Oxygen S-Cross CB shunt mod

[DBye]

Following on from this thread:
http://www.pedelecs.co.uk/forum/threads/oxygen-s-cross-cb-hunt-for-the-shunt.27196/

I've done the deed. Bought 3x R006 resistors rated to 2W and 2512 in size and piggy backed these onto the three R002's on the board.
It isn't my finest soldering job, but seems to be ok.
Before:

After:

The piggy backed R006's don't protrude far at all and don't interfere with getting the PCB back into the controller housing at all:
.
Unfortunately, I've not been able to test it out. My wheel is away for spoke replacement (2 broke on way to work, stupid roads) and a true/tension checking.

The bike does still turn on at least so that must be good sign surely?!

 

[Woosh]

very neat soldering!

 

[DBye]

Got my wheel back... It's awesome, does 18mph up the hills!

 

[DBye]

Following on from this:
http://www.pedelecs.co.uk/forum/threads/oxygen-s-cross-cb-intermittent-cut-out.28182/#post-382704

I replaced the battery connection with an XT-90. The original connector had melted all around the -ve terminal (I'll post a photo when I get a chance) and had stuck to the other connector.

I don't think the battery connection is rated to cope with this mod! I'd recommend either changing the battery connection at the same time or using a smaller resistor (@d8veh recommended an R010 previously) may avoid the issue.

Now I've got consistent power I've noticed that if I run the bike on level 6, Power mode, and use the special code to set the controller to totally unrestricted (well, 62mph), the bike will still cut out on long hills, and the section of bike frame housing the controller gets warm. I assume this is battery sag and the BMS cutting in.

If I use power level 6, Power mode, but restrict to 21mph I can avoid the cut out but get what I think is battery sag (after 7 miles with plenty of up hill the bike doesn't provide as much "go" up the hills).

Finally, if I set the bike to power level 6, Normal mode, I don't get the sag or the cut outs, but it isn't as awesome as it is when in power mode (the motor takes longer to kick in when peddling for example and acceleration is less).

I wish there was a way to set up the controller so I could use the +/- keys to quickly change between power/normal/eco. At the moment these scroll through levels 1-6 which seem to simply limit the speed. To change power level I have to press set for two seconds, press set again to select the power changer mode, press +/- to select the desired mode then press set again for 2 seconds to select it. Not particularly convenient when heading up hill, going over speed bumps with an irate commuter behind.

Perhaps I should just learn to enjoy taking my time!

 

[Deleted member 4366]

When you run in "normal" mode, the power is restricted. Those three levels bring in current limits. "Power" uses the maximum controller current, "normal" uses something like 70% and "eco" something like 40%. They can only be changed by reprogramming the CPU, for which you need special equipment.

Without a wattmeter, we don't know what current you're actually running. It might be an idea to change to the 010 resistors. maybe less will give you more.

 

[DBye]

Thank you, I thought that may be the case. I've got a new set of R002's in so I might just go back to those for the time being and see how it goes.

I thought I'd need to do that any way as will be easier to remove both the R002 and the R006 currently piggybacking together.

 

[DBye]

Before I do anything, I'm tempted to get a watt meter and see what it is doing.
Do you still recommend this one:
http://www.ebay.co.uk/itm/DC-50A-LC...6164a71&pid=100005&rk=1&rkt=6&sd=171870530730

Hopefully, if I'm thinking right, I can simply put XT90 connectors on the ends and plug it in between the battery and the controller.

 

[Deleted member 4366]

Before I do anything, I'm tempted to get a watt meter and see what it is doing.
Do you still recommend this one:
http://www.ebay.co.uk/itm/DC-50A-LC...6164a71&pid=100005&rk=1&rkt=6&sd=171870530730

Hopefully, if I'm thinking right, I can simply put XT90 connectors on the ends and plug it in between the battery and the controller.

That should be OK. It saves messing about to make a remote shunt.

 

[Mal69]

Following on from this:
http://www.pedelecs.co.uk/forum/threads/oxygen-s-cross-cb-intermittent-cut-out.28182/#post-382704

I replaced the battery connection with an XT-90. The original connector had melted all around the -ve terminal (I'll post a photo when I get a chance) and had stuck to the other connector.

Now I've got consistent power I've noticed that if I run the bike on level 6, Power mode, and use the special code to set the controller to totally unrestricted (well, 62mph), the bike will still cut out on long hills.

If I use power level 6, Power mode, but restrict to 21mph I can avoid the cut out but get what I think is battery sag (after 7 miles with plenty of up hill the bike doesn't provide as much "go" up the hills).

Finally, if I set the bike to power level 6, Normal mode, I don't get the sag or the cut outs, but it isn't as awesome as it is when in power mode (the motor takes longer to kick in when peddling for example and acceleration is

Do these sags and cutouts occur because you changed things on the controller side?

I ask because derestricted I notice no cut outs or sagging on hills and we have some pretty steep and long hills in this region of the UK.

Also you are worrying me when you talk about the original connector having melted, is this a potential future problem for me?

 

[Deleted member 4366]

He increased the current from his controller by about 30% (calculated). We don't know what it actually got increased to yet. You don't have anything to worry about.