GoldenMotor.com Forum

General Category => General Discussions => Topic started by: jkwok1 on August 10, 2009, 07:58:02 PM

Title: cutting out
Post by: jkwok1 on August 10, 2009, 07:58:02 PM: Hi, I put together a 36V e-bike using the Golden Motor DIY kit about 5 years ago. (I don't remember the kit part number) It is front wheel drive with SLA batteries. It's been working great until recently. It started to cut out under load. The batteries are fully charged and it is not caused by the brake switches. I am looking for any input for trouble shooting. Thanks in advance.
Title: Re: cutting out
Post by: muzza.au on August 10, 2009, 08:06:42 PM: Sounds to me like your SLA's are on the way out if they are five years old also. They're probably coming to the end of their life. You say they cut out under load so that probably means the batteries are experiencing voltage sag which would cause the LVC (low voltage cutoff) of the controller to cut in. If you can you can try putting a volt meter on the batteries while using it under load and take a note of the voltage and see if it drops below 29v which I think is the LVC.

Muzza.
Title: Re: cutting out
Post by: Helgeo on August 10, 2009, 08:09:25 PM: Did you use the same batteries all the time? Perhaps they have had it?
See if you can measure the voltage under load just before it cuts out.

My guess is that the batteries are not holding their charge anymore.

A "Watts Up" meter as used for electric RC-gear is very handy on our bikes, it will measure volts, current and power as well as accumulated milliamphours. They cost around USD 50,-

Helge

Edit: I see that Muzza just beat me on the finish line, but we seem to agree on the cause of your problems ;)
Title: Re: cutting out
Post by: Philip Lynott on August 11, 2009, 09:37:32 AM: I agree with the last two guys,

I have used SLAs in the past, but I recommend buying a lifepo4 pack instead
Title: Re: cutting out
Post by: jkwok1 on August 11, 2009, 02:12:59 PM: Good call guys. I put a voltmeter on it last night and sure enough it dropped to ~31v when it started to cut out. For replacement, what would be the recommendations? On average, I use the bike a few times a year. Thanks for all the input.
Title: Re: cutting out
Post by: Hardcore on August 11, 2009, 03:11:47 PM: if you can do 5 years on a sla pack, I would just get a new sla pack(much cheaper)
but be aware that if you buy an lifepo4 pack you would probably never ever have to
replace your battery pack again :o haha

i personally would go with a lifepo4 battery pack
Title: Re: cutting out
Post by: e-lmer on August 11, 2009, 11:49:09 PM: The important thing to note about LiFeP04 packs is that the
battery needs to NEVER be run dead.

If you run the cell voltage below a certain level it damages
the chemistry and ruins the cells.

They suggest storing the batteries at about 30% to 50% of full.
Title: Re: cutting out
Post by: jkwok1 on August 12, 2009, 05:13:18 PM: Thanks for all the input. I live in Canada. Where is good place for me to buy the Lithium batteries? Thanks again.
Title: Re: cutting out
Post by: muzza.au on August 12, 2009, 08:10:33 PM: Quote
Thanks for all the input. I live in Canada. Where is good place for me to buy the Lithium batteries? Thanks again.
I'm in Australia so I may not be too helpfull, but I've come accross this site http://www.ebikes.ca/store/store_batteries.php (http://www.ebikes.ca/store/store_batteries.php) in my research and I believe they are in Canada.

Muzza.
Title: Re: cutting out
Post by: Philip Lynott on August 13, 2009, 12:23:25 PM: Pingbattery.com is where I got my 48V20aH battery I've had it for months it works great and none of the cells have died (the BMS has an indicator led for each cell)
Title: Re: cutting out
Post by: jkwok1 on August 31, 2009, 02:21:29 PM: Hi, I just got my 36V 20Ah LifePo4 battery pack this weekend. Unfortunately, the charger that came with the package did not work. I still have my charger for the 36V SLA. I believe the output voltage and current of the SLA charger is lower than the Li charger. I am wondering what are the potential issues using the SLA charger on the Li battery pack? thanks in advance.
Title: Re: cutting out
Post by: Bikemad on August 31, 2009, 04:38:45 PM: You might want to check this out: SLA charger for LiFePO4? (http://endless-sphere.com/forums/viewtopic.php?f=14&t=6897&start=0)

It looks like it might be OK on a temporary basis, at least until you get the correct charger sorted.

Alan
Title: Re: cutting out
Post by: pieroh on September 04, 2009, 09:56:04 PM: Quote from: jkwok1 on August 11, 2009, 02:12:59 PM
Good call guys. I put a voltmeter on it last night and sure enough it dropped to ~31v when it started to cut out. For replacement, what would be the recommendations? On average, I use the bike a few times a year. Thanks for all the input.

I am using two Bosch 36V LI-ION fat battery packs, 2Ah each, connected in parallel. They are powerfull and ligh. My bike is equiped with a Minimotor 36V-250W that works great.
You´ll find the Bosch packs on ebay, from US sellers at 50$ each!

Peter
Title: Re: cutting out
Post by: TOM on September 07, 2009, 08:24:52 AM: I think you should replace your battery.Thanks
Title: Re: cutting out
Post by: GM Canada on November 04, 2009, 07:38:01 PM: Quote from: jkwok1 on August 12, 2009, 05:13:18 PM
Thanks for all the input. I live in Canada. Where is good place for me to buy the Lithium batteries? Thanks again.

If you are looking for lithium batteries check my site at www.GoldenMotor.CA

Currently, I have 36v16ah in stock and others on the way. Anything in stock I can get to your door in 3 to 5 days in Canada. Anything out of stock is drop shipped to you in 2 to 3 weeks. I have seen 9 days at shortest and 23 at the longest.

Gary Salo

Canada is Going Green at www.GoldenMotor.CA
Title: Re: cutting out
Post by: e-lmer on November 12, 2009, 02:20:11 AM: Gary;

How are your prices shipped to California (Still CA, kinda) for the
48V batteries?
I would like to buy one but it's over 600 to ship the 48V20AH
pack from China.