Wondering why my charge current is so hi

[Matrix]

I have a hybrid Conext SW Inverter / Charger.  The charger is run off of an incoming AC line (Gen or Line power).    It is capable of charging at 90 amps.   The batteries are Trojan L16H-AC 435 ah batteries. 

Doing some calculating,  it is my understanding that you should not charge the batteries at a rate higher than C/8 .... or about 54 amps.  And yet,  when I set the SW to charge,  and set my battery type to custom using 29.8v Bulk / 29.6v Absorb / 27v float ... when I start a charge at about a 55-65% SOC on the battery, the charger goes to Bulk and the charge amps shot up to 85+ amps. 

There is no way to control amps,  only volts in the charger.  (in the Classic 150  I could set an Amp Output limit).    I thought C/8 (54 amps)  was about the max I wanted to charge this 435ah 24v battery bank at.   If I lower the charge volts,  the batteries never fully charge as test with hydrometer.   But even if I do lower the volts the amps are still very hi.  Like about C/5.

  Help me understand what i am missing here.

[mike90045]

isn't there a setting for battery amp-hour size?

[Matrix]

isn't there a setting for battery amp-hour size?

Yes. I have it set to the battery size... 435ah.   I guess I could lower it and see what happens. If that lowers the amps

[mike90045]

there may be interacting settings, breaker size. battery size, generator size.    Go through your manual and see if Schneider has hidden any tidbits regarding those settings.  They are pretty obtuse about them.

[CDN-VT]

@matrix
Do you have a Schneider Electric Conext XW+/SW System Control Panel (SCP) ?
under advance you will find limits on charge & steps of charging . Or Conext Combox for Network Monitoring and Remote Access with a laptop.
I have a 6848 stack that im about to commission in , but i'm needing a BTS that I might of left @ the Midnite plant .

The trick to see advance is hold 3 buttons on meters enter ,Up & Down  advance shows , that works under charge also & a few places .
Like 141 for Outback

VT

[Matrix]

there may be interacting settings, breaker size. battery size, generator size.    Go through your manual and see if Schneider has hidden any tidbits regarding those settings.  They are pretty obtuse about them.

Schneider is Obtuse about a lot of things.  Terrible Manual

[Matrix]

@matrix
Do you have a Schneider Electric Conext XW+/SW System Control Panel (SCP) ?
under advance you will find limits on charge & steps of charging . Or Conext Combox for Network Monitoring and Remote Access with a laptop.
I have a 6848 stack that im about to commission in , but i'm needing a BTS that I might of left @ the Midnite plant .

The trick to see advance is hold 3 buttons on meters enter ,Up & Down  advance shows , that works under charge also & a few places .
Like 141 for Outback

VT

Hi VT,
Yes I use the Advanced settings and have the SCP and also have a battery monitor.  I am actually setting up and using the charger with Custom settings so that it is set up with the exact voltages thru the charge cycle that are called for my Trojan.  But when it starts charging the amps get really hi.  Like 90+ which is way over C/8 as recommended for the battery.   And it does this regardless if I use custom or the Flood battery type setting.

So I am going to try and lower the Amp Hour of the Battery setting to a value lower than my actual Amp Hours of 435 and see if that causes the charger to pump less amps.   

[Westbranch]

Matrix, how long does the unit deliver the >90Amps? Does it not decrease over time?

[russ_drinkwater]

I have not read my trojan info for a while, but isn't the charge rate of 20-40% of
rated amps the go?
If so what your charger is delivering is just a tad over recommended minimum.
If wrong I stand corrected.
The L16 trojans we have here are apparently the newer AC ones (with the carbon).
Same question as well, does the charge rate taper off after a while?

[Matrix]

Matrix, how long does the unit deliver the >90Amps? Does it not decrease over time?

It does 90 + in the bulk stage for about 1.5 hrs.  Then yes, it tappers in absorb down from 90+ to 7.5 amps over 2.5 hrs. 

[Matrix]

I have not read my trojan info for a while, but isn't the charge rate of 20-40% of
rated amps the go?

I have not ever seen a charge rate spec of 20-40% ... but it could be?

[Matrix]

Here is my charge cycle over the course of about 4 hours. 

[mike90045]

Matrix, how long does the unit deliver the >90Amps? Does it not decrease over time?

It does 90 + in the bulk stage for about 1.5 hrs.  Then yes, it tappers in absorb down from 90+ to 7.5 amps over 2.5 hrs.

Man, you are running your batteries down way too low, for them to be charging that hard.  If they are not getting warm, you are likely OK, but if they are getting hot, you are killing them.

Quickly running the math backwards, you are putting in about 150Ah, so if you are only discharging 20% daily, your battery bank is about 650ah ?? 

At least the charge tapers way down, and that means the batteries are still healthy.

[CDN-VT]

Same screen as type of charge with the System Control Panel (SCP) under advance
Scroll down to rate & amount of charge  .

It's worded wrong !
Cnglish  manual , hence why the tech support is bad.

VT

[Matrix]

Man, you are running your batteries down way too low, for them to be charging that hard.  If they are not getting warm, you are likely OK, but if they are getting hot, you are killing them.

Quickly running the math backwards, you are putting in about 150Ah, so if you are only discharging 20% daily, your battery bank is about 650ah ?? 

At least the charge tapers way down, and that means the batteries are still healthy.

I have 4 Trojan L16H-ACs that are in series and have 435ah.  When charging I have never seen the temp get higher than 90*F.  For the graph above the highest the temp ever got was 88*F

Here is what we have today (and this is my typical amount of daily depth of discharge):
- SOC measured by both the Whiz Bang Jr and SW Battery monitor: 68% SOC
- SOC measured by SG average all 12 cells: 1.221 which according to Trojan is just about 72% SOC (1.217 = 70%)
- Battery Temp: 76F using SW sensor on post / 67F using CC sensor on side in between batteries (out side air temp is 51F)
- Amp Hours used 139ah (according to SW battery monitor)

I only use the SW for charging every so often (like when there has been no sun).  So over 40 days of use since I started new with these batteries,  I have only every used the SW at its 90+ charge amps about 8 times at most. Most of the time I charge via the solar CC which never goes above 60 amps.

But I did figure out why the charge amps was running so hi when charging from the Conext SW 4024.  (see next post)