Combining 3 LiPo batteries?

General Discussion about electric bicycles.
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Wolfeman   100 W

100 W
Posts: 219
Joined: May 13 2014 12:09pm
Location: West Coast USA

Re: Combining 3 LiPo batteries?

Post by Wolfeman » Aug 15 2018 8:58am

Marv1337n wrote:
Aug 09 2018 1:33am

I'm currently thinking about replacing my 48V 13,6Ah 18650 battery with a 66,6V 20Ah LiPo battery.
I wanted to use 3 of these: ... -xt90.html
Now the question arises how to connect them in series and how to charge 3 of them?

Thanks for your help
Here is one of the best videos I've found that explains how to effectively and safely use Multistar LiPos on an ebike.
Barent with West Coast Electric Cycles also builds great quality and affordable series harnesses. I switched to Multistars a while back and they are fantastic. Good luck with your project.
Trek 4300 w/ H3580 Crystalyte at 3600W ... =3&t=82738
Worksman Mover M2020-3CB w/DD 750W front hub ... =3&t=96873

dirttorpedo   100 mW

100 mW
Posts: 48
Joined: Mar 21 2017 8:23am

Re: Combining 3 LiPo batteries?

Post by dirttorpedo » Aug 15 2018 3:04pm

mean well hlg-320h-24a
I've been using one of these to charge 6 paralleled 6s 10ah packs for about a year now. On the bike I configure for 20ah of 18s. Voltage and amps are adjustable and even though current drops to 0 once voltage is reached I unplug right away once charged. I check cells on all 6 bricks before and after the charge. Have only had to balance two or three times. I ride 2 or 3 time a week. Charge time from 3.7-3.8 up to 4.2 is about 3 hours. Should be the same for 3 20ah packs.
The Commuter: 2006 GT Kustom Kruiser- 16s LiFePo4 (25ah), generic Chinese motor, Grin 48v 35A
The Trail Bike: 1999 GT XCR-3000- 20s Calibike li-ion (15ah), H3540, Grin 72v 40A

knurf   10 W

10 W
Posts: 78
Joined: Aug 29 2016 12:15am

Re: Combining 3 LiPo batteries?

Post by knurf » Aug 16 2018 3:27am

I rarely hear about people using LiPo with a BMS. It is very beneficial to charging and safe discharging. Also the balance leads are right there, just carefully wire them to the BMS connector and plug it all in (Measure at the connector before, easy to get it wrong but not risky unless its actually being plugged in. The serial chain of the main battery power connections needs to be in the correct order). I use 4s and 6s balance extension cords and connect them to the BMS plug.

I started off using the RC chargers but have moved on to permanently mount beefy smart BMS with my LiPo. I get the non-saggy power delivery lipo can provide and guard them when they start "falling of the edge" off the discharge curve. Charging is safer and much easier involves just connecting one cable. I also get to monitor cell balance and temps from my phone while charging.

I have a acrylic outer shell for each brick and they are grouped with some velcro, rides in my backpack.

I'm not seeing myself going back to using them bare or stringing together 18650's (seriously, the shrink wrap on one of those cans is so thin it's incredible. Rubbing it with a rough towel too long will expose the metal).

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