My AGM battery is never getting charged with more than 12Amps in my RV solar setup.

[flajsdl]

Hi there,

As long as I have this setup my battery seems to be undercharged? (or perhaps this is normal) Even on the sunniest day the Tracer charges at 14.7V at 12 Amps for not even an hour. More like 15 minutes after which the amperage drops to 10A, 9A, etc. etc.

Then drops to below 1A within a few hours and goes into float (13.8V, 1 or 2 Amps, then less)

During wintertime, when my battery is getting emptier because of longer evenings I draw about 7 hours at 7A = roughly 50 Amps.

But still the Tracer doesn't charge it for more than 30 minutes at 12Amps even though there is plenty of sun during the day. Shouldn't it charge for a longer period of time at this high amperage?

Also when on hookup it seems the Victron Multiplus never charged the battery with more than around 10Amps.

Only when I use the watercooker that draws about 70 Amps the Tracer starts to charge with up to 24Amps but only during the time the watercooker is on.

My setup:

3 x 150 Watt panels
4215BN Epsolar tracer MPPT charger (30 Amp charger)
Victron Multiplus 12/800/8-16 inverter
250Ah Cellpower CPC AGM battery

 

[RandyP]

How long has the AGM battery been charged this way, meaning charged up to less than 100 SOC each cycle?
The battery could be suffering from under charging, developing crystals on the plates, etc. Some AGM's can be equalize charged to correct the problem, but only if the battery manufacturer recommends it. (LifeLine AGM's)
Death of many lead acid batteries is by not attaining 100% SOC nearly every cycle. Lead acid batteries take time to reach 100 SOC after the boost charge at the Absorb charge voltage level. If left at less than 100% SOC repeatedly, they loose their life.
The simple fix is to get a 100AH drop in LiFePO4 battery like a Battleborn and your problem is fixed. The 100 AH LiPo will nearly match the performance or the 225 AH AGM elecrically and outlive it by 3-4 times or more.

 

[flajsdl]

Thanks for your explanation. I learned about this recently. Yes it has probably been undercharged for years. The battery is damaged now. But that's not what i would like to know..

My question is;

What could I have done differently to avoid the systematic undercharging?

I mean, is it normal that the Tracer 30amp charger only charges at max 12A when not under load? It seems it can, in theory, charge with much more amps (about 24A). So why doesnt it? Can I force it to do so?

 

[gnubie]

Monitor the PV voltage when the battery is undergoing bulk charge. The Tracer will tell you what it is, I think. Compare that with the Vmp of the solar array. If the PV voltage is considerably higher than the Vmp during bulk charging some setting or thing must be limiting the current to the battery. To get the Vmp of the array, for panels in series add the Vmp of each panel; for panels in parallel if they are all the same model, the Vmp of one panel is the figure to use. I'll assume that your panels are in series since that would usually be best for MPPT chargers.

If your battery capacity has been reduced due to damage the charge current will be lower and it will become fully charged (to that new low capacity) sooner than you expect. That the Tracer does crank out 24 amps with water cooker on suggests that, unfortunately, your battery is likely damaged and simply can't sink all the current the Tracer can supply.

You have AGM batteries so they might be able to be recovered to some degree if they are damaged but it's best to rule everything else out first as the fix can degrade a properly working AGM battery, and that's not something you want if you can avoid it.

 

[flajsdl]

It's currently in bulk and the Tracer indicates the PV voltage ranges between 19.7V, 19.6V. up to 20V. Going down to 15.3V when a cloud blocks the sun.

I'm not sure what the Vmp is.. The Vmp (voltage at max power) is the voltage during bulk charging? The voltage that my Nasa BM1 and Epsolar Tracer display show, and that can be adjusted in User settings via the Tracer display? That's set to 14.7V and is showing 14.7V in full sun.

"That the Tracer does crank out 24 amps with water cooker on suggests that," isn't that normal? A 150 Watt panel produces approx an 8 amp current right? So my three panels can produce at most 24 amps?

If I remember correctly the Tracer never charged with more than 24 Amps and only when under load. When the inverter and other loads were off, it never charged with more than 12 a 13A.

 

[Ped]

Once bulk (constant current, variable voltage) voltage hits its preset point it goes into absorb (constant voltage, variable current) where it should hold that voltage and taper the current. It is doing so.

If youre using the battery daily you can raise float voltage up to saturation/bulk point and force it to absorp longer than the 180 minute limit in the tracer. Once the current falls below 1 amp you can consider it 100% soc. Unfortunately you cannot verify with a hydrometer for accuracy.

 

[gnubie]

It's currently in bulk and the Tracer indicates the PV voltage ranges between 19.7V, 19.6V. up to 20V. Going down to 15.3V when a cloud blocks the sun.

I'm not sure what the Vmp is.. The Vmp (voltage at max power) is the voltage during bulk charging? The voltage that my Nasa BM1 and Epsolar Tracer display show, and that can be adjusted in User settings via the Tracer display? That's set to 14.7V and is showing 14.7V in full sun.

"That the Tracer does crank out 24 amps with water cooker on suggests that," isn't that normal? A 150 Watt panel produces approx an 8 amp current right? So my three panels can produce at most 24 amps?

If I remember correctly the Tracer never charged with more than 24 Amps and only when under load. When the inverter and other loads were off, it never charged with more than 12 a 13A.

The Vmp is the voltage at which your panels produce the maximum wattage under standard test conditions. If you check the label on the back of the panel or on the manufacturers' web site you can find that voltage. From the voltages you are reporting the panels seem to be in parallel.

*edit*
I may have made an incorrect assumption about how you have the watercooker connected too. If the cooker is connected via the load output terminals on the charge controller you may well see 24 amps to it, but that could consist of 12 amps from the battery and 12 amps from the solar array. If the cooker is across the battery terminals then what I said is still a possibility.

 

[RandyP]

If the battery has been degraded, it will not accept a 100% new SOC. So try another battery, even a cheaper auto battery and adjust the charge profile for that battery type and see how the tracer does with a good battery. Then go buy a Battleborn LiFePO4 100AH battery, adjust the solar controller battery charge characteristics, and be happy for 10 Years.

 

[flajsdl]

These are the specs of my panels:

• Gewicht in kg: 11,10 kg.
• Type cel: monokristallijn
• Max. vermogen (Pmax): 150 W
• Max. spanning: 18,10 V
• Max. stroom (Imax): 8,31 A
• Open spanning: 22,40 V
• Kortsluitstroom: 8,66 A
• Rendement: ± 18 %

The voltage of the panels, according to the Tracer display ranges today from 18.3v to 20.6v.

The 24A I get when using the watercooker in full sun is put in by the Tracer /panels, the rest of the load (the other roughly 50A is sourced from the LB, as far as I can see on my monitors).

I suspect the Tracer works as it should because I got a new one at some point and it works similar.

The first AGM battery I had, same exact brand etc, turned out to be faulty -very strange readings on the NASA BM1/Tracer etc-- and I got a new one.

 

[gnubie]

OK, then the Tracer is not the problem. You are seeing the results of the degraded battery.

You will need to work out how much power you are pulling out of the battery on a daily basis to see if your system is capable of producing that at all, but you will actually need to produce more due to various losses in the process of actually charging the battery.

 

[flajsdl]

Degraded battery, absolutely. In the evenings it's at 13.3V first then goes down to 12.9v then quickly drops to 10.8v - 10.6v. So I think it's a matter of time before I really need to get a replacement when it's actually dead.

No my system is not capable of producing enough power during less sunny days. I'm going to get a gasoline generator to make sure I can charge this, and, more importantly, my next LB better. Especially since I want to be able to work on my computer with 30" screen during cloudy/rainy days during the day and evening. (drawing about 6A / h x 15 hours = 90A. for just one rainy day)

If I would get a 100Ah Battleborn LB, and keep using the Tracer 4215BN (30A charger) etc, would the Tracer push more amps into the LB than it has done so far since I had it? I mean, does such a LifePo4 battery encourage higher and longer bulk charges?

 

[SolarRat]

In the evenings it's at 13.3V first then goes down to 12.9v then quickly drops to 10.8v - 10.6v. So I think it's a matter of time before I really need to get a replacement when it's actually dead...

If it's doing that, it's dead now. Sounds like a dead cell in the battery, usually they cant be recovered.

 

[Ped]

If I would get a 100Ah Battleborn LB, and keep using the Tracer 4215BN (30A charger) etc, would the Tracer push more amps into the LB than it has done so far since I had it? I mean, does such a LifePo4 battery encourage higher and longer bulk charges?

This is a good topic for Will to do a video about. Not only does lifepo4 require much less solar it makes your current system produce more usable power because it doesnt need to absorb stage for hours.

 

[flajsdl]

If it's doing that, it's dead now. Sounds like a dead cell in the battery, usually they cant be recovered.

I heard from someone else with exactly the same LB in a van that he had let it drain without recharging for a few days if I recall correctly and his battery monitor showed 10.8V right in the beginning of the evening. This, after charging it with solar all day. Still he had light and power for his laptop all evening long.

In other words, my plan is to see how far I'll get with this battery and only replace it when I really need to, or perhaps when I can still use it but in case I'm back in my home country.

 

[flajsdl]

This is a good topic for Will to do a video about. Not only does lifepo4 require much less solar it makes your current system produce more usable power because it doesnt need to absorb stage for hours.

Might be a solution for me. I need something that pumps almost 100Ah back into the LB within a day at most, preferably in less time.

In hindsight it seems like getting an AGM battery was a bad choice anyway since I'm a fulltime RVer and solely charge my LB with solar. Meaning I never charge it with EHU. Also my RV alternator is 3 decades old and doesn't put in much amps either.

Of course the vendor didn't tell me this and I recently read that AGM's need a proper charge via electric hookup at least every two weeks or so to combat systematic undercharging as they cannot be charged fully with solar alone.

 

[RandyP]

Degraded battery, absolutely. In the evenings it's at 13.3V first then goes down to 12.9v then quickly drops to 10.8v - 10.6v. So I think it's a matter of time before I really need to get a replacement when it's actually dead.
..................

A resting voltage of 10.6 volts indicates a dead cell in a 12v lead acid battery. Time to replace it. It will continue to put a hell of a load on your charging system until it is changed out.

 

[SolarRat]

I heard from someone else with exactly the same LB in a van that he had let it drain without recharging for a few days if I recall correctly and his battery monitor showed 10.8V right in the beginning of the evening. This, after charging it with solar all day. Still he had light and power for his laptop all evening long.

In other words, my plan is to see how far I'll get with this battery and only replace it when I really need to, or perhaps when I can still use it but in case I'm back in my home country.

A sudden drop to 10.8ish v is almost always a sign of a dead cell. The other 5 cells may still be working perfectly fine, and 10.8v is enough for non-sensitive loads, like lights. I have a few old batteries with bad cells I'm keeping for outdoor lights (with a buck converter to 3.5v LEDs). I wouldn't use an expensive charge controller on them as they may damage it(?), but they can still be useful for some things. It sounds like you got a few good years out of it despite not having enough solar to charge it properly. If you had hooked it to an AC charger, just once a month, it probably would have greatly prolonged it's life.

What the heck is a LB?

 

[RandyP]

..................................
If I would get a 100Ah Battleborn LB, and keep using the Tracer 4215BN (30A charger) etc, would the Tracer push more amps into the LB than it has done so far since I had it? I mean, does such a LifePo4 battery encourage higher and longer bulk charges?

Yes, LiFePO4 batteries charge at max charger output amps until they reach about 14.6 v if the charger is unregulated. A charger will remain in boost state until the battery is charged to 100% SOC, no absorb charge. then the charger can be turned off or set for 13.6v or less as a max maintenance voltage.

 

[RandyP]

Thanks for your explanation. I learned about this recently. Yes it has probably been undercharged for years. The battery is damaged now. But that's not what i would like to know..

My question is;

What could I have done differently to avoid the systematic undercharging?

I mean, is it normal that the Tracer 30amp charger only charges at max 12A when not under load? It seems it can, in theory, charge with much more amps (about 24A). So why doesnt it? Can I force it to do so?

Some AGM battery brands (thehigher AH batteries) require a higher voltage charge about once monthly. Odyssey AGM battery,
ODYSSEY PC 2150S/ PC 2150T / PC 2150ST-M
Battery needs a 14.7 volt conditioning charge followed by 14.7 v maintenance pulses
If your solar battery charger was not doing this, the Odyssey PC 2150S would slowly degrade over time.
I think you need to get the right shore power charged for the job and charge an AGM battery fully at least once a month.

https://www.odysseybatteries.com/docs/ody_chargers_sheet.pdf

Odyssey PC2150 series battery

www.odysseybatteries.com

 

[SolarRat]

The voltage of the panels, according to the Tracer display ranges today from 18.3v to 20.6v.

Your CC is rated for 150v PV input. I would try hooking your panels in series for a ~58v feed to the MPPT, it may greatly appreciate the overhead. It won't fix your bad battery, but it may fix the cause of the bad battery....if lucky.