I recently purchased a Noco Genius 5 to act as a tender for my Westinghouse Wgen 9500DF portable generator, which has an on-board 12v battery. I have a Noco GC009 SAE adapter with the Noco. When I uplug the battery connection on the generator and plug in the Noco using the adapter, the Reverse Polarity light comes on. How can that be? The battery is wired properly, red +, black -. The SAE adapter appears to be red+, black -. What is wrong?
Noco Genius5 charger - Reverse polarity issue
- Thread starter donl1150
- Start date
Double check that wierd plug NOCO uses on it's charging wire. I almost forced mine to go together backwards once, until I figured out that the red tab on the male end needs to go into the recess on the female end.
- Joined
- Jul 11, 2014
- Messages
- 4,118
Don't assume that SAE means anything anywhere. Its just a plug and can be wired any way possible.
No point in contacting NOCO until you check the polarities with your multimeter.
Well, I didn't find my meter. But....I connected the Noco alligator clips to the battery through the same connection as the adapter was using and....bingo, the alligator clips work and Noco is charging the battery. Obviously, the adapter is cross wired, so I will contact Noco and let them know and request a properly wired one. Thx everyone. (I'm sure my meter will show up pretty soon. lol)
I had an interesting chat with Noco support. Told them of the reversed polarity issue and here was their response:
"We have had customers with the same issue in the past, and this was our engineering team's response: "Many SAE connectors on the market are reversed polarity, like for solar applications or something along those lines. The SAE plug the customer is using to connect to their battery may be reversed. The actual SAE standard states "The polarity of the connector, when installed in a vehicle and attached to a battery, is always such that no short circuit will occur if the exposed terminal were to touch the vehicle chassis. In most vehicles, this means that the exposed terminal connects to the negative terminal of the battery. Conversely, the positive terminal on a battery charger is exposed, to mate with the concealed one on the vehicle side. (On vehicles with a positive-ground frame, such as vintage British motorcycles, this is reversed.)" I would have the customer flip the connector that's on their battery and that should fix the issue. It's just this funny SAE standard that lets the polarity be switched depending on what devices you're dealing with ie solar, automotive, etc. They also sell devices like the ones linked below that flip the polarity of the connector if the customer doesn't want to swap the wires." https://www.amazon.com/Sunway-Solar-Connectors-Disconnect-Maintainer-3Pack/dp/B07GPGPTFV Please let me know if flipping the SAE connector as the engineers suggest solves the issue. I would also recommend using the clamps that came with your NOCO charger originally to connect to the same battery, or to another battery just to confirm that the charger itself is working properly and not showing the reverse polarity error no matter what it's connected to."
So I will order a reversing device.
"We have had customers with the same issue in the past, and this was our engineering team's response: "Many SAE connectors on the market are reversed polarity, like for solar applications or something along those lines. The SAE plug the customer is using to connect to their battery may be reversed. The actual SAE standard states "The polarity of the connector, when installed in a vehicle and attached to a battery, is always such that no short circuit will occur if the exposed terminal were to touch the vehicle chassis. In most vehicles, this means that the exposed terminal connects to the negative terminal of the battery. Conversely, the positive terminal on a battery charger is exposed, to mate with the concealed one on the vehicle side. (On vehicles with a positive-ground frame, such as vintage British motorcycles, this is reversed.)" I would have the customer flip the connector that's on their battery and that should fix the issue. It's just this funny SAE standard that lets the polarity be switched depending on what devices you're dealing with ie solar, automotive, etc. They also sell devices like the ones linked below that flip the polarity of the connector if the customer doesn't want to swap the wires." https://www.amazon.com/Sunway-Solar-Connectors-Disconnect-Maintainer-3Pack/dp/B07GPGPTFV Please let me know if flipping the SAE connector as the engineers suggest solves the issue. I would also recommend using the clamps that came with your NOCO charger originally to connect to the same battery, or to another battery just to confirm that the charger itself is working properly and not showing the reverse polarity error no matter what it's connected to."
So I will order a reversing device.
I dislike 12v SAE connectors for many applications/reasons.
The source/load thing often causes reverse polarity smoke release, and they also wear out as the socket opens, then the connection is also weak intermittent, and resistive and heats up passing currents that the 18awg, or 10awg wire should have no issues handling.
There are also issues with how the wire is crimped to conductor, under the molded boot, on some, easily pulling out.
I use Anderson Powerpole connectors now. No source / load issues, self wiping, and minimal resistance.
The 15 and 30 amp and 45 amp are all the same size housings, the 45s are for 10 Awg wire and crimping them is not easy, without their special tool. The 15 and 30 amp versions no special crimp dies needed.
I stuff 8awg awg into the 45s, and they handle 55 amps continuous without issue.
Andersons Can be made more.weather resistnt when needed, fill their live ends with dielectric grease before.seating, and liquid E tape/amazing goop, where the wires enter the housings.
The source/load thing often causes reverse polarity smoke release, and they also wear out as the socket opens, then the connection is also weak intermittent, and resistive and heats up passing currents that the 18awg, or 10awg wire should have no issues handling.
There are also issues with how the wire is crimped to conductor, under the molded boot, on some, easily pulling out.
I use Anderson Powerpole connectors now. No source / load issues, self wiping, and minimal resistance.
The 15 and 30 amp and 45 amp are all the same size housings, the 45s are for 10 Awg wire and crimping them is not easy, without their special tool. The 15 and 30 amp versions no special crimp dies needed.
I stuff 8awg awg into the 45s, and they handle 55 amps continuous without issue.
Andersons Can be made more.weather resistnt when needed, fill their live ends with dielectric grease before.seating, and liquid E tape/amazing goop, where the wires enter the housings.
SAE plugs inherenty swap the wires at each plug.
On the battery side, the covered terminal should be live (positive) and the bare pin ground. Depending on the original purpose of the adapter, the covered terminal may be the red wire or the black wire. Either way, connect them to the battery so the covered terminal is the live wire.
Likewise, a properly wired charger or load connector has the covered terminal negative and the bare pin positive.
Polarity reversing adapter connectors do exist for special cases like connecting two batteries in parallel.
On the battery side, the covered terminal should be live (positive) and the bare pin ground. Depending on the original purpose of the adapter, the covered terminal may be the red wire or the black wire. Either way, connect them to the battery so the covered terminal is the live wire.
Likewise, a properly wired charger or load connector has the covered terminal negative and the bare pin positive.
Polarity reversing adapter connectors do exist for special cases like connecting two batteries in parallel.
JHZR2
Staff member
How about some photos?
I came across this isse with genius 1.
After a charge, I noticed the engine cranking was not as speedy as after a cherge with my CTEK.
Running a test battery, I noticed the CTEK maintains the resting voltage at ~13v whereas ginius 1 @ 12.8v. This difference makes a noticeable difference to the cranking speed specially on smaller motorcycle batteries.
The CTEK charging cycle was also substantially longer than that of ginius.
Contacted genius but did not receive a convincing reply!
So now I just let it collect dust and stored as emergency back up charger only!
After a charge, I noticed the engine cranking was not as speedy as after a cherge with my CTEK.
Running a test battery, I noticed the CTEK maintains the resting voltage at ~13v whereas ginius 1 @ 12.8v. This difference makes a noticeable difference to the cranking speed specially on smaller motorcycle batteries.
The CTEK charging cycle was also substantially longer than that of ginius.
Contacted genius but did not receive a convincing reply!
So now I just let it collect dust and stored as emergency back up charger only!
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