suede e battery/charger

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Last seen: 12 years 9 months ago
Joined: Tuesday, June 15, 2010 - 06:15
Points: 4
suede e battery/charger

I'm looking at a year-old Suede E with a battery that's likely toast. The seller charged it for 24 hours, and the bike exhibited some power assist for a few minutes before the cutoff kicked in. The battery is showing 36 volts on a voltmeter, but the controller displays only one LED. The battery was left unattended for the last year. Plugging the charger in yields only a pulsating red LED. From all the problems I've read regarding this model I'm reluctant to buy it, even at the $250 asking price. I've been unable to locate a downloadable manual for this bike. Any help would be appreciated. Thanks.

NickyBow's picture
Last seen: 2 years 7 months ago
Joined: Wednesday, July 28, 2010 - 12:27
Points: 3
Re: suede e battery/charger

Hi, I've got two Giant Suede's (I like them!) and I have had a problem identical to yours with one battery, and I'd say it's a charging problem (So the cells could be ok).

After some research and testing I discovered that it was a faulty thermistor inside the battery (resistor that varies with temperature), so the charger won't start changing, It's a relatively inexpensive component so well worth trying before you write off the battery if you were to buy the bike (of course the cells may still be weak, especially if they've been sitting for a year). The manual says that flashing red is simply "a fault" so your fault may not be the same one but I think it's likely as there isn't much else inside that battery and I'm assuming that the charger is ok.

In addition there are two fuses inside the battery, one high rating and one low for the charging circuit. from your description I'd say that the high rating is fine and you can test the low rated fuse by measuring the voltage across the xlr charging socket pins. In addition if you're measuring no voltage on the middle (thermistor pin) then I'd say that's another indication that the thermistor's failed but if you are measuring somewhere under 36v (or lower than the +ve outer pin) at the middle pin then that's not conclusive.

What should happen is that the red and flashing amber should come on on the charger and amber will go solid after a few seconds. Then after a few hours the amber should go solid green.

Hope this helps!


Nick The Brick

Last seen: 4 years 7 months ago
Joined: Monday, June 22, 2009 - 12:24
Points: 524
Re: suede e battery/charger

Your 36 volt battery is not charged fully unless it reads over 40 volts, typically 42 volts. 36 volts is the "nominal operating voltage"--Shut off of the motor should occur near an operating voltage of 28 to 30 volts. If you cannot get it to charge to over 40 volts, and/or it heats up noticably when charging, it possibly has shorted cells. (sometimes shorted cells will re-activate, if individually supplied with a very high charging amperage for about 2 seconds-something like 50 amps.)--Bob

Robert M. Curry

Last seen: 9 years 4 months ago
Joined: Friday, November 22, 2013 - 13:16
Points: 2
Re: suede e battery/charger

NickyBow seems to have gotten very good information about the Giant Suede battery charger. I purchased a used Giant Suede-e bike last year and my charger started to behave in the same manner with only a flashing red LED. I started to unassembled the charger for reverse engineering and discovered that it is a switch-mode power supply controlled by a Benchmarq bq2004 fast charge IC now owned by Texas Instruments. You can search for a data sheet for this 16 pin DIP on the internet. My charger problem also appears to be related to the thermistor which is located inside the battery pack (36v, 10 AH). My thermistor measures about 11 kilohms at room temperature and appears to terminate charging when it heats up and measures about 6 kilohms. The valid ranges for the thermistor value and the battery voltage are very specific and described in the data sheet. If battery voltage and temperature are not within this tight range you will see a flashing red LED indicating a fault condition. If you attempt what I am doing be aware that the internals of this charger are not isolated from the 120V line. You must use an isolation transformer to safely probe the internal nodes within this charger. A voltmeter will suffice to measure the bq2004 pin voltages and determine if your values conform to the data sheet.


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