Charger faulty?

[andrewelectricbike1]

Had a couple of interesting days recently.
Suede E NiMh charger left charging.. I return and it had kicked into refresh mode! Normally requiring the press of a button.,.,
This has happened twice now. Anyone heard of this before?
Andrew

 

[flecc]

I've never heard of this Andrew. Do you leave the charger plugged into the mains between usages? Also, do you plug in the suggested sequence, whatever that is for this charger? Long shots, but worth checking.

 

[andrewelectricbike1]

That might be the problem.. leaving it plugged into the wall. I guess my routine has gone to pot during the christmas break. Really wierd though, nothing in the literature suggests this could happen!

The up side is that the suede battery refresh takes an absolute age, so providing the pack is fully charged each time, it should have little effect on my commute/range. I might seek out a spare charger somewhere just in case.
Andrew

 

[Flying Kiwi]

That might be the problem.. leaving it plugged into the wall.

I once had an electric scooter charger fail entirely by plugging it into the wall briefly before plugging in the battery. It's really important with "switching mode" power supplies that the load is connected before applying power. The same applies with PC Power supplies which can be damaged by applying power without loading them first (eg leaving them unplugged from the motherboard). Although the Twist manual doesn't seperately mention not to leave the charger plugged in while unused, the procedure for battery charging is clearly laid out step by step and the battery is always the first thing the charger is plugged into and the last unplugged. I'm sure the same should apply for the Suede.

The Twist battery refresh section mentions it may take up to 15 Hours (and that was with the 6.5 Ah battery used when the manual was printed , not the newer high capacity ones these days and on the Suede). I'd give it a try after unplugging the charger and allowing it to cool and after flattening the battery on the bike through normal use. If that still doesn't work then make the next recharge a "forced" refresh ie press the button and see if that re-initialises things again. My Twist manual mentions not to charge for over 24 hrs so if this is what has happened with your charger perhaps it needs to be re-initialised by starting from scratch.

 

[andrewelectricbike1]

Thanks m8. I hope I have not damaged it!
It charges fine, I just can`t trust it to drop to green without starting a refesh! I`ll see how it goes for the commute.
Thanks again!
Andrew

 

[flecc]

Though Flying Kiwi is right about the plugging sequence of switched mode supplies, especially with computer supplies, these much lower output bike chargers are almost invariably protected against actual damage from using an incorrect sequence. I very much doubt of you've damaged yours, the Twist's two charger types are both protected in this way, and so are the eZee NiMh and Li-ion chargers. These are so effective that I frequently use wrong sequencing, four years of doing that often with the two Twist chargers. The most important thing is to disconnect from mains between each charge.

The oddest case I've come across is a bike NiMh switched mode charger that won't work when correctly plugged. It will only start charging if mains is applied first, doubtless due to some oddity in the protection arrangements.

 

[andrewelectricbike1]

Thanks guys
I`ll get back to routine after xmas and see how it fares at work.

Whilst the charger is labelled Giant, it looks like a panasonic build with a new sticker.

 

[Flying Kiwi]

Though Flying Kiwi is right about the plugging sequence of switched mode supplies, especially with computer supplies, these much lower output bike chargers are almost invariably protected against actual damage from using an incorrect sequence.

Well thats what I thought about my scooter charger and it was lower output than the Twist charger. My advise to users is its better to be safe rather than sorry and to always follow the correct procedure.

Having made that point, I certainly hope that Andrews charger isn't permanently damaged. I suspect it's not if it hasn't blown its fuse and still charges and the only problem was that it sometimes automatically goes into refresh mode. The Panasonic charger supplied with the Twist wont go into refresh mode at all unless commanded to do so by pressing the button so I wonder if the problem may just be an intermittent refresh switch fault or something accidentally pressing on it (any cats walking around the area?). Hopefully the testing following correct procedures will reveal the problem has gone away.

 

[andrewelectricbike1]

cheers m8.
My usual procedure at work is plug in to the wall, plug in to the bike and switch on the charger. I might have disconnected from the bike during the holidays and left the charger switched on.. I seem to remember the power light being on when I returned.

But then I don`t think I powered down before the next charge. Perhaps the giant charger was a little too smart for itself?
Ahh well

Andrew

 

[Flying Kiwi]

But then I don`t think I powered down before the next charge. Perhaps the giant charger was a little too smart for itself?

My thoughts too. Let us know how you get on with your testing and good luck

 

[andrewelectricbike1]

mm Left it charging after I got home. Seems to have done it again!
Typical, just after the giant warranty ran out too!
The battery seemed warmer than usual.
Andrew

 

[Flying Kiwi]

mm Left it charging after I got home. Seems to have done it again!
Typical, just after the giant warranty ran out too!
The battery seemed warmer than usual.
Andrew

Do you think it may just be something like a loose refresh button - if you shake the charger, does it going into refresh mode? There was a known issue with charger failures for the Twist but this was a different problem where charging would cut short. I don't know about Suede charger reliability though.

There's still a chance Giant may entertain good will assistance toward a repair or replacement if the warranty has only just expired - especially if your dealer is willing to back up your case. In fairness I've never tried this with Giant (perhaps someone out there has and can comment). It happened all the time at the car company I used to work for and factors such as length of ownership of the brand, whether it had been serviced at approved dealers and whether there were multiple vehicles of this brand in the household all had influence. You'll need to act quickly, the sooner the better.

Let us know how you get on enquiring about this with your dealer.

 

[Sav]

My charger is one of the faulty Giant ones, though rather more out of date than yours. It had been left in a garage for two years since being six months old,

Giant were completely unhelpful in my case, even though the charger was supplied faulty.

I'm planning on buying the Yank battery pack and charger I looked at, though there is a question mark over the pack being exactly the same size as ours.

Will advise.

Chris.

 

[flecc]

I'll have the posting on the replacement Twist charger ready in a day or two now. It would be good to think it will suit the Suede as well, but I cannot verify that without access to a Suede battery as the NTC thermistor characteristics and signal voltage are vital for correct charging cutoff.

 

[andrewelectricbike1]

I'll have the posting on the replacement Twist charger ready in a day or two now. It would be good to think it will suit the Suede as well, but I cannot verify that without access to a Suede battery as the NTC thermistor characteristics and signal voltage are vital for correct charging cutoff.

I did not think the twist battery was the same voltage.. Is the twist battery 36 volts then?
I`ll try giant by email, but I don`t hold out much hope.
Andrew

 

[flecc]

Hi Andrew

I'd forgotten the Suede was 36 volt, unusual for Giant of course, but not surprising for what was a US motor.

 

[andrewelectricbike1]

36v helps because a 24v hub motor would never get me over the hills!
Andrew

 

[andrewelectricbike1]

Just to tidy up my loose end..

My charger "faults" when sat on my supplementary battery pack (on the rack).
When it gets hot, the charger kicks into refresh.

I moved the charger onto the seat when charging.. no problems now
Andrew

 

[flecc]

Thanks for the tip Andrew, heat sensitive Suede charger! Giant seem to have a special knack for odd charger problems.

 

[Flying Kiwi]

Giant seem to have a special knack for odd charger problems.

The problem with the original line of Twist (Panasonic) chargers was rectified by encapsulating the whole PCB and its components in a form of potting compound. I guess they must have found some components were overheating, it seems to have fixed the problem for me as this charger has been 100% reliable. Users have to follow the instructions and ensure the charger isn't powered from the mains with nothing connected on the battery plug though.

The suede manual shows a charger which has a fan in it. if Andrew's having heat related problems with that charger then, is the fan working with unobstructed vents? I think the reason why they've used 36 Volt power on the Suede is to compensate for the increased resistance of the long wiring to the hub motor - to help reduce electrical looses through heat. Regarding Andrew's comment about 36 V helping to get over the hills, the voltage isn't the important factor, the power of the motor and efficiency of power transmission is what matters. There are plenty of 24 Volt electric bikes that are better hill climbers than 36 Volt ones so voltage isn't an indication of power or hill climbing ability.