First time to 50% SOC

Hurricaner wrote:
A lot of bad info in this thread. The Iota can't possibly produce 14.8 volts into a large discharged battery bank. If it did it would destroy itself. As soon as the charger reaches its max amp rating it backs off the voltage to maintain that amperage output.

The only way a charger can control amperage output is to limit the voltage. If the charger tries to maintain 14.8 volts it will go up in smoke as the large discharged battery bank is capable of drawing far more current than the charger is rated for (55 amps). The charger will produce what ever voltage is necessary(up to 14.8 max voltage setpoint) to maintain that max amp set-point which is its rated output.

Sam

Most 3-stage chargers are either reach voltage cutoff and fall back to "absorption" mode and around 13.7 volts. OR they have a timed cut-off of 4 hours (in the case of my WFCO). This avoids cooking the charger.

I assume the Iota does the same, and may have reverted to 13.7 volts after 4 hours.

A lot of bad info in this thread. The Iota can't possibly produce 14.8 volts into a large discharged battery bank. If it did it would destroy itself. As soon as the charger reaches its max amp rating it backs off the voltage to maintain that amperage output.

The only way a charger can control amperage output is to limit the voltage. If the charger tries to maintain 14.8 volts it will go up in smoke as the large discharged battery bank is capable of drawing far more current than the charger is rated for (55 amps). The charger will produce what ever voltage is necessary(up to 14.8 max voltage setpoint) to maintain that max amp set-point which is its rated output.

Sam

just reporting what I have seen on the meters. Must be working half way right as I make it thru every night camping off the power grid just fine haha...

Here is where my meters are tapped in the system about five away from the PD9260C.


I'm down to two 85AH battery now after 6 six years of use and trailer is still buttoned up. Planning on setting up again in a couple of weeks here.

My interstates always did recover real quick when re-charging... When I am connected to shore power the PD9260C shows around positive 6 amps all the time on the current meter unless I kick in something that draws alot of current. Then the current meter will show more positive amps being drawn. If it is positive then it is being provided by the PD9260C. If it shows negative then it is drawing from the batteries.

The only time I see negative amps being drawn is when I am running off the batteries with no shore power connected. I have sometimes seen as much as 20 amps being drawn by my 120VAC and 12VDC items in this mode.

I will write a more detailed description for my files when I attack the system again next month.

I will STOP telling my battery story until I do more local tests with my Sears clamp on ampmeter and write it up again. Sure don't want to dispute what the XPORTS have to say about it...

From what I am hearing I must be way out in LEFT FIELD. I know I must put back into the batteries that gets taken out. My only big battery drain is usually from 8PM to around 11PM where I see a good 20AMPS being drawn for the two hours or more. The rest of the time I only see around 1 amp being consumed. Then around 8AM the next morning I see around 12.0VDC reading on my meters... Looks like I am putting back into my batteries around 53AMPS for 10-20 minutes and then 6-8 amp for around almost 5 hours... You are saying this does not offset the 20AMPs drain for 3 hours and the 1AMP drain for 9 hours.... When I start up the generator the second time during the day at 4:30 to 7:30 run time it almost duplicates the above readings starting out at 50AMPS or so and then dropping back to 6-8 amps for the rest of the time. ???

I will monitor it better when I get setup again and can reproduce all of this in my CAMP BACKYARD.

Like I said however I have been following this procedure for a few years now and maybe have camped off the power grid ten weeks or so total over the past couple of years. Made it back home every time by just running my 2KW generator for usually two hours in the morning and then three hours in the afternoon before starting my battery run again for that day/night period...

I must be reporting wrong numbers
Thanks for the reality check...

Roy Ken

MNtundraRet wrote:

Your Iota did go into "bulk" charging within a few minutes, and the output voltage would have been 14.8 volts. To see it you would need to read the voltage at the charger output terminals. Your converter/charger was working since to read the current (amps) outputting maximum rated 55 amps.

I understand now. My readings were taken from the Victron which is not at the output terminals of the converter. I think Sal would call this a measurement error. :) BTW, I'm not worried about the charging time, I'm not expecting this to be quick. Next time I'll check the converter terminals.

Also when the gen was on and the converter was putting out 55 amps, how many DC amps were being used inside the RV? Any DC lights or accessories is using part of those 55 amps so less are getting to the battery.

I agree with what others are stating. If the converter was putting out 55 amps the whole time and the batteries did not make it to 14.5 the converter is working normally. You have a large battery bank and a larger converter might work better.

Paul

RoyB wrote:
I will draw the 53amps DC for about 10-12 minutes and then it starts slowly dropping in current and in about 20 minutes or so it settles out at around positive 6-8AMPS DC. It will stay at this level for around two hours total time and then the PD9260C switches down to 13.6VDC. My current meter drops maybe an amp when this happens. This mode will continue for about another hour.

I would think your converter would put out way more than 6-8 amps if drawn down to 50% SOC.

mena661 wrote:
Thanks all. I was under the impression that the Iota went right to 14.8V. Didn't know it was like other converters that ramp to that voltage. That would explain the behavior. Although I do wonder why it went to 14.8 when I first connected it. About solar, it's on my list.

Your Iota did go into "bulk" charging within a few minutes, and the output voltage would have been 14.8 volts. To see it you would need to read the voltage at the charger output terminals. Your converter/charger was working since to read the current (amps) outputting maximum rated 55 amps.

Also; 3-stage chargers do not ramp voltage. Their output voltage is 14.4v , or whatever set or designed to be.

Reading voltage across battery-terminals is a different animal all together. Voltage shown starts with the battery's actual voltage (12.1 volts at 50% charge state) and then rises as battery gets charged.

You mentioned the Iota read 14.8 volts (across battery-terminals) almost immediately when tested on your newly installed L16 batteries. Normal reading since the batteries were almost 100% charged.

Everything has to deal with size of scale. My MH came with a 45 amp 3-stage charger and 220AH battery-bank. This represents charger-output of 20% of battery-bank capacity.

My Schumacher 40 amp multi-stage charger and separate 80AH 12v Trojan represents charger output 50% of battery capacity.

Your MH with a 55 amp 3-stage charger and upgraded 720AH battery-bank represents only around 7.5% of battery capacity.

A normal (recommend) ratio would be charger-output of 20% of battery-bank capacity. That means a 150 amp charger in your case. As mentioned by others having a good sized solar-panel setup can allow for a smaller charger size (80 or 100 amp).

To recap, your 55 amp charger was working correctly. It just was too small for recovering from a 50% state to "full" in a reasonable time on your battery-bank. Similar to a 10 amp charger on a single 65AH battery. Works but very slow.

Your comment about adding the BD charger would have worked at the time since both chargers would stay in "bulk" mode for a good amount of time because of the large size of the battery-bank.

Roy, something is not right with that performance as described.

You have 60amps on 255AH bank as rated---doubts about that!!!!

You get 55a instead of 60 because you have a PD in boost but we know about that "issue" so moving right along, here is what is supposed to happen:

With 55a "proper charger" on a 220AH bank doing a "50-90" you get (approx. of course--chargers/batteries vary a little)

-53 minutes of constant 55a while battery voltage rises steadily to 14ish (you report 12 minutes!!) at 72% SOC
- Amps then taper from 55a to 35a in another 26 minutes when you are at 80% SOC
-Amps taper down for another 60 minutes from 35 to 10a to 90% SOC.

Total time 139 minutes for the 50-90

Battery voltage at 12.1ish spikes to 13.4ish when charger turned on, then voltage rises steadily to 14.x before amps taper

Converter voltage stays a couple volts above battery voltage during this time, then converter voltage steadies and battery voltage keeps rising, shrinking the "spread." As the spread shrinks, amps taper.

So it looks like your 255AH is nowhere near that 255 amount, because your amps taper down so fast. Your time at constant 55 should be longer than 53 min with 255 instead of 220 as above example. This is showing even through the distraction that the PD would not perform "properly" even if the bank were in tip top shape. (never mind the PD vs other converter brands business---it is a distraction to this matter of the state of that battery bank)

ISTR Roy said his batts were on their last legs? Yep!

For whatever it is worth My PD9260C does this alittle different.

I use this three meter arangement inside my trailer to monitor my three 85AH Interstate battery bank.. Bank 1 has two 85AH in parallel and bank2 has only one 85AH battery in it. This is my total of 255AHs parallel battery capacity


At 8AM I am usually reading around 12.0VDC on both meters and my current meter is reading a minus 1AMP or so.

When I start up my 2KW generator to power up the PD9260C the two DC voltmeters jump to around 14.4VDC and my DC amp meter goes to positive 53-54 amps. The DC VOLTMETERS remain at around 14.4VDC.

I will draw the 53amps DC for about 10-12 minutes and then it starts slowly dropping in current and in about 20 minutes or so it settles out at around positive 6-8AMPS DC. It will stay at this level for around two hours total time and then the PD9260C switches down to 13.6VDC. My current meter drops maybe an amp when this happens. This mode will continue for about another hour.

After the total time of re-charging for three hours I can switch out my battery bank from the trailer and my panel DC voltmeters will read around 12.6 to 12.7 VDC. When i shut down my 2KW generator and go back to batteries the DC VOLTMETER panels reads the same 12.6 to 12.7VDC and you can notice a .1VDC drop start occurring as the day goes on. I usually get to run my 2KW generator again around 4:30PM to 7:30PM each evening before I really start drawing alot of DC current for the evening HDTV and other 120VAC items being used from my 600WATT Inverter as well as my direct 12VDC items directly connected to the batteries. The game plan of course is to have around 12.0VDC battery capacity at 8AM the next morning so I can do all of this all over again...

When hooked up to shore power I very seldom see the 13.2VDC readings coming out of my PD9260C converter/charger. My current meter very seldom drops below 1 amp when all is normally hooked up running off the batteries. The DC voltmeters always seem to be reading 13.6VDC.

Have observed these readings just about everytime we go camping off the power grids???

Roy Ken

MEXICOWANDERER wrote:

If you do your recharging in your driveway or RV park overnight, a slower rate is easier on the batteries. The question is "Where Is The Break Even Point?" I suspect in your case you may have an acceptable setup. Going camping for an extended period would jumble this all around however.

When I top charge a single 29, I start at around 12.65 and it takes 4 - 5 hours at 2-amperes to reach 15.0 volts. For the first half hour the amperage is in the 6 - 8 amp range.

I'm not much into acceptable. :) Should I throw in another charger even though I'm doing this on shore power or is 55 amps ok for that?

BFL13 wrote:
I didn't see in the OP whether the Iota stayed at 55 amps for a long time before going into Absorption.

The Iota blurb says it will go straight to Absorption (what they call their 14.2v level) but do 55amps at first at that 14.2. My 7355 will too but at 13.8v instead of 14.2 whoopee-do! :)

So just because it did 55a does not mean it was in bulk. You want to know if battery voltage ever got up past 14.2v. It looks like the OP did not get back to see what was happening and it could have done either, where it was at 14 by the time he got back to it?

It was 38 amps when I checked (@ 14V). Was about 4 hrs or so when I checked. I really don't know if it climbed into boost or not. I should've checked more often but I didn't have time to do that.

smkettner wrote:
I suggested to wait more than a week to check specific gravity to allow IOTA at least one destratification cycle before you worry about the finish charge. I think you will find that the batteries are fine with just the IOTA. Or the data point would be interesting if finish charge still seems needed.

14.7V won't finish charge these. At least not in a reasonable amount of time. 15V @ 8 amps on the HF manual gets it done in about 2 hrs, sometimes 3 AFTER the converter (old Paramode) or my portable reaches their respective "full". The BD's EQ setting takes longer than the HF manual but it uses a lower amp rate (4A). I do typically leave the batts on the converter for a week before I do any finishing charges just to see if they get them up to baseline SG but the converter (Paramode) only seemed to accomplish that if I kept SOC above 85%. I don't know if the Iota would do it at 85% SOC or not.

EDIT: MEX, if we ever do more than a weekend of camping, I'll probably get at least one of those adjustable voltage Powermax 100 amp converters that BFL has.