Rottweiler
Well-Known Member
I believe the EHC should be fused at a lower amp rating from the battery terminal.
Main fuse amps
- Thread starter Pddain
- Start date
Pddain
PHTM II
I agree. I just have to figure out if the 3rd wire coming off the red post should be moved to the battery terminal and fused. 20 amps seems to be the target, just need to figure out which wire I fuse and where it should terminate. Given someone put an 80 amp fuse in there, I am not sure I trust any of the wiring and where they are terminated. Fun project. All help is appreciated.
Mikeinjersey
Well-Known Member
Unless I'm misunderstanding, look at the bottom pic in post #10. Pic shows One wire(red heavier gauge) from the battery (+)with a fuse ( should be 40amp) going to the terminal block which has one Yellow connector which runs back to the VR. That Fuse protects the battery from a short or over-voltage from the charging circuit.
The second wire in the pic coming off the battery + ( black lighter gauge and yellow at the battery connection) has a fuse ( 20 amp). That wire connects back to the EHC and protects the EHC from a shorted out battery.
Note: Original diagrams do not show a fuse between the the battery and the EHC. Stock BDM didn't have that protection which is one extra reason why EHC's went south.
Knothead , please correct my explanation if I'm wrong I was just trying add some clarity to your post.
Sorry fellas i didnt get home from work till 3 30 this morning and just woke up about a hour ago.... Yes Mike you are correct...
Voltage regulator wire comes the the red post....40amp goes from the red post to the battery....20amp goes from battery to the ehc
Pddain
PHTM II
Thanks. I just have to make sure that the 3rd wire coming off the red post and going to a pin on the EHC harness is the one I should fuse with 20 amps and move it to the battery terminal. Given, when I pull the 40 amp fuse the entire bike shuts down, I am almost certain it is the correct wire that powers the EHC. I will be out at the shop tomorrow or Wednesday and will figure it out then. Let you know what I find and take pics.
That third wire on the red post has my radar up on what else may be wired wrong.
That third wire on the red post has my radar up on what else may be wired wrong.
Mikeinjersey
Well-Known Member
From your description the extra wire you speak of must go to the EHC. Your bike will run without the VR connected to the battery it just won't charge. To get a feel for what I mean disconnect the VR and leave the "3rd wire" connected and you will see that you have power. Now, leave the VR connected and remove the "3rd wire " and you will see no power the EHC and thus nothing will work.
You should end up with 2 different wires coming from the positive + post of the battery. One with a 20amp fuse (to protect the EHC from a faulty battery) and the other with a 40amp fuse ( to protect the battery from a faulty VR).
Last edited:
Jersey Big Mike
100K mile club
No you should have 3 wires.
1 from starter - BIG FAT WIRE
1 from FUSE inline with VR - to charge system
1 between Battery and EHC - to protect EHC
Mikeinjersey
Well-Known Member
JBM, I stand corrected but the cable to the starter was not really part of the discussion. We were discussing Circuit Breakers and Fuses used on BDM. For clarity I should have mentioned the cable going to the starter as you suggest.
Jersey Big Mike
100K mile club
I know I was not picking but is an old habit from writing documentation for things. Never assume anything. There's always some literal mind person that will be ok, 1,2, 3 -- oops better disconnect that they said only 2 wires.
Now I don't think for a second that pddain falls into that category but many people lurk and read these threads so I'd rather help avoid the issues for them.
Pddain
PHTM II
Thanks for all the help. We fused everything as recommended. The power lead for the EHC was on the Red post instead of the battery. Funny, in the old configuration ( EHC power lead and VR lead attached to the red post with an 80 amp fuse between the battery and the red post, we had significant electrical parasitic drain that would drain the battery in 3 days. The new configuration with a 40 amp fuse between the battery and the red post where the VR is terminated and the power lead for the EHC with a 20 amp fuse installed and terminated at the battery (not the red post) the parasitic drain virtually went away.
Anyway, it is all fused and terminated properly. Great advice folks.
Anyway, it is all fused and terminated properly. Great advice folks.
Rottweiler
Well-Known Member
Sounds like your on your way to riding without worry's Glad to hear it. 
Mastiff Rider64
Well-Known Member
That's common core math for ya...lol