New creation - and a question.

[OxygenJames]

Hello all.

Long time no speak - been putting some miles down on the Haibike (EQ Enduro FS - great great bike btw) - but my GF was continually complaining the Burisch was too big for her and would I make her a smaller electric bike please.

So - see attached for my creation. I got the motor and 800w controller off ebay for £185 then a 15 inch frame off ebay too and then stripped an old bike I had and Hey Presto! (the battery is going to be interchangable with the Burisch) - which leads onto my question.

OK - - here it is and fits her perfectly.

My question - does anybody know where I can get a spare battery cable - like the ones that screw into those bottle batterys? I am not having much luck on ebay and wondered if anybody knows a place to go? Otherwise I have to swap the lead each time we move the battery from the new small bike to the Burisch.

Like this:

If anybody does or has any idea where I could get one please let me know.

Thanks.

 

[Deleted member 4366]

Very nice creation, although flawed. I can't see that battery being able to supply enough power for that motor. It'll sag massively and probably cut out on hills. I hope I'm wrong. Let us know how it goes.

If it works, I've got one of those connectors you can have for a couple of quid, but I think you'd be better putting the money to a decent battery.

 

[OxygenJames]

Very nice creation, although flawed. I can't see that battery being able to supply enough power for that motor. It'll sag massively and probably cut out on hills. I hope I'm wrong. Let us know how it goes.

If it works, I've got one of those connectors you can have for a couple of quid, but I think you'd be better putting the money to a decent battery.

I'll get back to you on the connector if thats OK (and thanks for the offer) - another person may come through there - but re the battery - so far its been fine - did a 5 mile round trip no hills but no problem. Its the right voltage (36) and has 9ahr - seems like it should be OK. My GF is only 50Kg so that should help...

What sort of battery do you think would be better?

 

[amigafan2003]

It's not the capacity or the voltage that's in question - it's the C rate. That batt will only be rated to output about 350watts constant - pulling 800 watts from it regularly will reduce it's life massively. The Burisch controllers are limited to around 12amps I believe so that's a max 500watts from the battery fully charged.

What's the actual amp rating on the "800w"controller? I would be surprised if it's peaking nearer 1200 watts.

 

[OxygenJames]

Very nice creation, although flawed. I can't see that battery being able to supply enough power for that motor. It'll sag massively and probably cut out on hills. I hope I'm wrong. Let us know how it goes.

If it works, I've got one of those connectors you can have for a couple of quid, but I think you'd be better putting the money to a decent battery.

One other idea - what if I changed the controller for a 500W one - would that help? Is it the controller or the motor that you think is the problem? (I've got a spare 500W controller lying around doing nothing much and when we tried the bike yesterday it was FAST - so downsizing the controller might be a good idea in terms of stopping the wheelies!)

 

[amigafan2003]

One other idea - what if I changed the controller for a 500W one - would that help? Is it the controller or the motor that you think is the problem? (I've got a spare 500W controller lying around doing nothing much and when we tried the bike yesterday it was FAST - so downsizing the controller might be a good idea in terms of stopping the wheelies!)

Ignore the "500w" rating on controllers - they are meaningless. Look at the rated amps. You're looking at something like 12/14amps for that battery - typical of a "36v/250w" controller.

The trouble is, that big, heavy direct drive motor will feel gutless at that amp level.

For that motor - you need a big, powerful battery - something like 36V 20AH V2.5 LiFePO4 Battery Pack or four packs of 5s5ah lipo http://www.hobbyking.com/hobbyking/store/__8581__ZIPPY_Flightmax_5000mAh_5S1P_20C.html

 

[OxygenJames]

Ignore the "500w" rating on controllers - they are meaningless. Look at the rated amps. You're looking at something like 12/14amps for that battery - typical of a "36v/250w" controller.

The trouble is, that big, heavy direct drive motor will feel gutless at that amp level.

For that motor - you need a big, powerful battery - something like 36V 20AH V2.5 LiFePO4 Battery Pack or four packs of 5s5ah lipo ZIPPY Flightmax 5000mAh 5S1P 20C

Thanks for that! (not sure I wanted to hear it though) - so you think even if it does not cut out it will still wreck the battery? Hmmmmm. OK.

The other controller I have says Current Limit 14A. I could try it and see how it feels - if you're sure I will wreck the battery otherwise.

 

[OxygenJames]

It's not the capacity or the voltage that's in question - it's the C rate. That batt will only be rated to output about 350watts constant - pulling 800 watts from it regularly will reduce it's life massively. The Burisch controllers are limited to around 12amps I believe so that's a max 500watts from the battery fully charged.

What's the actual amp rating on the "800w"controller? I would be surprised if it's peaking nearer 1200 watts.

This is the kit in question btw: Here

 

[OxygenJames]

It's not the capacity or the voltage that's in question - it's the C rate. That batt will only be rated to output about 350watts constant - pulling 800 watts from it regularly will reduce it's life massively. The Burisch controllers are limited to around 12amps I believe so that's a max 500watts from the battery fully charged.

What's the actual amp rating on the "800w"controller? I would be surprised if it's peaking nearer 1200 watts.

I've asked the people who sold me the kits what the Amps rating is on the controller - they have yet to get back to me - btw I also found out that my battery has the following rating:

1. Operating current: 8-10A
2. Peak current: 24A

Which would mean it could peak at over 800W apparently OK. But you're saying it will still likely damage the battery given that you should not run it at peak too much? But wont the battery management system on the battery stop it from delivering too much power - in which case it would indeed cut out to protect itself - I am guessing you think even with that damage will be done. Is this right? I am learning as I go - as if you cant tell - I think tomorrow I will try it with the 500W controller rated at 14A and see how it feels - though I would like to keep the 800W one there seeing as its so quick with it! But not if its going to mess up that battery.

 

[OxygenJames]

I just found another set of specs on my battery (the bottle one in my pic at the start) - and it says:

Continuous Discharge Current: 13 A
Burst Discharge Current: 30 A

Which seems to mean it could handle a peak of just over 1000W.

Curious and curious-er.

 

[Deleted member 4366]

I seem to remember another forum member had trouble with his Burisch battery because it wouldn't give the current he wanted, but I can't remember the details. You can't just look up any details for a bottle battery because they're different inside. You have to ask Burisch what cells are in the battery if they'll tell you, or look inside to get the number off the cells. Most bottle batteries are rated at 1C, which means that they're happy to provide about 9amps. They can give twice that much for a short time, but the chemistry in them can't keep that up, so the voltage starts to go down (sag). If you fitted a voltmeter, you could see what the sag is. The BMS will have a current limit. It could be 20 or 25 amps. If you get too much sag, the BMS could cut off when it sees a cell go below the minimum (about 3v).
Over-loading a battery will shorten its life, but nobody can put a number on that. You're in the realms of the unknown.

it's always possible that Burisch up-rared the cells to the same as the OXydrive and Kudos bottle batteries, in which case you won't have a problem. You can get a good idea by looking at the LEDs on your throttle, which, hopefully, you've connected. If not, do it soon. There's three wires to the throttle connector plus another three. Two of those are for the switch (normally yellow and brown) and the remaining one (normally green) is for the LEDs, which goes to the battery.

If when you accelerate away, the LEDs go from green to red, your're over-discharging the battery. Green to amber is OK.

My 750w controller gives 30 amps, which would be too much for that battery even if it had high-discharge cells. I suspect that yours is 30 or 32 amps, but only a watt-meter will show it. for definite. Don't try and convert to watts. It's amps you should be looking at.

I've run a 30 amp controller off a 10 amp-hour battery before as a temporary measure, and it worked,but it shouldn't be done for long.

Assuming that your controller's 25 amps or more, you need a battery of at least 15 amp-hours. 20 amp-hours would be better. Alternatively you could use a smaller battery with either headway cells or lipos, which can both go over 10c.

 

[Scimitar]

This is the kit in question btw: Here

That's the Conhismotor kit I got a couple of years ago. I first used a 10Ah battery, and it was ok, but I always took it easy with that, because I'd always intended for it to total 15Ah for full-on use.
With that extra capacity, it flies along and nothing bothers it.
30+Amps is a breeze, from 6 stripped Bosch Fatpacks and their Konion cells.

 

[Scimitar]

My question - does anybody know where I can get a spare battery cable - like the ones that screw into those bottle batterys? I am not having much luck on ebay and wondered if anybody knows a place to go? Otherwise I have to swap the lead each time we move the battery from the new small bike to the Burisch.

Like this: View attachment 6108

If anybody does or has any idea where I could get one please let me know.

Thanks.

Similar to these?
http://2.bp.blogspot.com/-PRxAkddSa5c/UZvrEAWBrBI/AAAAAAAAAQA/9K_3FVk0Am4/s1600/ebike_connector.jpg
I don't know the exact source, but they're common enough.
Here's the page they were mentioned on
Top Secret EV Blog

 

[Blew it]

The plugs used are more usually found on CB radio microphones, available in 2, 4, 5, 6 and eight pins.

MIC PLUGS

Also on Ebay

EBAY

Maplins also stock them. Scroll down for Lkg Line Skt 4-way

MIC PLUGS

 

[OxygenJames]

The plugs used are more usually found on CB radio microphones, available in 2, 4, 5, 6 and eight pins.

MIC PLUGS

Also on Ebay

EBAY

Maplins also stock them. Scroll down for Lkg Line Skt 4-way

MIC PLUGS

Great - thanks for that.

 

[OxygenJames]

I seem to remember another forum member had trouble with his Burisch battery because it wouldn't give the current he wanted, but I can't remember the details. You can't just look up any details for a bottle battery because they're different inside. You have to ask Burisch what cells are in the battery if they'll tell you, or look inside to get the number off the cells. Most bottle batteries are rated at 1C, which means that they're happy to provide about 9amps. They can give twice that much for a short time, but the chemistry in them can't keep that up, so the voltage starts to go down (sag). If you fitted a voltmeter, you could see what the sag is. The BMS will have a current limit. It could be 20 or 25 amps. If you get too much sag, the BMS could cut off when it sees a cell go below the minimum (about 3v).
Over-loading a battery will shorten its life, but nobody can put a number on that. You're in the realms of the unknown.

it's always possible that Burisch up-rared the cells to the same as the OXydrive and Kudos bottle batteries, in which case you won't have a problem. You can get a good idea by looking at the LEDs on your throttle, which, hopefully, you've connected. If not, do it soon. There's three wires to the throttle connector plus another three. Two of those are for the switch (normally yellow and brown) and the remaining one (normally green) is for the LEDs, which goes to the battery.

If when you accelerate away, the LEDs go from green to red, your're over-discharging the battery. Green to amber is OK.

My 750w controller gives 30 amps, which would be too much for that battery even if it had high-discharge cells. I suspect that yours is 30 or 32 amps, but only a watt-meter will show it. for definite. Don't try and convert to watts. It's amps you should be looking at.

I've run a 30 amp controller off a 10 amp-hour battery before as a temporary measure, and it worked,but it shouldn't be done for long.

Assuming that your controller's 25 amps or more, you need a battery of at least 15 amp-hours. 20 amp-hours would be better. Alternatively you could use a smaller battery with either headway cells or lipos, which can both go over 10c.

That's great - thanks very much for taking the time to write that out.

To be on the safe side I just swapped over the controllers - so it now has the '500W' controller on it - and having just taken it for a test run it feels OK - not as fast as with the 800W controller - but I do not want to wreck the battery and from what you and others say I am running that risk if I left it as it was.

But thanks for the info - its good to realise what to look for when matching batteries to other components - which I did not know before this! I think we're all set now - my GF being a 'short ****' (her words not mine) - and weighing very little should mean she will be just as happy - though if and when they make a battery that can deliver 15Ahr in the size that will fit inside a 15inch frame then perhaps I will get that and put the 800W controller back in there!

Once again many thanks.

 

[OxygenJames]

For the record - this is the reply I got from the Ebay sellor that I bought the controller from - I had asked what was the rated Amps for that controller - peak and continuous.

The answer they gave me was this:

--------------------------

Thanks for your email

Please informed this kit needs 36V battery which should be the same as the kit, so the battery is direct current(DC), not alternating current(AC).

If the battery reaches 36V, the kit will work without any problem. And the AMP can be count with the voltage and power, please kindly see the formula below :
current=power / voltage ,that means 800W / 36V, it is about 22.2 AMP.

Our item has a safe setting, Voltage is constant, when the weight is over the max load capacity, power will increase, and current will increase at the same time. When the current is too large and over its maximum range, the item will stop working to avoide burning out, the power supply will interrupt to avoid burning out.

And the higher amp it can take should be 25 AMP

Have a lovely day my friend!

Please be free to contact us if you need.

----------------------------------

 

[jackhandy]

Nice one, James:

As always, you've been given the best advice by those wot know

Just to add a little perspective.... the 8fun kit we all know & love has a 9ah bottle battery & pulls 14 amps on hills, which causes voltage sag.

And watch that battery connector plug - As already noted, it's a CB radio plug & I believe rated @ about 4 amps max?
Not really suited to that motor/controller.

 

[Deleted member 4366]

I think that connector should be OK. I have one on this battery with Headway cells that I ran with 22 amps:
http://www.bmsbattery.com/packs/114-36v10ah-lifepo4-battery-38120-ebike-battery-pack-with-carrier.html

 

[Blew it]

And watch that battery connector plug - As already noted, it's a CB radio plug & I believe rated @ about 4 amps max?

Quite right Jack, they are rated at 5 amps per pin. I questioned the use of these plugs when used to connect the bottle battery to controller on Cyclotricity machines. The low rating is partly overcome by using all four pins to carry the load. The red conductor strands divided to two pins and likewise the black conductor. Even then, I've found it neccessary to snip off some of the strands so that they fit into the solder buckets of the plug. I remember throttling one of those machines along at full power for about a mile to see if the plug overheated......it didn't.