Alta Redshift EX bike dead after left charging overnight with key on.


Oded

Well-known member
Location
Israel
That's interesting. So, it's a 5-7 amp draw system. More than I thought.
It means carrying one hell of an external pack. And Rashid's warning about frying the ACM, pretty much sums it up.

Rashid, these DC to DC BCU failures are more common in the R or A packs? Why do they fail so often?
 

Rashid510

Well-known member
Forum's Sponsor
That's interesting. So, it's a 5-7 amp draw system. More than I thought.
It means carrying one hell of an external pack. And Rashid's warning about frying the ACM, pretty much sums it up.

Rashid, these DC to DC BCU failures are more common in the R or A packs? Why do they fail so often?

Back before we launched the R bikes, we had a batch of bad BRD boards (these are the smaller boards which act as relays/comms devices between the LTC chip on the HVPCBA to the BCU) which could lead to corner case condition which leaves the dc-dc live and kills the Vicor (DC-DC)

We tried to get to all the A-pack bikes and replace that part, but we never got to all of them. (We got about 90% of them) Since all the records of all the rework done to all Altas is long gone, its very tough to identify which packs were repaired (similar to Code 36 packs on the R bikes)
 

Oded

Well-known member
Location
Israel
My friend's Zero FX also have the DC to DC acting up (2 of them). Interesting that this part is such a troublemaker.
 

Oded

Well-known member
Location
Israel
So I played with it a bit more this morning. I fed 12v (actually 13.2) from a backup battery into the running light power feed. Attaching power makes the blue light on top of the battery pack start blinking with the key off or on and it draws 8w. Key on will start the bike and coolant pump and draw goes to about 60w. Hit the starter and it goes live and draw goes up to 65w. The bike appears to run fine and the draw seems constant except for lights. Hi/lo seems the same but brake lights draw 20w and blinkers 10w. With everything on I peaked at 90w.

This is an EX so I would estimate 45-50w draw with no lights or efficient led lighting. So a 10aH battery (120wH) should last a good 2 hours.

The huge caveat is if that external 12v system fails the bike dies instantly, so not really easily workable.

Also I am feeding power INTO the ACM somewhere it normally goes OUT.

If one were to attempt to use an external 12v system a better spot would probably be off the low voltage battery connector. That is where it would normally leave the pack. I’m guessing the 2 fat pins on the circular connector with red and black wires on the other side carry the 12v.

My next step is to drop the battery again and try to see if repair of the DC section on the BCU is an option. Maybe hook up multitool first.

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Out of curiosity, did you get any error codes when you jumped wire the bike?
 

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