Intermittent no-power after battery cycle on Baserunner_Z9 + G311 build (throttle lights on, controller stays off)

[jon.jude360]

Hello everyone, I have preface this post by saying I'm fairly new to this: both on a mechanical and electronic front, but I've been diving into the recent posts and information on here. I purchased my build from Grin in July, they were initially fairly helpful but now I dont hear back from them for at least 2-3 weeks, which is why I'm making this post:

Build / Equipment​

• Motor: Grin G311 front hub (no PAS)
• Controller: Baserunner_Z9 (V6), mounted in the battery baseplate / cradle
• Controls: All-in-One thumb throttle (no Cycle Analyst, no e-brakes; TripWire returned)
• Battery: Downtube pack on cradle with 4-spade connector interface to controller
• Wiring: Throttle-only setup (no regen, no PAS)

The issue (since late July):​

• Bike will run perfectly sometimes.
• After I turn off the system or remove/reinstall the battery to charge, the throttle voltage meter powers up, but the Baserunner won’t turn on (red LED off, motor unresponsive).
• After anywhere from half a day to 5 days, it may suddenly work again. If I leave it on, I can ride; if I power down, the problem tends to return.

What I’ve done so far​

1. Basic checks
   • Re-seated every connector multiple times; everything is clean/dry/sealed.
   • Confirmed correct polarity on the 4-spade battery/controller interface.
   • Confirmed no e-brakes in the loop and no Cycle Analyst.
2. Phaserunner Suite diagnostics
   • When the system does power, I can connect reliably and see live data; throttle input shows correctly; halls light up.
   • When the system doesn’t power, the controller won’t enumerate on any serial port (FTDI VCP drivers installed).
   • In “good” state, typical readings:
     • Battery Voltage ~ 40 V (Addr 265)
     • Light Supply Voltage ~ 13.3 V (Addr 289)
     • Faults and Last Fault = 0
   • In the past, I have seen addr:220 in the DEV panel (i.e., low-voltage/logic rail type fault).
3. Orientation / cradle suspicion
   • Pack mounts on a downtube cradle. It seems more prone to failing after removing/ reinstalling the battery.
   • When I un-house the controller and plug the 4-prong directly, it often connects more reliably than when everything is compressed inside the cradle/baseplate. That pointed me to a mechanical/electrical contact issue near the battery-to-controller interface.
4. Connector repair attempt
   • Found heat-darkened, oxidized joints on the 4-spade connector.
   • De-soldered/cleaned and re-soldered all four pins; then added a T-joint reinforcement with thicker copper to improve contact.
   • Result: bike worked ~25 minutes, powered down overnight, then back to no-power in the morning.
   • I did melt some plastic during an early de-solder; pins are still aligned, but the housing saw some heat.
5. Wiggle tests
   • If I fiddle/wiggle right at the controller base, it sometimes affects whether the controller comes on, suggests the intermittent is at or just inside the controller connector area rather than the throttle or motor cabling.
6. Software settings sanity
   • Motor temp sensing disabled (per support guidance), saved params.
   • No PAS or regen configured; throttle-only start expected.

Current status​

• Throttle display consistently shows pack voltage even if controllers red light is off.
• Controller intermittently fails to wake (no LED, no serial comms) after power cycles/removing the battery.
• Resoldering the 4-spade improved things briefly but did not solve it.
• Wiggle sensitivity near the controller base persists.

Is there more troubleshooting I can attempt? / Next steps I’m hoping to learn.

Thanks in advance for any guidance.

 

[Nix Liou]

Throttle display consistently shows pack voltage even if controllers red light is off.

That is likely just a voltmeter powering itself from the battery, and separate from the controller then.

Resoldering the 4-spade improved things briefly but did not solve it.

Scorched and damaged contacts are usually the symptom of a failure, not the cause. Do you have any pictures? Have you opened the baserunner up? It does sound like there may be a contact that has disconnected or similar.


I've also heard from several people that Grin has been pretty unhelpful with customer service the past few months... hopefully they sort that out, as it's been an annoyance to a few people with phaserunners.

Is there more troubleshooting I can attempt? / Next steps I’m hoping to learn.

You could attempt to see if there's a difference between simply power cycling the pack, or disconnecting and reconnecting it, since only one of those would apply physical forces to those contacts.

• Found heat-darkened, oxidized joints on the 4-spade connector.
• De-soldered/cleaned and re-soldered all four pins; then added a T-joint reinforcement with thicker copper to improve contact.

Can you show some pictures of this specifically?


As you can see in this picture, there's definitely some fine wires that could be a bit fragile.

 

[amberwolf]

• Resoldering the 4-spade improved things briefly but did not solve it.
• Wiggle sensitivity near the controller base persists.

I'd replace that entire connector, both the battery side adn the cradle side. I'd recommend finding a manufacturer / seller of them that uses good spring metal for the non-spade side, so that it properly mates with the spades and stays that way. Any poor connection will cause excess heat during use that can then damage the surrounding parts, deforming plastics, shifting things so the connection gets even worse.

Alternately, replace them with a completely different kind of connector that ensures a proper connection and allignment--this may require redesigning/rebulding the case and cradle to use these. One that can work well when used correctly for 60-80A is the Anderson SB50 series, or for higher currents the SB100 series, etc.

Keep in mind that any connector that is misaligned or not fully connected, or poorly crimped or solder to the wires leading to it, will have higher resistance than it should and so create heat that shouldn't exist, which can cause what you are seeing.


Also ensure that the solder joints are correctly made at the correct heat without melting the plastic. This usually requires a soldering tool with a large thermal mass, such as a large chisel-tip iron like the 80w weller I use for large connections:

A small tip and/or low wattage soldering tool will take a long time to heat a large connector / wire mass, and that allows time to trransfer heat into the surrounding plastics or electronics, which damages them. A large tip at a high wattage means there is enough heat there to quickly heat and melt the solder correctly into the connection without destroying surrounding parts.

Practice with this tool on the old parts until you consistently get a good connection without any new damage to surrounding parts, before touching the new parts.


I would also replace the actual wires from those connectors up to wherever they connect at the other end, because there could be one or more of htem that is broken inside it's insulation.

 

[jon.jude360]

That is likely just a voltmeter powering itself from the battery, and separate from the controller then.

Scorched and damaged contacts are usually the symptom of a failure, not the cause. Do you have any pictures?

Yes I've attached a picture of the solders joints BEFORE I desoldered them and rejoined them:

Have you opened the baserunner up? It does sound like there may be a contact that has disconnected or similar.

I'm unable to open up the baserunner, it seems to be sealed with some sort of rubber/tar

I've also heard from several people that Grin has been pretty unhelpful with customer service the past few months... hopefully they sort that out, as it's been an annoyance to a few people with phaserunners.

Yes, its frustration, i do understand staffing/hiring challenges though, and they've been very transparent about this.

You could attempt to see if there's a difference between simply power cycling the pack, or disconnecting and reconnecting it, since only one of those would apply physical forces to those contacts.

I attempt this frequently, I find the best solution is to un-house the cables from the battery craddle, jiggle them, and reconnect them fully extended.

I've attached this video that show's the pack losing power while plugged in.

Can you show some pictures of this specifically?

Unfortunately the only picture i took of my new solders is the T joint I made for the 4 spade connector attached: I should mention that my new solders are not the best looking, but I used 2mm rosin core solder, and did a few "tug" tests to ensure it was secure.

View attachment 380404
As you can see in this picture, there's definitely some fine wires that could be a bit fragile.

I see what you're saying about the interior of the controller, it's very finicky.

Grin has actually responded today and asked me to return the product for them to test in shop to see if it's faulty. Hopefully I'll have a better sense of next steps.

 

[jon.jude360]

I'd replace that entire connector, both the battery side adn the cradle side. I'd recommend finding a manufacturer / seller of them that uses good spring metal for the non-spade side, so that it properly mates with the spades and stays that way. Any poor connection will cause excess heat during use that can then damage the surrounding parts, deforming plastics, shifting things so the connection gets even worse.

Grin has asked me to send the product back, which is a relief because I wasn't even sure how to open the controller since it seemed tightly sealed with some sort of rubber/tar.

Alternately, replace them with a completely different kind of connector that ensures a proper connection and allignment--this may require redesigning/rebulding the case and cradle to use these. One that can work well when used correctly for 60-80A is the Anderson SB50 series, or for higher currents the SB100 series, etc.

Keep in mind that any connector that is misaligned or not fully connected, or poorly crimped or solder to the wires leading to it, will have higher resistance than it should and so create heat that shouldn't exist, which can cause what you are seeing.


Also ensure that the solder joints are correctly made at the correct heat without melting the plastic. This usually requires a soldering tool with a large thermal mass, such as a large chisel-tip iron like the 80w weller I use for large connections:
View attachment 380458
A small tip and/or low wattage soldering tool will take a long time to heat a large connector / wire mass, and that allows time to trransfer heat into the surrounding plastics or electronics, which damages them. A large tip at a high wattage means there is enough heat there to quickly heat and melt the solder correctly into the connection without destroying surrounding parts.

Practice with this tool on the old parts until you consistently get a good connection without any new damage to surrounding parts, before touching the new parts.


I would also replace the actual wires from those connectors up to wherever they connect at the other end, because there could be one or more of htem that is broken inside it's insulation.

Thank you for this, I really appreciate you giving me some clear guidance on how to repair this with soldering, I mentioned I'm a beginning at all of this, but eager to learn and build new skills. Soldering is something I thought would be easy but I think I need more practice.

Grin has asked me to return the part for them to inspect and replace if necessary. I have a huntch that the controller will be perfectly fine for them and once it's back with me I'll be [maybe] dealing with same issue.

 

[Nix Liou]

I wasn't even sure how to open the controller since it seemed tightly sealed with some sort of rubber/tar.

Probably sealant so water can't get in, yeah. Can sometimes be carefully opened with a sharp knife and a steady hand... Good that Grin got back to you though.

 

[amberwolf]

Soldering is something I thought would be easy but I think I need more practice.

Thankfully that's easy, just time consuming and uses up solder. You can take apart any old electronics you won't be reusing and practice soldering on the various bits inside, both big ones and small ones, until the joints you make look just like the ones that were already there, without changing the look of any thing else right next to the joint.

For big stuff like those lugs, power wires, etc., I recommend an iron like I described.

For smaller stuff I recommend a temperature-controlled version. There are cheap ones, but I use an actual weller that works great not only for soldering, but for plastics work using a separate set of tips (some of which I've modified for shaping or sealing small plastic bits--someday I need to make a post about that).


In this image

https://endless-sphere.com/sphere/attachments/img_4775-jpg.380464/

I'm not sure about hte solder joints to the wires themselves. I don't see any of hte usual wicking up into the strands that occurs in a typical solder joint, which may indicate the strands are not well-soldered to the connector pins. There also seems to be melting or deformation of the plastic the connector pins are secured in, which happens most often from applying hte soldering iron's heat for too long, while trying to get the solder to melt on the large-mass connector pins. That happens at the factories often enough, but is really common at the user end when too small an iron is used.

Grin has asked me to return the part for them to inspect and replace if necessary. I have a huntch that the controller will be perfectly fine for them and once it's back with me I'll be [maybe] dealing with same issue.

If the problem is the interface between battery and controller, and they dont' have the entire set of parts to work with, then that's certainly possible.

Problems like that are often caused by *both* sides of the connection, in combination...but it is more commonly caused by the "female" contact side, the contacts that enclose the other "male" side pins, usually by being spread out farther than they should be, and making poor contact with the pins. Sometimes that's from poor springiness, so that they work fine the first time, but every mating after that gets worse as the pins stay bent farther out than before. Sometimes it's poor metallurgy, or wrong metal type, so it is too soft and wears away, leaving a physical gap. Sometimes the pins themselves are fine, but the plastic they're housed in is too soft, or deformed, cracked, etc. The heating resulting from poor connections often makes these issues worse.