Search found 265 matches

by EVguru
Thu Dec 24, 2009 11:54 am
Forum: All things battery related
Topic: recharging a forklift
Replies: 11
Views: 11532

If the battery voltage is too low, it could be that it is very flat, or it could be that you have a failed/shorted cell (or several). In this case, it would not be a good idea to charge the battery because you could vent the failed cell, or overcharge the good cells. A really good intelligent charge...
by EVguru
Thu Dec 24, 2009 10:28 am
Forum: Cars,Vans and other road vehicles
Topic: Reverse
Replies: 9
Views: 11206

Your question has been answered - yes you can reverse a series wound motor using the appropriate contactors. What you can't do, to my knowledge, is use a series wound motor to give you regenerative braking. This involves reversing the field current but not the armature, or vice versa. As these wind...
by EVguru
Tue Dec 08, 2009 12:59 pm
Forum: All things battery related
Topic: Charger Suppliers?
Replies: 8
Views: 11389

It's not an EEPROM, an EPROM, or even a PROM it's a new one time programmable processor (SGS Thomson ST6 series). The last one I looked at wasn't code protected. Given the limitations of the design, I wonder what the Lithium profile actually is. I do have a new analogue board designed, but have yet ...
by EVguru
Tue Dec 08, 2009 12:03 pm
Forum: All things battery related
Topic: Charger Suppliers?
Replies: 8
Views: 11389

The Zivan NGx series chargers have a really pretty robust power stage. However the control logic is just plain weird and is unbelievably inflexible for a microprocessor based design. The feedback circuits are analogue and are controlled by a pair of digital potentiometers. I reverse engineered the c...
by EVguru
Sat Nov 21, 2009 9:15 pm
Forum: Conversions
Topic: Power/weight ratios
Replies: 45
Views: 4553

I put the question simply to make you consider the validity of your original question. I said nothing in my question about a single ratio transmission. If the vehicle was a cricket pitch roller, then an engine of 3hp might suffice. A forklift might use 20hp, whilst a town car with a top speed barely...
by EVguru
Wed Nov 18, 2009 12:22 pm
Forum: Conversions
Topic: Power/weight ratios
Replies: 45
Views: 4553

my original query was as to some sort of rule of thumb for motor power (meaning torque of course) to vehicle all up weight which will allow single speed transmission. I'm very sorry, you can't have one. Cedric can give you an estimate for his motor because he knows all the performance curves, but y...
by EVguru
Tue Sep 30, 2008 10:36 am
Forum: General
Topic: Gigavac contactors
Replies: 1
Views: 3702

Gigavac contactors

The commonly used Albright contact are Ok, but they're quite bulky, aren't sealed and have quite high power consumption coils. They used to be rated for 120VDC (with magnetic blow-outs), but are now rated 96VDC. They're actually fine for use at 144 volt or higher, but Albright don't have the equipme...
by EVguru
Fri Sep 26, 2008 10:02 am
Forum: Cars,Vans and other road vehicles
Topic: Lightest car to convert?
Replies: 30
Views: 26421

I'm converting a reliant kitten - they were pretty light (650kg ish from memory) & can be picked up reasonably cheap. They were fairly ropey when new mind you, & will not have improved in the 30 odd intervening years..... Doing up seems fairly reasonable though, parts seem easy enough to ge...
by EVguru
Thu Sep 11, 2008 3:39 pm
Forum: Conversions
Topic: Thoughts/help for a new boy....
Replies: 14
Views: 1499

Ideally a simple two speed gearbox would do the job, as few road going EVs need more than two gears, often quite widely spaced. Three gears; reverse is quite useful too! I know it's easy to do electrically, but you get it for free with a standard gearbox and you can remove the unused gears to reduc...
by EVguru
Thu Sep 11, 2008 1:46 pm
Forum: All things battery related
Topic: WHY USE HIGH VOLTAGE DRIVE SYSTEMS
Replies: 26
Views: 19371

I'm building an EV with a 660V pack (400V AC motor), and I'm a little worried about what kind of fuse and contactor to use. At upto 800VDC/20A (during regen) the fuse and contactor between batterypack and controller must be high-voltage, spark retarding type. Any ideas? I'm worried about you buildi...

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