PD 4645 still overcharging

[ovsa]

About 3 month ago I switched out the old Parallex convertor for the PD 4645 because the old one was boiling my batteries.
I was doing some battery maintenance today and noticed a lot of acid build up on the coach batteries. I have 2 fairly new 105a/h lead/acid wired in parallel.
Led me to believe they are still being over charged.

I read through the PD manual and tested the voltage output at 13.7v. Coach batteries are fully charged and read 12.75v.

I know the PD charger has an LED that flashes at intervals to let you know what stage of charging it is at.
When the batteries are 90% charged the charger is suppose to go into float mode at 13.6v. This is indicated by the LED flashing 2-3 per second .
When its fully charged at storage mode it goes down to 13.2v and the LED flashes every 6-8 secs.

Mine never seems to get out of the normal Mode which is once per second and 13.7v output.

Any one else have this problem? Is there any way to verify that it is not going in reduced mode. Any manual adjustments that can be made?

I've heard these are great convertors so i just want to eliminate the possibility of a faulty one.

Thanks

2003 Chevy Roadtrek 170 Popular.

[hbn7hj]

Originally Posted by ovsa

Any one else have this problem? Is there any way to verify that it is not going in reduced mode. Any manual adjustments that can be made?

Sure, push the button till you get the voltage you want. The button is near the red light on the fuse panel. Doesn’t explain why yours doesn’t automatically get there.

They a sell remote light and button to mount in a more accessible place.

[eric1514]

How long are you waiting? The change in mode is mostly timer based and it can take over a day after you turn it on to get to 13.2v.

PD says 90% charged but what they really mean is 4 hours. And when they say 'safely completes the charge' they mean another 30 hours. Then it will drop to 13.2v.

[RT-NY]

Originally Posted by eric1514

The change in mode is mostly timer based and it can take over a day after you turn it on to get to 13.2v.

Can you be more specific about "mostly" timer based? From what I can see on my PD4645, it seems that the drop from "boost mode" (14.4V) to "normal mode" (13,6V) is based on the battery's voltage. If, for example, I start the generator with the engine running is seems to always drop into normal mode presumably because it is reading the 14+ volts coming from the alternator.

By the way, does anyone know the precise effect of using the "Lithium-ion" mode (moving a jumper on the circuit board) on the charging cycle of the PD4645?

[SteveJ]

I had the PD 4645 in the RT.

It would bulk charge until it reached 14.4, then it went to absorb until it was full or the time ran out. Then it would drop to a 13.6 float for I believe 22 hours at which time it would drop and stay at 13.2. This was using a "maintenance free" 'DC" Walmart Maxx group 29 battery.

[booster]

12v wet cells are tough to figure out sometimes as the chemistries have been changing a lot. Many/most have gone to what would better be called combination starting/deep at best with others going to pure starting batteries.


It would be interesting to know what brand and model the batteries are to see what they claim for applications. Very few are pure deep cycle anymore.


I think all the automatic PD chargers run on straight timer setups so every time it gets turned on you will see 14.4 volts for 4 hours I think, then the 13.6/13.7v for nearly a day, then to storage mode of 13.2v. This kind of profile is going to cause some gassing, especially if the batteries are not discharged very far and see the 14.4v on top of full batteries for extended periods. Even the 13.7v will often cause some gassing and that goes on a long ways.


The algorithm chargers more commonly stop early, which is also a problem, so tough to choose what to get even if you changed. There are a limited number of expensive chargers that would be good, but they are also very large in comparison.


If you have room for them, going to two 6v batteries might be a better choice as I have found that, at least for the Trojans we had, the 6v GC batteries gassed less than the 12v models of Trojan we had. They also survived overcharging better over time and that is likely what you are seeing.

[RT-NY]

Originally Posted by booster

I think all the automatic PD chargers run on straight timer setups so every time it gets turned on you will see 14.4 volts for 4 hours.

As I mentioned just above, I do not think that this is correct. If I activate my PD charger when the battery voltage is high, it does not go to 14.4 volts for 4 hours. Is it possible that it reads the battery voltage when it is turned on and sets the mode based on that?

[booster]

Originally Posted by RT-NY

As I mentioned just above, I do not think that this is correct. If I activate my PD charger when the battery voltage is high, it does not go to 14.4 volts for 4 hours. Is it possible that it reads the battery voltage when it is turned on and sets the mode based on that?

Here is a link to the PD Charge Wizard page on their site. It shows the charge profile as starting at 14.4v and running 4 hours before dropping. This hasn't changed that I know of as it always used this diagram. I have never personally had a PD to run full tests on it, so no first hand information.



https://www.progressivedyn.com/rv/ch...charge-profile


This has come up in the past and users liked the fact that it would start a full charge on batteries that had some surface charge which would prevent a lot of chargers from starting. Or Magnum will not start if over about 12.7 volts, which is way too low to be full for us as that voltage can be as much as 10-15% discharged on our Lifeline AGMs if rested. After a short drive or if the solar is running and holding up the voltage at all, it will not start and could be down 25% or more. If we have less than full batteries I need to put the Magnum into full charge mode if the batteries are showing to high a voltage and it goes to float when plugged in.



PD doesn't say anything about a full charge initiation voltage, so can't say if they have put one in or not, or if past information was not correct.


If you are seeing this only when the van engine is running and the voltage going up to the PD absorption voltage of 14.4v or so, then this might be totally different than if the voltage were sitting below that at 13.0 volts or such. The OPs wet cells may rest as low as 12.6v or a bit lower depending on the chemistry, so would be a totally different thing than you are seeing with the motor running. Most people, including us, have probably never plugged in or started the generator with the motor running also, and then looked at the charger to check mode.



Sometime, if you get the chance, you might want to run a full charge on your batteries and let them rest a day. Check the voltage (probably in the 12.6-12.8v range) and then plug in to shore power only and see what voltage the PD goes to and what stage it shows. That would be good information for all of us to see.

[RT-NY]

Originally Posted by booster

If you are seeing this only when the van engine is running and the voltage going up to the PD absorption voltage of 14.4v or so, then this might be totally different than if the voltage were sitting below that at 13.0 volts or such.

Yes, this is a good point. As far as I recall it is *only* when the engine is running and the voltage is around that 14.4V number that the PD will drop out of boost mode (after I turn the engine off with the generator still running). A fully charged battery will not have this same effect. So perhaps it is not a feature of the PD to check the voltage, but somehow the high voltage is interfering with its normal time-based charge cycle. I will double check this later this week.

By the way, from what I have just been reading online, it seems that the Lithium-ion jumper on these PD chargers does away with these four modes and just supplies a constant voltage of 14.4v (or perhaps 14.6v, reports vary). Has anyone tried this jumper?

[ovsa]

thanks for that info... so when you say gassing off...it shouldn't be leaving any residue on the top of the battery should it?
Occasionally i notice a wet stain around the covers that i can wipe off but with my less accessible battery there was quite a built up of corrosion or solids.

[booster]

Originally Posted by ovsa

thanks for that info... so when you say gassing off...it shouldn't be leaving any residue on the top of the battery should it?
Occasionally i notice a wet stain around the covers that i can wipe off but with my less accessible battery there was quite a built up of corrosion or solids.

All non sealed wet cells will leave some residue around the caps and is from the gassing which is necessary to get a good charge. The hard part if figuring out how much is too much. How much water are they using? If a battery is running in a warmer area it will also charge faster and should charge at lower voltage so you can get more gassing that way also.


If your batteries are separated by some distance, they probably also have a substantial difference in cable lengths to them which can cause on to charge faster and gas more than the other. Are the batteries the same brand, model, size, and age?

[eric1514]

Originally Posted by RT-NY

Can you be more specific about "mostly" timer based? From what I can see on my PD4645, it seems that the drop from "boost mode" (14.4V) to "normal mode" (13,6V) is based on the battery's voltage. If, for example, I start the generator with the engine running is seems to always drop into normal mode presumably because it is reading the 14+ volts coming from the alternator.

By the way, does anyone know the precise effect of using the "Lithium-ion" mode (moving a jumper on the circuit board) on the charging cycle of the PD4645?

I say mostly timer based because depending on the state of my batteries, the PD charger will not always start in boost mode when I plug in my coach. Many times it has started in normal mode when I plug in after coming home from a long drive and my batteries are well charged. Therefore, I think it must be calculating what mode it wants to be in by reading voltage.

Also, my battery bank is large and if I run it down quite a bit, the PD charger will start in boost mode but 4 hours later when it drops into normal mode, my batteries are far from 90% charged. I have to push the button and put it back in boost mode for it to charge the batteries up to a level I (and my monitor) would consider charged. When it drops into normal mode for the second time I am well over 90% charged.

[ovsa]

it has been 48 hours..still at 13.7v output measured at the convertor and one second LED interval.

Batteries appear to be fully charged at 13.7v measured at posts with cables removed.

You say its a timer based program... so if i momentarily disconnect the shore power does it start all over again counting down?

Would have made more sense to have it voltage sensing.

thanks

[ovsa]

You would think that would be the best way to do it.

PD's literature says the wizard automatically determines which operating mode to choose , boost, normal, storage...

i would think that would mean voltage sensing.

Seems like that part is failing in mine.

One more thing... is it normal for the battery to measure 13.7v, all cables disconnected. ? Lead acid 105aH. couple of months old.?

Thanks everyone

[RT-NY]

Originally Posted by ovsa

it has been 48 hours..still at 13.7v output measured at the convertor and one second LED interval.

Batteries appear to be fully charged at 13.7v measured at posts with cables removed.

You say its a timer based program... so if i momentarily disconnect the shore power does it start all over again counting down?

. . . is it normal for the battery to measure 13.7v, all cables disconnected.

According to the "charge profile" linked to above, it is supposed to stay in "normal mode" (13.6v), which seems to be the mode that you are in, for 30 hours. But if you remove the cables from the battery (even briefly), maybe the converter senses that and starts over counting down? But it might not go back to "boost mode" (14.4v) because the batteries are already at such a high voltage (as the discussion above suggests -- perhaps it sets its initial mode based on voltage but is timer-based after that?).

I believe that it is normal for the batteries to stay at a high voltage for a while after disconnecting. You have to let them rest for several hours and then measure them to know what the correct voltage is.

[eric1514]

Originally Posted by RT-NY

According to the "charge profile" linked to above, it is supposed to stay in "normal mode" (13.6v), which seems to be the mode that you are in, for 30 hours. But if you remove the cables from the battery (even briefly), maybe the converter senses that and starts over counting down? But it might not go back to "boost mode" (14.4v) because the batteries are already at such a high voltage (as the discussion above suggests -- perhaps it sets its initial mode based on voltage but is timer-based after that?).

I believe that it is normal for the batteries to stay at a high voltage for a while after disconnecting. You have to let them rest for several hours and then measure them to know what the correct voltage is.

This is right. This is how mine acts. If I plug in with fully charged batteries it will start in normal mode and stay there for around 30hrs. If I were to unplug after say a day and plug back in, it will start the timer all over again.

I have a battery monitor so I can see how many amps are going into the batteries and if I don't like the mode the charger is in, I can change it. If the batteries are still accepting significant amps when it drops out of boost mode I put it back in. If the charger starts in normal mode but no amps are going to the batteries, I put it in storage mode.

[booster]

Originally Posted by eric1514

This is right. This is how mine acts. If I plug in with fully charged batteries it will start in normal mode and stay there for around 30hrs. If I were to unplug after say a day and plug back in, it will start the timer all over again.

I have a battery monitor so I can see how many amps are going into the batteries and if I don't like the mode the charger is in, I can change it. If the batteries are still accepting significant amps when it drops out of boost mode I put it back in. If the charger starts in normal mode but no amps are going to the batteries, I put it in storage mode.

Absolutely. Looking at the amps to the batteries only is the best way to tell if the batteries are full or not, but it should be done at full absorption for the best indication. Depending on the batteries you have the return, ending, tail, float transition (manufacturers can't seem to come up with one term for it) amps will be extremely consistent and accurate compared to other ways of determining full like voltage or amp hour counting. Wet cells will normally be in the 1-3% of the capacity of the batteries in amp hours, but seen in amps on the meter. AGMs will normally be .5 to 1%. TPPL AGMs will be lower at maybe .1-.3%. Get the correct amount from the manufacturer of the batteries.



If you look at the amps as soon as you come off of absorption voltage to either the 13.6v in a PD or whatever float you have in other chargers, it will almost always show zero or even negative amps from the residual surface charge. We see this all the time with our system if watching.


I can tell you for certain, if you do determine the correct float transition amps and then go by them for the charging you will be quite surprised by just how long it takes to get completely fully charged. If you have a big bank and small charger, it could be over 12 hours at absorption voltage. We have a 100 amp charger, set to run at 80 amps to keep it cooler, on our 440ah Lifeline AGM bank and from 50% down, 10 hours is not unusual at all. Lifeline specs .5%C on ours which would be 2.2 amps. Our settings don't have a 1/10 amp capability so we are set at 2 amps. I did test to see how low it would go if left longer and it would actually go to about 1.4 amps. It took a long time to do that little bit though. I asked Lifeline about that and they said that they determined the extra fullness you get is less beneficial than the harm from being at high voltage all that extra time, which certainly makes sense to me. It also takes into account the fact the amps at completion will go up a bit as batteries age.



When we go to float at 13.2v we run negative amps for a while which is feeding the van use so very variable, then a bit of time at zero amps, and then it will go to about 1 amp and very slowly taper down over the next couple of days to .1 amp at 13.2v.


The PD is capable of doing very high quality charging, as good as a very expensive Magnum, but takes manual intervention to do that by making sure it stays in absorption to the correct amp reading and then taking it directly to float, which PD calls storage, mode. The Magnum does all that for you with no intervention needed, but at a high price point.

[RT-NY]

Originally Posted by booster

The PD is capable of doing very high quality charging, as good as a very expensive Magnum, but takes manual intervention . . .

This seems to me to be the bottom line regardless of battery chemistry: if you want a relatively inexpensive system, you need to know the charging specs of your battery and get a charger that allows you to make adjustments manually. Then keep an eye on things to make sure that it is cycling according to specification. This is what I am intending for my lithium upgrade.

[eric1514]

One other thing that folks may or not be aware of.

When the PD charger is in boost mode it is not outputting at 14.4v all the time. It is attempting to bring your batteries up to 14.4 volts. What I mean is that you will only see 14.4 volts when the tail current is very small. As long as your batteries are still accepting a lot of amps, you won't see 14.4v. I've seen my charger drop down to normal mode after 4 hours when it had only reached 13.98v. The batteries were still accepting 12.1a. Time to push the button and get back to boost.

[booster]

Originally Posted by eric1514

One other thing that folks may or not be aware of.

When the PD charger is in boost mode it is not outputting at 14.4v all the time. It is attempting to bring your batteries up to 14.4 volts for a lot of that time. What I mean is that you will only see 14.4 volts when the tail current is very small. As long as your batteries are still accepting a lot of amps, you won't see 14.4v. I've seen my charger drop down to normal mode after 4 hours when it had only reached 13.98v. The batteries were still accepting 12.1a. Time to push the button and get back to boost.

How long it takes to get to full "boost" (absorption) voltage is totally dependent on the size of the charger, the capacity of the battery bank, and the acceptance of the battery (varies with brand and chemistry as well as SOC).


To get batteries full, you need to stay at the full boost voltage for a surprisingly long time, that will vary a bit based on the same criteria as stated above.


How long it needs to be in full voltage, absorption, mode reacts a bit backwards from what might be expected. It seems logical that a big charger on any given bank should be at full voltage less time than a small charge on the same bank, but that is not the way it goes in practice. The big charger will actually be at the full voltage longer than the small on is. The big charger will be faster in total time for charging, but a larger % of that time will be at full voltage.


This happens because once you get to full voltage the charge rate is only determined by what the batteries will accept and a big charger, with it's higher output, will be able to supply the max acceptance sooner.


For instance, an 80 amp charger on a 440ah AGM bank like ours will get into absorption voltage shortly before the amps start tapering from the 80 amps. At that point the batteries may only be 65-70% charged so it may need 6 or more hours to finish the charge to the .5%C tail amps. Put a 20 amp charger on the same bank with the same discharge % and it won't get full voltage until shortly after the batteries will only accept 20 amps. At that point the batteries may be at 85-90% charged, so it has less to finish and may take only 2-3 hours at absorption.


This is one of the reasons that timer based chargers that do a fixed absorption time, either by discharge amount or fixed, can't do a good job on many applications. Algorithm chargers try to compensate for this, but it is not easy to do and they tend to error to the undercharge side in most cases that I have seen.


The good out all of this is that in all the variances listed above, big/small charger, etc, the battery bank will always be full to 100% when the factory recommended full charge tail amps are met at absorption voltage. The charge will be correct with any size charger if it can stay in absorption stage long enough to get to the tail amps.


IMO, if you are using a PD charger with a shunt based monitor to control your charging, and you want to be accurate about it, you should base everything on the tail amps going to the battery at the absorption voltage. Tail amps at any other voltage are not accurate unless you have made a conversion chart based on what your bank gives at float when full, and it still won't be quite as good as at the absorption voltage, I think.


What are the tail amps at boost voltage and full batteries on your batteries? Did you get the recommended from the battery manufacturer? I think this is a step that many/most users don't do, leaving monitors at default settings and such, which can be very incorrect, especially on the newer Victrons that will show full charged at maybe 80% full with the defaults.


In general, if you have a large battery bank, maybe 400ah or larger and good sized charger to match, maybe 75 amps or larger, you should expect to see 8-10 hours to get to 100% from under 50% SOCl based on tail amps. If you are under that, you probably aren't getting fully charged. Even smaller banks take nearly as long, but don't spend as much time in bulk stage so might be 6-8 hours.