Newbie on a home made ebike. Can't set controller.

General Discussion about electric bicycles.
AngryBob   1 kW

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Re: Newbie on a home made ebike. Can't set controller.

Post by AngryBob » Sep 12 2020 5:04am

First, if you do not yet have a solid handle on why you use less power when going downhill, STOP making any decisions on changes to your system, until you figure out how it actually works.

There are not usually any specific setup changes you can make to a simple controller that will make any significant changes to performance, IF it is able to supply enough amps, which it sounds like it is well matched to your current battery, which is the main limiting factor.

The heat you feel on the outside of your motor is very well insulated from the actual hot internal components, think feeling the hood of a car in comparison to the engine block.

Search on Statorade, then search more on engine cooling. Make sure you pay very careful attention to the usage cases where these things become necessary.

If you wanted more speed, the options are a faster wind motor, or a higher voltage battery. A 5% increase in voltage will not have a large effect. Using a small fairing or just bending over in tuck position or even zipping up your jacket will likely have more effect.

A stored battery should be at least partially charged every 3-6 months or so. The BMS has a parasitic drain, not on the entire battery, but on just one parallel string, and over a prolonged period of time will totally drain and destroy those cells, making the entire battery a severe fire hazard and requiring cell replacement and a rebuild.

Either get someone to perform a periodic partial charge for you or disconnect the BMS from the battery. Or, get really good fire insurance and some new batteries when you get back.
"Not being treated like a dumb dick is one of the incentives we have to become less stupid." - Balmorhea.

Raider   10 mW

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Re: Newbie on a home made ebike. Can't set controller.

Post by Raider » Sep 12 2020 5:45am

Just as I thought. BMS drawing a trickle of power constantly. Well, that means I'll have to get someone to maintain the batteries for me while I'm home in Asia.
Or do a quick build with an arduino to monitor the voltage and charge it when nessesary. up to 80% or so. Should be easy enough.

Oh, well. Guess I'll wait and see what happends now, with dual batteries. A test drive is in order when the biulding are all finished.
Maybe the power skip is gone too..

Voltron   10 MW

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Re: Newbie on a home made ebike. Can't set controller.

Post by Voltron » Sep 12 2020 10:32am

Many of the newer BMSs put themselves to sleep so they aren't draining the battery during long disuse. Open question whether yours do that, but worth checking.

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Re: Newbie on a home made ebike. Can't set controller.

Post by Raider » Sep 12 2020 10:47am

Thank you for the tip. I'll contact the vendor. :thumb:

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Re: Newbie on a home made ebike. Can't set controller.

Post by Raider » Sep 14 2020 4:45am

Well, build are going forward. Somewhat. But, I noticed that when I put mu ohm meter to the xt 60 connector of the new battery, it reads 2V. Even with the battery swithced off. That's weird. The other one shows 0V.

Seems like the battery vendor don't have much of a clue when it comes to store batteries though. Told me to charge the battery 100% before putting it away. Then it should be ok for 8 months or so.
As most people know, storing a fully charged battery will weaken the capacity over time. So, not a good idea. I guess about 80% will do, then just set them on an automated charging circuit to keep it alive.

Batteries is on the bike, though. Shoe horned in. Even if I have a really open frame on my MTB, the controller and triangle battery takes up 100% of the space inside that frame. Even had to grind down the small nubs that the screws for the bottle holder sits in.
Stilll have the lighting circuit to put in though. Connecting the brake lights too. And draw the cables for it.
But, I did a small test yesterday.
Now, with the dual 52V battery packs, I have 40ah to use. Should last for bout 82 km on full throttle. The bike weighs in at about 26kg.
After connecting the battery pack I did a unloaded test run to see the maximum unloaded speed.
And low and behold, it is 66km/h. Or 41mph. Seems to be doing a tiny bit better than with one battery only. Hopefully that will also be the case on the road. When I have the time, I'll sit down and calculate the rpm.
So, so far so good.
Still don't have a clue as is my controller has the correct setup for 52V though.. There are stuff in that setup menu that still sounds greek to me..

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E-HP   1 MW

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Re: Newbie on a home made ebike. Can't set controller.

Post by E-HP » Sep 14 2020 8:37am

Raider wrote:
Sep 14 2020 4:45am
As most people know, storing a fully charged battery will weaken the capacity over time. So, not a good idea. I guess about 80% will do, then just set them on an automated charging circuit to keep it alive.
Speaking of not a good idea...hopefully you own the building and it's unoccupied. Maybe go to the battery forum, read the stickies, then ask how to do that safely.

Voltron   10 MW

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Re: Newbie on a home made ebike. Can't set controller.

Post by Voltron » Sep 14 2020 1:05pm

He's not wrong...☝️
Unattended battery charging is pretty dangerous.. it's during charging that most battery fires start.

I personally had what was a previously reliable 48v charger on a battery, was nearby and actually drifting off into a nap when the pattering of raindrops made me jump up to put away stuff in the yard.
Except it wasn't raindrops... It was the pressure relief valves on the cells starting to pop and hiss, and the entire pack was burning hot in my hands as I rushed it outside.
It was in a concrete area, with a smoke detector right above it, but hate to think about if it had gone off enough to jump flames across my clear area around the bike with no one to hear an alarm nearby. It was heading deep into thermal runaway, but there was no smoke yet when I heard it, so smoke detectors aren't adequate early warning systems for this kind of thing. The charger had out of the blue started putting out about 70v to the battery.

It was an eye opener about how fast it can all go sideways, even with previously trusty equipment.

Raider   10 mW

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Re: Newbie on a home made ebike. Can't set controller.

Post by Raider » Sep 14 2020 1:28pm

And as always, ask 15 persons, you'll get at least 16 different answers :)

Voltron   10 MW

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Re: Newbie on a home made ebike. Can't set controller.

Post by Voltron » Sep 14 2020 1:41pm

Re the battery vendors opinion... Their interest is usually in keeping you from trying to return the battery under warranty because the BMS killed it from a couple of months of storage. So they're more inclined to tell you to top it off before storage, as then it takes longer for the BMS to kill it, and maybe less worried about shortening the battery's long term usefulness, when it will be out of warranty by the time it shows.

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Re: Newbie on a home made ebike. Can't set controller.

Post by Voltron » Sep 14 2020 1:54pm

And if you ask 15 ebike people about the safety of automated unattended generic lithium battery pack charging near a
occupied residential dwelling, I'm really really hoping you get less than 16 opinions 🤞

AngryBob   1 kW

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Re: Newbie on a home made ebike. Can't set controller.

Post by AngryBob » Sep 15 2020 5:57am

This is where I chime in with an "Oh HELL no!!!" on the unattended automated charging.

With the possible exception of late Curtis, I don't think you would find one single person who would find that concept a good idea, even with theoretical unobtainium equipment.

Let's see, robotic arms for making and breaking the mechanical connection so the charger is not a constant power drain, continuous voltage monitoring of the battery and charger during charge, extreme coverage halon system in a sealed concrete enclosure, LTO batteries, massive insurance, single occupant dwelling, no children or elderly in residence, extra cash available for equipment replacement, and maybe being the seventh son of a seventh son.

Nah, still Oh HELL no!!!
"Not being treated like a dumb dick is one of the incentives we have to become less stupid." - Balmorhea.

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MadRhino   100 GW

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Re: Newbie on a home made ebike. Can't set controller.

Post by MadRhino » Sep 15 2020 3:00pm

Yep. No equipment can be trusted. I don’t even use a BMS. Battery at storage voltage unplugged off anything when not in use. Charging under direct supervision. Then, I charge bulk and fast, so never tempted to leave them charging alone.
Make it fool-proof, and I will make a better fool.
Current bikes
Street:
Trek Session 10 mod. Variable geometry. 70mph
Dirt:
Santa Cruz V10. 50mph

Balmorhea   100 kW

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Re: Newbie on a home made ebike. Can't set controller.

Post by Balmorhea » Sep 16 2020 3:13am

AngryBob wrote:
Sep 15 2020 5:57am
This is where I chime in with an "Oh HELL no!!!" on the unattended automated charging.
And yet.

Phone. Laptop. Cordless tools. Wireless router. Roomba. What have you.

Do you really apply the same precautions to every lithium battery on your premises? Because the same principles apply to all of them.
___________
Finish Reconstruction.

Voltron   10 MW

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Re: Newbie on a home made ebike. Can't set controller.

Post by Voltron » Sep 16 2020 3:54am

They're usually smaller than bike battery packs with less stored energy going off, so risk is intrinsically higher with larger batteries. And usually made by companies that have much more robust safety systems, who plan on staying in business a long time, not just folding and restarting in case of a fire. Proprietary chargers, actual quality control inspections, non counterfeit materials etc.

AngryBob   1 kW

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Re: Newbie on a home made ebike. Can't set controller.

Post by AngryBob » Sep 16 2020 4:10am

No, they don't.

Some of those devices have batteries measured in ounces, not pounds.

Those with large batteries have are made by companies that have rooms full of people concerned about preventing the company from having it's ass sued clean off due to defective products, materials, or design.

I don't think most chinese ebike battery makers are concerned with risk management in any way whatsoever.

When the consumer has no effective recourse to be made whole from the ravages of defective product, dangerous and defective products are far more commonplace.
"Not being treated like a dumb dick is one of the incentives we have to become less stupid." - Balmorhea.

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