NOCO Charger Question - MEP-803A w/Optima Red Tops

[Waukesha]

I'm scratching my head.. Below is for an MEP-803A with Optima Red Top batteries.

I had left my generator off the charger for 2-3 months as I dealt with a move. When the talking heads on TV started projecting ice & 2'+ of snow, I figured I should go start the generator and make sure it still works. It primed as normal, turned it to start and... CLICKkkkkk. So I pull out my trusty volt meter and it measures 13v on one battery #1, and 11.7v on battery #2. Based on some research online, 11.7v while low, isn't "dead" for an Optima Red Top. I ran out to the store to purchase a NOCO Genius 5X2, knowing that the NOCO Genius 7200 charging at 24v would never properly charge the two batteries.

Fast forward 12 hours or so, and the NOCO is flashing green on battery #1 (originally at 13v) and it's giving me a dead battery symbol on battery #2 (originally at 11.7v). I pulled battery #2 out of the generator to bench charge/diagnose. At the time of pulling, it was registering 12.7v (which according to Optima's website is close to 100% charged). I placed battery #2 on the NOCO 7200 overnight, and it charges the battery to 100% on its scale, and the volt meter measures 12.9V. I ran the repair/desulfanation function for 24hrs, battery #2 now registers 12.9-13v. I put the battery back in the MEP and it started up, albiet a little slowly, which I attributed to the 10* temp over the last 36hrs. Generator ammeter registered about 10 amps and slowly dropped back down to ~0-2 amps (couldn't tell exactly).

Fast forward to today.. I drove an hour round trip to exchange the NOCO 5X2 thinking that it was bad. I just returned home and installed the replacement charger and it's behaving like it's going to give me a dead battery symbol in ~10-12hrs. Behavior includes registering that battery #1 is 100% charged (which it is by all methods of measurement available to me), and for battery #2 the Noco 5X2 is showing a VERY slow progression from flashing 25% charged to 50%, 75%, and finally flashing 100% charged, at which point it will give me the dead battery symbol.

I should also note that load test battery #2 with a Schumacher BT-100 battery load tester and sitting is registers in the green, and under load voltage drops down to 11-11.2V (can only hold loads for ~10 seconds with this resistive type tester)

What gives?

 

[WWRD99]

I'm scratching my head.. Below is for an MEP-803A with Optima Red Top batteries.

I had left my generator off the charger for 2-3 months as I dealt with a move. When the talking heads on TV started projecting ice & 2'+ of snow, I figured I should go start the generator and make sure it still works. It primed as normal, turned it to start and... CLICKkkkkk. So I pull out my trusty volt meter and it measures 13v on one battery #1, and 11.7v on battery #2. Based on some research online, 11.7v while low, isn't "dead" for an Optima Red Top. I ran out to the store to purchase a NOCO Genius 5X2, knowing that the NOCO Genius 7200 charging at 24v would never properly charge the two batteries.

Fast forward 12 hours or so, and the NOCO is flashing green on battery #1 (originally at 13v) and it's giving me a dead battery symbol on battery #2 (originally at 11.7v). I pulled battery #2 out of the generator to bench charge/diagnose. At the time of pulling, it was registering 12.7v (which according to Optima's website is close to 100% charged). I placed battery #2 on the NOCO 7200 overnight, and it charges the battery to 100% on its scale, and the volt meter measures 12.9V. I ran the repair/desulfanation function for 24hrs, battery #2 now registers 12.9-13v. I put the battery back in the MEP and it started up, albiet a little slowly, which I attributed to the 10* temp over the last 36hrs. Generator ammeter registered about 10 amps and slowly dropped back down to ~0-2 amps (couldn't tell exactly).

Fast forward to today.. I drove an hour round trip to exchange the NOCO 5X2 thinking that it was bad. I just returned home and installed the replacement charger and it's behaving like it's going to give me a dead battery symbol in ~10-12hrs. Behavior includes registering that battery #1 is 100% charged (which it is by all methods of measurement available to me), and for battery #2 the Noco 5X2 is showing a VERY slow progression from flashing 25% charged to 50%, 75%, and finally flashing 100% charged, at which point it will give me the dead battery symbol.

I should also note that load test battery #2 with a Schumacher BT-100 battery load tester and sitting is registers in the green, and under load voltage drops down to 11-11.2V (can only hold loads for ~10 seconds with this resistive type tester)

What gives?

Knee jerk guess on the battery....possibly charging it overnight wasn't enough...not sure what a 7200 is as far as charge stye and amps...the noco 5x2 is really meant to top off and maintain and not charge up from a lower state of charge...I've also read that to get a red top to charge it needs to be hooked up to another battery that is charged then charge them together...kinda weird but it's a red top thing I guess.

 

[Evvy Fesler]

Knee jerk guess on the battery....possibly charging it overnight wasn't enough...not sure what a 7200 is as far as charge stye and amps...the noco 5x2 is really meant to top off and maintain and not charge up from a lower state of charge...I've also read that to get a red top to charge it needs to be hooked up to another battery that is charged then charge them together...kinda weird but it's a red top thing I guess.

Hooked up in parallel, right? For charging... Pos to pos, neg to neg, unlike the generator which is series?

 

[WWRD99]

Hooked up in parallel, right? For charging... Pos to pos, neg to neg, unlike the generator which is series?

That depends on the charger...if it's 12 volt or 24.

 

[Waukesha]

Hooked up in parallel, right? For charging... Pos to pos, neg to neg, unlike the generator which is series?

that’s correct, I’ve read that too. You’re using the known good to create a load/voltage that a charger will recognize.

Knee jerk guess on the battery....possibly charging it overnight wasn't enough...not sure what a 7200 is as far as charge stye and amps...the noco 5x2 is really meant to top off and maintain and not charge up from a lower state of charge...I've also read that to get a red top to charge it needs to be hooked up to another battery that is charged then charge them together...kinda weird but it's a red top thing I guess.

7200 = Noco Genius G7200 which is a 12/24V charger. It puts out 7.2A at 12V. That charger will bring the battery to “100%” according to its internal algorithm. However when plugged into the 5x2, it sits at 25% and will eventually tell me the battery is bad. Strange..

From what I’ve read, using the second battery in parallel can help when the Optima battery voltage is too low to get a battery charger to detect it (say <9 volts).

 

[Guyfang]

Knee jerk guess on the battery....possibly charging it overnight wasn't enough (I would agree. It sounds like it is only getting a Surface charge, not a deep charge)...not sure what a 7200 is as far as charge stye and amps...the noco 5x2 is really meant to top off and maintain and not charge up from a lower state of charge...I've also read that to get a red top to charge it needs to be hooked up to another battery that is charged then charge them together...kinda weird but it's a red top thing I guess. (well, no. its not a red top thing. Its with all the batteries of this type. And only when the battery reads below 7-5 VDC. When a battery, any type reads less then 5 volts DCV, most chargers refuse to "see it" and consider it not chargeable. So you hook a good battery up in Parallel to the empty battery, and let it charge for a few hours. Then disconnect the good battery and hook up your charger to the empty battery. I normally let my NOCO 7200 charge an empty battery at least 2-3 days. Then, if possable, I discharge the battery, deeply, and start the recharging cycle again. This has always given me better results. And then I load test it. I also use a device to check the battery for CCA, cold Cranking Amps. That info is on the battery, and if after doing the charging routine the CCA has not comeback up to at least 80--90% of the rated CCA, its a batter you need to keep an eye on.)

 

[Waukesha]

Knee jerk guess on the battery....possibly charging it overnight wasn't enough (I would agree. It sounds like it is only getting a Surface charge, not a deep charge)...not sure what a 7200 is as far as charge stye and amps...the noco 5x2 is really meant to top off and maintain and not charge up from a lower state of charge...I've also read that to get a red top to charge it needs to be hooked up to another battery that is charged then charge them together...kinda weird but it's a red top thing I guess. (well, no. its not a red top thing. Its with all the batteries of this type. And only when the battery reads below 7-5 VDC. When a battery, any type reads less then 5 volts DCV, most chargers refuse to "see it" and consider it not chargeable. So you hook a good battery up in Parallel to the empty battery, and let it charge for a few hours. Then disconnect the good battery and hook up your charger to the empty battery. I normally let my NOCO 7200 charge an empty battery at least 2-3 days. Then, if possable, I discharge the battery, deeply, and start the recharging cycle again. This has always given me better results. And then I load test it. I also use a device to check the battery for CCA, cold Cranking Amps. That info is on the battery, and if after doing the charging routine the CCA has not comeback up to at least 80--90% of the rated CCA, its a batter you need to keep an eye on.)

Thank you, Guyfang. When you say "I discharge the battery deeply", can you describe what you mean by that? Is there a certain voltage that you try to get the battery down to? What setting on the G7200 would you reccomend to use to recharge from this deeply discharged state?

Also, you mention that you'd leave the G7200 on the battery for "a few days". Is this just on the maintenance setting? or the repair setting?

 

[glcaines]

I recently replaced the Exide orbital AGM batteries in my MEP003A genset. They were a fantastic battery, and I got many more years of service than I expected. I went with the Optima Red Tops as a replacement. After one year, one of the Red Tops failed. I tried resurrecting the battery by doing repair, but did not succeed. O'Reillys tried to resurrect the battery as well and failed. It was replaced under warranty. I have heard that the Optima batteries are not as good as they once were when they moved manufacturing from the USA to Mexico. I always keep a NOCO 5X2 hooked up to the batteries. This is an excellent battery-maintainer, but is not designed to be used as a charger for a deeply drained battery. I also have several other NOCO chargers, including a few G7200 chargers. The G7200 chargers are great, but have been discontinued by the manufacturer. NOCO chargers are the best I've ever used.

 

[Triple Jim]

The terminal voltage of an unloaded battery might tell you the percent charge, but that's the percentage of its capacity in its current condition. A failing battery can appear to be 100% charged, but not be able to supply the current needed to start an engine.

 

[WWRD99]

Knee jerk guess on the battery....possibly charging it overnight wasn't enough (I would agree. It sounds like it is only getting a Surface charge, not a deep charge)...not sure what a 7200 is as far as charge stye and amps...the noco 5x2 is really meant to top off and maintain and not charge up from a lower state of charge...I've also read that to get a red top to charge it needs to be hooked up to another battery that is charged then charge them together...kinda weird but it's a red top thing I guess. (well, no. its not a red top thing. Its with all the batteries of this type. And only when the battery reads below 7-5 VDC. When a battery, any type reads less then 5 volts DCV, most chargers refuse to "see it" and consider it not chargeable. So you hook a good battery up in Parallel to the empty battery, and let it charge for a few hours. Then disconnect the good battery and hook up your charger to the empty battery. I normally let my NOCO 7200 charge an empty battery at least 2-3 days. Then, if possable, I discharge the battery, deeply, and start the recharging cycle again. This has always given me better results. And then I load test it. I also use a device to check the battery for CCA, cold Cranking Amps. That info is on the battery, and if after doing the charging routine the CCA has not comeback up to at least 80--90% of the rated CCA, its a batter you need to keep an eye on.)

ahhh so the 7200 is a fancy name for 7.2 amps...ok...that's not much at all. I'd charge for at least the 2 days at that low of an amp. I still have to get used to these chargers that don't let you charge dead batteries. I remove the board in my portable chargers so they'll output volts to anything. It sounds like the majority of his battery issue is with the charger not wanting to charge it. The 5 amp maintainer probably has a timeout that if it doesn't hit voltage it shuts down. If he has a regular charger then I'd use that but I guess it could be a bad battery as well. 10-12 amps is what I like to long charge with a low battery for a deep charge.

 

[WWRD99]

Thank you, Guyfang. When you say "I discharge the battery deeply", can you describe what you mean by that? Is there a certain voltage that you try to get the battery down to? What setting on the G7200 would you reccomend to use to recharge from this deeply discharged state?

Also, you mention that you'd leave the G7200 on the battery for "a few days". Is this just on the maintenance setting? or the repair setting?

I'd ditch the noco for this and get a regular charger that puts out more amps to get a deep charge. 7.2 amps isn't really enough to do anything unless you leave it on for days. The settings on that charger are not designed to charge a dead battery.

 

[Daybreak]

The NOCO G7200 has the capability to charge a dead battery. You simply hold the mode button, and then select the "Supply"
After a while, switch the mode back to 12v AGM charge, and let it do its thing.

 

[Beschneid]

Knee jerk guess on the battery....possibly charging it overnight wasn't enough (I would agree. It sounds like it is only getting a Surface charge, not a deep charge)...not sure what a 7200 is as far as charge stye and amps...the noco 5x2 is really meant to top off and maintain and not charge up from a lower state of charge...I've also read that to get a red top to charge it needs to be hooked up to another battery that is charged then charge them together...kinda weird but it's a red top thing I guess. (well, no. its not a red top thing. Its with all the batteries of this type. And only when the battery reads below 7-5 VDC. When a battery, any type reads less then 5 volts DCV, most chargers refuse to "see it" and consider it not chargeable. So you hook a good battery up in Parallel to the empty battery, and let it charge for a few hours. Then disconnect the good battery and hook up your charger to the empty battery. I normally let my NOCO 7200 charge an empty battery at least 2-3 days. Then, if possable, I discharge the battery, deeply, and start the recharging cycle again. This has always given me better results. And then I load test it. I also use a device to check the battery for CCA, cold Cranking Amps. That info is on the battery, and if after doing the charging routine the CCA has not comeback up to at least 80--90% of the rated CCA, its a batter you need to keep an eye on.)

What is a good battery maintainer for a 24v system. Does the maintainer have to be a 2 bank version or since the batteries are in a series, would a 24v maintainer work. I trust a plug in version more than a solar, we can go days without the sun. There are times that my solar doorbell camera needs to be plugged in during the winter here in New England

 

[Coug]

After charging the battery to full, let it sit for a few days to a week before doing anything else to it.
Then check for voltage, and if voltage is good, do another load test.


My guess is you will find that the battery, while it will charge up and pass a load test immediately after charging, won't actually hold a charge for very long.
You can try the repair mode again for a few days, but from what I've seen the repair mode is mostly for flooded lead acid batteries, and designed to burn off the lead whiskers that grow between plates as the battery is charged/discharged, and to deal with sulfation. If the battery is having other issues then it won't help.

What is a good battery maintainer for a 24v system. Does the maintainer have to be a 2 bank version or since the batteries are in a series, would a 24v maintainer work. I trust a plug in version more than a solar, we can go days without the sun. There are times that my solar doorbell camera needs to be plugged in during the winter here in New England

the noco gen5x2 is a great maintainer for 24V dual battery systems.
A regular 24V charger isn't as good as dual 12V charging because it can't do anything to compensate for differences between the batteries (even batteries manufactured immediately after each other can have slightly different resistance and load values that only get further apart over time)
I'm sure there are other brands, but in the years I've been using NO.CO products I have had really good luck with them (not much compared to some people, but between multiple chargers and jump packs, I'm over $1k into their products, and all of it other than the gen5x2 in my HMMWV is at least 2 years or older)

 

[Beschneid]

Thanks Placed 5x2 on order last night

 

[Guyfang]

Thank you, Guyfang. When you say "I discharge the battery deeply", can you describe what you mean by that? (I got a bunch of 12 DCV light bulbs, and hooked them up to my battery. Let it sit there until it gets dim. I try and discharge it to 7-9 volts. Then hook up the battery charger and use the repair Function.) Is there a certain voltage that you try to get the battery down to? What setting on the G7200 would you reccomend to use to recharge from this deeply discharged state?

Also, you mention that you'd leave the G7200 on the battery for "a few days". Is this just on the maintenance setting? or the repair setting? I just saved a 12 volt, 830 AH battery. It took 2 and a half days to at last turn on the green light, and keep it on. Sometimes it can take that long or longer. I just plug it in and walk away. Once a day look at the green light.

 

[WWRD99]

The NOCO G7200 has the capability to charge a dead battery. You simply hold the mode button, and then select the "Supply"
After a while, switch the mode back to 12v AGM charge, and let it do its thing.

View attachment 887255

so it has a 5 amp charge or 7.2 amp agm or lithium....I can see how this charger could be kinda confusing since a 1.5 amp repair is more like a float charge...I guess they got something in these that makes that low of a charge do something.

 

[WWRD99]

Thanks Placed 5x2 on order last night

I have one and it works great! I have the 803 though....one thing I found was to unplug it before you start the genset...on mine it won't make power if I do...no idea why. Other than that it works great keeping the batteries up to snuff.

 

[Waukesha]

Update: I've left the NOCO 7200 in repair mode for the last week (7 days). The repair light is still flashing red, and the green 100% light is still flashing. I believe this is indicating that the battery won't get to 100% charge (per the NOCO 7200 algorithm?)

How long can/should I leave this battery in the NOCO repair mode? The battery is sitting in an insulated but unconditioned garage (probably 40*). The battery feels warmer than the ambient temperature, but not hot.

 

[WWRD99]

Update: I've left the NOCO 7200 in repair mode for the last week (7 days). The repair light is still flashing red, and the green 100% light is still flashing. I believe this is indicating that the battery won't get to 100% charge (per the NOCO 7200 algorithm?)

How long can/should I leave this battery in the NOCO repair mode? The battery is sitting in an insulated but unconditioned garage (probably 40*). The battery feels warmer than the ambient temperature, but not hot.

looking at the picture above repair mode is 1.5 amps....get it on the charge mode of 7.2 amps and see if that brings it up...1.5 amps is just a float charge.