Alternator charging light staying on. Renogy DCC50S

[fred_jb]

You know what Fred, but I've got that same shunt to fit! I bought it all in May, but with one thing and another, I've not the time to fit it all.

I've got the DCDC50S fitted to mine now, and was just wanting to see it working before I fit the shunt and lithium.
with the engine and ignition off, does your DCDC50S charge from the starter battery? (Far left hand LED lit up red) Mine does, albeit only drawing small current, until the starter battery drops to 12.6V. It seems strange to deplete charge from the starter battery.

Is yours a smart alternator?

Hoping you can help me out here!

There is a bit of a problem with the terminogy used with these kind of units. When they refer to an alternator input it is not a direct connection to the alternator, instead it is a connection to the starter battery +ve which in turn connects to the alternator. So, if it says it is charging from the alternator, in reality it is charging from the starter battery. Unless you connect a proper D+ signal it has no way of knowing if the alternator is actually charging the starter battery and so has to infer this from the level of the starter battery voltage which can obviously be misinterpreted in various scenarios. This can lead to charge being taken out of the starter battery when the alternator is not providing charge to it which is what seems to happening with yours.

My van has a smart alternator and I have connected the D+ signal to the B2B, but would have done so even if it wasn't a smart alternator. As far as I can tell the B2B now only operates to take charge from the starter battery and send it to the leisure battery if the engine is actually running, which is what I want.

Interestingly if the leisure battery is fully charged and you have solar panels connected it seems that it will use the solar input to charge the starter battery instead, and I think I saw this happening the other day. To me this raises the question of how suitable this charging regime is for the AGM starter battery as you can only specify battery type for the leisure battery and I have that set to lithium.

These are my current readouts, with the weak winter sunshine only providing about 45W from my 280W solar panel array!

I have disabled the Electroblock trickle charging of the starter battery, so am relying on the Ablemail unit to keep it topped up, though that, the B2B and the shunt seem to disagree slightly on the voltage reading. The Ablemail unit basically passes charge to the starter battery if the leisure battery is above 13V and the starter battery is below 12.5V.

 

[growly_bear]

My van has a smart alternator and I have connected the D+ signal to the B2B, but would have done so even if it wasn't a smart alternator. As far as I can tell the B2B now only operates to take charge from the starter battery and send it to the leisure battery if the engine is actually running, which is what I want.

Thanks again. So can you confirm that as soon as you switch off the engine, the charge light extinguishes immediately? If it does, I'll fit the DCDC50S D+ to the EBL.

I read in my manual, that yes the starter battery is charged once the leisure battery is deemed to be fully charged, and so no need to have an alternative method of keeping the starter battery charged. However, I would like to switch off the lithium at 80% when not being used, but this will confuse the DCDC50S! Although reducing the float voltage could go some way to helping...

I'll send a "Case" to Renogy asking what the battery type is for the starter battery for when the solar is charging

 

[fred_jb]

Thanks again. So can you confirm that as soon as you switch off the engine, the charge light extinguishes immediately? If it does, I'll fit the DCDC50S D+ to the EBL.

I read in my manual, that yes the starter battery is charged once the leisure battery is deemed to be fully charged, and so no need to have an alternative method of keeping the starter battery charged. However, I would like to switch off the lithium at 80% when not being used, but this will confuse the DCDC50S! Although reducing the float voltage could go some way to helping...

I'll send a "Case" to Renogy asking what the battery type is for the starter battery for when the solar is charging

Thanks for raising the case with Renogy. It will be interesting to hear what they say about that.

Yesterday I moved my switch for the D+ into the centre console to be accessible while driving and looked in the app at what happened when switching on and off. At first it didn't seem to stop charging immediately, but that might be just lag in the app. I will try again today and take the cover off the rear of the seat so that I can see the lights on the unit.

While investigating if my switch was working properly I wasn't sure if the voltages were correct as something else the converters had connected to the D+ seemed to be putting 2-3 volts on the line when I expected it to be zero. More investigation required today!

 

[growly_bear]

Thanks for raising the case with Renogy. It will be interesting to hear what they say about that.

Yesterday I moved my switch for the D+ into the centre console to be accessible while driving and looked in the app at what happened when switching on and off. At first it didn't seem to stop charging immediately, but that might be just lag in the app. I will try again today and take the cover off the rear of the seat so that I can see the lights on the unit.

While investigating if my switch was working properly I wasn't sure if the voltages were correct as something else the converters had connected to the D+ seemed to be putting 2-3 volts on the line when I expected it to be zero. More investigation required today!

I'll be sure to report back, although it does sometimes take a few messages each way!

Thanks for the trouble which you are going to, and hoping that you find it useful too.

There is always something to fathom out! I've just ordered a clamp meter to add to my toolkit.

 

[fred_jb]

I'll be sure to report back, although it does sometimes take a few messages each way!

Thanks for the trouble which you are going to, and hoping that you find it useful too.

There is always something to fathom out! I've just ordered a clamp meter to add to my toolkit.

No problem, and as you say it is useful to me too.

I have just done some more testing of the charging behaviour. I didn't write anything down, so I'm relying on my sometimes defective memory, but the following is more or less what I am seeing:

I watched the red light and also monitored charging current on the One Core display. Initially I had the D+ switched off when I started the engine, but the red light came on and the display showed a fairly high level of charging so I think it was happily working in non-Euro6 mode. However, the current then dropped right down though the red light stayed on, which I suspect was the Euro6 alternator going into energy saving mode and dropping its output voltage. If I then switched on the D+ signal the current ramped back up to 50A. If I switched it off the current dropped right down to more or less zero but the red light didn't go off, though when I went through the cycle again the red light did go off when the D+ was switched off.

My conclusion is that the charger will always work if it sees enough voltage at the starter battery regardless of whether the D+ is applied which I guess it what you would expect as it is designed to work with either type of alternator and with or without a D+ signal. However once the Euro6 alternator behaviour kicks in, which is not immediate, it then becomes responsive to the D+ signal. The red light seems a little random at times, but looking at the charging current in the app confirms that the charging goes on and off as expected with the D+ signal once the engine has been running long enough for the Euro6 alternator to do its thing.

I hope that helps.

Regarding turning off charging at 80%, I know this is the recommendation for maximum life for lots of lithium battery types, including those in EVs, but I have also read that it only makes a marginal difference, so I'm not sure what to believe on this. It would be interesting to see what the B2B makes of this if you turn off accepting charge in the battery's BMS. I suppose it depends on how this is accomplished by the BMS. I could imagine it must be an physical electronic switch as just changing to a fully charged status would not necessarily stop devices sending charge to it. That would probably look to the B2B as if the battery had been disconnected, though if the BMS was still allowing outgoing current then the B2B would still be able to sense the leisure battery voltage, which might confuse it. I suppose in the worst case it might damage the B2B, but hopefully it has protection against this sort of thing. I think if I decide to limit charging of the battery I will do it with the D+ switch and the breaker switch I put in the solar panel wiring.

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[growly_bear]

My conclusion is that the charger will always work if it sees enough voltage at the starter battery regardless of whether the D+ is applied which I guess it what you would expect as it is designed to work with either type of alternator and with or without a D+ signal. However once the Euro6 alternator behaviour kicks in, which is not immediate, it then becomes responsive to the D+ signal. The red light seems a little random at times, but looking at the charging current in the app confirms that the charging goes on and off as expected with the D+ signal once the engine has been running long enough for the Euro6 alternator to do its thing.

Thanks Fred. This makes complete sense to me, and my dumb alternator is mirroring what you see with your D+ connected.

Regarding turning off charging at 80%, I know this is the recommendation for maximum life for lots of lithium battery types, including those in EVs, but I have also read that it only makes a marginal difference, so I'm not sure what to believe on this. It would be interesting to see what the B2B makes of this if you turn off accepting charge in the battery's BMS. I suppose it depends on how this is accomplished by the BMS. I could imagine it must be an physical electronic switch as just changing to a fully charged status would not necessarily stop devices sending charge to it. That would probably look to the B2B as if the battery had been disconnected, though if the BMS was still allowing outgoing current then the B2B would still be able to sense the leisure battery voltage, which might confuse it. I suppose in the worst case it might damage the B2B, but hopefully it has protection against this sort of thing. I think if I decide to limit charging of the battery I will do it with the D+ switch and the breaker switch I put in the solar panel

I've also read the same re 80% and it only having a limited affect on longevity.

I did pull the leisure battery fuse and the DCDC50S came up with a low battery error, so I'll not be able to turn the BMS off. On my Jiabaida JBD BMS I can turn it off with a mechanical switch or use the app software. I, like you would think that there would be protection in place to protect the DCDC50S in the event of a leisure battery fuse blowing.

Another thought re keeping the battery connected would be that when it is fully charged that current would be diverted from solar to the starter battery and then not needing a starter battery maintenance charger...

Lots to think about.

 

[fred_jb]

Lots to think about.

Definitely - my latest unforeseen issue is losing the mains indicator light on the LT100 control panel. This was because I completely disconnected the mains supply from the EBL to avoid a quite large current drain from the internal EBL circuitry after I removed the 20A fuse which lets it charge the leisure battery. I am now buying a little module which drives an LED from a mains supply and will patch that into the system to get the mains indicator working again.

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[growly_bear]

Here's the reply from Renogy. Really fast answer

"I understand your question regarding the battery types that our 12V 50A DC-DC On-Board Battery Charger with MPPT is designed to charge, especially concerning the starter battery settings. This charger is indeed versatile, allowing it to charge auxilliary batteries with a specification of flooded, gel, AGM, and lithium batteries."

"For the starter battery, however, we recommend using only non-sealed, vented, flooded, or wet-cell lead-acid batteries. This type of battery is optimal for ensuring consistent trickle charging and maintaining the longevity of both the charger and the battery."

This DCDC50S is a really great piece of kit

 

[growly_bear]

Hi fred_jb, I'm still waiting on the answer to the Renogy 'Case' I raised regarding the 12.7v cut off to stop engine/alternator charging when the engine is off. However, I read one of your posts saying that you have an Ablemail trickle charger fitted? Is it the AMT12-2?

As my LiFePO4 house battery will be rarely 100%SOC, the DCDC50S will never trickle charge the starter battery.

If I fit a trickle charger, the starter battery could then exceed the 12.7v DCDCS alternator charge voltage and think that the engine is running and charge from the starter battery causing a loop!

How did you get around this?

 

[autorouter]

If I fit a trickle charger, the starter battery could then exceed the 12.7v DCDCS alternator charge voltage and think that the engine is running and charge from the starter battery causing a loop!

This is an unavoidable problem if you use starter battery voltage to trigger the B2B on and off. That's why it's best to use only the D+ to trigger the B2B for anything but really simple systems.

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[1967bowesj]

I fitted a 40a dc dc from renogy and found it would stay on charging even after engine and d+ signal was zero, raised two cases and after doing bit of research found an answer. Renogy finally came back in a very poor way to say use a relay!! They will not admit that the dc dc has an issue. As it happens using a 80amp relay triggered by the d+ can give you great control on the sub standard dc dc, ie you can fit a switch to the d+ for when you dont want the house battery at 100% say ready for storage.

 

[growly_bear]

This is an unavoidable problem if you use starter battery voltage to trigger the B2B on and off. That's why it's best to use only the D+ to trigger the B2B for anything but really simple systems.

Thanks autorouter. Fed has set his up to the D+ and exhibits the same situation.

The Renogy unit only has a D+ to connect for smart alternator. A sense wire is not fitted for dumb ones; it picks this up within the unit. So the D+ doesn't override.

The Renogy 12.7v to start the charger up is the critical value which i wish was a little higher.

Happy to be wrong though!

 

[fred_jb]

This is an unavoidable problem if you use starter battery voltage to trigger the B2B on and off. That's why it's best to use only the D+ to trigger the B2B for anything but really simple systems.

What he said! I use the D+ signal to control the DC-DC and have this going through a switch so that I can easily disable it. I am not now seeing a problem such as in the previous post, though have noticed that the charging does not stop immediately when I turn off the D+, but ramps down over a few seconds, which is probably a sensible way to do it to avoid shocks to the system. Mine is the 50A version.

 

[growly_bear]

I fitted a 40a dc dc from renogy and found it would stay on charging even after engine and d+ signal was zero, raised two cases and after doing bit of research found an answer. Renogy finally came back in a very poor way to say use a relay!! They will not admit that the dc dc has an issue. As it happens using a 80amp relay triggered by the d+ can give you great control on the sub standard dc dc, ie you can fit a switch to the d+ for when you dont want the house battery at 100% say ready for storage.

Well that is absolutely ridiculous!

I've been in contact with Jonathan at Ablemail, who tells me that their trickle charger is configurable to charge up to 12.6v which would stop the DCDC from kicking in and charging the house battery.

I'd expect Renogy to be able to make their charge voltage configurable though!

 

[growly_bear]

What he said! I use the D+ signal to control the DC-DC and have this going through a switch so that I can easily disable it. I am not now seeing a problem such as in the previous post, though have noticed that the charging does not stop immediately when I turn off the D+, but ramps down over a few seconds, which is probably a sensible way to do it to avoid shocks to the system. Mine is the 50A version.

Can I ask what your smart starter battery voltage is usually at after the engine is switched off?

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[autorouter]

The Renogy unit only has a D+ to connect for smart alternator. A sense wire is not fitted for dumb ones; it picks this up within the unit. So the D+ doesn't override.

Are you sure it's not just badly worded? With a smart alternator, using a D+ is the only sensible way to trigger it. With a dumb alternator, using a D+ is the best way. But you can get away with triggering from the alternator/starter battery voltage in simple situations, where you don't have anything at all charging the starter battery

 

[fred_jb]

On a related issue, I have had a problem with a mysterious beeping which was driving us mad on a recent trip when I had the DC-DC turned on. It came and went for no apparent reason. On return I started the hunt for the culprit which was not a low battery in fire or CO2 sensor as I had expected, but turned out to be the Renogy shunt giving a high voltage warning. However the Fogstar app showed no alarms in the BMS history log so the battery did not see anything of concern.

The Renogy app briefly showed that there had been a high voltage warning from the shunt, but that immediately disappeared and doesn't seem to have been recorded in a log. I think it said something like 14.75V.

I have tried to checked the settings on the DC-DC but when set to Lithium battery type most of the settings are greyed out. The charge voltage was set to 14.4 and I eventually was able to change it to 14.3 to see if that helps. I found that the Core One display is a pain for this as it lets you see the settings on the DC-DC but doesn't let you change them in the DC home app if it is paired with the display. Instead I had to use a spare phone not paired to the display and paired only to the DC-DC.

Maybe the Fogstar battery stops accepting charge when full, leading to the charging voltage rising though I would have thought that would be a transient effect. However, the alarm kept going for about 20 mins on both outward and return journeys. This happened soon after setting off on the outward journey with a nearly full battery, and when almost home after setting off with only 75% after a night off-grid. This would seem to indicate that it happens once the battery is full and that maybe the DC-DC is very slow to detect this?

 

[growly_bear]

Are you sure it's not just badly worded? With a smart alternator, using a D+ is the only sensible way to trigger it. With a dumb alternator, using a D+ is the best way. But you can get away with triggering from the alternator/starter battery voltage in simple situations, where you don't have anything at all charging the starter battery

I understand completely what you are saying and agree!

The installation instructions state no additional sense wire for traditional alternator and the D+ only needs installing if its a smart alternator.

With the engine off and if i watch the starter battery voltage, the starter battery charge light (indicating DCDC charging house battery) extinguishes at 12.7V and the DCDC turns off.

 

[growly_bear]

On a related issue, I have had a problem with a mysterious beeping which was driving us mad on a recent trip when I had the DC-DC turned on. It came and went for no apparent reason. On return I started the hunt for the culprit which was not a low battery in fire or CO2 sensor as I had expected, but turned out to be the Renogy shunt giving a high voltage warning. However the Fogstar app showed no alarms in the BMS history log so the battery did not see anything of concern.

The Renogy app briefly showed that there had been a high voltage warning from the shunt, but that immediately disappeared and doesn't seem to have been recorded in a log. I think it said something like 14.75V.

I have tried to checked the settings on the DC-DC but when set to Lithium battery type most of the settings are greyed out. The charge voltage was set to 14.4 and I eventually was able to change it to 14.3 to see if that helps. I found that the Core One display is a pain for this as it lets you see the settings on the DC-DC but doesn't let you change them in the DC home app if it is paired with the display. Instead I had to use a spare phone not paired to the display and paired only to the DC-DC.

Maybe the Fogstar battery stops accepting charge when full, leading to the charging voltage rising though I would have thought that would be a transient effect. However, the alarm kept going for about 20 mins on both outward and return journeys. This happened soon after setting off on the outward journey with a nearly full battery, and when almost home after setting off with only 75% after a night off-grid. This would seem to indicate that it happens once the battery is full and that maybe the DC-DC is very slow to detect this?

What high voltage have you set the alarm on the shunt to?

 

[fred_jb]

Can I ask what your smart starter battery voltage is usually at after the engine is switched off?

After everything has settled the starter battery is around 12.5V and the leisure battery is about 13.2V. From memory, I think the Ablemail unit is set to only trickle charge the starter battery if it is below 12.5V and the leisure battery is above 13V.

I was wondering if this sort of device doing trickle charging of the starter battery from the leisure battery could be momentarily making the DC-DC think that the alternator is running. I would have hoped that using D+ to trigger the DC-DC would avoid this, but maybe the unit has an either/or approach where either a D+ signal, or a starter battery voltage of over 12.7V will kick it into action?

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[fred_jb]

What high voltage have you set the alarm on the shunt to?

I have changed it from 14.7 to 14.8 to see if that helps, again after a long rigmarole of turning off the One Core display and connecting the DC Home app on a spare phone directly to the shunt as that seems to be the only way to get a settings change to save successfully.

 

[growly_bear]

I have changed it from 14.7 to 14.8 to see if that helps, again after a long rigmarole of turning off the One Core display and connecting the DC Home app on a spare phone directly to the shunt as that seems to be the only way to get a settings change to save successfully.

That's 3.7 per cell...

I would expect one cell to go into OVP at 3.65V which would keep the battery voltage much below 14.8V

What does your shunt history show?

Mine is set at 14.2V. Only installed 2 weeks ago, but mine beeps occasionally and I've not got a proper idea why...

This is this morning taking daughter to school

 

[growly_bear]

After everything has settled the starter battery is around 12.5V and the leisure battery is about 13.2V. From memory, I think the Ablemail unit is set to only trickle charge the starter battery if it is below 12.5V and the leisure battery is above 13V.

I was wondering if this sort of device doing trickle charging of the starter battery from the leisure battery could be momentarily making the DC-DC think that the alternator is running. I would have hoped that using D+ to trigger the DC-DC would avoid this, but maybe the unit has an either/or approach where either a D+ signal, or a starter battery voltage of over 12.7V will kick it into action?

The starter battery don't charge voltage is 12.7V. So that's why i see a difference to you as my battery is 12.8V. It settles over 4 hours to 12.7V, and the DCDCS charge turns off. This would be OK over the short term. But if I connect a trickle charger and the starter battery goes over 12.7V it'll be in a charging loop. But from what you say (which confirms what Jonathan at Ablemail) if I set it to smart settings it'll work fine.

 

[Lenny HB]

I've been in contact with Jonathan at Ablemail, who tells me that their trickle charger is configurable to charge up to 12.6v which would stop the DCDC from kicking in and charging the house battery.

I quite like the Ablemail as a product but not impressed with their technical support.
I contacted them about there charging profiles for lithium with a smart alternator.

The reply I got was BS, they think it's a good idea to only charge the starter battery to 12.4v so the alternator has room to top it up on over run.

IMO not what you want in a Motorhome, you want the starter battery fully charged not under charged which puts the battery at risk.

 

[growly_bear]

I quite like the Ablemail as a product but not impressed with their technical support.
I contacted them about there charging profiles for lithium with a smart alternator.

The reply I got was BS, they think it's a good idea to only charge the starter battery to 12.4v so the alternator has room to top it up on over run.

IMO not what you want in a Motorhome, you want the starter battery fully charged not under charged which puts the battery at risk.

There are so many factors within all of this, no less the airbag failures which occur all to often.

When my old system, with a dual output MPPT, was topping up the starter, I regularly saw voltages of 13.8V which I felt was too high. Too low also causes me airbag alarm (having had one replaced). I've read that their values can be tweaked using a bluetooth dongle and their app https://www.ebay.co.uk/usr/ablemaielectronic0 but this is a bit steep ££!

Strangely, for me, their lithium/smart voltages will probably work for me.

However, I have seen this on Alliexpress

https://www.aliexpress.com/item/400...FnDOIdnJ&utparam-url=scene:search|query_from:

(don't shout me down )

My initial thinking is that so long as the voltages are closely set then current flows won't be high, but I'd need to do some experimentation!

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[fred_jb]

That's 3.7 per cell...

I would expect one cell to go into OVP at 3.65V which would keep the battery voltage much below 14.8V

What does your shunt history show?

Mine is set at 14.2V. Only installed 2 weeks ago, but mine beeps occasionally and I've not got a proper idea why...

This is this morning taking daughter to school



View attachment 978031

Well, the shunt does not control the max voltage applied to the battery - that is a function of the DC-DC charger and the BMS of the battery. As far as I can see the shunt is not an active participant in this - it is just a reporting device. Changing the shunt alarm voltage setting should have no effect on the battery as it is just the threshold for the shunt to trigger an alarm. As the accuracy of measuring voltages seems to vary between the shunt, the DC-DC, and my LED guages, then it could be that the shunt is reading high and alarming unnecessarily, which is why I decided to set the threshold higher at 14.8V.

 

[Ian_H]

The reply I got was BS, they think it's a good idea to only charge the starter battery to 12.4v so the alternator has room to top it up on over run.

Isn't this exactly how Fiat etc set their smart alternators to operate? Here's a fiat forum q&a

 

[fred_jb]

There are so many factors within all of this, no less the airbag failures which occur all to often.

When my old system, with a dual output MPPT, was topping up the starter, I regularly saw voltages of 13.8V which I felt was too high. Too low also causes me airbag alarm (having had one replaced). I've read that their values can be tweaked using a bluetooth dongle and their app https://www.ebay.co.uk/usr/ablemaielectronic0 but this is a bit steep ££!

Strangely, for me, their lithium/smart voltages will probably work for me.

However, I have seen this on Alliexpress

https://www.aliexpress.com/item/4000527664577.html?spm=a2g0o.productlist.main.11.34787b55DDFMQ7&algo_pvid=595130ab-5c67-46d1-8523-0cd11d46d894&algo_exp_id=595130ab-5c67-46d1-8523-0cd11d46d894-5&pdp_npi=4@dis!GBP!1.13!0.79!!!1.42!1.00!@2103956a17313649693828947e2b12!10000002686645626!sea!UK!0!ABX&curPageLogUid=Y0cuFnDOIdnJ&utparam-url=scene:search|query_from:

(don't shout me down )

My initial thinking is that so long as the voltages are closely set then current flows won't be high, but I'd need to do some experimentation!

Yes the Bluetooth module for the Ablemail is rather pricey but I bought one in the end as it lets you use the app which allows much easier control of the unit and has a nice display of the battery voltages.

 

[growly_bear]

Well, the shunt does not control the max voltage applied to the battery - that is a function of the DC-DC charger and the BMS of the battery. As far as I can see the shunt is not an active participant in this - it is just a reporting device. Changing the shunt alarm voltage setting should have no effect on the battery as it is just the threshold for the shunt to trigger an alarm. As the accuracy of measuring voltages seems to vary between the shunt, the DC-DC, and my LED guages, then it could be that the shunt is reading high and alarming unnecessarily, which is why I decided to set the threshold higher at 14.8V.

I know that it's just an alarm setting, and maybe I wasn't clear. I guess that your shunt could be over reading, but surely that's easy to check and compare with bat voltage Vs App

 

[fred_jb]

I don't think I would trust the AliExpress item, and in any case it doesn't seem to include any BT connectivity, so has less adjustability than the Ablemail unit.

However, it does seem like a more sophisticated version of the BatteryMaster type devices in that it actually uses a relay to turn charging on or off according to the voltage thresholds you set, though how stable these are with temperature changes is open to question.

Still, as far as I know the BatteryMaster type gadgets are entirely passive devices which just use the voltage drop across a diode to control charging, which is a very crude way to do it!

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