Battery meter/life question
Howdy,
On saturday I ran a real world max range test. With fully charged batteries (pack was at 76V) a second rider and the lights on I wanted to do 40 miles (37 is the most I will need from a full charge.) The bike was fine and the low voltage light didnt even blink under full acceleration. (This is the 21 60AH lfp model.) Voltage on the pack was 69V. I decided to keep going until the light blinked under full accel. About 7 miles more and the light started blinking. So I went home (about 1/2 a mile.) I checked the voltage again and it was at 67.8V. My question then is. No light on accel = 69 V / 21 average (i know thats not the best way but I dont have test leads on the batts yet) = 3.28; light on under full accel = 67.8 v /21 = 3.22V.
Nominal voltage on lifepo is 3.2. So, since both of these readings are above 3.2 did I still have significant stored energy to continue and should I worry about the light under full acceleration? I want to get a feel for range and when to quit with about 30% life left (to keep it out of the danger zone for lower cells and to have 3000 cycles if needed.) Once I get my test leads on I will be able to tell how balanced the cells are. I can say the top 6 are all within .1V of each other but I cant easily get to the bottom 15. Oh and anyone not using their thundersky charger and want to sell it?
thanks
dex
Right that is correct. Stop grab a meter and check. My volt/fuel tank meter on the right isnt graduated but does drop under load so I can assume that it accuarately shows sag. But sag to 2.5V isnt the same (in my understanding) as 2.5V static where you should absolutely charge the battery or is my understanding incorrect. I will have to hook up something that tells me how much i've taken from (AH) the pack that really is the only way to be sure I suppose. Thanks for the answer.
If you don't want to pay the $$ for a cycle analyst, a simple volt meter mounted on the bike is very cheap better than nothing.
Thats not a bad idea. Im going to try to graduate the "fuel" meter on the right side. Its nothing but a volt meter without numbers (high med low) that sort of thing but it may not be good enough for my needs so that meter and some waterproofing may do the trick.
dex
Hi everybody,
This is Joe from Budapest, Hungary. I am glad that I found this forum as I see there are several devoted people around here who use the EFUN-3000 scooter for commuting, just like me. I would like to hear about your experience concerning the lead-acid battery life. I just bought mine ~2 months ago with B.B. batteries dated 2008 May. I commute daily 15 km to my office where I have the possibility to charge up before return home in the afternoon. So it is 30 km daily but it is all year around (only the snow stops me for a few days before it is cleaned up). I use the factory-supplied 60V charger but also have small battery desulphators on each 12V battery in the string which I expect to lengthen their life.
So far so good, they work flawlessly in the 4 degree (Celsius) winter cold but I am curious what to expect concerning realistic battery life.
Are there users here who have been using their VRLA battery equipped EFUN-3000 bikes daily (min. 7200 km / year) and their batteries lasted several years? Low battery life expectancy is my biggest worries.
Regards,
Joe
One consideration is you aren't measuring the voltage under load during time of use. You're measuring the voltage after stopping. Right?
Battery voltage recovers as soon as the power draw decreases (or goes to 0) and it can be misleading to measure the voltage once you've stopped and had time to find the volt meter and hook it to the battery pack.
It's better to have a meter showing you voltage and current draw while you're riding. I use the Cycle Analyst for this as well as PakTrakr. It's extremely enlightening.
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