Suspected Converter Problem

[LipschitzWrath]

Hey guys, back again. Hoping to gain some insight into an ongoing problem we've had this summer.

RV is a 2004 Fleetwood Terry Quantum AX6 365FLTS.

The rv came with a factory installed WFCO 8855 converter. First things first. If you go to their website, you will see 8855's are 220v input. This may be the case now but certainly wasn't in 2004. Mine is 120v input and I have photographic proof. Let's please not waste time disputing this.

WFCO says the 9855 would be pretty much an equivalent now.

Anyways, onto the issue. I am wondering if there may be a problem with my converter. The reason I suspect it is because of generally poor performance. In the off season, I replaced the single group 24 battery the PO was kind of enough to leave me with a pair of Group 31 AGM batteries, 105Ah apiece.

It seems that this charger takes forever to charge these things. We're talking like if the wall panel shows 2/3 full, I need to run the generator for like 8 hours to charge them.

On a recent trip, the Batts showed 1/3 full and even after running the generator for seriously like 12 hours, they only showed 2/3. This seems slow. I know the indicator system probably isn't scientific level accuracy, but reading at the Batts with a multimeter seems to corroborate.

Other weird issues:

Sometimes at night with our 12v lights on in the camper (LED retrofits), I can see the lights flickering.

I get substantially different readings on the multimeter if I probe the output terminals of the converter versus the batt terminals. This despite the cables connecting the two being less than 4 feet long. For example, I forced the converter into boost mode. When probing the outputs, I got like 14.46v. At the batt terminals, I get like 12.43v. This seems especially odd to me considering any other time I probe battery terminals with a charger connected and charging, it seems like I'm reading the charger output voltage.

Lastly, I pulled the troubleshooting chart from WFCO and followed all steps. According to the chart (link below), my converter is fine. But it certainly doesn't behave like it's fine. I know PD advertises that when in boost mode, it takes 2-3 hours to bring the battery bank to 90%. Admittedly, this WFCO isn't as good as a PD, but 12 hours? Really?

http://wfcoelectronics.com/wp-content/uploads/2015/11/New-Flow-Chart-for-WF-9800-Series.pdf

I have my eye on a PD9260, but I don't want to spend the money if there's something else wrong.

This past weekend the batteries were completely dead and we brought them home to charge on a more "conventional" charger. It took a long time, but it worked.

Any ideas? Are my batteries just THAT big? Or is there something else going on?

Tell me what you guys think.

[LipschitzWrath]

BFL13 wrote:
For this example just think converter instead of inverter, same deal here:

When I had the inverter to battery set up with an inverter that has two pos and two negs this all came up about splitting the amps. Using a two- battery bank---

If you put a pos and neg to each battery, then each battery supplies 1/2 the amps the inverter is drawing (in theory)

the same wires also act as parallel links between the two batteries, so you don't need another set of wires for that.

OR, you can put two pos and two negs across the bank per Method 2, and now you do need the parallel links. You don't have to worry if each is doing exactly half or just a little from one and a bunch from the other due to various possible reasons.

If you go with the first way, as soon as you get your Trimetric shunt in the mix, now you can't get a Method 3 situation, because the two negs now go to the shunt one end and then another fat wire goes from shunt to battery.

EDIT--the circuit breaker on the pos should be at least a 60 amper now that you will be getting full amps across it from the converter. Often that fuse or breaker is OEM undersized because they know their wiring makes it impossible to achieve full amps.

I *THINK* I understand what you are saying. I guess my follow up question is - wouldn't you want the load on each battery to be half? Maybe I'm misunderstanding, but it sounds like you're implying there are problems that go with that. I'm curious what they are.

I think that the shunt can be integrated just fine. The two negative cables (1 running to each battery) go to one end of the shunt, everything else goes to the other end. Nothing can make it to either battery without going through the shunt.

Valid point on going with the 500A shunt to future proof against an inverter install. Looks like the terminals on the 500A are 3/8" bolts so I would have to replace or drill out all the ring terminals I just put on those cables. Bummer.

In the other thread, you said those bolts are pretty short. Could you merely put longer bolts in there? I've got some serious stacks going as is.

[BFL13]

For this example just think converter instead of inverter, same deal here:

When I had the inverter to battery set up with an inverter that has two pos and two negs this all came up about splitting the amps. Using a two- battery bank---

If you put a pos and neg to each battery, then each battery supplies 1/2 the amps the inverter is drawing (in theory)

the same wires also act as parallel links between the two batteries, so you don't need another set of wires for that.

OR, you can put two pos and two negs across the bank per Method 2, and now you do need the parallel links. You don't have to worry if each is doing exactly half or just a little from one and a bunch from the other due to various possible reasons.

If you go with the first way, as soon as you get your Trimetric shunt in the mix, now you can't get a Method 3 situation, because the two negs now go to the shunt one end and then another fat wire goes from shunt to battery.

EDIT--the circuit breaker on the pos should be at least a 60 amper now that you will be getting full amps across it from the converter. Often that fuse or breaker is OEM undersized because they know their wiring makes it impossible to achieve full amps.

[LipschitzWrath]

BFL13 wrote:
I am not clear whether the battery bank supply to the DC panel is split.

The battery bank supply to DC panel is not split. The DC panel is fed from a breaker. On the other side of said breaker is where both battery positive cables are connected. Thus, the DC panel is fed off both batteries.

All battery cables are equal length in an attempt to equalize resistance.

[LipschitzWrath]

BFL13 wrote:
Yes, you want a fuse on the pos wire from converter to battery. You want a battery fuse on the battery to DC panel pos wire too. Often in an Rv where the converter is by the fuse panel, that is the same wire so just one fuse near the battery pos post.

You don't want the converter on the same side of the fuse as the DC panel, which you understand from the above, so why leave it like that?

Unless there is a fuse elsewhere in the camper, I cannot achieve the protection you describe without installing another breaker.

Furthermore, unless there is a fuse elsewhere in the camper, this protection did not exist prior to yesterday's work.

BFL13 wrote:
IMO just have the (single pair of #4) converter-battery wires by themselves and that's that. Then have your collection of wires from battery to fuse panel, with any (each) pos wires being fused near the battery.

I'm having trouble following you. Are you saying connect the converter wires directly to the battery, and then put all the DC load wires fed from the battery via the breaker? Where is the protection from battery to converter?

BFL13 wrote:
I think you have converter output with 1/2 (sort of) going to each battery. I am not clear whether the battery bank supply to the DC panel is split.

That is not the same thing as balancing, where all the amps go to and from the bank as though it were one big battery.

I have the converter output wire to a stud, then 2 identical cables hooked to the stud, one running to each battery. In the link I quoted, this guy identifies this as "Method 3" and says it achieves perfect balancing, although stud terminal space can become limited. With only 2 batts, I would assert that methods 2 through 4 all acheieve perfect balancing. I believe you are describing "Method 2". I selected method 3 instead because if I ever decide to install 2x 6V batteries in place of each 12V battery, the wiring will be simpler.

[BFL13]

I think you have converter output with 1/2 (sort of) going to each battery. I am not clear whether the battery bank supply to the DC panel is split.

That is not the same thing as balancing, where all the amps go to and from the bank as though it were one big battery.

Do you still have the parallel links between the batteries from before as well?

Yes, you want a fuse on the pos wire from converter to battery. You want a battery fuse on the battery to DC panel pos wire too. Often in an Rv where the converter is by the fuse panel, that is the same wire so just one fuse near the battery pos post.

You don't want the converter on the same side of the fuse as the DC panel, which you understand from the above, so why leave it like that?

IMO just have the (single pair of #4) converter-battery wires by themselves and that's that. Then have your collection of wires from battery to fuse panel, with any (each) pos wires being fused near the battery.

BTW you can test for which wire is doing what by using your meter to see if it is "live" between its ends. Or what you think is the other end of a wire, but don't know for sure.

[LipschitzWrath]

What is your concern? Splitting amps? I don't get it.

I have a 4ga cable running to each battery positive AND negative? Is this a problem?

I don't believe I have any circuit protection bypassed. The converter output goes to one side of the breaker, the batts are on the opposite. So the converter has to go through the breaker to charge the batteries.

The converter is on the same side of the breaker as the DC panel. There may not be any protection there, but if there isn't now, there never was. I don't know there is a large fuse downstream somewhere (I haven't seen one), or maybe they let the branch fuses take care of that. The one exception here is that when I used the "return" wire from the DC panel as a second "feed", the converter can now dump it's current into the DC panel without any circuit protection via the old "return" wire. Now, if the old "feed" wire has no circuit protection, then this is no different and all I did functionally was double the number of feed wires to the DC panel without any protection bypass.

Phrased a different way, here's what's connected to the breaker

"Input" - Batteries (only)
"Output" - Converter ouput, DC panel feeds

Is this in error?

EDIT - If you go to the link earlier in this thread: http://www.smartgauge.co.uk/batt_con.html

I used method 3. I don't see what I did wrong.

[BFL13]

"....serve as a ground junction. From there, I ran a new 4ga ground cable from the converter to the junction block. I also ran separate 4ga grounds to each of the two batteries. I then ran a 4ga ground from said junction block to the frame ground"

Not clear. You want the negs to go to the one battery and the pos to the other battery. If you split the negs one to each battery, you might have a "situation" (or not)

The battery to frame ground should be on that same one neg post. don't ground both batts to the frame. (if that is what you did)

Good that you got rid of that voltage drop 🙂

EDIT-- I think what you did was merely add a second parallel neg link between the batteries, but that won't split the amps in half like I was worried about unless you do the same with the positives?

EDIT-2 yes you did! Plus, you might have the "circuit breaker" (DC) acting as the "battery fuse" by-passed for at least the #8s going back to the fuse panel. Hard to tell exactly.

IMO just make it simple and have the one pair of #4 wires converter-battery balanced across the bank. Then have another set of wires going from battery bank to DC panel, with the frame as the neg path for much of that, and the DC circuit breaker on the pos path close to the battery and no by-passing that with a second pos wire.

I think! ? 🙂

Anyway, IMO put just one neg (or both of them)from the junction to the one battery neg post on the other battery from the one the pos is on. And do the same with the two positives.

[BFL13]

pianotuna wrote:
Cydog15,

Surely you can't be serious that BFL13 is being paid. Is it an attempt at humor???

PT, better to ignore all this. For here, just take his "info" as being garbled, and go with the two companies' websites--imperfect as they now are, but being worked on 😞 --- for specs etc.

I am more interested in how the OP is making out with his project!

[LipschitzWrath]

BFL13 wrote:

LipschitzWrath wrote:

BFL13 wrote:
Besides the other wiring routes, you might have extra long pos wire converter-battery for a "battery disconnect switch" located way inside the rig, requiring extra miles of wire. Not sure if that "return" wire is from that or what. Something to watch out for.

Where might this battery disconnect be hiding? I feel like I have looked in almost every nook and cranny of this camper and never seen one. Would it be unheard of for my camper to NOT have one?

My new battery lug crimping tool arrives tonight so I will be redoing all the battery cables tonight.

No, not unheard of. Komforts had them in the kitchen on the wall by the microwave. Was a push -pull knob thing. Some RVs have them by the door. Some have a red switch , some rockers. If you can't find one probably isn't one.

If you can, IMO by- pass the wall junctions for your two short wires converter-battery. the pos and neg don't have to be the same length since it is a circuit. (You will now have one going farther to the second battery)

The zoo from battery to DC panel doesn't matter so much, but always nice to have it simple and know what each wire is for.

I peeked around last night, couldn't find anything resembling a battery disconnect.

That said, I did complete the battery cable upgrade last night. I added a single stud-type junction block in the crawlspace to serve as a ground junction. From there, I ran a new 4ga ground cable from the converter to the junction block. I also ran separate 4ga grounds to each of the two batteries. I then ran a 4ga ground from said junction block to the frame ground. In addition, rather than removing the existing 8ga grounds running from frame-converter and frame-batteries, I also hooked them to the junction block, providing several additional redundant ground paths to the frame.

On the positive side, I first took the existing 8ga positive converter output (presumed to feed the DC panel inside) and hooked it to the same stud on the circuit breaker that the "return" wire back from the DC panel was hooked to. The thinking there was to essentially turn the "return" wire into a second "feed" wire.

Next, I ran a new 4ga cable from positive converter outlet to the same stud referenced above, essentially taking the place of the aforementioned wire. Lastly, I ran two new 4ga cables from the opposite stud on the circuit breaker to each of the batteries.

I kind of went overboard on the "balancing", as now each battery has its own positive and negative (and 4ga, at that). But hey, I had the wire laying around and the lugs came in 25-packs, so the added cost was minimal. Besides, if I ever decide to go with a bank of 4x 6V batteries, the cabling won't have to be redone.

So what was the result? Essentially zero voltage drop, that's what! I plugged in the converter, and instantly it went into boost mode. I measured 14.46v at the converter outlet terminals. I then took a deep breath and measured at both sets of battery terminals - 14.48v!

We are going to see if Sam's Club will exchange the two batteries for us to be on the safe side. THey have an 18-month free replacement and we bought them last May, so fingers crossed. I really do think that they're okay, but now that my charging issues are resolved, I'd rather start fresh and be sure.

The wife and I are headed out to the lake this weekend for camping again, so I will be able to report back with some real-world testing. Although, now that I installed a 200w solar system, I don't know how much use the converter is going to get. That's a nice problem to have.

[pianotuna]

Cydog15,

Surely you can't be serious that BFL13 is being paid. Is it an attempt at humor???

[Cydog15]

BFL13 wrote:

Cydog15 wrote:
You're also going to find the LK will stop at 13.8 volts in the bulk mode and never fully charge in the 3 stage mode. Have one on my bench as we speak. You need the Boondocker for 14.7 bulk. We're doing several upgrades this weekend on a small fleet of trucks and there is a difference. I'm actually trying to get them to give us 14.9 bulk but in the auto mode but not getting anywhere. PDI is willing .

The one on your bench would not be deck mount PM3-LK then. I suspect it is a version of a PPC "lower portion" converter, which is still under development for its charging profile, but which will include a boost voltage of approx. 14.5v when it is finished.

Be interesting if you could post a photo of it and show its brand label with model number etc. Also where did you get it? There has to be a story there.

Your Boondocker you have said is a 1260, must be a modified version of that from what you have also said, not clear exactly. Where did you get that and what was done to it by whom? You did say it has a different charging profile that includes a two-hour bulk stage, eg.

You seem to know a lot. Mine came from Best and it's clearly different than the Powermax you are proud of. I only know it has a higher boost voltage. I do think you are paid by them. I was told they start with a higher amp unit and derate them and even cost more to do that.

[BFL13]

LipschitzWrath wrote:

BFL13 wrote:
Besides the other wiring routes, you might have extra long pos wire converter-battery for a "battery disconnect switch" located way inside the rig, requiring extra miles of wire. Not sure if that "return" wire is from that or what. Something to watch out for.

Where might this battery disconnect be hiding? I feel like I have looked in almost every nook and cranny of this camper and never seen one. Would it be unheard of for my camper to NOT have one?

My new battery lug crimping tool arrives tonight so I will be redoing all the battery cables tonight.

No, not unheard of. Komforts had them in the kitchen on the wall by the microwave. Was a push -pull knob thing. Some RVs have them by the door. Some have a red switch , some rockers. If you can't find one probably isn't one.

If you can, IMO by- pass the wall junctions for your two short wires converter-battery. the pos and neg don't have to be the same length since it is a circuit. (You will now have one going farther to the second battery)

The zoo from battery to DC panel doesn't matter so much, but always nice to have it simple and know what each wire is for.

[LipschitzWrath]

BFL13 wrote:
Besides the other wiring routes, you might have extra long pos wire converter-battery for a "battery disconnect switch" located way inside the rig, requiring extra miles of wire. Not sure if that "return" wire is from that or what. Something to watch out for.

Where might this battery disconnect be hiding? I feel like I have looked in almost every nook and cranny of this camper and never seen one. Would it be unheard of for my camper to NOT have one?

My new battery lug crimping tool arrives tonight so I will be redoing all the battery cables tonight.

[BFL13]

Besides the other wiring routes, you might have extra long pos wire converter-battery for a "battery disconnect switch" located way inside the rig, requiring extra miles of wire. Not sure if that "return" wire is from that or what. Something to watch out for.

[BFL13]

pianotuna wrote:
You are missing that power factor may be around 0.7 on the wfco and that a a 2k Yamaha really only does 1600 va.

If the wfco does 14.6 x 75 /.7 = 1564 watts

Power factor on the PD is also 0.7

Since you may have a Victron in your future I would not bother to replace the wfco unless it fails.

Getting solar into the "act" may eliminate the need for the wfco, too.

To add to that , PT is using the DC output watts instead of the AC input. Here are the numbers for the 75 amper from a Kill-A-Watt, with the converter being powered by a Honda gen (a 3000is)

123.8v, 13.64a, 1241w, 1693VA, 0.73PF when doing 75a output set at 14.8v, battery at 14.08 and rising.

Yes, keep the 8855 and gizmo booster, and rewire that zoo with new wire to replace any old, corroded wires. 3 ft (6ft circuit) #8 is good for the 55 amper but #4 can't hurt. You might even see 60 amps with that.