New em3ev battery question

11spokes · Mar 15, 2017

Hi,
I have just purchased a 20s 10p battery from em3ev. Which I'm very happy with quality looks awesome!
Just wondering if someone can help me out. It comes with 3 positive and negative sets of wires coming from the battery. It has the Anderson plugs for charging which I believe can be plugged directly into the charger without pre charge connectors as long as the charger is switched on first. Is this right?
Then it has 2 sets of xt90 pre charge connectors coming from the battery. They have also given me 2 xt90 wires/connectors one of which I will connect to my controller. Just wondering why there are two positive negative xt90 connectors coming from the battery. Sorry this maybe a stupid question but if anybody can give me some info I would be very happy.
I have included a pic of the battery and connectors.
Thanks!

Sunder · Mar 15, 2017

Would be nice if you actually included the pics...

11spokes · Mar 15, 2017

Here's the bad bugger. :lol:

Sunder · Mar 15, 2017

That doesn't look like inrush control, so my guess is that it's for much bigger controllers, that need to draw BIG amps reliably.

Although XT90 is supposed to be able to do 90amp, that's really the destruction point, not the ideal point. It also only accommodates 10AWG wire, which for any significant length is rated for 45-55amps, depending on insulator, and cooling.

A decent quality 10P 18650 can probably deliver 150amps in bursts, hence if you are going to do anything like that, you need to use both connectors to avoid melting everything to slag.

11spokes · Mar 16, 2017

Thanks Sunder,

Ok well I'm starting with a 40a controller so I will just use the one XT90 connector. At a later date I may use a larger controller in which case I would use both XT90 connectors.

What about charging? Would I need a pre charge XT90 Connector to connect to charger? Or is it fine just to connect Anderson plugs as long as charger is on?

spiros · Mar 16, 2017

why you don't aske em3ev Joseph and Moon will explaine you everything
I have buy several kits from them for me and my friends and they are always very helpfull with all questions

Sunder · Mar 16, 2017

11spokes said:
Thanks Sunder,

Ok well I'm starting with a 40a controller so I will just use the one XT90 connector. At a later date I may use a larger controller in which case I would use both XT90 connectors.

What about charging? Would I need a pre charge XT90 Connector to connect to charger? Or is it fine just to connect Anderson plugs as long as charger is on?

You don't need in-rush control if you turn the charger on first, then connect the battery. Even from dead flat (3v per cell = 60v @20S ) connecting to open current (4.2v per cell = 84v @ 20S), the voltage difference isn't enough to cause massive currents, and in fact, the current will be "rushing" from the charger to the battery, which is less damaging than from a 60v battery, to a dead cold 0v charger.

11spokes · Apr 2, 2017

Hi guys,

Finally have the bike going. It's awesome fun!!!

My battery came with a 3a charger but I also have a 10a charger.
Just wondering if charging at 10a would shorten battery life?
It's 84v battery fully charged 29ah Samsung 30q 18650 cells.
I have included some pics.

Thanks Ben.

nutnspecial · Apr 2, 2017

Cool man!
Whatever your cells are rated for is a good boundary for the charging side- And they've gotta be rated higher than the .3C charge (30ah / 10amp) you're planning, so enjoy the 3 hour full charge VS 10 hour!!!

11spokes · Apr 2, 2017

Thanks nutspecial.

That makes sense so I would only be charging at .3c for a 30ah pack with a 10a charger.

The Samsung 30q are rated at 5c discharge. Can anyone tell me the Maximum amps I could charge at before I would be shortening the lifespan of this pack?

I only discharge the battery at around 2c absolute max. And I'm only charging to around 90% or around 82v.

I'm hoping to make this pack last as long as possible.
If charging at a slower rate extends the life I'm happy to do that.

I think I charge no more than 10a what do you guys think? :roll:

Thanks Ben.

torker · Apr 2, 2017

Cool machine.. I would like to see a better pic of that torque arm.. you make it ? 30 ah is huge. You should have some good range. That bike looks like my Rincon,,.. I am also waiting on a batt from em3ev .. 8)

Warren · Apr 2, 2017

If you ride like many folks on here, you will be doing a lot more battery degradation during riding than charging.

I have a 12s (39v volt nominal) 30 Ah Ping LiFePO4 pack on my low power mid-drive bike. I have charged it at 10 amps, 1/3 C, for five and a half years. This is about my average discharge rate as well. Doing fine after five and half years. I can still pull 24 Ah out of it, but with a bit more voltage sag than when new. My CA shows I have pulled 8,008 Ah out of it. I have logged 601 rides as of yesterday. The CA shows 585 charge cycles.

nutnspecial · Apr 2, 2017

11spokes, i have no idea without research whether the cells are rated .5 or 1c (or whatever) for charge but I'm guessing it's something like that. I'm also guessing (as usual

), that all cell manu's derate charge amperage much much more than their discharge ratings and that going to their full spec'd rating for charge does no additional noticable degradation to them. The more impactful things are likely pushing discharge ratings in amps and ah, ambient temps over lifetime, and total time @ > storage voltage. Em3 would be the first opinion on the subject if it was my battery though- they know what they're doing!

11spokes · Apr 3, 2017

Hi guys,
I have been using the 10a charger. Only took 2 hours to charge from 66v to 82v.
Batteries were very slightly warm after charge but im guessing this is normal.

I went for a 53 km ride today. Pushing hard ( not pedalling haha) the whole way and lots of hills. and had the 66v left after ride. CA was saying I used 24ah Glad I went for the 30a pack as I'm a not the lightest bloke at 140kg. Would like to see how the bike performed if I was under 100kg haha.

Torker yes I made the torque arm myself. It's probably a bit of overkill but wanted to make sure nothing would break. It clamps to the axle. Also have one I bought on the other side. I will attach some pics. What kind of battery are you buying from em3?

Warren if I get that many cycles out of my battery I'd be happy. I have heard LiFePO4 last a long time.

torker · Apr 3, 2017

Nice.. I always wanted a ebike with range like that.. I am just getting a 36 v 15.5 ah with the newer 33g cells. I guess they call it a dolphin or bottle battery. It shipped and I should have tracking this week..
I use to use lipo. My son jumped on the bike to look for one of our dogs that got out and puffed all three :? Bike has been hanging in the rafters since..
Oh and nice torque arm. Won't have to worry about that motor spinning out.. I have some pics of mine in my link. I just used some of the hardware that came with my 9c kit and modded it and my FSR has 4) 1/8' steel pieces file to fit tight.

999zip999 · Jan 4, 2020

How much for the 20s10p pack ? Was there any other. Sizes or shapes ?

amberwolf · Jan 4, 2020

999zip999 said:
How much for the 20s10p pack ? Was there any other. Sizes or shapes ?

probably better to look at the em3ev site itself for current info than ask about prices/etc for items bought and posted about three years ago.

New em3ev battery question

11spokes

100 mW

Sunder

10 MW

11spokes

100 mW

Attachments

Sunder

10 MW

11spokes

100 mW

spiros

10 W

Sunder

10 MW

11spokes

100 mW

Attachments

nutnspecial

10 MW

11spokes

100 mW

torker

100 kW

Warren

100 kW

nutnspecial

10 MW

11spokes

100 mW

Attachments

torker

100 kW

999zip999

100 TW

amberwolf

Administrator

Similar threads