Search found 87 matches

by fivari
Oct 15 2013 3:54am
Forum: Battery Technology
Topic: My Lifepo4 dies quickly
Replies: 66
Views: 8133

Re: My Lifepo4 dies quickly

Do you have any means to charge the low string individually through the balance leads for cells 3, 6 and 10? That might be much faster. A phonecell charger would do. Just take an old charger: outside of the DC-plug is negative, inside is positive. Put some small piece of wiring in the balance lead c...
by fivari
Oct 11 2013 2:29am
Forum: E-Vehicles General Discussion
Topic: * * * The 1000 Mile Club * * *
Replies: 145
Views: 22960

Re: * * * The 1000 Mile Club * * *

In August I passed the magic 10 000 km on one of my electric scooters. 3750 km of them on a set of SLA, the others on LiFePO4-pack 48V35Ah. It is still going strong. But now the season to commute electrically is over, although... I go by train now, in a way that is also commuting electrically. http:...
by fivari
Oct 04 2013 5:17am
Forum: Battery Technology
Topic: How to charge my lead acid batteries
Replies: 28
Views: 3421

Re: How to charge my lead acid batteries

Phone batteries and your batteries are different chemistry and need completely different treatment. NEVER leave lead-acid batteries discharged. Even after a small ride, recharge as soon as possible. Altough you don't need to top charge them every time. A car battery is fully charged all the time and...
by fivari
Oct 02 2013 3:07am
Forum: Battery Technology
Topic: Voltage drop on load - Lipo battery
Replies: 10
Views: 2707

Re: Voltage drop on load - Lipo battery

The LVC has to take into account the voltage sag under load. And then, all depends on the IR of te cells. I have this homemade pack from recycled laptopbattery cells, that are not comparable with the Lipo-pack with 20C characteristics and higher. Even at 1C, the voltage sags down quite heavily under...
by fivari
Oct 01 2013 5:18am
Forum: E-Vehicles General Discussion
Topic: eCars - Compared! - 2017 update
Replies: 77
Views: 21241

Re: eCars - Compared!

Chalo wrote:
The fingers wrote:I want a Chevrolet Corvolt.
For "a little" over half a million bucks, you can have something much better than that:
Or this Eliica family car?
by fivari
Sep 26 2013 9:30am
Forum: Battery Technology
Topic: Adding 2nd pack: for range
Replies: 27
Views: 1853

Re: Adding 2nd pack: for range

I read through the topic. This is how we do it in Florida. :) http://motorbicycling.com/showthread.php?t=37952 If I understand well, you just connect both packs with different chemistry and different end of charge voltage in parallel without any diodes . Isn't the 10s pack @ 42V overcharging the 11s...
by fivari
Sep 26 2013 3:53am
Forum: Battery Technology
Topic: Adding 2nd pack: for range
Replies: 27
Views: 1853

Re: Adding 2nd pack: for range

If you'd like to add a small battery to the main battery. Switching the batteries half way is not an option since the small battery won't be capable of delivering enough power/current. The diodes might be necessary to prevent current running between both batterypacks. This is definetly the case when...
by fivari
Sep 16 2013 6:03am
Forum: Battery Technology
Topic: The battery man
Replies: 1
Views: 400

The battery man

Just for fun: the abilities this guy has could mean the problem to carrying too much battery weight. Just be a battery yourself.
http://player.vimeo.com/video/38313889?portrait=0
by fivari
Sep 11 2013 8:00am
Forum: Battery Technology
Topic: Please avoid ebay seller "rchobby*2012" ( BC168 charger)
Replies: 16
Views: 1874

Re: Please avoid ebay seller "rchobby*2012" ( BC168 charger)

I bought mine here: http://www.aliexpress.com/snapshot/220833071.html for 69.90$.
I am using the charger since april: works fine. Works fine. Only, the wires are too tiny to charge @ 8Amp.
Power supply is a 12V copmuter power supply that I modified somewhat.
by fivari
Sep 11 2013 2:53am
Forum: Battery Technology
Topic: Voltage drop under load
Replies: 17
Views: 2428

Re: Voltage drop under load

So you got it used ? Where did the battery come from ? V-power or bms battery or em3ev ? Did you check the voltage output of the charger ? I bought it New from cnebikes.com Today it was even worse. Charged it to 54,5v yesterday evening. This morning it showed 54,2 volts. Thrashed fast down the stre...
by fivari
Sep 09 2013 6:28am
Forum: Battery Technology
Topic: Voltage drop under load
Replies: 17
Views: 2428

Re: Voltage drop under load

Another question I have before coming u wiht a diagnosis: what chemistry are you using?
by fivari
Sep 05 2013 6:15am
Forum: E-Bike Technical
Topic: Increasing max voltage for regenerative braking
Replies: 8
Views: 1074

Re: Increasing max voltage for regenerative braking

Whatever, thanks for all the effort you did.
Now it is my turn to try things out.
by fivari
Sep 05 2013 1:35am
Forum: E-Bike Technical
Topic: Increasing max voltage for regenerative braking
Replies: 8
Views: 1074

Re: Increasing max voltage for regenerative braking

Thanks, I will read these threads.
Just to be sure. In the case it all corresponds, I have to increase this R15 to increase the regen voltage?
by fivari
Sep 04 2013 6:01am
Forum: E-Bike Technical
Topic: Increasing max voltage for regenerative braking
Replies: 8
Views: 1074

Increasing max voltage for regenerative braking

I have an e-scooter conversed from 48V SLA to Lithium. Furthermore, on my daily commute, I am combining 48V LiFePO4 (16s) in series with a homemade 2s Li-ion battery pack. This gives me more power, more range, higher speed, higher torque etc… Unfortunately, this combination will not allow me to use ...
by fivari
Sep 03 2013 2:25am
Forum: Battery Technology
Topic: LiFePO4 or regular lithium ion cell?
Replies: 32
Views: 2910

Re: LiFePO4 or regular lithium ion cell?

Later, I checked the voltages of each cell group with results as follows: 3.95, 3.96, 4.17, 3.91, 3.90, 3.89, 3.90, 3.89, 3.89, 3.89 Then I will say the hvc should be about 4.2V at cell group no.3. But at this moment, the balancing function of the bms is not working properly. Am I correct? You defi...
by fivari
Sep 02 2013 4:14pm
Forum: Battery Technology
Topic: how on earth am i to charge one cell?
Replies: 88
Views: 5895

Re: how on earth am i to charge one cell?

I have had a similar problem with my battery pack. One of the strings slowly lost charge. After two weeks, the capacity of the 32 Ah pack went down to 18 Ah. Always the same string that is losing energy. The balancing process is too slow to overcome the bleeding in a practical way. Besides, balanci...
by fivari
Sep 02 2013 10:01am
Forum: Battery Technology
Topic: how on earth am i to charge one cell?
Replies: 88
Views: 5895

Re: how on earth am i to charge one cell?

Did you mean 8s pack?
WIth my pck, the cells do go down to 3.3V relatively quickly, A few hours and the majority is down to 3.35.
That the single string was still at 3.41proves that this one string can hold a charge. What is the capacity imediatly after you charged?
by fivari
Sep 02 2013 9:51am
Forum: Battery Technology
Topic: how on earth am i to charge one cell?
Replies: 88
Views: 5895

Re: how on earth am i to charge one cell?

I have had a similar problem with my battery pack. One of the strings slowly lost charge. After two weeks, the capacity of the 32 Ah pack went down to 18 Ah. Always the same string that is losing energy. The balancing process is too slow to overcome the bleeding in a practical way. Besides, balancin...
by fivari
Aug 29 2013 3:52pm
Forum: Battery Technology
Topic: power meter question
Replies: 11
Views: 716

Re: power meter question

I am using the same as cwah for checking my charging. No need for a separate 12V power source. The high voltage of the battery is taking care of powering the meter
by fivari
Jul 25 2013 2:52am
Forum: Battery Technology
Topic: Broken multimeter...can it be repaired?
Replies: 9
Views: 747

Re: Broken multimeter...can it be repaired?

Thanks for the suggestions. I do have another working multimeter and so I was able to check the fuse. The multimeter is completely dead: no screen, no sound. It is odd that they don't warn you for this kind of mistakes or make the multimeters in such a way that it does not harm the meter when you to...
by fivari
Jul 24 2013 3:42pm
Forum: Battery Technology
Topic: Broken multimeter...can it be repaired?
Replies: 9
Views: 747

Re: Broken multimeter...can it be repaired?

Here are two pictures.
Image
Image

and the links to the high resolution versions:
back
front
by fivari
Jul 24 2013 3:15pm
Forum: Battery Technology
Topic: Broken multimeter...can it be repaired?
Replies: 9
Views: 747

Re: Broken multimeter...can it be repaired?

Thanks Dnmun, but the fuse is OK, it must be something else.
by fivari
Jul 24 2013 2:56pm
Forum: Battery Technology
Topic: Broken multimeter...can it be repaired?
Replies: 9
Views: 747

Broken multimeter...can it be repaired?

Hallo, today I broke my third multimeter while I was testing my charger. It always happens the same way: I am measuring resistance, ion the low range, the one that beeps when there is good contact. Then I measure over the fuse, but with the mains still connected (stupid me). A small spark and the mu...
by fivari
Jun 15 2013 4:56pm
Forum: Battery Technology
Topic: When to charge lifepo4
Replies: 14
Views: 1528

Re: When to charge lifepo4

You have 16s, but this BMS takes the ground from the power wire and does not use a separate sense wire. On amber, the charger is charging and the voltage equals the total voltage of the battery. Ok I put the battery on the charger,there are two lights,one is red the other is on amber,after 15 min th...
by fivari
May 28 2013 3:49pm
Forum: Battery Technology
Topic: bulk charging 18650 cells
Replies: 22
Views: 4226

Re: bulk charging 18650 cells

I balance charge a large number of cells with a Hobbyking RC charger by putting them all in parallel between two sheets of aluminum foil. It is slow but easy and cheap. I bind them together with a small elastic band. I connect to the aluminum foils using two aligator clips.