Tidalforce improved performance

tno

10 W
Joined
Jan 19, 2007
Messages
77
I added 4 nimh cells in series and 4 in parallel to the standard TF hub battery that I have paralleled to a 8ah SLA.
The total voltage at full charge is around 47.6v and the TF won't start. So I disconnect the 4 extra nimhs and rev it a few times and reconnect the 4 nimhs to get a volt reading around 47.1v on a drainbrain. Now the TF starts up.
On full charge the amps go up to 37 and the watts go to 1600. During the first few miles, amps stay around 1500 and then level off to around 1300 as the battery wears down. There is improved acceleration and hill climbing speed making the bike much more fun to ride. Without the extra 4 nimhs, the max amps was 33 and max watts was 1150. Also, Regen now goes on at around 24mph rather than 20mph. It would be nice to boost the volts up to 72v.

I think that can be done by isolating the internal hub controller's logic power line and feeding 36v into it. Then feed 72v into the mosfets. Don't know how hard that would be. That would also require replacing the 55v mosfets with 100v ones and upgrading the 50v capacitor.
 
It's often possible to isolate the output stage from the rest of the electronics and run it at a higher voltage. A battery tap or dc-dc converter can supply the correct voltage for the logic.

Unfortunately, not that much is known about the TF, and it is very complicated. The output stage isolation trick has worked on many other controllers, so it is a proven strategy.

I bet that thing could fly with 72v.
 
I'll try to open the motor cover and check out the controller when I'm not riding the TF as much. my X5 is out of commission with a broken spoke so this is my main ride now.
 
tno,

This is VERY exciting stuff for us TF owners! Thanks a bunch for posting.
I am a manager at the TF Google boards and have taken the liberty of pasting your post there for all to enjoy.

Please join us if you'd like--this is possibly the most exciting info I've seen about our rides since owning one! We'd love to have your ongoing input.

Regards,

Larry Hayes

http://groups.google.com/group/Tidalforce
 
I tried to get to top speed but there wasn't enough room on a flat road before slowing down for traffic. The TF goes to the mid 20's pretty fast but takes awhile to get to 30mph. going up a slight gradient of around 1-2% the bike hit 33mph and then backed off to a constant 29mph. This is after 1.5ah was used up. The battery consist of the 8.5ah nimh hub battery paralleled to a 8ah SLA and then serialed to a 17ah, 4 cell nimh (2x4 8.5ah nimh saft cells).

I fully charged all batteries before the ride today and the voltage read 48.5v. The TF cutout voltage is 47.1v. To get the bike to start up, I connected the SLA 1st to get a volt reading of 46.5. Then I turned the key to on and pressed the "A" button while depressing the throttle. The motor instantly starts before the controller can cut out due to the 48.5v from the hub battery. After 2 blocks or so, the voltage backs down to 47v. The paralleled SLA gives the bike more power when accelerating from a stop. With this setup I can keep up with traffic a lot better. I couldn't do that with just the hub battery.
 
t, Very interesting! Questions, If I may --
1) you have a regular and not an X version, no?
2) Are 4 Saft cells exterior of the hub?
3) How are the SLA and 4 Saft cells conected to the system -- in parallel with the hub via the B pack rear conector?

Thanks,
Al
 
I have the X version. I didn't know that when I bought it though.
The 36v SLA is parallel to the Hub battery (connected to the B battery input). There is no diode protection. The SLA always has lower volts than the Nimh so there is no danger of nimh explosion. And I don't think the nimh has high enough volts to gas the SLA.
Then the 4 extra nimh's are connected in series after the 36v batteries (hub battery and SLA). I connect another 4 nimh's in parallel to this pack because a single series of 4 nimh's get really hot under load and there is noticably more power with 2 sets of 4 nimh's. I only charge the 2 sets of 4 nimh's to around 80-90% to prevent voltage depression at full charge (so that one doesn't discharge into the other and explode it)
 

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