Search found 363 matches

by Jeremy
Sat Jan 22, 2011 2:30 pm
Forum: All things battery related
Topic: Ping Batteries in cold weather
Replies: 49
Views: 40012

Re: Ping Batteries in cold weather

Connecting Ping packs in series can blow the BMS if one pack of the two shuts down because of a low cell condition or because of over-current. Connecting them in parallel is OK, but best done with a couple of low voltage drop diodes, either Schottky diodes of a suitable voltage and current rating, o...
by Jeremy
Mon Jan 17, 2011 9:58 am
Forum: Events
Topic: Land's End to John o'Groats EV Challenge
Replies: 11
Views: 10253

Re: Land's End to John o'Groats EV Challenge

Ballast to be a 70kg inertia flywheel that is spun up to silly thousands of revs by means as a braking device, which is then engaged to drive the vehicle when moving off from a stop, or when ascending a steep hill :) Deker :roll: It worked OK for flywheel powered buses (http://en.wikipedia.org/wiki...
by Jeremy
Sun Jan 09, 2011 9:10 am
Forum: All things battery related
Topic: Working out battery internal resistance.
Replies: 5
Views: 5774

Re: Working out battery internal resistance.

Not that wise, I'm afraid, and not that old either (although I am now retired.........). This method isn't super accurate, as it doesn't take true account of the effect of pulling pulsed power from the battery (to do that needs a measurement with a super-imposed AC component) but it's good enough fo...
by Jeremy
Sat Jan 08, 2011 12:09 pm
Forum: All things battery related
Topic: Working out battery internal resistance.
Replies: 5
Views: 5774

Re: Working out battery internal resistance.

If you can measure the current flowing from the battery and the battery terminal voltage (right at the battery terminals) then that is all you need to work it out. Here's the procedure: Connect an accurate voltmeter directly to the battery terminals and an accurate ammeter in series with battery pow...
by Jeremy
Fri Jan 07, 2011 9:29 pm
Forum: All things battery related
Topic: Super capacitors anyone?
Replies: 6
Views: 10884

Re: Super capacitors anyone?

Yes they are far, far, bigger and heavier than batteries of the same energy storage capacity. Self discharge is comparable to batteries. They are for sale because they are now readily available, but they aren't a substitute for a battery, by any stretch. Their advantages are that they have a very hi...
by Jeremy
Fri Jan 07, 2011 5:32 pm
Forum: All things battery related
Topic: My new ping- lights on BMS not working
Replies: 15
Views: 14278

Re: My new ping- lights on BMS not working

Woah! Chill dude! I have two bikes. The one I'm talking about is this: http://www.evalbum.com/1370" onclick="window.open(this.href);return false; It's the Sakura s200, which uses 36v 15ah batteries to power a 200w motor, and I have indeed replaced like for like. Just got a reply from Ping - it migh...
by Jeremy
Fri Jan 07, 2011 5:29 pm
Forum: Hybrid's Corner
Topic: Contactor-based Power Assist
Replies: 10
Views: 23860

Re: Contactor-based Power Assist

By pure chance, someone's just posted the spec for the original Briggs and Stratton Etek motor on the ES forum. As I thought, the rpm limit is fairly low. Here's a cut and paste of the spec: 12 HP Peak, 2.7 HP continuous Voltage........................50 VDC Max Nonload Current.....6 AMP Max Nonload...
by Jeremy
Thu Jan 06, 2011 7:33 pm
Forum: All things battery related
Topic: My new ping- lights on BMS not working
Replies: 15
Views: 14278

Re: My new ping- lights on BMS not working

That's odd. Have you replaced like with like in terms of usable capacity, current delivery capability and voltage? As I recall your bike was running on 48V SLAs of 28Ah, plus an additional pack of 48V 20Ah, giving you a total of 48V, 48Ah. I believe that you've now decided to replace this massive ba...
by Jeremy
Thu Jan 06, 2011 9:58 am
Forum: All things battery related
Topic: My new ping- lights on BMS not working
Replies: 15
Views: 14278

Re: My new ping- lights on BMS not working

Yes, that's normal. The LEDs will gradually turn off as the surface charge bleeds off and the cells all equalise.

Jeremy
by Jeremy
Wed Jan 05, 2011 9:08 pm
Forum: All things battery related
Topic: My new ping- lights on BMS not working
Replies: 15
Views: 14278

Re: My new ping- lights on BMS not working

My guess is that the noise was the input capacitors in the switched mode charger charging up, as it was plugged into the mains. These little switched mode chargers have a heck of a surge current at power on.

Jeremy

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