EbikeE and BMC for Comfort and Range

[Alan B]

Thinking about batteries

I ordered three of the 5S 8AH Zippy's by mistake a couple weeks ago, intending to get the 6S variety. I wonder if I should use them on this bikeE at 15S. That would give me a bit more speed, probably just at or over 30 mph. Three of them is only 440 watt hours, so perhaps get three more and have essentially 900 watt hours. 15S is not the best setup for charging, but it can be handled.

I was originally planning for 18S as it matches my other bike, but that is a bit fast for this setup at about 35. Plus those batteries are paid for, so the incremental cost is rather lower than some other approach. Except for the charger which is a longer term investment. The RC charger will work at 6S or 5S, so the only difference is that I would probably want another bulk charger, or a way to easily regulate the bulk charger to 15S and 18S. It would sure be nice to have an easily settable bulk charger. And that is certainly possible.

[Alan B]

By the way, just listening to the latest podcast, and I want to say - there is NO duct tape or electrical tape on this build!

The Vet-Wrap used to hold the batteries and wires is much nicer than duct tape, and doesn't stick to anything but itself.

[ryan]

But isn't vetwrap stretchy? I'm all for skipping duct tape, but is that really an improvement?

[Alan B]

Yes it is stretchy, but it has a "maximum stretch", so I stretch it to the max, and it holds things very snug since it doesn't want to stretch any further. After a few wraps there is no moving, almost like a plaster cast, as the force and strength compound. Since there is no adhesive, it doesn't leave a mess on anything. Since it is highly frictive, and stretched, it applies a lot more tension than duct tape. So stuff is clamped in place. It only sticks to itself, but after a few wraps it is really snug.

When using it to wrap bandages you don't wrap it this tight. It would cut off circulation.

[ryan]

Well good morning, Alan. Looks like we share early bird status as well. (Though I have a sleepless toddler as my alarm clock.)

Thanks the the vetwrap tip. I'll pick some up at Walgreens today and give it a shot.

[Alan B]

Good Morning. I often wake at 4am and get on for awhile. My toddlers are somewhat over 21 and sleep till noon these days when they can.

I didn't know Walgreens carried it. Good tip. I use the 4" width mostly, though 3" is okay too. I generally order from Amazon and it comes from a horse or pet supply type. Mostly black but is available different colors. Give it a try and let me know what you think. It is easy to remove and if careful can be used again but it is not as neat when re-used.

[ryan]

Looks like Walgreens only has the 2" version. I ordered 10 yards of black from Amazon. Is that enough to wrap up my 18S4P pack? Thanks.

[Alan B]

Probably. That's the fully stretched length they quote, as I recall. What are you going to wrap them to? You can wrap yours into pairs easily enough. If you want to unitize them you might put a thin plastic or wood piece underneath and wrap them to that? Even just wrapping into pairs makes them a little easier to handle.

[ryan]

Yup, pairs (plus nearby wires). Mostly for wire management since I have such a tight space to work with. I was going the duct route but you swayed me.

[Alan B]

I think you'll like it. Easier to unwrap and work with. A little harder to get the wrap started, but take a turn around one battery and that anchors the end, then wrap from there.

[Alan B]

Another wrap I'm going to try is the clear plastic pallet type wrap. Not as strong, but see through and waterproof pretty much when overlapped a few turns. I'm going to put that over everything after the vet wrap anchors the batteries. I'll give it a try on this recumbent soon.

I'm thinking about setting this bikeE up with four 6S 8AH zippys. That should give me enough range to do my commute. Strap them to the main beam, 2 above and 2 below. Move the controller under the seat. Mount a trunk rack on the rear deck. Add a mirror and lights and good to go for longer rides and the commute! Perhaps a bulk charger and battery medics? Or the 14S RC charger??

[Alan B]

I figured the manual would tell me the chainring size, but there are more than one possible so I'll have to measure it. They mention 46 and 52. It looks like 52 to me. Apparently it is a 130 mm mount type, and it is the same as my Schlumpf speed drive mounting. So I could install that Schlumpf in the BikeE and get 1:1 and 1.6:1 front ratios. I have 11-32 or so in the rear. The 11 seems to be good up to the mid 20's or so. Not sure I need any more pedaling speed than that. 1.6x would be about 40 mph pedaling speed.

90 rpm times 52/11 times 20 inches times pi / 12 inches/foot times 60 minutes per hour / 5280 ft/mile is 25 mph

so 20 mph is 72 rpm, assuming that 52 teeth is right.

The inexpensive 7 speed freewheel (DNP?) on the gearmotor is heavy and the spacing doesn't seem to quite match the SRAM shifters. So I might swap the OEM freewheel back in. I will need a freewheel tool to do that. But it might be worth doing. Perhaps at the same time I should put a disc brake on the motor just to camouflage it a bit (there are no mounting tabs for a disc brake).

[Alan B]

Here's a SeaHorse SE300 case:



So how much Lipo will fit?



Above shows one layer of four 6S 5AH plus one 6S 2.6AH, two layers will fit for a total of 1.2kwh

Then with another brand of Lipo:




Above shows one layer of three 6S 8AH, two layers will fit for a total of 1.1 kwh.

In either case the boxes are fairly full but there is some room for wiring and LVC/HVC boards.

It would really be nice to have a setup that would hold either one or two of these boxes on the bikeE. The 100 mile ride would need two, the rest of the time one would be sufficient, perhaps even one that was less than full, or had a charger in there as well.

But how to carry them?

[liveforphysics]

That's a nice case Alan. Good rigid waterproof package that holds enough LiPo to get around just fine.

[Alan B]

Thanks Luke. They are pretty cost effective too, much lower cost than the nice Pelican cases, and a little lighter though it is hard to compare that. Almost hate to drill holes in them they are so pretty, but that will happen soon enough.

[grindz145]

Wow only 30 bucks, thats really freaking good. Lipo really deserves more than a soft case

[StudEbiker]

I am fairly certain that the front chainring is 110mm bcd, not 130.

[Alan B]

OK on the chainring, I was going by a website on that, not a measurement. I'll measure it. There are variations between models on a number of items, so it might be right for some other model.

[Alan B]

The SE-300 case weights about 2.5 pounds empty.

Loaded with six 6S 8AH Zippy batteries it weighs about 19.5 pounds, so figure about 20 pounds with the wiring. Very close to three pounds per battery. Not quite as light as duct taping them to the bike frame.

[veloman]

Wow only 30 bucks, thats really freaking good. Lipo really deserves more than a soft case

Hehe, I had my lipo booster pack wrapped in chloroplast (from an old sign), then package taped to the bike. It's a shame to put a light battery in a heavy case. Try to engineer a secure case that is light.

[Alan B]

A 2 pound case is too heavy for an 18 pound battery? This battery doesn't feel light!

This is post #2500 for me! Amazing!

[Alan B]

I ordered the wire for the battery wiring. I have the connectors. The interconnections are made by crimping four wires into the PowerPole 75 amp 6 gauge pins. These pins will take four 12 gauge wires very nicely. No soldering required. Three of the four connections go to batteries, the fourth goes to a bank charging connection so each 6S bank can be individually charged with a 6S RC charger that I already have.

Unfortunately I never got around to getting the 12 gauge silicon wire so that is on order but will delay the project a few days.

I still need to come up with a nice mounting scheme for the cases and controller. I could use the wood rack that I made temporarily but would like to come up with something a bit nicer for long term.

Edit - updated the diagram from the 18S shown before to the 12S appropriate for this thread.

[ryan]

It's great to see how a professional diagrams a setup. I've got so much to learn.

What fuse are you using? Would you recommend it for my setup?

Also, can you clarify your precharge setup? Which Resistor?

[Alan B]

Fuses are a really good idea. Seems like my maxifuse holders aren't as big as Ryans, but they do take space. Not sure which I'll use here yet. I have some others:



You can bolt onto these fuses with flexible wire, and then heatshrink over them. Mouser or Digikey had them, they are electric vehicle fuses. Not cheap but not terribly expensive. They are bigger than maxifuses but not needing a holder helps some. I also think that bolting to a maxifuse might be a better way to use them. More on that theme to follow.

How about this:

Drill a #10 hole in each lug of a maxifuse. Use two wires and two ring lugs bolted to each maxifuse lug. One ring lug on each side to get maximum surface contact area. Then join the two wires into the bullet, so the two wires are in parallel. Use two #10's or #12's on each side of the maxifuse. Use a brass #10 screw or bolt to bolt them together to improve the conductivity, though most current will go wire to ring lug to fuse lug anyway. I suspect that would be adequate for 50 amps, but try it and then check to see if the connections get hot. If they stay warm or cooler then it passes!

I have also used fusible link wire on systems like these. Make up a short fusible link section with ring lugs on the ends, or perhaps bullets or whatever connector fits your setup. Maybe put some clear silicon high temperature tubing over the fusible wire in case it melts to try to keep it from the batteries and other vulnerable bits.

[Alan B]

I measured the bolt hole spacing on the front chainring to be 64.7mm. Multiply that by 1.7 to get 110mm bolt circle diameter.

So 110mm it is, not 130. The Schlumpf speed drive I have is the same.