Help with Lipoly

[Addicted]

Ok so i plan two use two zippy 7s 5800 mah packs in series for a schwinn scooter i have,later for a gng bb project.I Don't know much about this yet so bear with me!.Can i just wire them in series and monitor the voltage with an old multimeter i have so i Don't discharge them too much?I could mount it on the handlebars.If that Won't work what will i have to do.I've seen someone selling a lipoly protection kit here but funds are an issue right now,trying to do this as cheap as possible.

Thanks!

 

[Addicted]

Ok so i just did a little looking around online and from what i understand as long as you Don't discharge below 80% of the pack you are ok.So i could run this pack down to about 40 volts right?

 

[icecube57]

I really wouldnt mess with 7s unless I really had too...
Due to the dual balance taps.

80% rule is a good one. Or stay between 4.15v and 3.6v a cell.

 

[Addicted]

Aren't the balance taps just for when you are charging?

 

[BikeFanatic]

Others will disagree here, But I always run my lipo one Parallel and I like those Turnigy 5.8 AMPHR packs because they give me the range I need
10 miles and with juice left over. I have run them for a year no puffyness, However I do feel that you need some LV protection, and hobby king has cheap buzzers that will work. I run 2 six series packs for 12 series 5.8 amphours, I am not aware of the 7 series batteries.
They are heavier than the usually 5 amp hour and bulkier as well. I have a 9 C with a 25 amp controller.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=16214

 

[BikeFanatic]

No do not let your 14 series pack get to 40 volts. Do not run them below 49 volts that equals 3.5 volts a cell. That even may be too far down. I would plan on stopping at 3.68 volts a cell, as there is not much left after that, maybe 1/2 a mile range, and one cell always falls first so If you push it much further you will get 4 cells at 3.60, 4 at 3.5 one or two at 3.4 and so on.

 

[Addicted]

So all i need to do is wire them in series and monitor the voltage,that would be the same thing as an alarm right?..I Don't have to do anything with the balance taps when on the scooter correct?

These are the packs i want to run. Also do you think that will be too much voltage for 48v applications?

https://www.hobbyking.com/hobbyking/store/__21384__ZIPPY_Compact_5800mAh_7S_25C_Lipo_Pack.html

 

[Addicted]

No do not let your 14 series pack get to 40 volts. Do not run them below 49 volts that equals 3.5 volts a cell. That even may be too far down. I would plan on stopping at 3.68 volts a cell, as there is not much left after that, maybe 1/2 a mile range, and one cell always falls first so If you push it much further you will get 4 cells at 3.60, 4 at 3.5 one or two at 3.4 and so on.

Thanks,How did you figure that 49 volts.I would like to know the formula incase i decide on two different packs.

 

[BikeFanatic]

Well hot off the charger voltage is 58.8 for the batteries you selected. You are using one of those new bottom bracket drives right?
I am not familiar with the controller. The caps and the fets on the controller have to be rated to that voltage, I hope someone familiar with that set up will chime in.

You hook up the two batteries in series then do not worry about the balance taps. I use a cheap hobbyking voltage checker to peak at ther single cell voltage post ride and also sometimes mid ride .

https://www.hobbyking.com/hobbyking/store/__6589__Battery_Monitor_2_6S.html

oops that only does up to 6 series , but you get the idea.

 

[Addicted]

Well for now i was going to use it for a Schwinn stealth 1000 scooter,After that the mid drive from gng.if i burned up a controller or whatever i was just going to upgrade it.Maybe i would be better with two 6s packs.

 

[BikeFanatic]

Two six series is more traditional set up and works with most 48 volt controllers. that's how i run my bike. 7 series is an unusual configuration,
Maybe you should go for the six series and you can add a 3 series or two series later as you learn the limits of your system.

 

[Addicted]

Ok thanks guys i think i have a good idea of how to do this now.Def going to go with 6s packs.

 

[Addicted]

Ok here is my shopping list,Can't wait to get this stuff!...Please take a look and let me know how this looks to you.


2 https://www.hobbyking.com/hobbyking/store/__9935__ZIPPY_Flightmax_5800mAh_6S1P_30C.html

1 https://www.hobbyking.com/hobbyking/store/__7028__Turnigy_Accucel_6_50W_6A_Balancer_Charger_w_accessories.html

2,one for the packs one to change the scooter plug over. https://www.hobbyking.com/hobbyking/store/__18603__HXT4mm_Battery_Harness_14AWG_for_2_Packs_in_Series.html

2 https://www.hobbyking.com/hobbyking/store/__7227__Hobby_King_Battery_Monitor_6S.html

Edit,decided on 4 packs incase i get stranded,Can't hurt to carry backups.

 

[BikeFanatic]

I guess you are not from the USA, because you are buying from the hobby king international warehouse. If they have a warehouse in your country the battery shipping will be cheaper.

The acccucell charger , YOU ARE BUYING TWO OF THEM ? those will charge at 2.2 amps per hour so will take 2-3 hours to charge. You should
get two so you can charge your pack in 3 hours. those 50 watt charger are slow, they require a 12 volt power supply you canget those for 10 dollars. You may consider a 150 watt ( 8 series charger) it will be quicker but you will need a more powerful power supply.

The problem with starting Lipo, the charger cost almost as much as the battery.

I like that alarm, cheap and good.
Personally I find the Turnigy more reliable than the zippy. less puffers. just a tad more expensive.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=10288

those connectors might work, you are going to solder them on to your packs?. Make sure you make the bullets compatible for conecting in series so that you can easily plug the negative into the positive.

 

[Addicted]

I guess you are not from the USA, because you are buying from the hobby king international warehouse. If they have a warehouse in your country the battery shipping will be cheaper.

The acccucell charger , YOU ARE BUYING TWO OF THEM ? those will charge at 2.2 amps per hour so will take 2-3 hours to charge. You should
get two so you can charge your pack in 3 hours. those 50 watt charger are slow, they require a 12 volt power supply you canget those for 10 dollars. You may consider a 150 watt ( 8 series charger) it will be quicker but you will need a more powerful power supply.

The problem with starting Lipo, the charger cost almost as much as the battery.

I like that alarm, cheap and good.
Personally I find the Turnigy more reliable than the zippy. less puffers. just a tad more expensive.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=10288

those connectors might work, you are going to solder them on to your packs?. Make sure you make the bullets compatible for conecting in series so that you can easily plug the negative into the positive.

Didn't know about the international site,woops.

I only got one charger,time for charging Doesn't matter to me.

Why would i solder the connectors,should i?

 

[dogman dan]

FWIW, If you don't have alarms or other means to stop discharge, you'd be better off to stop discharging even sooner.

3.65 or 3.7v per cell will help avoid an accidental drop below 3.5v. Past 3.65, voltage will drop very very fast, and past 3.5v it will drop instantly.

So stopping at 3.7v, before the cells head over the cliff will help a lot. 3.7 x 12 = 44.4v. So stopping a 12s pack at 44v is wise.

That's resting voltages, so if you know your batteries sag 2v for example, under load, you could ride till you see 44v under load, then start really watching your voltage at that point by stopping to see what your resting voltage is.

5 or 6 ah would be enough for a smaller scooter, but I'd still recomend more size if the scoot is high powered, like 800-1000w. Longer rides with less worry about dod.

 

[Addicted]

Ok the specs for the alarms i got for the 6s packs Don't match up with what you guys are saying here.The alarm would go of at about 3.3v per cell.I'm confused.


It is configured to work like this:
Blue light shines: 22.2V and up
Blue light flash: 22.2v ~ 20.4v
Red light shines: 20.4v ~ 19.8v
Red light flash with sound: below 19.8v

 

[DAND214]

I also prefer the turnigy's over the Zippy's. I have both, but have less problems with the Tunigy's. I only using 20c packs but 4p. https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=16207 They are cheap almost 2 for 1 price. Shame they are out of stock at the moment.

Almost 2 years running 15s4p with a Mac8t 45 amp Infinion controller on BlackComb. All cells balance out bulk charging to 62.4v. About 4.15 per cell. My Zippy's have been a more of a pain o keep balanced, Have replaced a couple 6 cells. It is also 15s4p running the same power train on a Mongoose Tech-4.

Both rides are great handling and smooth ride. batteries are on the frame or in the small triangle in the tech-4

Dan