Solar Powered Cart for Racing (Coolest thing I've seen on RCTech in some time)

[dr_hfuhuhurr]

This is by FAR the coolest thing I've seen on RCTech in a LONG time!!!

From Ed Anderson: (Posted in another thread)
Not sure this is the place for this but… what the heck

That picture in the other post was at the unofficial HPI challenge a couple years ago. We were hoping for a large turnout… It was a two day event.

By the time I got to that event I had upped the system here at home to 4 panels and 4 batteries. Before this event, I ran everything off inverted AC power, and I had just put DC on the cart. Everything up to the cart was mine, but the timing equipment belonged to another RD. (so I don’t know his specs) But, here is what I set up that day.

12v DC
Dell laptop
AMBrc decoder (ran off USB cable from laptop)

120v inverted AC
PA system
Panasonic tractor printer
TP charging rack (older 3.3 volt one)

Saturday was cloudy and overcast, with maybe 1-2 hours of sun (had me worried). The system ran from about 8am to 5-6pm without a hick-up! But it did run the batteries down to about 10.5v.

Sunday I swapped out the batteries to the other set…. Sunny day.. ran about 7 hours… no problems!

But come Monday morning the Sunday batteries topped off and were at full charge in 20 minutes. The Saturday batteries took 5 days to bring up to full charge! That’s telling me the system ran off the batteries that day.

Now when I use it

12v DC
AMBrc3 decoder
Dell laptop
Sirius satellite radio (will try out next use)

120v inverted AC
Yamaha stagepass 300 PA
Okidata tractor printer
Alpha 4120 display

SGI
2x 15 watt amorphous panels from Northern tool ($100ea) (28”x38”, 1064si for a total of 30 watts) (3 for sale now)
Charge controller from Northern ($35) (for sale, package deal with panels)
2x deep cycle batteries from Wal-Mart ($80ea)
2x 700/1400 watt vector AC inverters from eBay ($55) (didn’t need 2 but the guy had free or $1 shipping on the second one… cheap for inverters)
Plastic wagon from Northern (around $40) (on sale, whole wagon was cheaper then metal wagon kit… plus it was plastic)

$490 ++ The rest of it will be up to how you want to build it.

SGII
65 watt Kyocera crystalline panel ($450) 25”x30”, 750si for a total of 65 watts
Morningstar charge controller SK-12 (weather proof) ($100)
2x Optima deep cycle batteries ($190ea)
2x 700/1400 watt vector marine AC inverters from eBay ($65) (same guy from eBay)
Next time out will be trying a 400/800 watt inverter (inverters consume power… even when not in use. Bigger they are the more the use… why I run some equip. off DC

$995 ++ hardware changes

Why the SGII build

1) Can’t leave things alone
2) Wanted a smaller footprint
3) Didn’t want to have to break it down every night or be concerned about rain when I’m not here
4) Ruined 4 pair of pants and two shirts…. You don’t think you got any acid on you but the washing machine tells a different story. And the dog rides in the back of the truck… don’t want the acid residue.

Really nothing to it, panel, controller, batteries, and inverter. From the playing around I’ve done…. It could be done with 35-40 watts of solar and 1 deep cycle battery. BUT!!! that’s if you have all "sunny days". I don’t know if 1 battery would carry you through a cloudy day. One other thing!! Some things don't like to run on square wave AC!! Something you have to be willing to experiment with. Battery chargers are one... I know a few people who have smoked Dewalt chargers on them.

Hope I didn’t bore any body.

[d4man]

Very cool!!! And self sufficient!!!

[Ed Anderson]

And it runs my fridg about 7.5-8 months a year.... Saves me about $10 a month... But I don't have kids that keep the doors open, so it only runs once or twice an hour for... 8-16 minutes.

[Ed Anderson]

Couple more early pictures

[Ed Anderson]

Normally, there are two more 30watt panels that slide on the sides... when at home. But I've been cleaning up some lose ends so they didn't make it on this week.

[Ed Anderson]

Got a few more things done this weekend. Mounted the smaller inverter, finished the battery hold down. Still have to add the fuse box and new banana jacks.

[d4man]

Ed, seriously, submit some pictures with a detailed explanation and I am pretty sure you'll be in one of the big RC mags.

[RB FIVE]

Excellent work my friend.

[Dave H]

Very cool. Maybe I could use this to power my chargers, I've never got around to getting a generator (hey I've only been doing this about 20 years LOL), already got the deep cycle battery and an inverter. Any sites with info on the panels and their controller that you could share would be sweet.

What's the deal with the acid? Is it just the batteries?

[Ed Anderson]

Originally Posted by d4man

Ed, seriously, submit some pictures with a detailed explanation and I am pretty sure you'll be in one of the big RC mags.

Funny, it's been together 2.5 years... hadn't thought of it. Only reason it came out was a solar descussion on another thread.

Have to look into it.

[Ed Anderson]

Originally Posted by Dave H

Very cool. Maybe I could use this to power my chargers, I've never got around to getting a generator (hey I've only been doing this about 20 years LOL), already got the deep cycle battery and an inverter. Any sites with info on the panels and their controller that you could share would be sweet.

What's the deal with the acid? Is it just the batteries?

DO NOT PLUG YOUR CHARGER INTO AN INVERTER!! or do so at your own risk.


The power needs of a RD (what this was built for) is far less then that of an electric racer.

If you're happy charging off your 1/1 car now (without it running), you'll be fine. Most electric racers like the higher voltage of a power supply... so I don't think most would go for this. I have charged 1000mha packs for micros at the same time. But used DC for the charger.

Most AC chargers are actually AC/DC chargers... no need for an inverter... just use DC. The "cheap" inverters generate square wave AC. One of the things we have found out that don't like SW is battery chargers... I wouldn't risk it. Another thing is "some" motors.

Something else about an inverter... it consumes power. Not only that.. there is loss. You would be generating DC (solar), inverting it to AC, then back to DC (transformer, rectifier in the charger)... to many things to waste power.

I was happy with the performance of the northern charge controller... it just wasn't weather proof. I leave this thing outside... set it up the night before to catch the morning sun. I used to break it down at night (or with the threat of rain) .. then set it up in the morning... pain in the ars. There are lots of dealers out there... even on eBay.

I could have went with this CC, http://store.sundancesolar.com/mo6ampsuchco.html But I knew I was going to be adding to the system (more amps)... It is addictive! You open the box and the panel is making power... Its just finding a good way to store it/use it.

The Acid... its bad news! When a battery charges/discharges, it boils off water. That vapor condenses on the case...water evaporates.. and you're left with the acid (some might splash out too). But its there with any flooded battery. The Optimas are gel cells.. so you don't have that problem.

Those Wally world batteries are heavy... and the carts a little awkward. I would have to take one out every time to load it up... how I got acid on me.

How much water have I used?... In 2.5 years I used about .5 gallon in four batteries (**make that 5). But most of that was when they were new. I just added to them for the second time the other day.

When I changed the build over to SGII, I washed it down with a baking soda solution... you should have seen that! It was a cart full of foam... acid everywhere

If you are going to use a flooded battery it should be in some kind of container (marine battery box???) Not only can it damage fabric... It can cause some serious burns!!

** one battery wouldn't hold a charge and had to be returned shortly after I bought it.

[Dave H]

Originally Posted by Ed Anderson

DO NOT PLUG YOUR CHARGER INTO AN INVERTER!! or do so at your own risk.

Oh I agree, I charge with DC off of the marine battery. The inverter is just for the soldering iron and a small charger for the marine battery. And it's not a square wave cheapy, it's an industrial job that does true (almost anyway) sine. Intended for powering sensitive data acquisition equipment on full scale vehicle development. Oh, and I use a "smart" charger for the marine battery, which reduces, but does not eliminate, the acid issue. And I'm damn careful with it. Granted it's a real Rube Goldberg affair, I got tired of cords being tripped over and generators that I was begging off of running out of gas. The battery gives me a very stable power source for the chargers, and the small charger for it prevents my car battery being ran down quickly before I lose track of it.

I even use this set up for really big indoor races with power, as I've seen a few circuit breakers go in my time.

Excellent points though. Thanks!

[Ed Anderson]

I've looked at the true sine... they are just big $$. I'm pretty happy with the charge controllers, I don't think its over charging. But the acid is still there (even on car batteries). They always look dry... but its there.

Something I found with the solar panels and charging. 20watts of solar per battery (that I have) gives a nice charge. If I load up the panels on one battery it takes forever to charge. The controller keeps cycling back and forth from charging to trickle. And 15 watts seems to take forever too.

Sounds like you'll be happy with a 25-30watt panel. That and a charge controller and you're all set.

LMK if there is anything I can help with.

[BigDogRacing]

That's awesome Ed- now if we could just get EZ=UP to make a top for our pop up canopies out of flexible solar panels...lol

What about covering the sunshade over the driver's stand with solar panels?

[HarKonnenD]

Ed - It's Sab from RCCA. Are you able to hook up a Power inverter for a dc charger? As you said it's not great for charging say a pack with 5000mah 7.4v nimh or lipo right?