105ah battery

I'm looking for some help. I'd like to put together 52 volts/48 volt motor and controller. I still need to decide on that but I'm appealed to the rc stuff. I'm used to pulling a Bob trailer behind my full suspension trek. So I've got all the space I need for battery.
Here's where I need help, lifepo4 or lipo I think they are the same. The multistar brand sells lipo batteries in a number of voltages and amp hr rating. Is there a connecter I can use to connect smaller battery packs together? To make 52 volts 105amp hr, or even the possibility 52 volts in 30-40amp hr with a connector. I'm looking for something simple that uses the factory plug from the battery. If I did it in the smaller range I'd just get enough supplies to equal 3 assembled pack for a grand total of 105 amp hr give or take.
Thank you for your help

Since there's different kinds of plugs on different RC packs, you'll probably wind up having to build your own series and parallel harnesses.

But there are people that have done it before, and some of the threads about that are here:
https://endless-sphere.com/forums/search.php?keywords=lipo*+connect*&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search

THere's others too, but those are a starting point.

FWIW, you can series connect the packs, if they are the same, with the stock connectors. Then make parallel harnesses to add 48v packs into larger size.

Say you have four 5 cell packs and two 3 cell packs, all 5 ah in size. Connect two of the 5 cell packs in series. black wire to red. then add the 3 cell pack the same way. Now you have a 13 cell pack, at 48v 5 ah. Do this twice, and now you have two. To make it a 48v 10 ah pack, you need to parallel them.

Connect in parallel, by making your own Y cable to combine two packs. This adapter would have one black and one red on one end, and on the other end, connected like a Y, two of each color. Plug that in black to black, red to red, and now the ah add up, instead of voltage adding up like when you connect in series.

You sound like you want a huge battery, so in your case you would need a y connector, but with many many wires on one end, and one red and black on the other end. more like an octopus connector.

You can do series / parallel connections many ways, but this method will require the least adapter connectors to made by you. Series first, then parallel them.

Tape up all connections on the series packs, so they don't accidentally unplug themselves during the ride.

A 105ah thats 48volts will be a very large battery pack.
Thats 105ah x 48v = 5.04KWh
Unless your doing sports ebiking like a Stealth Bomber etc I would say your going to be overly worried about your pack going bad somewhere, just one puffer cell hiding among all those cells will be a challenge to spot, I would stick to 18650s is my 2cents.

thank you for the link on all the other disccusions. i found them very helpful. i didnt know that you could series connect battery cells and then combine them with a parallel connection on top of that. im still unsure how that works. i know the flow of current will take the path of least resisitance. and i remebered watching a video of someone welding a pack toghter and they where basicallly short circuiting a circuit/ touching the negetive and positive terminals toghter timed approiatly with the right amount of pressure and contact. which got me thinking about a real mig welder which i was more familiar with and all the bright light it produced.
i read that you could screw up the cells if not done right. im still learning. but how could you go wrong? anyone? if series muliplies amp and parallel multipies volts. series connects postive terminal to negitve terminal. and parallel connects all the postive with positive and all the negative to negative. what am i missing?

105amp sounds like a lot. im looking to ride all day. around 100 miles or more. still sound over worried about my pack? maybe but im thinking not. open for sugguestions

A 105 volt battery on a electric bike would take you far enough each day on your ride. This way you can have some sleep rest your ass your legs and go to bed 105 amp hours equals 60 to 190 miles are more especially if you pedal start and go by the byways where there are no red lights that's the reason a ship goes from Alaska to Long Beach there are no stop lights

Manuponapples said:

i read that you could screw up the cells if not done right. im still learning. but how could you go wrong?

Click to expand...

Fireball if you short across packs or cells, and it'll probably happen so fast you can do nothing about it but walk away. Look up member SoSauty and his accident connecting stuff up wrong at a race.

Also fireball if you overcharge or overdischarge cells or packs, under some conditions.

Very occasionally fireball just because it's RC LiPo, but there's usually a root cause.

if series muliplies amp and parallel multipies volts. series connects postive terminal to negitve terminal

Click to expand...

That's backwards, and it's not multiply, but simply add.


If you're not sure about any of it, look up the RC LiPo basics / noob threads, as there are good explanations in there.

After that, if you're still not sure, then based on what you think you understand of it all, you should draw up diagrams of exactly what you want to do and how you want to hook them up, wire by wire, and post them in this thread. Then we can see if it's correct or not, and help you understand why so you can correct it, before you build anything. Then you'll understand where everything connects, because it's very important to get right.


Something else you'll want to look up is charging RC LiPo, because there are various ways to do it, and all of them have advantages, and all of them have disadvantages. You have to decide which are more important to you, so you can decide which method you want to use.

Manuponapples said:

105amp sounds like a lot. im looking to ride all day. around 100 miles or more.

Click to expand...

105Amp-hour (not 105amp) is a lot, especially at 52v nominal (14s). That is about 5.4kWh, which is more than twice as big as the 2kWh pack in my SB Cruiser trike.

That pack weighs quite a lot--about 35lbs. It's not RC LiPo, which is probably a tiny bit lighter, but not enough to make a difference in this quantity. So your pack will weigh, at a guess, about 90-100lbs.

FWIW, my SB Cruiser is very heavy, very unaerodynamic, and used in stop/start traffic for commuting and cargo hauling. That 2kwh pack still gets me at least 40 miles of range, even then, using around 1Ah/mile at 14s (52v nominal), at 20MPH top speed, 15-16MPH average.

Most bikes use less than half that--even my also big and heavy CrazyBike2 uses less than half that, so I'd probably get 80+ miles of range with it, using that pack.

I suspect you could get by with less than 40Ah at 14s, but it does depends on your actual power usage, which itself depends on speed, weight, terrain, wind, and desired acceleration rate from a stop as well as how often you have to do that.

In lithium, 105 ah is huge, motorcycle size or even small car. In lead, too big for a bike to carry. Even in lithium, its going to be 75 pounds. A lot of weight even for a trailer.

For most bikes, typical use, the need is about .5 to 1 ah per mile. So 105 ah would be enough for 100 miles range, riding very fast.

When I wanted 100 miles range at 15 mph, I packed 40 ah. 2kwh, about like AW's big trike carries. I'd suggest you start out with a 48v 20 ah pack, then add more later. This is how I accumulated a big range capacity. I would buy 500-1000 wh each spring. This gave me some fresh battery every year, and by the third year, I had a very large pack. The three year old stuff would be pretty tired by then, but able to extend range a lot when needed. Most of the time, I only needed to carry 48v 20 ah, 1000 wh. 20 miles fast, or 40 slow.

Charging that big of a pack is also an issue. Even at 1500w that would take a while to charge safely. Maybe, two similar size packs would be easier to manage and you could have several smaller packs that you could use like reserve wh's?

Just as a comparison, my .50cal ammo can pack is about 20Ahr @ 52v. It weighs 13.5 lbs. I can go about 50 miles on that if I stay under 20mph. My butt will get tired before the battery.