05-24-2021, 03:14 PM | #1 |
Not Yet Wild
Join Date: May 2021
Location: SC
Posts: 35
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solar panels?
Any of you guys running solar panels? Interested in how efficient a solar panel with voltage boost would be with Lithium Ion Phosphate batteries like the RoyPow S51160.
Seems it would be great for charging the battery and also to increase run time by charging while driving. Need to be able to step up the voltage from the panel to 56-58 volts per Roypow. I'm sure it can be done but I have zero experience with this. |
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05-25-2021, 12:50 PM | #2 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: solar panels?
First, you need to find a solar charge controller that is sufficient for your specific voltage. Last time I looked (a year or so ago) you could find charge controllers for lead acid, but I couldn't find one for a 57.6v lithium battery. Assuming you do find one, then you have to consider the watts provided vs the watts used.
I just looked and there is a 310 watt solar panel that I picked at random, it is 39.1 inches wide and 77 inches long, so you can fit one on your roof. It's $227 for the panel. Using a hypothetical cart drawing 70 amps at 20 mph at 50.0v means 3,500 watts continuous to keep it moving at 20mph. Acceleration is more expensive so we'll ignore that. The panel above is a bit shy of 1/10th the power consumed. So let's just assume you find a better panel that is 350 watts (1/10th the power consumed). In this scenario, if your current cart can only do one hour of full speed running then with the panel on the roof getting full power and ignoring any losses, your cart can do 1 hour and 6 minutes. Or, if you drive the 20 miles and stop and get perfect sunlight then it could potentially charge the pack in 10 hours. Although that's not real world. Now add in clouds and off-angle sunlight and tree shade and say you get 70% of the rated power. Add in losses due to slightly increased wind resistance and weight (pretty small, but making it real as we can). Add in losses due to less than perfectly efficient charge controller and whatnot and for a 'regular' golfer or neighborhood user I don't think it makes sense. If you are a prepper that uses the golf cart for 2 to 10 miles a day in a sunny environment, then it may make a lot of sense. Your Mileage *Will* Vary. |
05-25-2021, 04:31 PM | #3 |
Getting Wild
Join Date: Mar 2021
Location: Ancient City
Posts: 112
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Re: solar panels?
Ideal conditions with a premium panel might get you 4-5 amps charging.......
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05-25-2021, 06:28 PM | #4 |
Not Yet Wild
Join Date: May 2021
Location: SC
Posts: 35
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Re: solar panels?
yea, I see what you are saying. Definitely not feasible to use solar energy to drive an electric golf cart full time without charging. I was thinking more like when I drive it to the beach and park it for a while, it could be getting some recharge. The Lithium Ion Phosphate batteries claim a much faster recharge time ( 2-3 hours vs. 8-10) over FLA batteries.
I was reading on another forum for e-bikes (much smaller batteries of course) where they use a 12 volt solar panel, a voltage boost unit and the solar controller with good success. I'll attach a link for reading if interested. but I don't think the technology is fully ready for a 52 volt 160 ah golf cart battery. https://endless-sphere.com/forums/viewtopic.php?t=81736 |
05-26-2021, 06:48 AM | #5 |
Not Yet Wild
Join Date: May 2021
Location: SC
Posts: 35
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Re: solar panels?
After some more research, maybe the technology is here. Also considering for a street cart, part of the time will be downhill, stop signs or stop lights, parking lots at restaurants, grocery stores, bars, beach, etc. So the solar charger will be charging during times when the cart is not pulling energy. And with an efficient Lithium Ion battery, the overall daily range may be extended by a significant amount. Maybe in the 15%-25% range depending on conditions and stopped time.
Here is what Genasun said about their charger controller/voltage booster for this application: Hi Jim, Our (waterproof) GVB-8-Li-56.8V-WP-RETAIL is designed to charge that battery configuration. The two solar panel (PV) input parameters that need to be adhered to on that controller are: A) The PV input voltage at maximum power (Vmp) needs to be 43.0V or less. *note- The Vmp is different (a little less) than the Open Circuit Voltage (Voc) B) The PV input current at maximum power (Imp) needs to be 9.0A or less. *note- The Imp is different (a little less) than the Short Circuit Current (Isc) https://sunforgellc.com/wp-content/t...eet-2018-1.pdf We can also develop custom multistage charge profiles for Lithium Batteries on non-waterproof controllers via the pricing schedule of SKU: GVB-8-Li-CV-RETAIL. I can assist if desired, this article touches on the topic. Please let me know if I can be of further assistance or if you have any questions either by replying to this email or contacting me directly at 760-208-2149. -- Ryan Gurin techsupport@sunforgellc.com https://sunforgellc.com/wp-content/t...eet-2018-1.pdf https://beta.blueskyenergyinc.com/pr...energyinc=true |
05-26-2021, 02:26 PM | #6 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: solar panels?
I looked at my logs. My cart draws up to 304 amps on acceleration and when on the flat ground after it gets up to cruising speed it takes about 70 amps continuous to keep it there.
The solar charge controller states the max input is 350 watts. If it's 100% efficient then that's 350 watts in, 350 watts out. At, say, 52v then 350 watts is just shy of 7 amps. If we assume the cart's average consumption is 100 amps (which I think is low) that solar settup would be providing 7% back to the system under perfect sun, perfect efficiency and assuming no losses. Then you have to consider any stops. If they are short stops, it's worse since the bulk of current is consumed from a stop. If they are long stops then it's better since the panels have more time to work. Buuut, in support of your idea... I saw a Taylor Dunn airport industrial cart (pretty long) that had 6 panels on a custom built support structure so the panels acted as a roof. With that many panels the owner said he never had to charge it. He had support struts that could also angle the panels to catch more sun and the struts doubled as anchors for his hammock so he could cruise to the lake/beach/park and have a shaded hammock with him wherever he went. If you want to do this with one panel, I think you're spitting into the wind. If you want to do what it takes to make it work then several panels (and the associated charge controller(s)) and it could work. |
05-26-2021, 03:32 PM | #7 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: solar panels?
I found a link to the TD cart. He added a trailer with 4 more solar panels and an inverter and was using it to power a window unit AC and a washing machine...
https://www.youtube.com/watch?v=U_nCJDpkHqQ&t=5s He said the whole getup (ten 180 watt panels) was good for theoretically 1800 watts but is likely only producing 1200. Seeing all this makes me think that maybe there's more to your idea than I originally thought... The solar charge controller will need to be beefier, but if you can somehow get four 300 watt panels up as a roof structure you'll have a cart you never have to plug in as well as a solar generator system. |
06-10-2021, 06:07 AM | #8 |
Not Yet Wild
Join Date: May 2021
Location: SC
Posts: 35
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Re: solar panels?
I have a tower top with canvas Bimini. So I need a flexible panel. There are some draw backs to the flexible panels. Looks like a 175 watt is about the maximum one that is reliable and the right size. with my 51 volt, 160 Ah lithium battery, it would take over 2 days of sunlight to recharge 25% of the battery. So it's not very effective as far as recharging goes. The only other benefit I see "might be" is I think the RoyPow charger will charge the battery to appox. 53 volts. The solar charger shown "may" charge the battery to 56 volts. So the extra 3-4 volts may be worthwhile. The battery is good for that voltage but not sure it's worth the expense and trouble.
See comment below: Hi Jim, That 100 watt panel is acceptable, you could use two of them (wired in series) if you desired. It is a 100W panel, generally speaking you can anticipate ~65% of the power to be available on average, especially when flat. You can also anticipate the power to be available to average out to around 7 hours a day when in the sunlight. 70W X 7 hours = 490 Wh 490Wh divided by 51.2V (nominal voltage of your battery) = 9.5 Ah charged per day. As I mentioned before, that battery has a capacity of 160Ah, so if it was 25% discharged (down 40Ah), I'd anticipate it would take around four days for that panel to bring it back to full. If you had 200W of solar, you would half the time. Let me know if you have any questions Please let me know if I can be of further assistance either by replying to this email or contacting me directly at 760-208-2149. Regards Ryan Gurin SUNFORGE LLC Product Support Engineer |
06-30-2021, 02:37 PM | #9 |
Not Yet Wild
Join Date: May 2021
Location: Seabeck, WA
Posts: 29
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Re: solar panels?
Interesting. I just pulled two flexible 100 watts panels of the roof of my RV. Just goofing around I came here to see if it was viable to put them on the roof of my cart. For the price of a compatible solar controller, I may give it a shot…
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09-19-2021, 08:46 AM | #10 |
Not Yet Wild
Join Date: Mar 2020
Posts: 15
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Re: solar panels?
Yes! This can be done.
The charge controller you are going to want is Victron. I have a bunch of their stuff for off-grid solar in my cart, on the truck, etc. Check out the website, its super detailed, and everything is app based, and programmable. My current monster build has 112ah of Lithium Ion, and I have a 477w panel for the roof. You'll want to put in a smart shunt as well which ties to your phone and monitors energy consumption/production in real time. Yes, Victron is a little pricey. No, having a runaway situation with your cart's batteries is not good, and makes it worth it. Having it all tie into your phone via an app is very handy as well. Allows you to get a good feel for how hard everything is working. |
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