Help finding bms

J

joetemus

100 mW
Joined
Apr 11, 2013
Messages
48
Location
Iowa, USA
I'm in the research stage of my build and I'm planning on running 100V to a x5305 crystalyte motor. I am also planning on buying 60 headway 38120s running 2 packs of 30 in series. Now im in search for a bms. I really wanted to buy a zephyr, but that thread seems to be dead, and the link is broken. I was planning on running 2 16 cell bms, but only using 15 of them on each board, and since the other 30 are in parallel with these they should be fine without them. Is there any other bms boards you would recommend for this situation?

Also, would only 30 batteries in series be able to provide enough current to not limit the bike too much, instead of 60? The only reason I said 60 is because I wanted to alter the controller to be able to provide more current.

EDIT: Found out that the 38120HP cells can provide 200A, this way i can provide enough current without having to run 30s2p. This cuts the weight in half and about 2/3 the cost too! Any reason I shouldn't go this route?
 
5305 on 100v sounds like a fun tire smoker.

The battery question is fairly easy, more is good, to the point where it gets hard to carry. With that kind of performance in mind, you will cherish having less sag under load. The main thing is how many amps you will offer up that motor. The more amps you want, the more you will want no voltage sag.

Clueless on the bms though.
 
dogman said:
It will take a hell of a big load to get a 5305 to pull 100 amps for very long. But it should jump off the line real nice having it for the first 5 feet.

The battery question is fairly easy, more is good, to the point where it gets hard to carry. With that kind of performance in mind, you will cherish having less sag under load.
Click to expand...

So your saying that 60 batteries would be a better choice? I have a plan for mounting them, so that shouldn't be the problem, its the price. If I can get away with using only 30 batteries without damaging them I would rather go along those lines.

Would it be easier to find some more high performance batteries with a higher discharge? I don't need many amp hours, because it is only a 3.5 mile ride to work, and I can charge it there.
 
Most of us turn to RC lipo when we want big amps. Touchy to maintain compared to "safer" lifepo4. But how is 100v of anything 'safe"?

20c beats 10c lifepo4, but the good stuff is 30-40c.

How many amps do you plan on, I'm assuming anything less than 40 amps would be a waste of time. 10 miles worth of 100v lipo is less than 10 ah. Easy to go both ways on it.

I haven't looked up the size of the lifepo4 cell you mean to use. 10 ah or less?
 
I've got a 24s1p headway pack... and my 80amp controller can sag the voltage enough that the bms can cut me off after 5min of WOT riding from a fresh charge.... :-(

i need more cells asap tbh!
 
dogman said:
I haven't looked up the size of the lifepo4 cell you mean to use. 10 ah or less?
Click to expand...

http://headway-headquarters.com/38120s/
Here is the link to the batteries, I don't plan on buying them here, because I can find them elsewhere for $15.70/cell. I'm planning on up to around 100amps (10kwatts should be fun :wink: ) If these cells were out already I would buy 30 of these for the extra discharge rating http://headway-headquarters.com/38120hp/
 
knighty said:
I've got a 24s1p headway pack... and my 80amp controller can sag the voltage enough that the bms can cut me off after 5min of WOT riding from a fresh charge.... :-(

i need more cells asap tbh!
Click to expand...

What bms are you using with those headway cells?
 
Particularly given the shorter ride planned, I'd be inclined to run RC lipo myself. Cheaper to buy just 10 ah, lighter to carry.

I happen to have just bought some more, and stocks are very short at Hobby King at the moment. 6s packs make a nice 24s package. 100v fully charged, 84v discharged. You'd need 6 of them.

But lipo has it's dark side, I won't go to sleep while some is charging in my house, no way.

10 ah of the headways would definitely get you to work and back, but best if you used only 30amps. Still 3000w, enough to go fast. That would stay within the 3c spec for headways. Ignore that stuff about 10c burst. Sure, it can do it, but it's gonna damage them.

Lugging 30s 2p headway cells every ride, PUKE. Fine though, if you have a longtail made to lug a big awkward load.
 
dogman said:
I happen to have just bought some more, and stocks are very short at Hobby King at the moment. 6s packs make a nice 24s package. 100v fully charged, 84v discharged. You'd need 6 of them.
Click to expand...

What packs do you recommend. Do you use a bms with this? I feel like youd almost have to. I will look around for higher discharging lifepo4 before I commit to these, since I'm fairly new to this I don't know if I trust myself enough yet.

Also, I contacted headway, and the 38120HP are in stock, and they can provide up to 200A. This way i can just run 30 in series and cut the weight in half, without limiting the amperage. Also itd be $700 for the battery pack instead of $1000 so this would be a huge plus!
 
you should always use a BMS to protect the battery and to balance it. hacking some BMSs to 15S from 16S is not as simple as you think.

agnius found these guys and some of us are ordering lipo BMSs from them. they also have the lifepo4 BMS too: http://www.bestekpower.com/
 
dnmun said:
you should always use a BMS to protect the battery and to balance it. hacking some BMSs to 15S from 16S is not as simple as you think.

agnius found these guys and some of us are ordering lipo BMSs from them. they also have the lifepo4 BMS too: http://www.bestekpower.com/
Click to expand...


Would you recommend lipo over lifepo4 in this situation?

I think this is the website I have been looking for! thanks for the link. Will defiantly check them out
 
no need to be defiant. they are very helpful. look over the offers on their website and contact henry zhang: henry@bestechpower.com

i am about to order a buncha BMSs from them too. lemme know if you wanna be part of it to keep the shipping charges down except it will require another shipping to you too. but maybe it will go in a jet pack if you are in the US.
 
definitely* autocorrect :roll: I live in the US, so if the shipping is cheaper to have you order a bunch then ship me mine separate I don't mind waiting longer to get it if it saves some money. I can run 2 15s bms for a 30s pack correct?
 
not sure why you decided on 30S but they do go up to 26S with this hi current jobbie which i expect will be around $100 which is cheap but i can get quotes for you or you can email henry: http://www.bestekpower.com/832v26spcmbmspcbforli-ionli-polymerbatterypack/PCB-D138.html

and if you only go to 72V nominal or 90V DC there is this one: http://www.bestekpower.com/768v24spcmbmspcbforlifepo4batterypack/PCM-D131.html

you need to figure out what you will use for a controller and if it will handle the voltage and current and then the charger too. start thinking how much you wanna lose and how long you want the battery to last wen you make the battery decisions and weight is one of them with headways.

lifepo4 will last longer, and much heavier for the headways, lipo is cheaper initially it seems unless you can find a deal for the lifepo4 cells. if you wait long enuff at hobby king for them to offer you a deal on the window then you can buy the 6S 5Ah turnigy packs for about $45 each. 4 in series to make 24S lipo. 100V. double that to make 10Ah wide, it is now 8 of the $45 HK packs, $360 for 1,000 Wh, plus shipping. $75 for the 24S BMS from these guys, $160 for a EMC-1000 900Watt charger. before you even buy the bike, real money.
 
dnmun said:
not sure why you decided on 30S but they do go up to 26S with this hi current jobbie which i expect will be around $100 which is cheap but i can get quotes for you or you can email henry: http://www.bestekpower.com/832v26spcmbmspcbforli-ionli-polymerbatterypack/PCB-D138.html

and if you only go to 72V nominal or 90V DC there is this one: http://www.bestekpower.com/768v24spcmbmspcbforlifepo4batterypack/PCM-D131.html

you need to figure out what you will use for a controller and if it will handle the voltage and current and then the charger too. start thinking how much you wanna lose and how long you want the battery to last wen you make the battery decisions and weight is one of them with headways.

lifepo4 will last longer, and much heavier for the headways, lipo is cheaper initially it seems unless you can find a deal for the lifepo4 cells. if you wait long enuff at hobby king for them to offer you a deal on the window then you can buy the 6S 5Ah turnigy packs for about $45 each. 4 in series to make 24S lipo. 100V. double that to make 10Ah wide, it is now 8 of the $45 HK packs, $360 for 1,000 Wh, plus shipping. $75 for the 24S BMS from these guys, $160 for a EMC-1000 900Watt charger. before you even buy the bike, real money.
Click to expand...

How do you order from them? It looks like they are a wholesaler (?)
 
nope, they are a manufacturer. they make BMSs for the battery makers so if you buy more than 100 at a time you can get a price break. i think they make the BMS for BMS battery.

you can email henry at the address i posted. tell him i sent you, hehe. lotta good that will do ya.
 
dnmun said:
not sure why you decided on 30S but they do go up to 26S with this hi current jobbie which i expect will be around $100 which is cheap but i can get quotes for you or you can email henry: http://www.bestekpower.com/832v26spcmbmspcbforli-ionli-polymerbatterypack/PCB-D138.html

and if you only go to 72V nominal or 90V DC there is this one: http://www.bestekpower.com/768v24spcmbmspcbforlifepo4batterypack/PCM-D131.html

you need to figure out what you will use for a controller and if it will handle the voltage and current and then the charger too. start thinking how much you wanna lose and how long you want the battery to last wen you make the battery decisions and weight is one of them with headways.

lifepo4 will last longer, and much heavier for the headways, lipo is cheaper initially it seems unless you can find a deal for the lifepo4 cells. if you wait long enuff at hobby king for them to offer you a deal on the window then you can buy the 6S 5Ah turnigy packs for about $45 each. 4 :D in series to make 24S lipo. 100V. double that to make 10Ah wide, it is now 8 of the $45 HK packs, $360 for 1,000 Wh, plus shipping. $75 for the 24S BMS from these guys, $160 for a EMC-1000 900Watt charger. before you even buy the bike, real money.
Click to expand...

I wanted 30s because 30s lifepo4 is around 100v. I would do the lipo rc packs if i can find a good guide on how not to make them explode. Lipo is starting to sound better and better except for the whole thermal run off stuff.
 
the reason for using the BMS on the lipo is to prevent them from overcharging or over discharging and to protect the output from shorts. if you don't short them out to a higher voltage battery or directly shorted to ground and if you avoid overcharging them they are safe. they do not spontaneously explode. if you shorted the output of a BMS of a lipo battery to the output of another lipo battery of higher voltage then the high voltage pack would immediately begin charging the low voltage pack and when one cell reached the HVC then the BMS would shut off and prevent the low voltage pack from over charge and igniting. that is why you use them, and to balance the pack so it does not go outa balance with age. you can bulk charge at higher rates than with balanced charging if you have a BMS to protect it.
 
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