Advice needed about voltage drop

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I have installed a mo.lock RFID ignition switch as with the CNW estart I have put on there isnt room for what has always been a non-standard install location for the stock ignition switch.

It works fine when kicking the bike but, it cuts out after a quick tap with the estart and looks like I need one of these (which GTiller and I thought I wouldn't need due to the having the 2MC).

The mo.lock backup capacitor is used to level short-term voltage drops to the main relay.

If cranking the engine via the electrical starter is slow and resistive, very large single cylinder capacities or high compressions can cause significant voltage drops. Implementing a backup capacitor prevents short-term voltage drops from de-energizing the main relay.

Advice needed about voltage drop


In NZ, you can get these shipped from AUS for $45-66!!! It appears to be a small electrolytic capacitor - probably of the $1.50 type. I have asked motogadget what the spec is, but they are closed moving their shop location and I guess they would rather sell me a cap.

From looking online, i cant find any specific info - just info on caps for compressors or electric motors. This one has calcs that get me to about a 15uF cap (assuming 1.4kw for the starter, which I also found via google).

Does a 22uF electrolytic sound right to those of you who know more about this stuff than I do? What min VDC for the cap - 25, 50, 63? RB, Low ESR, Bipolar?

Schematic below - note this sits behind a 1A fuse.

mo.lock_pos_earth.png


edit: corrected uF
 
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I'm not a interweb closet electrical engineer, but would the 2MC capacitor and springy dingy Andover sells work? A battery eliminator reg/rect might also work. Not sure either of those solutions would save you any money.

I'd talk to/email Matt. I would think he has dealt with just about everything related to making the starter work.
 
I have the 2MC already installed on the bike in its proper place. GTiller and I originally thought that would work, but I think the drop occurs right at the RFID receiver which shuts the relay off.
 
I have installed a mo.lock RFID ignition switch as with the CNW estart I have put on there isnt room for what has always been a non-standard install location for the stock ignition switch.

It works fine when kicking the bike but, it cuts out after a quick tap with the estart and looks like I need one of these (which GTiller and I thought I wouldn't need due to the having the 2MC).

The mo.lock backup capacitor is used to level short-term voltage drops to the main relay.

If cranking the engine via the electrical starter is slow and resistive, very large single cylinder capacities or high compressions can cause significant voltage drops. Implementing a backup capacitor prevents short-term voltage drops from de-energizing the main relay.

Advice needed about voltage drop


In NZ, you can get these shipped from AUS for $45-66!!! It appears to be a small electrolytic capacitor - probably of the $1.50 type. I have asked motogadget what the spec is, but they are closed moving their shop location and I guess they would rather sell me a cap.

From looking online, i cant find any specific info - just info on caps for compressors or electric motors. This one has calcs that get me to about a 15mF cap (assuming 1.4kw for the starter, which I also found via google).

Does a 22mF electrolytic sound right to those of you who know more about this stuff than I do? What min VDC for the cap - 25, 50, 63? RB, Low ESR, Bipolar?

Schematic below - note this sits behind a 1A fuse.

View attachment 82417
You can try Revival Cycles in Austin,Tx as they are very familiar with MotoGadget units.
 
Does a 22mF electrolytic sound right to those of you who know more about this stuff than I do? What min VDC for the cap - 25, 50, 63? RB, Low ESR, Bipolar?
What you'd be looking for is an aluminum electrolytic cap with a voltage rating of at least 25 volts. The 2MC cap is about 4700 uF, and the one you show by moto yo's doesn't look to be much bigger than that. Something like this would suffice:

Amazon product ASIN B011NATCBS

However...

The EE in me can't justify how something that small could help your situation. As you said, the starter is 1.4 KW, which is over 100 amps. A capacitor that could supply 100 amps for a couple seconds would be bigger than your battery. That said, if they didn't work motogadget wouldn't be selling them.

The typical automotive "Bosch style" relay has a dropout voltage of about 5 volts. That means your battery is dropping below that voltage when you push the button. Something's wrong. I suspect that your battery isn't up to the task or you have wiring issues.

The solid state relay (SSR) mentioned above would have a dropout voltage that's lower than your relay, but the voltage drop across its "contacts" would be higher than a mechanical relay.
 
I have installed a mo.lock RFID ignition switch as with the CNW estart I have put on there isnt room for what has always been a non-standard install location for the stock ignition switch.

It works fine when kicking the bike but, it cuts out after a quick tap with the estart and looks like I need one of these (which GTiller and I thought I wouldn't need due to the having the 2MC).

The mo.lock backup capacitor is used to level short-term voltage drops to the main relay.

If cranking the engine via the electrical starter is slow and resistive, very large single cylinder capacities or high compressions can cause significant voltage drops. Implementing a backup capacitor prevents short-term voltage drops from de-energizing the main relay.


In NZ, you can get these shipped from AUS for $45-66!!! It appears to be a small electrolytic capacitor - probably of the $1.50 type. I have asked motogadget what the spec is, but they are closed moving their shop location and I guess they would rather sell me a cap.

From looking online, i cant find any specific info - just info on caps for compressors or electric motors. This one has calcs that get me to about a 15mF cap (assuming 1.4kw for the starter, which I also found via google).

Does a 22mF electrolytic sound right to those of you who know more about this stuff than I do? What min VDC for the cap - 25, 50, 63? RB, Low ESR, Bipolar?
The capacitor is still across the entire bike and will act like a tiny battery assisting the battery - negligible value. The specs for the mo.lock say it works from 8-18 volts. You should not be dropping below 8 volts when starting - bad battery? Bad connections somewhere? Also, have you verified that the mo.lock is dropping out and not the relay. You could test power the mo.lock with a 9-volt battery and see if it's the mo.lock or relay (disconnect black wire and connect to the 9-volt negative and the 9-volt positive to earth).

AFAIK, the original 2MC capacitor was 6500uf. I still install them but I use 10,000uf caps that are the same size and fit the spring. I don't believe it will solve the problem but you could try that to see if a cap is the answer.

Here's the one I use: Amazon product ASIN B011NATCBS
 
You should not be dropping below 8 volts when starting - bad battery? Bad connections somewhere?
Thinking about this, I'm wondering if the problem is with the moto gizmo. Let's say e-start drags the battery down to 10.5 volts. That's still above the dropout voltage of the typical relay. But if the mo.lock relay drive goes high resistance there might be enough voltage drop across it to deprive the relay of its ability to stay energized. Me thinks a voltmeter check may be in order.
 
Next time I'll read a post before responding. Maybe.

Sorry about the 2MC suggestion that is already in place. Inexcusable behavior on my part.

This won't make any sense, but did you ever try the e-start with the molock outside of the speedo cup?

Are the running lights wired to come on during an e- start?

I'm with the battery not having enough juice or there is something off with the wiring group. Not necessarily something wrong with how you did it, but something in an old part of one of the sections in the harness. Weak crimp kind of thing?
 
The capacitor is still across the entire bike and will act like a tiny battery assisting the battery - negligible value. The specs for the mo.lock say it works from 8-18 volts. You should not be dropping below 8 volts when starting - bad battery? Bad connections somewhere? Also, have you verified that the mo.lock is dropping out and not the relay. You could test power the mo.lock with a 9-volt battery and see if it's the mo.lock or relay (disconnect black wire and connect to the 9-volt negative and the 9-volt positive to earth).

AFAIK, the original 2MC capacitor was 6500uf. I still install them but I use 10,000uf caps that are the same size and fit the spring. I don't believe it will solve the problem but you could try that to see if a cap is the answer.

Here's the one I use: Amazon product ASIN B011NATCBS
I will give the 9-volt test a try.
 
What you'd be looking for is an aluminum electrolytic cap with a voltage rating of at least 25 volts. The 2MC cap is about 4700 uF, and the one you show by moto yo's doesn't look to be much bigger than that. Something like this would suffice:

Amazon product ASIN B011NATCBS

However...

The EE in me can't justify how something that small could help your situation. As you said, the starter is 1.4 KW, which is over 100 amps. A capacitor that could supply 100 amps for a couple seconds would be bigger than your battery. That said, if they didn't work motogadget wouldn't be selling them.

The typical automotive "Bosch style" relay has a dropout voltage of about 5 volts. That means your battery is dropping below that voltage when you push the button. Something's wrong. I suspect that your battery isn't up to the task or you have wiring issues.

The solid state relay (SSR) mentioned above would have a dropout voltage that's lower than your relay, but the voltage drop across its "contacts" would be higher than a mechanical relay.
The battery works fine when I plug in the standard keyed ignition. It is a 18ah Shorai and holds a full charge for weeks. I havent load tested it, so you may be right.

Judging by the size and the location of their backup (and that they note it can be required) I am thinking the issue is with the mo.lock rfid units design and it is dropping out. The cap obviously cant power the starter, so it just must be to bridge the voltage drop to the RFID receiver itself?
 
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Next time I'll read a post before responding. Maybe.

Sorry about the 2MC suggestion that is already in place. Inexcusable behavior on my part.

This won't make any sense, but did you ever try the e-start with the molock outside of the speedo cup?

Are the running lights wired to come on during an e- start?

I'm with the battery not having enough juice or there is something off with the wiring group. Not necessarily something wrong with how you did it, but something in an old part of one of the sections in the harness. Weak crimp kind of thing?
No worries.

No, havent tried it out of the cup. But it does power on everything ok, just when starting it cuts out.

It is all wired in live at start. I do use the headlight toggle so just the running lights are on at start (tail light is LED).

It could completely be a wiring issue. The harnass is new four years ago, but it does have some modifications to it so it certainly could be one of the crimps. But, if I take the mo.lock out of the equation by putting back in the stock ignition switch, it works. So, I will look more closely at the wiring I did for it.
 
Definitely not a older wiring issue like I was thinking it might be if it works with the molock out of the ignition circuit. As you say maybe the new wiring for the molock, or some weird EMI/RFI/RFID/whatever interference thing when the starter kicks in. That's why I mentioned trying it out of the metal speedo cup.

Is the finger switch electronically isolated from the metal mount, and the rest of the chassis inside that cup?

Are you sure your magic finger isn't passing by too close and shutting it off when hitting the starter button? ;)

Not addressing the voltage drop though. Just jabbering.
 
Definitely not a older wiring issue like I was thinking it might be if it works with the molock out of the ignition circuit. As you say maybe the new wiring for the molock, or some weird EMI/RFI/RFID/whatever interference thing when the starter kicks in. That's why I mentioned trying it out of the metal speedo cup.

Is the finger switch electronically isolated from the metal mount, and the rest of the chassis inside that cup?

Are you sure your magic finger isn't passing by too close and shutting it off when hitting the starter button? ;)

Not addressing the voltage drop though. Just jabbering.
The RFID switch in the cup is in a plastic housing with metal nuts embedded in it. I am assuming that is isolated since there is a separate ground wire from the switch. Magic finger is on other side of the handle bar.
 
Good call @marshg246 on the 9v battery test - it turned over fine repeatedly with that hooked in at the 1A fuse junction w/o fuse. So, now I think just need to find the appropriate capacitor size.

I sent a mail to Revival to see what they say.
 
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