then we would have enuff conserved to shut down all the gas turbine electric generation and then the CNG could drive 20% of the car fleet and the electricity saved would carry another 20% in plug in hybrids, or straight EVs.
use the grid for charging and not wasted on resistance heating. except where natural gas is not available, but most of the world uses propane for cooking, without a network of pipelines, jsut a guy that rides around on his bike delivering cooking gas in tanks.
we just went over the top here because energy has been free since the saudis started pumping oil to the max after we won the war. WW2 that is. now its almost over.
spinningmagnets
100 TW
Here's a story from the http://www.builditsolar.com website. Lee has a solar-PV powered shop, and wanted to convert his gasoline lawnmower to electric.
Ended up getting several non-working 120V corded E-mowers very cheap, and added a DC motor. Once he got that working, he figured out how to charge it off of his shop battery. Probably many ways to skin a cat, and this isn't the only way. Might be worth a read...
http://www.builditsolar.com/Projects/Vehicles/LeeMowerCharger.htm#Update2
Ended up getting several non-working 120V corded E-mowers very cheap, and added a DC motor. Once he got that working, he figured out how to charge it off of his shop battery. Probably many ways to skin a cat, and this isn't the only way. Might be worth a read...
http://www.builditsolar.com/Projects/Vehicles/LeeMowerCharger.htm#Update2
torker
100 kW
Like Dak664 said if you could get 3 panels- assuming 36 v that were about the right size you could just about do it without a charge controller. Or I wonder if this is fully adj.http://sunelec.com/index.php?main_page=product_info&cPath=22&products_id=39
It shows 12 to 48 volts for 150+ not bad.
It shows 12 to 48 volts for 150+ not bad.
TylerDurden
100 GW
It might be feasible to directly use a 36v charger from 48V PbA. Some may work on >40VDC.torker said:
TPA
10 kW
The charge controller is a critical pivotal component in a pv system.
If you spend more there you will not regret it.
I have the xantrex xw-mppt-60 controller.
The benefit is that you can use any input voltage from 20-140V, and you can output to a 12,24,36,48,or 60v battery setup.
Not to mention that it tracks maximum power point.
$500-$600 is not bad for that kind of flexibility.
It allows for future upgrades since it does not keep you in a "voltage requirement box".
I also recommend a higher voltage (36 or 48V) inverter to keep the amp draw from the batteries lower.
If you spend more there you will not regret it.
I have the xantrex xw-mppt-60 controller.
The benefit is that you can use any input voltage from 20-140V, and you can output to a 12,24,36,48,or 60v battery setup.
Not to mention that it tracks maximum power point.
$500-$600 is not bad for that kind of flexibility.
It allows for future upgrades since it does not keep you in a "voltage requirement box".
I also recommend a higher voltage (36 or 48V) inverter to keep the amp draw from the batteries lower.
Russell
1 MW
Golden Motor has a solar charging solution;
I found it selling for CAN$519 here;
http://www.goldenmotor.ca/shopping/pgm-more_information.php?id=27&=SID#MOREINFO
There's a thread on their message board here;
http://goldenmotor.com/SMF/index.php?topic=937.msg5313#msg5313
Here it is on their main website for US$505 (delivered)
http://www.goldenmotor.com/batterypack.htm
-R
I found it selling for CAN$519 here;
http://www.goldenmotor.ca/shopping/pgm-more_information.php?id=27&=SID#MOREINFO
There's a thread on their message board here;
http://goldenmotor.com/SMF/index.php?topic=937.msg5313#msg5313
Here it is on their main website for US$505 (delivered)
http://www.goldenmotor.com/batterypack.htm
-R
lots'a morsels surfacing in this thread - much appreciated all.
* * *
@ Russ,
Yes, I saw that PV system. For $500, I see sparse technical data and I'd wage that GM's warranty falls far short of the typical 20-25 year offered by reputable PV manufactures'. I also found no mention of MPPT. [Edit: GM states, "One Year" on all our products].
Again, cheers to all....
* * *
We certainly agree TPA. The efficiency gained by using MPPT alone is typically 15 to 30 percent, that's in addition to the broad flexibility you mentioned. I contacted Morningstar tech support and was informed that the MPPT CC I was interested in, would indeed accommodate the Sanyo 60v PV. However. he said it would NOT output high enough for 36v battery charging.... said 12-24v only. Bummer.TPA said:
@ Russ,
Yes, I saw that PV system. For $500, I see sparse technical data and I'd wage that GM's warranty falls far short of the typical 20-25 year offered by reputable PV manufactures'. I also found no mention of MPPT. [Edit: GM states, "One Year" on all our products].
Again, cheers to all....
dak664
1 kW
- Joined
- Aug 17, 2008
- Messages
- 317
I am not a fan of standalone MPPT charge controllers. Using your numbers a MPPT controller produces more kWh a day for less money if $500 is less than 15%-30% of the cost of the panels, so the breakeven is $1500-$3500 panels/$500 MPPT vs. $2000-$4000 panels. The MPPT improvements are highest in the winter when you probably won't be ebiking as much, and If you use less than the available daily energy, typical in battery charging applications where the battery goes into float during the afternoon, then IMO the $500 is better spent on redundancy in panels and charge controllers.
Buck charge controllers would give much of the efficiency improvement for a lot less, not the venerable PWM controllers like the Trace C40 which just chop the panels to the battery to limit current but the new ones that use a coil to trade excess voltage for more current. A $100 buck converter and 200 watts of panel would charge a 36V/10AH battery by noon most days, for ~$500 total.
If spending >$4000 then grid tie is the best option if available, as it uses all the available energy and offsets the kWh used in charging the battery without the losses of an intermediate battery. Most grid tie inverters use MPPT, and the newer ones can also charge backup batteries against power outages.
The amorphous orange Kaneka 48 volt panels were a good deal a year ago at $3 a watt, but they haven't dropped much since. But it seems the OP places efficiency high on the list, wanting the PV panels to be as small as possible.
Buck charge controllers would give much of the efficiency improvement for a lot less, not the venerable PWM controllers like the Trace C40 which just chop the panels to the battery to limit current but the new ones that use a coil to trade excess voltage for more current. A $100 buck converter and 200 watts of panel would charge a 36V/10AH battery by noon most days, for ~$500 total.
If spending >$4000 then grid tie is the best option if available, as it uses all the available energy and offsets the kWh used in charging the battery without the losses of an intermediate battery. Most grid tie inverters use MPPT, and the newer ones can also charge backup batteries against power outages.
The amorphous orange Kaneka 48 volt panels were a good deal a year ago at $3 a watt, but they haven't dropped much since. But it seems the OP places efficiency high on the list, wanting the PV panels to be as small as possible.
Ok I know I am going to sound like a complete moron when I ask this question but here goes. Would it be possible to use a solar charger to extend the range of your battery? If it were the light weight flexable panel. Of course it would only be usefull on a trike, unless you like bikes with wings. But you could mount it on a sunshield that alot of trike manufactures now offer. I found this one http://www.batterystuff.com/solar-chargers/P362watt.html even though it is really expensive. It has some pretty impressive features. One being 62watts @12v, if I am not mistaken that is 5.16ah. But at $819, it's a little rich for my blood. Just an example of the extreme. THey have a wide variety at reasonable prices.
KAZUALT
KAZUALT
