Battery meter/life question

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dexion
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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

reikiman
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Re: Battery meter/life question

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.

- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
- Electrified Electra To

dexion
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Re: Battery meter/life question

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.

Old_Scoot
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Re: Battery meter/life question

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.

http://cgi.ebay.com/NEW-3-1-2-Digital-Blue-LCD-DC-0-199-9V-Volt-Panel-Meter_W0QQitemZ390073927924QQcmdZViewItemQQptZLH_DefaultDo...

dexion
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Re: Battery meter/life question

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

joe1973
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Re: Battery meter/life question

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

E-FUN 3000W with 5×12V VRLA BB batteries dated 2008 oct.
commuting 15 km (9 mile) and back, recharge inbetween in the office.
Currently (21 October 2011) at 10800 km (6350 mile) and still going...

byt
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Re: Battery meter/life question

Hi, Joe!
I just bought one of these EVD's.
I heard that desulphators significantly help battery life.
What kind of desulphator are you using and how did you hook these up?
I'm a non-tech type, so simple is better.
thanks,
bernie
tao [at] purdue.edu

joe1973
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Re: Battery meter/life question

Hi Bernie,

The desulphators I connected to each battery in the string (5 alltogether) is this type: http://www.panelectron.hu/battery_activator.html but I am sure that you will find a source for similar devices on the other side of the ocean, there are many of them on the internet. From other applications I know they really work and have great hopes that they add considerably to battery life.

I have put ~3000 km into the bike since I have it, so far without noticing any decrease in the travelling range or speed/acceleration. The way I calculated the battery pack should last a minimum of 2 years (~15000 km) in order to buy new batteries from the price of the petrol I saved during those years.

On some forum I read horror stories of battery packs not lasting a year but I hope this is just down to general ignorance of people not knowing how to treat lead-acid batteries. On the other hand I also talked to someone who has been using his E-bike for 4-5 years, same battery pack, without any problems.

So I'll see how it goes for me.

Regards,
Joe

E-FUN 3000W with 5×12V VRLA BB batteries dated 2008 oct.
commuting 15 km (9 mile) and back, recharge inbetween in the office.
Currently (21 October 2011) at 10800 km (6350 mile) and still going...

randalson
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Re: Battery meter/life question

Hey - how about an update on your total mileage and battery condition? What depth of discharge do you average? How many charge cycles? ETc. Thanks!~

joe1973
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Re: Battery meter/life question

Hi, I am at 5500 km now, batteries are still ok, I see no change in their performance. I charge them up after each 15 km route so they do not get near any discharged state really. Next spring I plan to take out the batteries and check electrolit levels whether any of it evaporated during the hot summer months (I can only hope that the cells can be opened). Anyone has any battery experience to share with others, please post it.
Regards,
Joe

E-FUN 3000W with 5×12V VRLA BB batteries dated 2008 oct.
commuting 15 km (9 mile) and back, recharge inbetween in the office.
Currently (21 October 2011) at 10800 km (6350 mile) and still going...

joe1973
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Joined: Thursday, December 10, 2009 - 00:30
Points: 14
Re: Battery meter/life question

Hi,

I would like to ask whether anybody has a used E-FUN-D 3000W model for sale with residence within the European Union? I had an accident at the weekend and the front of my bike broke badly, repair is not feasible. The VRLA batteries are intact and still the original ones, they had 11500 km in them and still going... I would like to see when they give up eventually so I am interested in a bike without batts.

Thanks, Jozsef

E-FUN 3000W with 5×12V VRLA BB batteries dated 2008 oct.
commuting 15 km (9 mile) and back, recharge inbetween in the office.
Currently (21 October 2011) at 10800 km (6350 mile) and still going...

LeftieBiker
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Re: Battery meter/life question

I can't address this directly, but as the owner of a 10 year old Lepton that still runs on the original AGM batteries, I think I can give advice on SLAs, anyway. Since you aren't going too deep on discharge, the other thing you have to make sure to do is start the pack recharging *immediately* upon arriving at work. Just sitting around for half an hour 40 - 60% discharged can measurably shorten battery life with SLAs.

joe1973
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Re: Battery meter/life question

I can't address this directly, but as the owner of a 10 year old Lepton that still runs on the original AGM batteries, I think I can give advice on SLAs, anyway. Since you aren't going too deep on discharge, the other thing you have to make sure to do is start the pack recharging *immediately* upon arriving at work. Just sitting around for half an hour 40 - 60% discharged can measurably shorten battery life with SLAs.

Thanks for the comment, I never leave my bike partly discharged, either. May I ask what distance you can use these 10 year old batteries for (summer and winter) and what milage they suceeded so far?

E-FUN 3000W with 5×12V VRLA BB batteries dated 2008 oct.
commuting 15 km (9 mile) and back, recharge inbetween in the office.
Currently (21 October 2011) at 10800 km (6350 mile) and still going...

PzlPete
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Re: Battery meter/life question

For what it is worth, comparison wise....I have the 4000li, with twenty 40ah Thundersky batteries. And I have just over 5,100 miles on it.

I am reading 79.4V at full charge, which quickly diminishes to around 69V. I have a range of around 36 or 37 miles. Brand new the bike would pretty easily do 45 miles. So there has been some decrease over those 5,100 miles.

joe1973
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Points: 14
Re: Battery meter/life question

For what it is worth, comparison wise....I have the 4000li, with twenty 40ah Thundersky batteries. And I have just over 5,100 miles on it.

I am reading 79.4V at full charge, which quickly diminishes to around 69V. I have a range of around 36 or 37 miles. Brand new the bike would pretty easily do 45 miles. So there has been some decrease over those 5,100 miles.

Thanks for sharing this info. Are you using BMS for your cells and how old are they?

E-FUN 3000W with 5×12V VRLA BB batteries dated 2008 oct.
commuting 15 km (9 mile) and back, recharge inbetween in the office.
Currently (21 October 2011) at 10800 km (6350 mile) and still going...

PzlPete
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Points: 157
Re: Battery meter/life question

No BMS on the 4000Li. My cells are dated Dec 2008, but I purchased the bike new in Jan 2011.
Overall I am extremely pleased with the bike and its performance. Some portion of the decrease in range is due to the larger rear tire I installed, so I believe the batteries are holding up very well to this point.

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