Time to go Lipo. Design / setup questions & ideas.

[Tincan]

Gents,

It's come time to get some Lipo on the scooter.

Currently using 8 x 12v 7ah lead.

I have spend the past week now reading over nearly every topic i can find on the matter and have built what i believe will work for what i need.

Essentially I need to have a setup that i can plug the mains into, have the chargers on board and take care of the rest (still checking things on occasions)

I have used
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=14694
Turnigy 5000mah 22.2v 40c for power
and
two http://www.hobbycity.com/hobbycity/store/uh_viewitem.asp?idproduct=10327
Hobbyking Quattro 4x6 for charging.

I'm going to build a 133.2v 5ah pack to start off with. My commute to work is rather short. The CA tells me i pull about 1.3ah from the current setup on my trip.

I do however want to build on it in stages, giving me in the end 20ah to essentially go for a rather long ride.

One of the main stipulations is the need to be have it configured and left configured without the need to plug and unplug things when it comes time to recharge / discharge. This is due to the battery locations on the scooter and where i will place the chargers.

This is what i have in mind for the original setup.


Rather simple, one battery per port, balance wires plugged into each port, giving me one port spare on each charger. I will be using these for something else down the track, so they wont be wasted.

As i go, i will add onto this, like so.


Essentially just running the additional packs in parallel.

Can anyone see potential issues with this setup?

 

[GGoodrum]

I'm sorry, but this won't work with the 4x6 chargers because they don't have isolated grounds. These types of chargers are meant for charging up to four separated 6s packs. You'd have to use six of the individual chargers, each driven by its own isolated 12V supply. Also, you can't just leave these sorts of chargers connected all the time, as they will drain the cells. I'm afraid there's not really an off-the-shelf, "plug'n play" solution for what you need, which is to not have a bunch of connections to make in order to charge/balance each time.

-- Gary

 

[Tincan]

Thanks Gary.

So 6 individual chargers would be needed.

A simple relay opening and closing say the pos between the battery and the charger should be enough to open the circuit when not in use right?

Shane.

 

[neptronix]

You will need a lot of individual chargers, and you will also have to separate the packs each time in order to balance charge them.

Also for that voltage, i have no idea what charger will handle that amount of voltage all at once for bulk charging.

Also, why do you want 40c batteries? 20c-25c batts work fine for even the most high powered eBike setups. I don't think you'll be lacking discharge power at all.

the hyperion net duo will do 14s at a time. I believe 2 can be linked up to do 28s. That's 103.6v nominal with only 2 serial groups to separate if you need to balance charge. is 103.6v enough for ya? with far less voltage sag, it will probably be a huge improvement over the SLA to begin with.

 

[Philistine]

I run 20S4P, and I use the exact method you detail in your second picture (ie with four strings, and one Quatro charger), but i disconnect the series connections between the strings of packs everytime a charge, and the charger is not connected between charging. I have also parralleled the balance wires and use those to balance charge each string seperately. It also takes me a long time to charge (2 hours +) because i am using one quatro charger for such a big pack (each string only getting something like 2.5 Amp). But even if you could put switches on all those connections (ie the connections between charger and packs and between each series connection), that is a lot of switches and things that can go wrong. But I guess if you had effective switches for all those connections, and remembered to switch them everytime you were meant to it would work?

 

[Barry]

Shane

You may have already read these posts. If not take a look, you may find them useful in deciding on a charging solution.

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=19399
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=14842&start=15#p226580

Unfortunately both of these examples require you to have a separate charge and discharge configuration.

Barry

 

[MrKang]

Hi Tincan

what type of scooter do you have? picture or link would be nice.

if you use 6S x 6 =36S = 151.2V hot of the charger..

 

[Tincan]

Mr Kang, It's just a generic chinese scooter, i had a lot of pics in my build thread but looks like my image host went belly up. I'll have to fix that.
152v off the charger isn't that big of an issue either, the Lyen is rated to 150, so should be ok.

Thanks for those links Barry, One of the threads i had read but not the other. I guess I was just being lazy in my quest for trying to keep it simple.
I did find a youtube clip where Doctorbass modified the turnigy 4x6 charger to be independant for power supply. I'm still considering that option, running two of them and feeding it 6 chunky power supplys. (im only needing 6 chargers right now)

Keep in mind, im only going to start off with 6 packs, then build on it.

 

[Tincan]

Took on board what you said about not needing to go 40c.

The reason i was originally going down that path is due to wanting to run delta / star switching and knowing that delta is a little more hungry on the juice it wouldn't hurt.

Being that even on the SLAs im getting an averagre cruise speed now of 55km/h, that's only 5km/h off my target speed, I don't think i will bother with the phase switching any more. Also going from 96v up to 132 and being lipo will give me the end result im after.

So... today... I bit the bullet and started to order the packs.
5000mah 22.2v 6s1p 20c

I'm still deciding on the charger setup, but I figure if i start buying them now, it takes the pain away from the end cost
With any luck ill get more than my 3km i currently get out of the SLAs (yes, that's how rooted they are :lol: )

 

[Tincan]

1st shipment turned up today...

Quite impressed with them, no swelling. Haven't checked the voltages yet.

Ordered the charger and another pack today. Next week i'll order another 3 and get things happening.

The are considerably smaller than i first thought.

Going to order some low voltage alarms for the packs to keep safe, just unfortunately they will have to come from China as the Aus warehouse doesn't stock them.

One little question i have, when the packs are in the discharge config, 6s1p to start with giving 5ah @ 132v.

If one pack drops slightly in voltge, will it level itself out with the other 5 packs?

 

[Tincan]

Pack 1
Cell 1 = 3.82
Cell 2 = 3.81
Cell 3 = 3.81
Cell 4 = 3.81
Cell 5 = 3.81
Cell 6 = 3.81
Overall = 22.9v

Pack 2
Cell 1 = 3.81
Cell 2 = 3.82
Cell 3 = 3.81
Cell 4 = 3.81
Cell 5 = 3.82
Cell 6 = 3.81
Overall = 22.9v

Rather happy with that.

 

[neptronix]

One little question i have, when the packs are in the discharge config, 6s1p to start with giving 5ah @ 132v.

If one pack drops slightly in voltage, will it level itself out with the other 5 packs?

Unfortunately that is not the case from what i've seen. Not in a parallel config anyway.
I have been running off of 2x 5s packs in serial lately and 1 pack that i left about 0.5aH out of never ends up 're-balancing' itself when both are stuck on the charger left in a parallel connection. There is always a small voltage discrepancy which has continued for 5 cycles, going on 6.

I ran 10s2p for a bit and had one pack take a huge dive in voltage too. The other parallel pack didn't even things out.

BTW sorry to nitpick a technicality but you aren't running 6s1p, you're running 36s1p.

 

[Tincan]

One little question i have, when the packs are in the discharge config, 6s1p to start with giving 5ah @ 132v.

If one pack drops slightly in voltage, will it level itself out with the other 5 packs?

Unfortunately that is not the case from what i've seen. Not in a parallel config anyway.
I have been running off of 2x 5s packs in serial lately and 1 pack that i left about 0.5aH out of never ends up 're-balancing' itself when both are stuck on the charger left in a parallel connection. There is always a small voltage discrepancy which has continued for 5 cycles, going on 6.

I ran 10s2p for a bit and had one pack take a huge dive in voltage too. The other parallel pack didn't even things out.

BTW sorry to nitpick a technicality but you aren't running 6s1p, you're running 36s1p.

Ahh yes you are right!

Yeh, i didn't think it would level out.

Cheers!