Batteries charging slow

[darrellr]

Originally Posted by Aussieguy

battery will dictate the rate of charge
so if the battery only accepting 60amps total
it will draw only 60amp total from both chargers

I set my solar it has bluetooth...... to charge at same voltage that converter produces

This is not true of WFCO chargers. They will adjust charging current, they are not CC chargers. As soon as I tested with the same draw down on the batteries but covered the solar panels, the charger output the proper current. Uncover the panels, all of the sudden the charger severely limited current. It is easy to test if you have a WFCO like mine (WF-9865-AD) and enough solar. In my case, it took about 24 hours to charge my batteries back to full from ~18% because the charger was not outputting the proper current. Tested again with the trailer inside storage, took about 3-4 hours from 21% back up to 100%.

[Larry-NC]

Originally Posted by darrellr

This is not true of WFCO chargers. They will adjust charging current, they are not CC chargers. As soon as I tested with the same draw down on the batteries but covered the solar panels, the charger output the proper current. Uncover the panels, all of the sudden the charger severely limited current. It is easy to test if you have a WFCO like mine (WF-9865-AD) and enough solar. In my case, it took about 24 hours to charge my batteries back to full from ~18% because the charger was not outputting the proper current. Tested again with the trailer inside storage, took about 3-4 hours from 21% back up to 100%.

All the modern (e.g., post-Y2K or so) Flooded lead-acid converters are like that. See the discussion on Page 7 here.

[darrellr]

Originally Posted by Larry-NC

All the modern (e.g., post-Y2K or so) Flooded lead-acid converters are like that. See the discussion on Page 7 here.

My charger is autodetect and was in LFP mode. Here is the manual, page 6-7. These are CV chargers, not CC chargers.

[Larry-NC]

Originally Posted by darrellr

My charger is autodetect and was in LFP mode. Here is the manual, page 6-7. These are CV chargers, not CC chargers.

Exactly why I was careful to state "Flooded Lead-Acid converters."

[darrellr]

Originally Posted by Larry-NC

Exactly why I was careful to state "Flooded Lead-Acid converters."

Gotcha - but no one on here was discussing FLA, only LFP. I was confused I guess.

[Chuck_S]

This is not true of WFCO chargers. They will adjust charging current,

Actually they don't adjust the current (amperage) they adjust the voltage.

The voltage differential determines which way the current flows and the bigger the difference how fast it flows. Just like the voltage regulator in your car or any battery charger. Folks often ignore this and connect a pair of batteries in parallel where the weaker battery will immediately start to siphon power (charge itself) from the stronger until they're both dead. This is why starting and house batteries are typically on Off-1-Both-2 switches. They're only connected to each other in the Both position.

-- Chuck

[darrellr]

Originally Posted by Chuck_S

Actually they don't adjust the current (amperage) they adjust the voltage.

The voltage differential determines which way the current flows and the bigger the difference how fast it flows. Just like the voltage regulator in your car or any battery charger. Folks often ignore this and connect a pair of batteries in parallel where the weaker battery will immediately start to siphon power (charge itself) from the stronger until they're both dead. This is why starting and house batteries are typically on Off-1-Both-2 switches. They're only connected to each other in the Both position.

-- Chuck

No, you are not correct on this. These are constant voltage (CV) chargers, you are talking about constant current (CC) chargers or CC+CV, which PDs are. WFCO is not.

[Elliot Mess]

Update:After 3 days of boondocking I still had 70% charge on the 200 ah so I left everything on overnight and discharged the batteries. After doing that the charger was putting out close to 30 amps according to the Victron software.

It seems to me that the Progressive Dynamics needed to see those batteries more discharged before it would kick into gear, once discharged, probably under 20% it went to town.

The Victron software showed 40% SOC but also showed 12.96 volts, that would be 20% for LifePO4 batteries.

I think the Victron software was never reset. I also found the batteries were defined in settings to be full at 13.6 I changed that to 14.4 That would make the percentage of SOC reading useless.

I'd love to get that in the 20's up to 40 amps and I can check wiring later when my driveway is paved and I can get under it!

When it is fully charged which should take 5 hours or so, I'll reset the shunt software.

[Elliot Mess]

Perhaps the charger was in storage mode.

Or the battery's BMS was limiting the charge rate, maybe it needed to be reset by discharging.

[Hclarkx]

First, that 61% initial SOC was not a reliable number. Batteries from the factory must be topped off to "reset" or "calibrate" the SOC before it can be trusted. Until then the indicated SOC is pretty much a random number.

The battery BMS or an external shunt will reset its indicated SOC to 100% when the batteries are fully charged, usually by hitting 14.4V or slightly less (unless set differently).

There is also a voltage setting that kicks the charger into bulk mode. Knowing what this is is very helpful. Until voltage is drawn down below that setting, the charger will not go into bulk mode (a constant internal voltage followed by a current limiter). I've seen 13.0V which means no bulk charging until the battery is pretty well discharged (below 50%). This would be okay if there's a generator handy or one is on a power post. 13.3 makes more sense in most situations, e.g., with solar, in that this is about 96% SOC and will result in a top-off each morning when the sun comes up regardless of how much was taken out of the battery over night.

Some chargers will go into bulk mode regardless of voltage when re-booted.

The slow charging could very well be voltage drop. A 1 volt drop (round trip) can make 14.4 V at the charger into 13.4 V at the battery. The battery will charge fully with 13.4 V but it will take days or weeks. Though with 3 amps, there can't be much voltage drop. It's possible the PD was in float mode and never got kicked into bulk mode for some reason. A good read of the manual would help here.

The 45 amp original charger probably used #8 wire and if it's long enough or has some bad terminals along the way, it would surely limit the PD's higher potential bulk current.

[Hclarkx]

Originally Posted by Hclarkx

First, that 61% initial SOC was not a reliable number. Batteries from the factory must be topped off to "reset" or "calibrate" the SOC before it can be trusted. Until then the indicated SOC is pretty much a random number.

The battery BMS or an external shunt will reset its indicated SOC to 100% when the batteries are fully charged, usually by hitting 14.4V or slightly less (unless set differently).

There is also a voltage setting that kicks the charger into bulk mode. Knowing what this is is very helpful. Until voltage is drawn down below that setting, the charger will not go into bulk mode (a constant internal voltage followed by a current limiter). I've seen 13.0V which means no bulk charging until the battery is pretty well discharged (below 50%). This would be okay if there's a generator handy or one is on a power post. 13.3 makes more sense in most situations, e.g., with solar, in that this is about 96% SOC and will result in a top-off each morning when the sun comes up regardless of how much was taken out of the battery over night.

Some chargers will go into bulk mode regardless of voltage when re-booted.

The slow charging could very well be voltage drop. A 1 volt drop (round trip) can make 14.4 V at the charger into 13.4 V at the battery. The battery will charge fully with 13.4 V but it will take days or weeks. Though with 3 amps, there can't be much voltage drop. It's possible the PD was in float mode and never got kicked into bulk mode for some reason. A good read of the manual would help here.

The 45 amp original charger probably used #8 wire and if it's long enough or has some bad terminals along the way, it would surely limit the PD's higher potential bulk current.

Also, of course, #8 is only good for around 40 amps so should not be used at a higher current.

The battery BMS cannot limit charge current other than simply shutting it off if voltage gets too high for the battery or charge current gets to high for the BMS.

As others have mentioned, a thorough cleaning of all terminals along the charge circuit is a good first step (along with larger wire from charger to battery if needed). This is a maintenance item and should be done ever couple of years.

[Elliot Mess]

Well I spoke with Progressive Dynamics tech support and they told me that the battery goes into full charge power at 13.3 volts.

I have no idea why it was stuck in storage mode, at this point in time I just have to wait until it is discharged enough to try charging it again, right now we're between trips.

Once the driveway is paved and I can get under the motorhome on a creeper I'll be examining and cleaning any wires and terminals I can find (as well as sealing up holes that mice can get in.)

Thanks for all the great info!