Pre-charge relay

[auraslip]

http://i.imgur.com/tsidV.png

This is it!
ICS inc makes the kh1 on delay timers. This is exactly what we needed They are time adjustable via a resistor. They also make time delay relays, but they are probably more expensive. They do have a 48 and 110 vdc models of both the small timer and the relay. This way you could run with out the dc-dc.


No need for a kill switch or secondary precharge switch

Since the battery is directly connected to the controller and the only current passing through the BMS is for the relay, you can use a BMS rated for the smallest amount of power.

Since the controller is precharged, their will be no spark in the relay. This means you can use a very common low voltage / high amp relay.

No need to constantly leave the DC-DC, or the controller via the ignition cable. No slow drain.

 

[texaspyro]

I think that you will have lots of issues getting the DC-DC to respond/work the way you want it to...

 

[auraslip]

Yes, of course your probably right. The real issue is the dc-dc. If it didn't need a precharge, the 12v output could be wired up with a 555 ic timer and a relay for the main power.

This route would work fine. Iirc slow drain from the controller with the ignition cable disconnected is .01 amps or ~1.2 amps a week, but I don't about the slow draw from the dc-dc. It's inside my latest, build so I'll have to test it before I do this. I don't think it will be a problem because I use my bike everyday, and leave it plugged in when not in use.

Next up is tackling the charger/fan issue.

 

[auraslip]

This one uses voltage dividers to drop the battery pack down to 12v for the relay, a precharge resistor for both the dc-dc and controller, a dpst switch to activate both, and a 555 timer to give the controller a chance to precharge before the relay switches on. This is all theory. I just wanted to post it for posterity. In the future I might tackle it, but I think i'll stick with the simpler route.

 

[auraslip]

I found this kit http://www.quadrikits.com.pk/timers.html
$5!!

It certainly makes life easier. Will post more soon.

 

[auraslip]

http://i.imgur.com/tsidV.png

This is it!
ICS inc makes the kh1 on delay timers. This is exactly what we needed They are time adjustable via a resistor. They also make time delay relays, but they are probably more expensive. They do have a 48 and 110 vdc models of both the small timer and the relay. This way you could run with out the dc-dc.