# Curtis low voltage cut off



## dhrivnak (Sep 25, 2008)

Is there a way to adjust the low voltage cut off for a Curtis 1231C? The manual says there is a low voltage cutoff at 63V But with a lithium pack we really should never drop below 100V. Can I field adjust it? Thank you


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## cruisin (Jun 3, 2009)

I would suggest you monitor your voltage yourself and take action when it is down to about 2.75v per cel instead of allowing the controll to shut down and strand you where you DONT want to be. It would be best if the controller would alarm instead of shutting down. The 1231C cannot be changed as it is a dumb controller.


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## dhrivnak (Sep 25, 2008)

Thank you. We are monitoring the batteries and we have ThunderSky Lithium batteries. I was trying to determine the range but there is a hill about 1/4 mile log to get to my neighborhood. The pack is a nominal 144V and I was 115V at the bottom of the hill. Half way up the pack voltage dropped to 80V and I has gone into 1st gear and was doing 20 in a 40 MPH zone. I was amazed at such a sudden drop off. I pulled off as soon as I could and charged for 30 minutes but it seems by then 3 or possbly 4 of my 48 cells were damaged.


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## Roy Von Rogers (Mar 21, 2009)

dhrivnak said:


> Thank you. We are monitoring the batteries and we have ThunderSky Lithium batteries. I was trying to determine the range but there is a hill about 1/4 mile log to get to my neighborhood. The pack is a nominal 144V and I was 115V at the bottom of the hill. Half way up the pack voltage dropped to 80V and I has gone into 1st gear and was doing 20 in a 40 MPH zone. I was amazed at such a sudden drop off. I pulled off as soon as I could and charged for 30 minutes but it seems by then 3 or possbly 4 of my 48 cells were damaged.


 
What voltage per cell each did you have afterwards.

Roy


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## dhrivnak (Sep 25, 2008)

Since we have not yet decided on a BMS I have been watching the cell voltage closely. Normally the cells, at rest are within .1V and it seems to change which is highest or lowest. I would typically charge to about 3.8V cell and after a drive would be about 3.1V.

But this time two cells were below .5V and one at 1.2V. The rest were about 2.1, so there was a big divergence at this point.


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