Posted by William P. N. Smith on July 9, 2005, 6:10 pm
Hi,
One of my golf carts has one of those Curtis meters that reads about
50% charge state when the golf cart controller thinks the battery is
fully discharged (and then goes into a slow, limp-home, battery
preservation mode). Which one is right, and what's the common
rule-of-thumb for voltage versus state-of-charge. Trojan T-145s in a
48V bank, if it matters. It's hard to get the Curtis meter out to
read it's exact configuration model number, but that's on my list.
I've been using 11.7 for discharged and 12.7 for fully charged for a
12V nominal battery bank in my weather station, which I probably
picked up from this newsgroup, is that pretty good?
[Yeah, I realize that voltage is pretty inaccurate without letting the
battery bank sit for 24 hours, but I don't have that kind of time to
take a cart out of service...]
Thanks in advance for any thoughts!
Posted by Steve Spence on July 9, 2005, 7:55 pm
Have you read http://www.uuhome.de/william.darden/carfaq9.htm ?
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html
William P. N. Smith wrote:
> Hi,
>
> One of my golf carts has one of those Curtis meters that reads about
> 50% charge state when the golf cart controller thinks the battery is
> fully discharged (and then goes into a slow, limp-home, battery
> preservation mode). Which one is right, and what's the common
> rule-of-thumb for voltage versus state-of-charge. Trojan T-145s in a
> 48V bank, if it matters. It's hard to get the Curtis meter out to
> read it's exact configuration model number, but that's on my list.
>
> I've been using 11.7 for discharged and 12.7 for fully charged for a
> 12V nominal battery bank in my weather station, which I probably
> picked up from this newsgroup, is that pretty good?
>
> [Yeah, I realize that voltage is pretty inaccurate without letting the
> battery bank sit for 24 hours, but I don't have that kind of time to
> take a cart out of service...]
>
> Thanks in advance for any thoughts!
>
Posted by William P. N. Smith on July 9, 2005, 8:33 pm
>Have you read http://www.uuhome.de/william.darden/carfaq9.htm ?
If you mean http://www.uuhome.de/william.darden/carfaq9.htm#charged
I've just read it, but it doesn't tell me anything new, except that
battery manufacturer's numbers trump everything else.
Posted by Steve Spence on July 9, 2005, 11:17 pm
well, last I read it it gave info on full charge voltages and discharged
voltages.
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html
William P. N. Smith wrote:
>
>>Have you read http://www.uuhome.de/william.darden/carfaq9.htm ?
>
>
> If you mean http://www.uuhome.de/william.darden/carfaq9.htm#charged
>
> I've just read it, but it doesn't tell me anything new, except that
> battery manufacturer's numbers trump everything else.
>
Posted by William P. N. Smith on July 9, 2005, 8:19 pm
William P. N. Smith wrote:
>rule-of-thumb for voltage versus state-of-charge.
I've found my numbers. At one point:
Fluke DVM reads 49.0V
http://www.trojanbattery.com/Tech-Support/BatteryMaintenance/Testing.aspx
says that's ~60% charged
The controller on the cart reads 48.8V, and claims that's 39% charged
The Curtis "battery meter" reads 8 segments out of 10. Curtis meters
read one of three discharge profiles:
N = 2.04VPC full, 1.73VPC empty
G = 1.97VPC full, 1.75VPC empty
W = 2.02VPC full, 1.85VPC empty
I can't make any of these correspond with the Trojan numbers above.
Specific Gravities read from 1.170 (50%) to 1.201 (65%)
My Brain Hurts! 8*)
[I'll take fully charged readings tomorrow morning...]
XML site map
>
> One of my golf carts has one of those Curtis meters that reads about
> 50% charge state when the golf cart controller thinks the battery is
> fully discharged (and then goes into a slow, limp-home, battery
> preservation mode). Which one is right, and what's the common
> rule-of-thumb for voltage versus state-of-charge. Trojan T-145s in a
> 48V bank, if it matters. It's hard to get the Curtis meter out to
> read it's exact configuration model number, but that's on my list.
>
> I've been using 11.7 for discharged and 12.7 for fully charged for a
> 12V nominal battery bank in my weather station, which I probably
> picked up from this newsgroup, is that pretty good?
>
> [Yeah, I realize that voltage is pretty inaccurate without letting the
> battery bank sit for 24 hours, but I don't have that kind of time to
> take a cart out of service...]
>
> Thanks in advance for any thoughts!
>