|
|
Post by madmacks on Oct 23, 2015 6:22:03 GMT -8
I set up my MT-5 meter a while ago and as part of the set up I used/entered the hour amp hour rating listed for my batteries (4 Trojan T105REs, 2 12v strings) recorded at the 20 amp hour rating, which I believe is 450 AH for my config. As the doco doesn't mention which AH rating to use I assumed it was the 20 hour rating. Can someone confirm that?
|
|
|
|
Post by Admin on Oct 23, 2015 14:43:12 GMT -8
Hello Sir,
That is correct you would use the 20 hour rating.
O.C
|
|
|
|
Post by spiderbob on Oct 24, 2015 16:35:14 GMT -8
So your saying that two 6v batteries (I'm using two for what I have) each rated at 230 AH each, wired in series for 12v which is still 230 AH rating (the AH is not doubled in this case), why don't you use that figure for set up?
|
|
|
|
Post by tabber on Nov 29, 2015 16:31:14 GMT -8
Confusing to me! I thought the AH rating was doubled in series like the voltage. Ummm...dunno here, waiting to see what the answer is. Something gets doubled, right? If not, then what's the benefit to connecting two 6 volt batts into 12 volt to begin with?
|
|
|
|
Post by spiderbob on Nov 29, 2015 18:45:28 GMT -8
I believe it only doubles when in parallel, not in series. It would take 4 6v batteries each pair in series to get 440 amp hour. Now I'm confusing myself. Lets hope admin. wakes up tomorrow and answers this.
|
|
|
|
Post by jsb2000 on Nov 29, 2015 18:50:17 GMT -8
Confusing to me! I thought the AH rating was doubled in series like the voltage. Ummm...dunno here, waiting to see what the answer is. Something gets doubled, right? If not, then what's the benefit to connecting two 6 volt batts into 12 volt to begin with? Voltage in series is additive but current capacity in series is not. Current capacity is additive in parallel. Madmacks original post said he was using 4 batteries configured in 2 12V strings. Each battery is a 6V battery with 225AH capacity, So, with his configuration, he's connecting two batteries in series to make 12V, connecting the other two in series to make 12V, and then connecting the two sets in parallel to double the current capacity. The end result is a 12V, 450AH battery bank. You still use the 20 amp/hour rate to charge it, regardless of the capacity. |
|
|
|
Post by spiderbob on Nov 29, 2015 20:07:52 GMT -8
Now, back to my original question in another thread, sense it came up in this one, why use the 20 amp/hour rate?
|
|
|
|
Post by jsb2000 on Nov 30, 2015 19:20:21 GMT -8
Now, back to my original question in another thread, sense it came up in this one, why use the 20 amp/hour rate? My guess is that the 20 amp/hour rate is the "sweet spot" when it comes to charging/discharging. Slower charge rates are more efficient but take longer. Faster charge rates are more inefficient (create wasted heat) but take less time. The 20 amp/hr strikes a nice balance between the two. |
|
|
|
Post by spiderbob on Nov 30, 2015 22:26:37 GMT -8
But isn't the amp/hour rate dependent on the temperature of the battery, or shouldn't it be? Hence the new temp sender they now have for that purpose.
|
|
|
|
Post by jsb2000 on Dec 1, 2015 6:26:48 GMT -8
But isn't the amp/hour rate dependent on the temperature of the battery, or shouldn't it be? Hence the new temp sender they now have for that purpose. Yes and no. Think of the 20 Amp/Hr setting as a "starting reference point" from which the temperature compensation makes slight adjustments. |
|
|
|
Post by spiderbob on Dec 1, 2015 7:01:09 GMT -8
Makes sense, I suppose that is why only one (that I'm aware of) MTTP has the ability to attach a temperature sender directly on the battery. I had a feeling that it was not "really" needed.
|
|
|
|
Post by Admin on Dec 1, 2015 10:48:52 GMT -8
Hello Guys,
Thank you for answering his questions I have been away for the past few days. Hope you all had a great Thanksgiving.
O.C
|
|
|
|
Post by jacinto on Jul 15, 2016 8:21:51 GMT -8
Hi, I got a little confused with the answer of 20 AH for the setting of the mt-5. I got 4 6 volt golf cart batteries rated at 208 ah in series for a 24 volt system using Renogy mppt 40 cc. what is the correct entry in the settings that I need to input in the BATTERY CAPACITY (The default as per manual is 200AH.
Appreciate your replies!
|
|
|
|
Post by xyz on Jul 18, 2016 4:18:42 GMT -8
208 or do a capacity test as in discharge the batteries and meter their their current capacity.
|
|
|
|
Post by jacinto on Jul 18, 2016 11:52:19 GMT -8
Thanks xyz. That's what I thought, although I rounded it originally to 210 since it jumps in 10 ah intervals.
|
|
