DenisC

Model #: 005882-0 Serial 6047890
Propane or Natural Gas: NG
Length of gas pipe feeding the generator: 16 feet
Size of gas pipe feeding the generator: 1 inch
How long since the last full maintenance: July 2019
How long have you experienced this problem: 1 day
Unit installed January 2011

My Genmon monitor sent me a text this morning, "Check Battery".  I looked at the battery voltage and it was down to 12.3 volts.  Normally I never see it below 12.6.  

Checked all battery connections at generator, very tight on the posts.
Checked T1 voltage at the connection block at generator, got 120V.
In January 2020 I replaced both battery cables and battery.  It started fine for exercise last Saturday.

Hooked up my voltmeter to test the amperage going through the system by unhooking the negative cable from the battery and placing voltmeter in series.  With 7.5 amp fuse plugged into the top of the controller, reading was .275 DC amps.  Removed 7.5V amp use, went to zero.  Plugged fuse back in, reading .275.  So does not appear to be charging.

I unpowered everything from the generator.  Battery, N1/N2/T1 fuses from transfer switch.  Unplugged the connectors from the bottom of the controller thinking I may have a wiring problem somewhere.

I checked continuity from the pin in the connector where T1 is located with the wiring block where T1 comes from the transfer panel.  Good continuity.

I checked wire 13 from the other connector to the post on the starter contactor where it hooks up to feed the positive battery cable.  Good continuity there.

I looked at the pins in the connectors, none appear to be "pushed back" so they wouldn't make contact with the controller.  Pins in the controller are tight and don't wobble.

Before I go any further I'm hoping one of you folks might have some additional steps I can take next to see if I can solve this once and for all.

Thanks in advance for your help.  Below is a link to the post I made last year with this same problem, and a photo of the controller.

https://www.zillerstore.com/post/low-battery-error-battery-4-5-volts-8kw-10157717?pid=1308794628

9C9BB0F7-4098-44E8-9E58-6A7671C6C39D_1_201_a.jpeg 

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grsthegreat
Hate to say this, but that’s a built in check that appears every year. Press enter 2 times to clear. There is no problem. you can also drain the battery a bit by starting up the generator 3-4 times and let it run a minute or so. see if charger clicks back on.
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Peddler
Did you replace the controller last year or is that for another generator?  Check battery can be an automatic reminder but 12.3 is pretty low and I would think the charger should have been on.  I use a DC amp probe so I don't have to disconnect the battery cable but if your meter is set right it should show a charge of 1-2 amps.  I didn't see where you said how old the battery is, if it is more than 5 years I would start with a new battery and then monitor the battery voltage over 24 hours. 
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DenisC
grsthegreat wrote:
Hate to say this, but that’s a built in check that appears every year. Press enter 2 times to clear. There is no problem. you can also drain the battery a bit by starting up the generator 3-4 times and let it run a minute or so. see if charger clicks back on.


I thought the same thing about the error message “Inspect battery”.  But this message has happened now on 1/17/20, 2/26/20, and again on 5/6/20.  

Didn’t think to start and see if charger kicked in again.  I didn’t want the battery to get too low.

thx for the suggestion
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DenisC
Peddler wrote:
Did you replace the controller last year or is that for another generator?  Check battery can be an automatic reminder but 12.3 is pretty low and I would think the charger should have been on.  I use a DC amp probe so I don't have to disconnect the battery cable but if your meter is set right it should show a charge of 1-2 amps.  I didn't see where you said how old the battery is, if it is more than 5 years I would start with a new battery and then monitor the battery voltage over 24 hours. 


The battery was replaced along with the cables in Jan 2020.  Controller is original as far as I know.  I was never charged for a new controller when it was under dealer service.  

Right now I’m recharging the battery on a charger.  

I’m definitely not getting 1-2 amps charge.

thx
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DenisC
I should have noticed before there is a discrepancy on part numbers.  I also went back and checked - this is for sure the original control board.

When I downloaded the parts list off the Generac site it says the control board is a 0H6680B part number.  But the board I have says 0H6680A. 

So I’m really confused.  I’m a homeowner and don’t have access to the systems many of you do.  Is it possible to look up what the correct part number should be based on the model and serial number of the unit (1st post above)?

Based on what I’ve read on this forum (thank you!) I think the controller does the charging.  That’s why I did the wire tracing to see if there was an open wire somewhere.  By reading this site it appeared that the T1 and the 13 wire were the main elements in the charging circuit.

Here is a photo of the bottom of the board.  Thx again.

D0EF7AFA-2314-4773-80FA-06BA1731D2F8.jpeg 
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Peddler
If this is your controller and it isn't charging the only thing you can do is replace it.  This controller requires an interface to allow your wiring to work with the standard controller.  I can look in the morning for the part number but if you just order the controller alone it will be cheaper but won't connect to your harness.  
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DenisC
Peddler wrote:
If this is your controller and it isn't charging the only thing you can do is replace it.  This controller requires an interface to allow your wiring to work with the standard controller.  I can look in the morning for the part number but if you just order the controller alone it will be cheaper but won't connect to your harness.  


Thanks Peddler.  Having checked the wiring as described in my first post, am I missing anything obvious in my troubleshooting?  Other than a new controller?

I added a photo of the amp reading from my voltmeter.  It stayed around .275 even when the battery got down to 12.2 volts.

thx again

EF47FAB0-5FC2-4942-AA4E-BB99B71B7F71.jpeg 
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Peddler
Ok to replace the controller shown in the picture above you need Generac P/N 0H6680DSRV which includes the interface module so your harness will work.  My only concern is that since your showing a charge, even though it is a small one , is that this charger tappers off the amperage as the battery reaches full charge.  If you were to put a fully charged battery in and then shut the gas off and ran the unit through several crank cycles to pull the battery down to say 12 volts then see if the charge amperage increases any.  This controller replacement is an expensive undertaking so you want to be sure you of the problem.  If charging is the only problem you could tie a battery tender to the T-1 circuit to just take care of that assuming the controller works otherwise.
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DenisC

Peddler wrote:
Ok to replace the controller shown in the picture above you need Generac P/N 0H6680DSRV which includes the interface module so your harness will work.  My only concern is that since your showing a charge, even though it is a small one , is that this charger tappers off the amperage as the battery reaches full charge.  If you were to put a fully charged battery in and then shut the gas off and ran the unit through several crank cycles to pull the battery down to say 12 volts then see if the charge amperage increases any.  This controller replacement is an expensive undertaking so you want to be sure you of the problem.  If charging is the only problem you could tie a battery tender to the T-1 circuit to just take care of that assuming the controller works otherwise.


Thanks Peddler,
Wow, I looked up the part and $700 is certainly a load of money for a 9 year old generator.  

I will put everything back together and do the test you suggest with getting the battery voltage down and see if the charger kicks in.  

This problem has been very frustrating because it has been kind of intermittent.  9/9/19, 1/17/20, 2/26/20, and again on 5/6/20.  It definitely does not seem like the “timed” one year error message.  When I get one of these messages and check the battery voltage the voltage is always below 12.6, which is when I usually see the charger kick on.

I love the idea of the battery tender.  Based on reading this site it seems the tender needs to be at least 2 amp output or it will not keep the battery charged if the utility power is out.  

If you or anyone happens to have a model number for a suitable one that would greatly appreciated.  I will install the tender if I don’t get the new controller.  Everything else functionally seems fine with the controller.

thanks again.

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GMc
Here's one that alot of members have used;
https://www.costco.com/Battery-Tender-Power-Plus-3-Amp-Charger.product.100241973.html
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DenisC


Thanks very much, I’ll take a look.
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DenisC
Peddler wrote:
Ok to replace the controller shown in the picture above you need Generac P/N 0H6680DSRV which includes the interface module so your harness will work.  My only concern is that since your showing a charge, even though it is a small one , is that this charger tappers off the amperage as the battery reaches full charge.  If you were to put a fully charged battery in and then shut the gas off and ran the unit through several crank cycles to pull the battery down to say 12 volts then see if the charge amperage increases any.  This controller replacement is an expensive undertaking so you want to be sure you of the problem.  If charging is the only problem you could tie a battery tender to the T-1 circuit to just take care of that assuming the controller works otherwise.


Thanks Peddler,
I did a test starting with a battery charged to 13.2 V.  Did a couple of starts.  The generator exercised normally on Saturday.  I also simulated an outage and the generator started and transferred normally.  All the time I watched the battery voltage using the Genmon monitor.

Battery went to 12.4 V, I got the “Inspect battery” warning on the controller again.  Does not appear to be a “timed” message.
I watched the battery eventually go down to 11.8 V and I shut everything down again so I wouldn’t damage the battery.  Clearly the charger isn’t working.

I ordered the 3A Battery Tender that GMc referenced.  You mentioned to wire the hot side off the T1 circuit.  Where is the best place to hook up the neutral side of the Battery Tender power?

Have you or anyone here seen the Nexus controller just stop charging the battery?  Everything else seems to work OK so far on the controller.

thanks in advance
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78buckshot
DenisC, you can connect the neutral side of the Battery Tender to the neutral bus, probably a couple of open ports on the bus, it's under the black plastic cover that hides the rest of the terminals in the generator. You will see a ground bus and neutral bus, ground is with green wires, neutral is white wire and two larger black wires from the stator. I can't remember off hand seeing just the Nexus charger give up the ghost but that doesn't mean it hasn't happened.
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DenisC
78buckshot wrote:
DenisC, you can connect the neutral side of the Battery Tender to the neutral bus, probably a couple of open ports on the bus, it's under the black plastic cover that hides the rest of the terminals in the generator. You will see a ground bus and neutral bus, ground is with green wires, neutral is white wire and two larger black wires from the stator. I can't remember off hand seeing just the Nexus charger give up the ghost but that doesn't mean it hasn't happened.


Thanks Buckshot, I will take a look for that neutral bus.  I’m hoping the Battery Tender arrives tomorrow.

I will report back when I have everything hooked up.
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Peddler
We have had a few stop charging but not many.
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DenisC

78buckshot wrote:
DenisC, you can connect the neutral side of the Battery Tender to the neutral bus, probably a couple of open ports on the bus, it's under the black plastic cover that hides the rest of the terminals in the generator. You will see a ground bus and neutral bus, ground is with green wires, neutral is white wire and two larger black wires from the stator. I can't remember off hand seeing just the Nexus charger give up the ghost but that doesn't mean it hasn't happened.


Buckshot, thank you for the great instructions for hooking up the battery tender.  

Peddler, thanks for the suggestion to try the tender vs. the new $700 board!  Saved me $640 it looks like.

 GMc, thanks for the model of the tender.

I installed the tender Tuesday.  Voltage has been steady 13.1 except when cranking for exercise yesterday.  A few minutes after exercise was done, battery back at 13.1 volts.

Yay!!!

I noticed on the controller that there is some “goo” for lack of a better term that oozed out left of the fuse.  I highlighted the area with a red circle in the photo below.  I wonder if something under there has to do with the charging circuit?  Everything else seems to work with the board (for now).

Thanks again.  And thanks to Ziller for having this board!

DD1D3247-5195-483E-998B-5CCC365A1D52.jpeg 

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78buckshot
The dark residue may be from insects, normally we find ants have infested the control and will result in failure, or it may be from the original charger circuit and overheated components.
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VNV1967
I get that Pesky Check Battery Light twice a year on my 10KW. When I had the original wet cell in the unit it was always low on water. After removing the small fuse on top of the controller I would pull the battery cables off and use a battery brush on the terminals and then add a thin coat of grease (Old School) on the posts. 

Last year the the Check Battery came on after service. At that time I knew the Battery had finally eaten it self up. So I replaced it with a Gel style Duracell maint free sealed battery. 2 days ago the amber caution light came on and their was the check Battery Indication. A few pushes on the button and away the amber light and warning went.
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VNV1967
78buckshot wrote:
The dark residue may be from insects, normally we find ants have infested the control and will result in failure, or it may be from the original charger circuit and overheated components.


Funny you say that about ants... I had a choke problem and found something moved in the housing and fouled the choke...Don't know WTF this is...L.O.L. IMG_20160803_112852230_HDR.jpg 
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DenisC
I wanted to provide a quick update and thank you all again for your help on my Nexus battery charging problem.  Charging has worked fine ever since I attached the Battery Tender on May 17.  This past Thursday we had an outage of about an hour and a half, and the generator performed flawlessly.  
The Battery Tender enabled starting of the generator, kept battery the charged while it was running.  I have a Genmon unit hooked to it (controller not encrypted thankfully) and I could see the battery charging.  Slower charging when running vs. when not running, but everything worked great.

Thank you again, this saved me over $600 and I appreciate it.
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