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Trojan T105 RE's with Axpert 5KVA and BMV702


Valken

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Hi All,

Ok, let me start with directing the question to SuperDIY and Viper as you guys have the same equipment.

1. At what voltage do you charge your T105RE's and at what voltage do you float?

2. What setting are you using on your BMV 702 for charge detection and tail current?

My SOC goes to 100% way to quick. I just have the one bank of (8 X 6V) T105RE's

 

Thank you,

Regards.

Valken

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3 hours ago, Valken said:

2. What setting are you using on your BMV 702 for charge detection and tail current?

My SOC goes to 100% way to quick. I just have the one bank of (8 X 6V) T105RE's

You have to fiddle. Each battery bank has it own personality for want of a better term.

Have a look at this video and use it as a starting point and modify keeping in mind that a battery is not full when you start floating only a couple hours later. Float is traditionally when batteries accept <3% of their capacity.  I know my batteries (260 Ah) are full when they accepting less than 120W. They drop from 120W to 60-70W in minutes.

 

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Thank you Chris! I started out with that video from your very earlier posts. I am afraid however i just don't get it or it just doesnt seem to work for me or i am really doing something wrong.

@superdiy @viper_za Would you care to share your settings - Just want some point to start with.

 

I must say this is my first Flooded batteries (Trojans T105 RE's)

 

They have been charging since around 11am this morning (First charge from factory) Thank you TTT! And they are right now still Bulk charging? (Sitting at 58.4V and around 6A now)

 

Is this right?

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12 minutes ago, Valken said:

Is this right?

Yes it can be. Depends on the amps they are charged at.

From completely drained to full charged can take a long time depending on the charger.

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19 minutes ago, Valken said:

They have been charging since around 11am this morning (First charge from factory) Thank you TTT! And they are right now still Bulk charging? (Sitting at 58.4V and around 6A now)

 

Is this right?

You are in late absorb. Plonky's Landrover analogy is the best comment of 2017.

It's not a problem. Just set the inverter as high as it will go, and make sure it spends enough time on absorb/float so the batteries are fully charged.

It's a bit like when you drive a land rover and the speed limit is 80km/h. Then you just do whatever you're capable of... :-P

Since you cannot get up to the Trojan's recommended bulk voltage you are going to spend more time in absorb to get the same level of charge. Watch your Axpert. When the middle LED come on solid it is running in float according to its charge algorithm (which is a bit eccentric). If this LED has been on solid for a couple of hours I'll say your there (i.e. fully charged).

My tail current is 2.8% and charge detection time 30 minutes. It is as good as I am going to get. At 2.7 % it takes foreeeeeever to kick over to 100% SOC.

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38 minutes ago, Valken said:

Thank you for the feedback Chris. I have mine set similar. But it still goes to 100% like hours before it should.

 

 

Capture.JPG

Lower your tail current further perhaps by 0.2% at a time leave it for a couple of days and if still not right lower further. I ended up using charge detection time to get a more accurate 100% SOC on my batteries 2.8% is too short and 2.7% too long.

What current are your batteries accepting this morning?

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25 minutes ago, Valken said:

Thank you Chris. I will try that and I think I'm also going to use a longer detection time especially since i cant charge at full specified voltage.

Last I checked it was just under 5 amps

You are very close to 100%. The batteries may take a longer charge 1st time round as there may have been a small amount of  sulphation if there was a little self-discharge whilst the batteries waited for a loving home. 4A would translate to 200W which is definitely on the final straight. Even a full bank will accept 100W or so. All that happens is that this energy causes water molecules to split into hydrogen and oxygen. In vented batteries these gases escape. In VRLA batteries these gases are trapped (unless pressures are excessive) and reconstituted into water on discharge.

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Hi Valken

Mine is set to 58V for bulk and 52.8 for float.

It is a bit confusing because I have 2 different datasheets for the T105REs and there might be more. The fact that the datasheets differ does not bother me too much, but the fact that the bulk and float voltages, indicated on the different datasheets differ, worries me a bit more.

From the older datasheet

  • Absorption charge: 2.35V - 2.45V / cell => 56.4V - 58.8V for the 48V bank
  • Float charge: 2.20V / cell => 52.8V for the 48V bank
  • Equalize charge: 2.58V / cell => 61.92V for the 48V bank

From the newer datasheet

  • Bulk charge: 59.28V for the 48V bank   (2.47V / cell)
  • Float charge: 54.00V for the 48V bank   (2.25V / cell)
  • Equalize charge: 64.80V for the 48V bank    (2.7V / cell)

All voltages at 25°C

I have not changed the tail current settings on my BMV - it is still on factory default.

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  • 4 weeks later...

The only way to know for certain where you are with regard to SOC, is to take SG readings at the end of the charge cycle. Otherwise your guessing.

You should measure the gravity in all cells to start off with, from there on you can use a pilot cell to get a quick idea of the whole bank. 

Absorb voltage should be adjusted using this method, as mentioned, each battery bank seems to have a personality . A T105 per Trojan is at 100% SOC at 1,280 @  25deg

In short, a hydrometer is a must with anyone who has a flooded battery bank. 

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On 1/26/2017 at 8:02 AM, superdiy said:

Hi Valken

Mine is set to 58V for bulk and 52.8 for float.

It is a bit confusing because I have 2 different datasheets for the T105REs and there might be more. The fact that the datasheets differ does not bother me too much, but the fact that the bulk and float voltages, indicated on the different datasheets differ, worries me a bit more.

From the older datasheet

  • Absorption charge: 2.35V - 2.45V / cell => 56.4V - 58.8V for the 48V bank
  • Float charge: 2.20V / cell => 52.8V for the 48V bank
  • Equalize charge: 2.58V / cell => 61.92V for the 48V bank

From the newer datasheet

  • Bulk charge: 59.28V for the 48V bank   (2.47V / cell)
  • Float charge: 54.00V for the 48V bank   (2.25V / cell)
  • Equalize charge: 64.80V for the 48V bank    (2.7V / cell)

All voltages at 25°C

I have not changed the tail current settings on my BMV - it is still on factory default.

Possible reason for the two different charge spec sheets is that Trojan did in fact change thier recommended charge current for batteries manufactured after a certain date. In addition, the SG spec of a full battery also went from 1,265 to 1,280. 

I forget what the date was but sure its on the net somewhere.

 

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