Progressive Dynamics converter and AGM batteries

BFL13 wrote:
I doubt you are running your alternator charging that long to see the overcharge set in. Not too clear on that.

I only run the alternator for about an hour for inital boost voltages and currents, and even then only in extremely generator-noise-sensitive camping situations.

Usually I'm able to some time later use the little Honda EX650, the big Onan, or a drive to another campsite to fully charge the AGMs.

We've never stayed in one place drycamping for longer than about 6 days. The Honda or Onan usually keep up the batteries in those rare instances. The Honda runs at a 54 dB sound level when delivering it's full current and can keep it up for 5-6 hours on 1/2 gallon of regular gas.

If I ever add solar, it will be portable so we're not tied to camping in the sun in order to use it.

I hope I can get buy with doing all of the above if we're able to fit in a trip to Alaska next year.

Hey, this is getting really complicated. Simple answer to the OP: I have a PD 45 amp charger. I have two 6 volt Lifeline AGM's. I wanted the AGM's primarily because my battery spaces are small and I can mount them on their side for easy hookup also there is no maintenance. When I bought them, I talked to Randy at Best Converter. At the time, he had been running the same batteries with the same charger for 6 years on his own personal RV with no issues. That was good enough for me. I have been running them for 3 years. They work great. I mostly boondock and have 200 watts of solar and use a Trimetric. I do not have and do not want a generator.

pnichols wrote:

BFL13 wrote:
Phil, you charge at the Float voltage so of course you don't see the overcharge thing.

BF, I base what I said on - after the AGMs have been fully charged on whatever charger - I start up the cold V10 engine such that it's alternator jumps to, and holds, around 14.4 volts for awhile. The RV batteries' ammeter doesn't budge ... it just sits there still showing near zero amps acceptance by the batteries. Recall that this is with a 130 amp alternator that is capable of delivering around 70 amps at engine idle speeds. (The alternator is over-driven, so it spins at far greater RPM than what the big engine is idling at.)

That's what I mean when I say that my AGMs seem to hit a solid wall preventing the acceptance of any more current once they're full up.

When I see it, it is after many hours of tapering amps at 14.x (14.4 or 14.8 depending on which AGM) till amps are down to 0.5 Then soon after hitting bottom, amps start back up again. Before that, you do test to see if your are all the way full by doing that higher voltage and watch amps jump but quickly fall back again. Mex calls that hitting the wall. But if you leave it at 14.x amps will go back up and the battery heats up.

I think all we are talking about is how long that takes and I get the notion that your "awhile" doesn't last long enough to see that--which is good! You don't want to see that.

I doubt you are running your alternator charging that long to see the overcharge set in. Not too clear on that.

MEXICOWANDERER wrote:
They want to drive the vehicle maintenance shop insane with problems.

I double doubt it.

MEXICOWANDERER wrote:
They use exclusive not-available-to-the-public secret control devices to prevent catastrophic failures.

I double doubt it again.

How it's "wrong" the way I charge my RV AGMs has never been electro-chemically explained to me in over 12 years of charging the way I do.

Deep down inside the little battery designer that I never was seems to say to me that inadequate exposure to charging voltages over 14 volts over time harms my AGMs ... even though they appear time after time to be full using lesser voltages for long enough times.

Is their capacity affected the way I do it ... and if so exactly how and why?

Boy ... I hope I haven't been kidding myself all along by thinking I saved precious retirement money by not replacing the RV's perfectly functioning, 13.5-13.8 volt, almost fixed voltage, stock, near-$200, ... built-in Parallax converter. (Actually I did replace it once with the exact same 7345 OEM model that came in the rig due to early life failure of the original OEM Parallax, but that was years ago.)

BFL13 wrote:
Phil, you charge at the Float voltage so of course you don't see the overcharge thing.

BF, I base what I said on - after the AGMs have been fully charged on whatever charger - I start up the cold V10 engine such that it's alternator jumps to, and holds, around 14.4 volts for awhile. The RV batteries' ammeter doesn't budge ... it just sits there still showing near zero amps acceptance by the batteries. Recall that this is with a 130 amp alternator that is capable of delivering around 70 amps at engine idle speeds. (The alternator is over-driven, so it spins at far greater RPM than what the big engine is idling at.)

That's what I mean when I say that my AGMs seem to hit a solid wall preventing the acceptance of any more current once they're full up.

SARCASM

Look under the hood of any fire engine or ambulance in the USA and you will find an AGM battery or two...

Why?

They want to drive the vehicle maintenance shop insane with problems.

Or

They use exclusive not-available-to-the-public secret control devices to prevent catastrophic failures.

Some folks would love it if people would swallow these fallacies. They find fault when the rain stops and rainbows appear.

Sheesh

Phil, you charge at the Float voltage so of course you don't see the overcharge thing.

If your Flooded batts lost electrolyte on their set Float voltage, then that voltage was too high for the temperature. Eg 13.2 is for 77F. Don't you guys in CA need your parkas when it gets down to 77F? :)

So far my RV's two paralleled 12V Group 31 batteries seem impossible to "over charge".

Once they're fully charged per the ammeter reading under 0.5 amps, the ammeter refuses to read higher regardless of what real world charging voltage that I apply to their terminals. They seem to hit a rock wall on accepting any more current.

That's a welcome relief from my good old wet cell battery days. When fully charged and a charger with any voltage from about 13.4-13.5 volts on up was left still connectetd to them - they would sit there and bubble away until their water was gone. Back then I called that "over charging".

My AGM batteries have 13.5-13.8 volts on their terminals for weeks and weeks when the RV is sitting in the back yard. During this time their ammeter just sits there reading around -0.1 to +0.1 amps (around the resolution of the ammeter).

It's easy to over-think-it with AGM RV batteries ... at least in my experience. I wonder if lithium RV batteries would act the same way?

• Gotta make it easier for him BFL13 :)
• With 300 watts of solar on the roof it really helps to simplify charging
• In the morning run the generator for tasks like vacuuming, preparing breakfast
• The converter will be charging the batteries as well
• When charging amps drop to 30, shut off the generator and let the solar do it's job. At that hour try to minimize hotel loads like TV. Let the panels invest everything into the batteries
• In the afternoon when solar gets weaker look at the ammeter
• If there is more than say 5 amps going into the batteries the next charge cycle keep the generator on longer
• You need to get the panel (full sun) charge amperes down to 3 or less in the afternoon
• The easiest way to twiddle this easier is to increase solar amps when you get a chance
• Adding 200 watts of solar in a mix/balance like yours is the smart way to go
• After spending a week or two boondocking you need to do a 100% charge before putting the batteries at rest at float. Keep pushing that button on the pendant until amps drop to one amp or less.

And no

Regular batteries are no easier to take care of properly.
This isn't like baking a cake there is a LOT of leeway here
Start off by running your generator one hour then let the solar take over. How many amps are going into your batteries at the end of the solar day? To verify start your generator again. How many amps, now?

This is all tinkering. What is the number one responsibility is to get those battery at 100% charged when you get home.

I would not trade down from AGM for all the maple syrup in Quebec and you have no idea how much I love maple syrup. :)

DAS26miles wrote:
Checking with PD intelli-power and says it works with AGM's. Looking at Duracell Utra Platinum Group 27 AGM's. $220 each less 10% ordering online and picking up. Not too bad. Just the 92ah I don't care for. I was hoping for 100ah but if it recharges 5 times faster, it shouldn't make a difference. I was using my generator for and hour in the morning and 2 hours in the evening and still down 10 accumulating amps per day. Solar only kept it from dropping any further in daytime. But by third day I was down 30 amps on the third evening after charging. I'm hoping that the AGM's will get it charged back closer to full. I know part of the issue is the PD Intelli converter chgarger claiming to get the batteries up to 90% within 2-3 hours and another 15 hours to fully charge.

Say you head out with a full pair of 27s at 180AH. You don't need to recharge until down to 50%.

If you need to run the gen for an hour next morning, that means you used 90AH. So you do a 50-80. 30% of 180 is 54 AH. Can you get by till morning? Doesn't look too good if you use 90.

If you do the 80-90 another 10%, that's 18AH more for almost another hour of gen time, so you replaced 54+18= 72AH. Not enough to be above 50% next morning.

You need more battery! Get two 6s instead of two 27s. Bank is now 225AH, leave home with that and next day down 90 to 60%, and do a 60-80

So up 50AH and at 80% or 180, and do another day of 90, now down to 90/225= 40% Now you need some gen time for the morning of the third day. A 40-80 is 40% or 90AH so back in business.

Do 40-80s. How often? A couple more days, no big deal going just below 50%. How many times a year? Or do a 40-90 and then a 50-90.

From the OP's description, besides other issues, it looks like recharging by gen when already above 80% so a low amp, long time recharge to get not many AH restored. That is why they invented the 50-80, so as not to waste gen time. Recharge down in SOC where the batts can accept all the charger's amps.