Single 40Ah pack or Dual 20Ah packs

[DragonPhyre]

First things first: This forum is awesome. I have lurked here for QUITE a while reading and getting information from you guys. So much so that I successfully built my first ebike last winter! It was a blast riding around all summer on a quiet, clean, and way too much fun bike that I built. Put it away once the temps got too cold for the face and the battery packs... And now winter around these parts is starting to start/end and I have that desire to get out there again... As well as try to upgrade my bike battery pack, so that I can downgrade my middle section on my person... Heh...

Currently, I have 4x12v 12Ah battery packs that I have in a nice-but-clearly-not-made-for-batteries set of panniers that I want to upgrade to LiFePo4 so I can shed some weight and/or get some more range out of. But then that got me to thinking that if I got two packs, and ran them parallel that I could put them on the sides of the rack in some ammo cans as well as not putting too much strain on the batteries.

Is this a good idea, or a bad idea?

 

[dogman dan]

What are you planning to do? 48v 40 ah of lifepo4 is a lot of weight, too much to carry daily unless you want to take long tours.

A single 48v 15 ah ping battery should be pretty good for you. Only 15 pounds, and range will be 20-35 miles depending on the speed you ride. You can carry it on one side pannier, and then balance the other side enough with some tools and such.

If you do want 60-70 mile range, then a second 48v 15 ah ping can be bought.

 

[dnmun]

you are gonna replace the 4 SLA with two separate 48V lifepo4 packs?

are they ping packs or vpower packs you intend to use?

48V 40Ah is pretty big for any lifepo4 pack. gonna need a yuba monda to carry it in the back.

with 2 packs you will have extra cost from the fact that it is more complicated and requires more parts to build two packs rather than one. ping does build packs that are split into two sections, and use just one BMS. but just the regular 48V20Ah pack is already pretty big.

but it can be done, don't let these diode people convince you that you need diodes. jeez.

 

[jtdiode]

It sounds like you are running 48V 12Ah lead battery right now. If you went over to a 48 volt 15 amp hour Ping you would see a drastic improvement over what you have right now. You might get close to double your range with a lot less weight and the voltage won't sag on you as much when the batteries are discharging, so you should see the same performance untill they are dead. I have the 48V 15Ah ping on a trek mountain bkie with the E-bike kit direct drive rear motor and at 30 mph without pedling it runs about 20 miles. At 20 mph I get over 30 miles without pedling.

 

[999zip999]

I vote for a 48v 20ah ping. At 22amps.

 

[dogman dan]

48v 20 ah ping just too big and awkward to carry well on most bikes. 5 pounds lighter, the 15 ah is much nicer. Often fits in frame triangles when a 20 won't. Still a shitload of range for most peoples needs.

Still wondering what exactly he needs 40 ah for. Two 48v 20 ah pings would be appropriate for a longtail cargo bike with nice pannier style racks to carry them on. 100 mile range if ridden slow.

 

[The Mighty Volt]

48v 20 ah ping just too big and awkward to carry well on most bikes. 5 pounds lighter, the 15 ah is much nicer. Often fits in frame triangles when a 20 won't. Still a shitload of range for most peoples needs.

Still wondering what exactly he needs 40 ah for. Two 48v 20 ah pings would be appropriate for a longtail cargo bike with nice pannier style racks to carry them on. 100 mile range if ridden slow.

This is all true- a 36v 20Ah duct-tape 18650 is an absolute bee-atch......that said the 20Ah will give a slightly superior Amperage than the more rudimentary 15Ah.

 

[Lebowski]

If you want to run 2 batteries instead of 1 for weight distribution reasons, I think it'll be
much easier to run two packs in series as compared to running 2 packs in parallel.

With parallel packs you can get into nasty problems with voltages needing to be equal, one
pack discharging into the other etc etc. All this can be overcome with some electronic component
and parallelling the cells etc etc, but its much easier just to connect two packs in series (where
you don't have any of these issues).

Personally, I'm going to run two 48V 10Ah packs in series...

 

[dogman dan]

Well, three days and still no reply from Dragon. Maybe he's using a library computer?

Very true, a good way to carry 48v 20 ah, or 48v 30 ah would be panniers. Each pannier could have 24v 10 or 24v 15 ah in it.

I just wonder why he'd want to carry 40 ah on every single ride unless it's crosscountry riding. A 48v 15 ah ping carried in the frame triangle is good for 20-30 miles. About as much daily ride as most people can stand.

 

[DragonPhyre]

What are you planning to do? 48v 40 ah of lifepo4 is a lot of weight, too much to carry daily unless you want to take long tours.

A single 48v 15 ah ping battery should be pretty good for you. Only 15 pounds, and range will be 20-35 miles depending on the speed you ride. You can carry it on one side pannier, and then balance the other side enough with some tools and such.

If you do want 60-70 mile range, then a second 48v 15 ah ping can be bought.

My main concern was amp draw, I didn't want to get limited by the battery pack (or damage it) when I need to get some extra speed/power. I usually just cruise around going like 10mph while 'pedaling' to keep the fuzz from bothering me. But when I am on a back street, and there's nobody around... Well, lets just say that I like to test the limits of my vehicles.

The weight would be a minor issue, as I am currently lugging around 4x12v SLA which I think was somewhere like 37-40lbs.

you are gonna replace the 4 SLA with two separate 48V lifepo4 packs?

are they ping packs or vpower packs you intend to use?

48V 40Ah is pretty big for any lifepo4 pack. gonna need a yuba monda to carry it in the back.

with 2 packs you will have extra cost from the fact that it is more complicated and requires more parts to build two packs rather than one. ping does build packs that are split into two sections, and use just one BMS. but just the regular 48V20Ah pack is already pretty big.

but it can be done, don't let these diode people convince you that you need diodes. jeez.

Yes, I currently have the 4 SLA that I want to ditch. What a horrible battery technology when your only redeeming quality is the cheapness of you... The two packs I was looking at was vpower--but I have read some reviews on them and I don't want to spend bunches of money on something that I can't return/fix. There is a local battery place near by that said they would build me a pack... Maybe I would have to inquire there.

And split packs sound interesting... I was wondering if this would be possible, so that there is only one 'pack' to charge. Convenience!

It sounds like you are running 48V 12Ah lead battery right now. If you went over to a 48 volt 15 amp hour Ping you would see a drastic improvement over what you have right now. You might get close to double your range with a lot less weight and the voltage won't sag on you as much when the batteries are discharging, so you should see the same performance untill they are dead. I have the 48V 15Ah ping on a trek mountain bkie with the E-bike kit direct drive rear motor and at 30 mph without pedling it runs about 20 miles. At 20 mph I get over 30 miles without pedling.

I think that is where I want to be... I want to be able to wack the throttle wide open from a standstill, and just cruise. The cops around my area are starting to get REALLY fussy with cars and issuing tickets for going 2mph over the speed limit and for quick trips to the corner store and just getting out and whatnot I would rather just get out the bike. I usually keep it under 10mph and 'pedal' as mentioned before, so they haven't stopped me yet. :lol:

48v 20 ah ping just too big and awkward to carry well on most bikes. 5 pounds lighter, the 15 ah is much nicer. Often fits in frame triangles when a 20 won't. Still a shitload of range for most peoples needs.

Still wondering what exactly he needs 40 ah for. Two 48v 20 ah pings would be appropriate for a longtail cargo bike with nice pannier style racks to carry them on. 100 mile range if ridden slow.

I also wanted to think about upgrading to a cargo bike in the future for grocery runs to the not-so-local farmers market. Luckily there's not too many hills where I live. Pretty flat area.

If you want to run 2 batteries instead of 1 for weight distribution reasons, I think it'll be
much easier to run two packs in series as compared to running 2 packs in parallel.

With parallel packs you can get into nasty problems with voltages needing to be equal, one
pack discharging into the other etc etc. All this can be overcome with some electronic component
and parallelling the cells etc etc, but its much easier just to connect two packs in series (where
you don't have any of these issues).

Personally, I'm going to run two 48V 10Ah packs in series...

I had wondered if they made them like this, but don't LiFePo4 packs come with the BMS already integrated so you can't split a 20AH pack into two 10AH packs yourself? I don't know, and don't really mind if I have to plug in two packs and have a physical disconnect between them. I'm not afraid of a soldering iron.

Well, three days and still no reply from Dragon. Maybe he's using a library computer?

Very true, a good way to carry 48v 20 ah, or 48v 30 ah would be panniers. Each pannier could have 24v 10 or 24v 15 ah in it.

I just wonder why he'd want to carry 40 ah on every single ride unless it's crosscountry riding. A 48v 15 ah ping carried in the frame triangle is good for 20-30 miles. About as much daily ride as most people can stand.

Funny thing is that I thought I had the forums set to send me a notification instantly, and turns out it was set to OFF! HAHAHAhahahaha.............

I will have to look into seeing if the pack will even fit there as the bike I have is a cruiser and there is not a lot of space in the triangle. I was thinking about getting some ammo boxes and bolting them onto the sides of my rear rack for hard-packs.

 

[dogman dan]

Works better to be addicted, and logged on to the forum 24/7.

Based on what we know now, I'd suggest a 48v 15 ah ping too. Love mine, and it will not get too whacked by full throttle riding for 20 miles nonstop. Pings customer service is really worth the extra few bucks compared to the ebay sellers.

Another factor is the size and weight of the 48v 15 ah is pretty easy to fit on bikes, while the 48v 20 ah won't fit into most bikes triangles, and affects handling too much if carried on the rear rack. Start with one, and if you find you really need more range, then get another and you'd have 70 mile capability riding slow, or 40 miles at full speed.

If on the other hand you wanted 40 mph or had a 40 amp controller, then we would direct you to batteries with higher c rates.

 

[DragonPhyre]

Works better to be addicted, and logged on to the forum 24/7.

True enough... But I've got it sorted now so no more sadness.

Based on what we know now, I'd suggest a 48v 15 ah ping too. Love mine, and it will not get too whacked by full throttle riding for 20 miles nonstop. Pings customer service is really worth the extra few bucks compared to the ebay sellers.

I am gathering that as well, from what I have been reading about HK Vpower and the like. I wonder if the pack will fit into my frame... I would like to have the weight better distributed in the center.

Another factor is the size and weight of the 48v 15 ah is pretty easy to fit on bikes, while the 48v 20 ah won't fit into most bikes triangles, and affects handling too much if carried on the rear rack. Start with one, and if you find you really need more range, then get another and you'd have 70 mile capability riding slow, or 40 miles at full speed.

Yes, having all that weight on the rear rack makes for a HORRIBLE ride. Plus, you crush your rack down with 40lbs of batteries.

If on the other hand you wanted 40 mph or had a 40 amp controller, then we would direct you to batteries with higher c rates.

I was looking at the thread where someone was running 100v and 100Amps on a front wheeled bicycle (Method was his name) and was literally burning rubber at the twist of the throttle. That is exactly why I did not go with the front motor, and went with the rear instead.

 

[dogman dan]

Well, call me a slacker, I was only racing a bike with 40 amps of 100v on the front wheel. One day on the track = one tire. Definitely burning rubber, but it was sure fun. The racer has a rear motor now though.

Front hub is fine for boring commuters that go 25 mph, but even then the front tire would spin a tad on the starts.

Depending on your bike frame, a 48v 15 ah ping might fit in the triangle. It won't if the top tube is low, as has become the style on newer hardtail mtb's. It will fit in older style frames. Cut a cardboard square 6" by 13". If that fits, you should be able to fit the ping for sure.

Another great alternative would be emissions free. There you can get a very good A123 battery in a triangle shape that fits most hardtails. Cellman is definitely on the vendors we trust list. Not as fast service as some, but he will get a quality battery to you.

Once you go lithium, you will open a huge new world with your ebike. Range is everything, but 10 ah is enough for most. Just depends on your needs, and if you can charge at work or school.

 

[DragonPhyre]

Well, call me a slacker, I was only racing a bike with 40 amps of 100v on the front wheel. One day on the track = one tire. Definitely burning rubber, but it was sure fun. The racer has a rear motor now though.

If I get a little extra money, I am thinking about going 2WD on my next bike. This one is fun and it definitely still gives me The Grin when the battery is fully charged, the wind is in my hair, and the streets are wide and flat... But come on. Two motors on a nice frame? Yeaaaah.

Front hub is fine for boring commuters that go 25 mph, but even then the front tire would spin a tad on the starts.

Before I really sat on my bike, the first test was spun up in my living room... And because I didn't have the brakes on yet I had to stop it on my floor--which left a nice little skidmark on the living room floor. Whoops! I never really considered a FWD because of the loads of road gravel and crappy roads around here and I was concerned with grip. Seems my fears were right on the money, even though I don't really hit the throttle full open from a dead stop most of the time.

Depending on your bike frame, a 48v 15 ah ping might fit in the triangle. It won't if the top tube is low, as has become the style on newer hardtail mtb's. It will fit in older style frames. Cut a cardboard square 6" by 13". If that fits, you should be able to fit the ping for sure.

This is the exact bike I bought to build this... At the time, I absolutely NEEDED a project and I blew all my cash on the motor, controller, and batteries and She Who Shall Not Be Ignored balked at the price of the bike frames I wanted to use... So a frame at Walmart was used just so that I could get started on the project.

I'm the kind of guy where if I don't have several projects going at once I get fidgety. And I just got my tax return so I had to have something BIG to satisfy me for the rest of winter. I realize now that the choice of bicycle is the main limiting factor of the overall build--but the good news is that I can get another frame and whatever now because I have a much better job. I wanted something that was all steel, as I heard horror stories about the motor spinning free in aluminum frames and ripping the wires out of the motor and other badness. And plus shocks seemed to add in more complexities than I wanted to tackle at the time. So basic steel, no suspension frame it was. Then I got the BRILLIANT (read: Incredibly Stupid) idea that I should get a bike with a rack ALREADY on it so I could save some money! Blech... I mashed that rack dead to the fender on the first ride, on the first bump I hit. 40-ish pounds of battery jumped up and then WHAM. Flat rack.

This is almost the bike that I have, the paint color looks different but everything else looks the same:

Another great alternative would be emissions free. There you can get a very good A123 battery in a triangle shape that fits most hardtails. Cellman is definitely on the vendors we trust list. Not as fast service as some, but he will get a quality battery to you.

Saaay whaaaat? I thought these triangle batteries were things of myths and legends! Now this looks like something that I would really consider! I wish I was just better with google sketchup so that I could model things better. It seems that this program is TOO simple and it is really frustrating to make simple things like a triangle with some set dimensions on it... Free hand it is fine, but when you KNOW what you want to make, it is hard to make it exact. This program seems to excel at fudging, and flop when it comes to precision.

Once you go lithium, you will open a huge new world with your ebike. Range is everything, but 10 ah is enough for most. Just depends on your needs, and if you can charge at work or school.

Charging is not that big of a deal, as I don't need this as my main transportation. It would really just be in the summer, which around these parts is few and far between.

 

[DAND214]

Lebowski wrote:
If you want to run 2 batteries instead of 1 for weight distribution reasons, I think it'll be
much easier to run two packs in series as compared to running 2 packs in parallel.

With parallel packs you can get into nasty problems with voltages needing to be equal, one
pack discharging into the other etc etc. All this can be overcome with some electronic component
and parallelling the cells etc etc, but its much easier just to connect two packs in series (where
you don't have any of these issues).

Personally, I'm going to run two 48V 10Ah packs in series...

I hope yourealize that's over 100v off the charger! Have Ping split a 48v20ah pack. they work great.

Dan