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Post by dachurchpcguy on Jul 24, 2016 10:45:07 GMT -5
Doh! So close! 13 out of 15 cells in the 48V battery are good. I'll probably add a few cells from the 36V battery to make a good working 48V LiFo pack. It will be tricky because the cells in the 48V pack are 12AH and the ones in the 36V are 5AH. Different dimensions as well. I may just hold off on it until I buy the electric scooters from the guy, if I can get them at the right price.
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Post by dachurchpcguy on Jul 24, 2016 20:38:13 GMT -5
I ordered a bunch of those "hover board" battery packs from ebay, you know, the ones that catch fire. They're rated between 4.0Ah and 4.4Ah. Hover board motors draw about 350 watts so I put two in parallel to make sure I could handle the 500W hub motor. I have a Tenergy Watt meter and power analyzer from my ebike so I wired it in. Wow, what a difference! The bike hit 20mph on level ground, 15mph on sections the SLA pack would only do 10mph on. This highlights the difference between the limits that SLA batteries can put out and the "c" rating of lithium based cells. The SLA pack was a higher 12Ah design compared to the 8.8Ah lithium pack. The Tenergy meter provided more insight into the actual specs of hub motor system. Here's some of what I saw: 1017 Watts peak 29.62 amps peak 8.295Ah used 281.3 watt hours The motor pulled about 840 watts in normal riding, not peak, this is what I saw every time I looked down at the meter. This tells me that the hub motor isn't the 500 watt unit, it's the later 800 watt unit. The battery packs actually put out 4.15Ah each, not bad, the sell for around $50 each on ebay. They did get pretty warm, not dangerous, but warm. Three packs would be safer, plus it adds capacity. $150 per battery pack is cheap if you plan on using the hub motor for more than short stints. If you just want it as a backup, or to use the hybrid mode, then SLA would probably be okay at half the price. The bike went 14.1 miles on the little battery packs, so a triple pack should go around 20 miles or so. You can't calculate it exactly, but that's better than I expected.
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Post by FrankenMech on Jul 24, 2016 21:13:43 GMT -5
I was thinking three packs in parallel might be a good option also, closer to the ratings for the other cells. The parallel packs may not last long though. I don't know anything about the lithium cell characteristics.
Make sure you carry a fire extinguisher on that thing. A CO2 unit may be best.
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Post by dachurchpcguy on Jul 24, 2016 23:14:30 GMT -5
There have been more than a few posts on parallel packs at Endless sphere. It all depends on the strongest pack, it will carry the load when the others die.
Most of the issues with the hover board packs happen during charging. I use a low amperage charger so that's not an issue.
The other issue is a short circuit, if the pack isn't protected.
If my math is correct I was drawing at about 3.21c. The addition of another pack should get that down to 2.24c, much more manageable.
I have some packs on the way that are enclosed in UL rated housings to protect the device. I don't know if that's going to matter much if I keep the loads to something more reasonable.
Another option would be to switch to a 500 watt controller, that would get it down to 2.1c with just two packs.
I really don't plan to ride this thing 14 miles on electric. My commute is 2 miles, my son's is 5 miles. We plan to run on gas with the hub motor as backup.
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Post by FrankenMech on Jul 25, 2016 1:34:57 GMT -5
With the hills around here I would be running with electric assist if possible.
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Post by dachurchpcguy on Jul 25, 2016 15:57:37 GMT -5
With the hills around here I would be running with electric assist if possible. When I get some "free time" I may see if I can get both systems running at the same time. If I can't find a dual control throttle for Hybrid #6, I may put a thumb throttle on the left side. This would enable me to control both motors as needed. I'll have to find where the motor controller gets its power and add my own connection and switch, separate from the hybrid control relay.
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Post by FrankenMech on Jul 25, 2016 19:40:56 GMT -5
When you find some of that 'free time' sketch out the circuits that you know. After a while you can probably put them together and draw a schemo. It will have holes to fill but you should be able to fill them in time.
Adding a throttle position sensor to the carb linkage should not be too bad of a job. I don't know what kind of resistance the controller is looking for.
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Post by dachurchpcguy on Jul 26, 2016 23:13:07 GMT -5
I built a power source out of three 4.0AH 36V hover board packs and took the bike for a spin. I figured the 12AH would get me to 20 miles or so. Top speed rose to 21mph on flat road, acceleration was a bit better. Peak wattage used hit 1105 watts. I paid more attention to the power used as I rode along. 930 watts on acceleration, as little as 500 watts on level ground. This time I went to a short but steep gully in the road. It's about 1/8th mile but each side is pretty steep. I went there with the pack freshly charged. It made it up under it's own power, but not very fast. One side is steeper than the other and it slowed to about 5mph on the steep side. A gas powered scooter slows down to about 15mph on the same hill section. The packs took me 22.6 miles at a faster average speed. I used about 11.85AH out of the rated 12AH, not bad. These packs were built better than the ones from the first test. They were in plastic enclosures and the battery protection worked too well! Once they reached 33V the packs shut down totally. That caused my meter to stop displaying so my 11.85AH figure is about as close as I can estimate based on my last reading. The packs got warm, but not as hot as when I ran with just two packs. I can't be totally sure how hot they were because the batteries are encased. I may repeat the test with the cheaper, bare pack. Cheap, $20 bare pack:Better, $49 enclosed pack:One huge difference is that 12AH of lithium batteries takes up a LOT less space than three 12V SLA batteries. I could probably fit one or two more in there AND I didn't have to move the the controllers to make room for them. The great thing about the hybrid was that once the batteries had been depleted I simply started the gas engine and rode home! I should mention that a standard 36V 10AH battery pack runs over $200 from China. These were shipped from the US and the "expensive" 36V 12AH solution was $150 and the were shipped Priority Mail. The "cheap" solution was $60. More power, faster ship, and cheaper. Actually, the "cheap" solution was less than what I paid for my SLA pack.
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Post by Chris Cristini on Jul 27, 2016 0:08:13 GMT -5
dam batteries are getting cheaper every day.
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Post by FrankenMech on Jul 27, 2016 19:26:56 GMT -5
What kind of cells are those in the 'cheap' pack? They look almost like Sub-C cells.
The 'cheap' pack may be better than the enclosed pack. There is less 'insulation' that blocks cooling. Is there good air circulation in the battery and electrical compartments? Heat kills.
For my scoot battery I buy cheap SLA batteries off Amazon. My first battery was a DOA wet cell. I used a dead 7?AH UPS battery to replace it for testing during the PDI and left it in. It did not have enough capacity to carry the UPS but it worked for over a year in the scoot. It never failed but it was getting weaker. I replaced it just on general principles.
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Post by dachurchpcguy on Jul 28, 2016 3:55:09 GMT -5
All the hover or balance board packs are made up with 18650 cells. Some claim to be Samsung cells, but I doubt it at these prices. I can't complain, they're cheap and have enough capacity. I do expect them to deliver a couple more years of use over the SLA lifespan. SLAs will give you 1-2 years service.
Now that I have tested them I will be removing the better packs from the plastic case. This should allow them to cool better.
I've purchased all my SLA batteries from ebay. The three 10AH batteries were $57.99, that's cheap for a pack that should deliver 15-20 miles on electric only.
The thing to remember about SLA batteries is that they deliver based on their rating. 10AH batteries will deliver more current than 7AH, typically that means more power and higher speeds. Lithium batteries deliver based on their "C" rating. Tool lithium battery packs can sometimes deliver up to 20c. That means that a 1.5AH pack can sometimes deliver 30 amps!
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Post by FrankenMech on Jul 28, 2016 13:38:15 GMT -5
I have seen 'C' and 'AH' ratings used similarly in calculations of current and capacity. The internal resistance and plate area of the battery seems to determine how much current a battery can deliver under load. I really forget how to calculate the internal resistance though. My brain has fried too many times.
They use SLA batteries in a lot of those battery booster systems sold for emergency starts on auto engines. I have never tried it but people say a 7AH SLA will start a car.
I have purchased SLA batteries with an unknown pedigree from Amazon and name brands at the local Electronic Supply company. The unknown China batteries are a lot cheaper. I think most of the SLA batteries are made in Asia anyway. There are fewer 'environmental' entanglements outside the USA.
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Post by dachurchpcguy on Aug 8, 2016 7:52:28 GMT -5
Back from vacation . Hybrid #4 (red) is sorted, at least for gas, I haven't tested the hybrid modes yet. This one is staying home for my son. It was in worse shape than the first red one so it won't be sold. It had been dumped hard. The right brake lever is bent, the mirror was broken off so that I either need to remove the stud or replace the lever. Body panel scraped bad enough to gouge the plastic almost through. It needed an intake, carburetor, and battery. (I'm sensing a theme here.) The original intakes were made of some sort of inferior rubber, they are all hard and some have large cracks in them. Worse than I would expect for an eight year old machine. The horn didn't work initially and I didn't bother replacing it. It started working on it's own during a test run. The one I pulled off the other scooter may have the same issue, I assume it's just a stuck diaphragm. I'll wack it with a hammer a few times and see what happens. The next two machine will not be easy. Hybrid #5 has an extremely weak spark. I tried a new coil and CDI unit, must be the magneto. (Damned X-Men!) This will be my bike, it's the 48V 2009 model. Hybrid #6 has a bunch of parts stripped off of it, the one critical part missing is the throttle assembly. This will be tough to replace since it has both a mechanical and electronic throttle combined. If I can't find one I'll take it off #5 and run separate throttles on mine. I'm thinking about a thumb throttle for the left handlebar.
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Post by FrankenMech on Aug 9, 2016 9:02:11 GMT -5
Vacation is OK.
Like I said before, A pot running off the throttle cable down by the carb may work for the electric throttle. You can check the existing throttles for a value and wiring.
The molded rubber intakes are piss poor to begin with. They make aluminum ones that connect to the carb with a rubber or maybe silicone hose and two clamps.
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Post by dachurchpcguy on Aug 27, 2016 11:46:14 GMT -5
I went down with some sort of stomach bug, missed a week of work, still catching up. I do have some updates though:
Hybrid #4; This bike had been dumped hard as I said in an earlier post. The fuel gauge, horn, and electric throttle didn't work and the right mirror was broken off. I pulled a couple panels off, the throttle connections were loose. Electric mode works fine now, hybrid mode does not work at all! Fuel gauge is still busted, it may be the sending unit. When I had the panels off I managed to remove the broken stub from the right mirror! Horn just started working on it's own.
This is my son's bike but I've ridden it a few times. It's a bear when cold but after 1/4 mile it runs fine. I'm really happy with the ride, width, and length of the hybrids. I sit normally in the seat, there's room for a passenger behind me. I have to sit on the back of the seat on my 49cc Taotaos. The width feels more natural, my legs don't feel squeezed together when I put them on the floorboards, unlike the Taotaos.
I have the 125cc version in my hands, it belongs to the PO and I'm repairing it in exchange for one of the electric models. Pictures to come ...
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