Bad Converter Charger

BFL13 wrote:
Errin says he has a 35 if you call him.
I ran a couple of 100AH AGMs that said 27 amps charging limit. I used my 55 amper which was 1 amp over (1/2 amp per battery) I don't think the batteries noticed the extra amp! :)
The real trick is to charge them at 14.4ish all the way till amps taper to 0.5a/100AH, so 1 amp doing both together. That means you need an ammeter. I used my Trimetric for that.

After the amps get down to that, then reasonably soon afterwards, drop to the spec float voltage adjusted for temperature.

I apologize in advance for the obvious... some of it is just thinking out load...

Your talking about 1 amp over. 45a out of my solar system is the most I've seen so far after putting it together recently. As the earth tilts for higher sun angle I'm expecting slightly more than that 45a. How much more I don't know. Still 45+35=80a thats 20 amps over max battery spec. For Battery longevity sake the battery temperature plays a huge part of that life scale. I'm going to assume 30 amps max limit keeps safety vents shut. The more amps dumped in over a certain threshold there opens the safety vent & out goes the liquid drying out the agm batts.

I have a 60amp Renogy MPPT charge controller that shows me amperage & has RBTS (Remote Battery Temp Sensor) connected to the batts so it adjust for temp. Mines set for 3mv. My batts spec for 14.5-15.0v @25C cyclic charge. I set it for 14.6v. It goes into a "Absortion mode", Renogy calls it "Boost Mode", which is the same thing as bringing the voltage up, as you stated, then tapering down the current over a period of time.

I can set a timer on this Absorbtion mode from 1-10 hours. Currently set at 2 hours (default). I'll have to watch it over several days to get an idea of how many hours is needed in that mode to get down to about 1-2 amps then go into float mode.

BFL13 wrote:

1. They require a 20% charging rate when you can arrange that at least every few cycles. They have a max charging limit of about 30%.

No, 20% Charging rate is not a requirement. Batteries want to stay charged up at all times for long lifespan.
Although close to your 30% max statement my Specific Batt. Mfg. Says 30A Max that is 27.28% Splitting hairs maybe but I want to stay as close as possible to these ratings.

BFL13 wrote:
2. You can only get them to accept 20% when they are under about 75% SOC or above that SOC they will go straight to the Absorption Stage with tapering amps with those amps being under the 20% desired.

No, 20% Charging rate is not a requirement. In all my Learning, as a matter of fact, Shallow discharges equal Long battery lifespan in Deep cycle application.
Absorption State is where the real stuff happens. That is the top 20% to completely charge the battery. As long as that is being completed down to a taper than your battery is completely charged.

BFL13 wrote:
You need at least a 40 amp converter for when there is no sunshine, and the solar will only meet the 20% spec on a sunny mid-day period for a short time before amps drop as the sun gets

Yes, This will Especially be true In the winter time. I will need to use the converter/charger more during the winter months so I need to decide wisely.

BFL13 wrote:
You need to get the batts down under 75% to meet the 20%, and to get any time in Bulk at 20% you need the batts even lower in SOC at the start of the recharge.

No, There is no requirement to, unnecessarily, discharge below 75% just to meet a random 20% charge rate. In all my learning, as a matter of fact, Battery manufacturers are clear on one thing The SHOLLOWER the discharge the longer the lifespan.

The batteries want to be maintained & charged up towards the top & no lower than 30% discharge at all times for longest lifespan. That means shallow discharges are the best for longevity of batteries period.
If I use 25% or less discharge level everyday on these batteries they WILL last longer than 26%+ Discharge everyday. I'm not worried about BULK mode as you are.
It's the top 20% charge that completely charges the battery. That is done by Absorption Mode. So long as the batteries are fully charged soon as possible & I use Shallow Discharges my batteries WILL last longer than 26%+ discharge.
If my batteries go into bulk mode for short time & then Absortion Mode for the remaining top 20%.. GREAT! That means I'm shallow discharging them for longer lifespan. :)

BFL13 wrote:
I had this problem, and when leaving the campground for home with the batts nicely down below 75%, the drive home with alternator charging plus solar got them above 75%. So at home I did the recharge on shore power, but was not meeting the AGM 20% spec, only the 0.5a/100AH spec. What to do?
Before leaving the campground I disconnected solar and alternator charging so the batts stayed low. That means you need a way to do that. Solar is easy since you should already have a switch method between array and controller so you can disconnect the array before disconnecting the battery and VV as required by some controllers--Morningstars eg.

Think it's obvious by now but I must ask out loud...

You purposely disconnected your solar & alternator, intentionally left your batteries below 75% SOC, just to see some 20% "bulk up" charge rate?

In all my learning, as a matter of fact, the battery manufacturers state to charge up your batteries AS SOON AS POSSIBLE! This is what I try to accomplish.
I do NOT want the batteries to stay in a Low SOC for any longer than necessary. Every Battery spec I've looked at says charge up asap not keep them low intentionally. This can negatively impact lifespan.

BFL13 wrote:
Alternator charging disconnect depends on the rig. Pull the 7-pin or put in a switch on the line to the house batts if a MH.

If my batteries need a charge I would never prevent the battery from charging back up ASAP if any source is available to do so. I want my batteries charged back up asap for longer lifespan.

BFL13 wrote:
Now what about the other problem of going over 30% when on solar and converter and they are adding their amps? First, the battery has its own acceptance rate limiting where it will accept more amps at a lower SOC and at a higher voltage. Your voltage needs to be 14.4ish to meet the AGM spec, so that is fixed--set that for the controller and your adjustable converter you are getting. They will add their amps having the same set voltage.

14.4 is not within my AGM batt mfg. but close it's 14.5-15v@25c The battery may have it's own limit acceptance but the battery trying to resist the extra current, over maximum limit, can cause extra heat & displace some things inside. Higher Temperature negatively impacts lifespan. That is why I will charge it within it's Max spec. rating

BFL13 wrote:
If your converter will do at least the 20%, just use that and shut off the solar until amps taper well down, then shut off the converter.

I want to use the solar as the primary charge. That's the whole point of my Invested Heavily in solar/batteries. Most of how I roll is mostly away from shore power. If that is not enough in the day then I'll fire up the generator & top it off. This will happen some times in the winter travels.

BFL13 wrote:
And you do need the ammeter to see when you are down to 0.5a/100AH, but usually only at home, since you won't run the gen that long while camping--maybe doing 50-90s-- or on solar you will be doing more like 75-95s and never get them that full either. A Trimetric or similar monitor with shunt will do the ammeter job. (not the solar display which also shows the amps to loads--a monitor shows only battery)

My Phone shows me charge amperage, no ammeter necessary, & I can read it under load or no load conditions. It also shows me load amps in separate table. I will set the Absortion mode time to fully get the batteries current down to 1-2a then go into float.

BFL13 wrote:
BTW that is how solar kills batteries! Doing shallow cycles that never quite get the batts full, so they sulphate sooner than they would normally. You have to break that pattern and do a proper deep cycle to true full every so often, even if it is a PITA to organize.

Your saying If I, routinely, LIGHTLY discharge my batteries my solar panels somehow won't ever charge them back up completely b/c I'm not Deep Discharging them below 75% SOC in order to get some "required 20%" charge rate & will destroy my batteries?

Are you sure your not stuck in the old "Memory Effect" Days?

In Any case This is contrary to what battery manufacturers state.

In all my learning, as a matter of fact, shallow discharges equal LONGER Lifespan. When it comes to solar Shallow discharges not only charge up sooner but allows MORE available solar charging at the top to recharge the batts completely vs deep discharging them & getting a minimum 20% Charge rate.

Battery specs usually show batteries discharged no more than 30% get's long lifespan & best value for Deep Cycle application.

In all of my learning, the fact is, the least you discharge the battery the longer the lifespan.
Guess what gets the longest lifespan of my batteries... Hint: It isn't, routinely, discharging them down over 25%. My battery has 10 year lifespan@25c in float mode (which is the least discharged mode).

wa8yxm wrote:
The problem with the 6300 is three fold two of them are
Very slow charger
Does not know when to stop
The result is if the batteries need charging takes a long time
And if they don't it boils them dry

I've read about this. It was simple tech that did it's job but, perhaps, not well according to todays technology. I'll cut these old works horses a break & say both of mine lasted almost 3 decades w/occasional use.

dad4papa2 wrote:
When my 6300 was in my MH it was terrible at boiling the batteries dry. I had to watch them all the time and even lost a set do to my egnorance on the first set of new batterries I put in. got about 8 months out of them and they were gone.

I feel for your batts $RIP$ but these were what was on the market as factory equipment. I've read many pages on these units & people where not pleased w/their performance.

dad4papa2 wrote:
I purchased the Xantrex about 12 years ago and it has performed totally over my expectations!! I would buy another one if they still make them!!

Xantrex seems to be highly regarded in their field. Do you still run it?