couple of battery pack questions.

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motomech
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Re: couble of battery pack questions.

Post by motomech » Oct 11, 2017 8:22 am

You can get better energy density (size and weight) by using higher capacity cells or using LiPo packs in parallel. I'm intrigued by the 22.2v 10A LiPo packs. My main concern is the lower voltage (44.4v nominal vs. 48v nominal). I'd probably be inclined that direction before I'd build a battery pack myself. The 36v packs are economical, but do add a bit of weight if you want to go relatively long distance. The weight doesn't bother me a lot. After all, I could shed a lot of that weight by running four packs and recharging at work. But with a heavy hub motor, it can add up to be a fair amount of weight.
There isn't that much difference in the real World, A one, possibly 2 mph higher top speed is possible w/ the 48V pack. This can be off-set to a large degree by less sag likely to be seen w/the LiPoly. For any given space, weight and cost, more LiPoly can be "packed-in". My 2S/2P, 12S/20Ah pack, comprised of 4) MultiStar 6S, 10Ah bricks, weighs 13.6 lb.s and can fit inside a shoe box.
The MultiStar, low-volatility, large capacity, 10C bricks have been a real boon for us who don't need a high-discharge rate.
The fact that it is often deeply discounted @ Hobby King is "icing on the cake".
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, Crazy Bobs run ghetto tubeless. 25 mph. Mean Well HLG-320H-54A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 14S LiPoly elifebike 9-FET 20A controller. 23 MPH.
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Re: couble of battery pack questions.

Post by wturber » Oct 11, 2017 8:59 am

motomech wrote:
You can get better energy density (size and weight) by using higher capacity cells or using LiPo packs in parallel. I'm intrigued by the 22.2v 10A LiPo packs. My main concern is the lower voltage (44.4v nominal vs. 48v nominal). I'd probably be inclined that direction before I'd build a battery pack myself. The 36v packs are economical, but do add a bit of weight if you want to go relatively long distance. The weight doesn't bother me a lot. After all, I could shed a lot of that weight by running four packs and recharging at work. But with a heavy hub motor, it can add up to be a fair amount of weight.
There isn't that much difference in the real World, A one, possibly 2 mph higher top speed is possible w/ the 48V pack. This can be off-set to a large degree by less sag likely to be seen w/the LiPoly. For any given space, weight and cost, more LiPoly can be "packed-in". My 2S/2P, 12S/20Ah pack, comprised of 4) MultiStar 6S, 10Ah bricks, weighs 13.6 lb.s and can fit inside a shoe box.
The MultiStar, low-volatility, large capacity, 10C bricks have been a real boon for us who don't need a high-discharge rate.
The fact that it is often deeply discounted @ Hobby King is "icing on the cake".
I'm surprised that the weight isn't that much different. Six of the 36v packs weigh 12lbs and deliver 896 watt hours (nominal) - about the same as your four LiPoly bricks?!? Given that you can get good quality 18650 cells that deliver around 3000mah per cell, and the lack of a metal casing on the LiPoly cells, I expected a weight savings, not a similar weight. Are you sure about that weight? Are you maybe using the shipping weight of the battery and not the actual weight? Either way, I'm sure they take up less volume. Six of the 36Volt packs can fit in a shoebox, but it would be a moderately large one.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couble of battery pack questions.

Post by Kenny'sID » Oct 11, 2017 4:04 pm

wturber wrote:
Kenny'sID wrote:I, decided on a 14s/10p pack...it'll fit nicely for both applications/bikes, and it's a little more than the 18AH which someone suggested here/elsewhere?

Question: Can someone please tell me how many AH the mentioned pack will be?
It will be 10 * the Ah of one cell. The "10" comes from the number of cells in parallel (10P). So if your cells were 2100 mah (2.1amp/hours) , you would have a 21 amp/hour pack.
Kenny'sID wrote: How many mAh can these vary 100/200? more? Or is that not really a concern if I do the lay them out in a row thing from low to high and keep grabbing one from each end till I have what I need?
The standard is to use all identical cells. I have no idea what the reasonable work-arounds are if you don't do that. I'd think that not having well matched cells is generally considered a "bad thing." But others with more experience can probably give better real world, practical insight into that.
Kenny'sID wrote: One more question: On the 36v ebay packs I just mentioned, there is no way to get those to work with a 48v system without tearing into them, nothing feasible anyway? right?
The general advice here seems to be to tear the packs apart and rebuild them to suit. There are clear advantages to doing that. You can custom shape the battery pack for a better custom fit. You can customize the voltage and capacity. You can create very high voltages and amperage configurations.

But that's not what I did. I'm using a DC-DC boost converter - which is pretty non-standard. Bottom line is that it is working fine for me. I've been commuting 32 miles round trip through a hilly area with a 1000watt direct drive with no problems. I put about 540 miles on my bike in about a month. I use either five or seven packs wired in parallel. When I can stop working 12 hour days in a few weeks, I'll probably reconfigure into two groups of four packs in parallel. Five packs are enough to get me to work and back and then a few miles on one charge. But I've been using seven packs lately to put less strain on the batteries and to have more flexibility to take side trips and/or go faster on some days.

The boost converter hurts efficiency a bit - probably by 5-7%. I run mine set to a 54v output. Its real world power limit (delivered to the controller/motor) set this way is 1175watts (the battery draw peak is about 1250 watts). My 48v 13A controller pulls a maximum peak of 26A. When it pulls more than the converter can deliver, everything shuts down for about five seconds and then power self-restores. That's not good when accelerating through an intersection or beginning a hill climb. I resolved this problem by using my S-LCD3 display to limit the controller to 80% of its maximum output. I no longer get any shut downs from demanding too much power from the converter.

So the converter limits my max power by 20% and I'm losing about 5-7% of my battery capacity. But I like the modular nature of my system. If a pack misbehaves, I can just pull it out and test it (I can plug my 10s charger in and check the pack balance if I wire in a BMS bypass) and replace a pack if it isn't performing properly. On the road, I could just disconnect a failing pack and leave the others connected. As a newbie to ebikes, I've avoided the whole business of designing and welding or soldering packs together (weld or solder? Nickel strips or fuse wire? Make sure strips aren't just nickel plated. Solder or weld? Build a cheap battery welder? Holders or not? If holders, which ones? What about the BMS? It isn't rocket science, but it does take more time and effort than rigging up a wire loom for multiple pre-made packs and mounting a DC boost converter.

I think the DC boost converter is fine for a commuter ebike if the rider likes to pedal along a bit on hills and/or when accelerating from a stop. If you crave more performance, then you'll want more than the 20 amps and 1175 watts that the DC boost converter can deliver. I see there's a 50/30A converter that might deliver 1500 watts (more than my controller should pull). If that device is smaller, it might be better than the converter I'm using. But that converter will deliver about 4 amps more than my controller can handle. My bike will do over 30mph unassisted on the flats. It handles hills with up to about a 10% grade with only mild effort needed from the rider. I'm commuting 16 miles in about 45-50 minutes on the downhill run to work and in about 50 minutes to 55 minutes on the uphill run back home. I could probably go faster, but I've been tending toward conservative use of power.

BTW, perhaps the biggest negative with those 36 volt packs (from alarmhookup on ebay) is that they are based on 2150mah cells. You can get better energy density (size and weight) by using higher capacity cells or using LiPo packs in parallel. I'm intrigued by the 22.2v 10A LiPo packs. My main concern is the lower voltage (44.4v nominal vs. 48v nominal). I'd probably be inclined that direction before I'd build a battery pack myself. The 36v packs are economical, but do add a bit of weight if you want to go relatively long distance. The weight doesn't bother me a lot. After all, I could shed a lot of that weight by running four packs and recharging at work. But with a heavy hub motor, it can add up to be a fair amount of weight.
Thanks all for the very helpful replies...this one really has my attention, I thought about the converter but after being shut down (rightfully so) on a few things over the course of this, I decided not to mention it for fear of looking stupid, but you give some very impressive feedback on using the packs with fairly few drawbacks. That might be just the thing for me. It would also give me some built packs to look at and as someone else mentioned, help me figure things out with hands on, or at least eyes on before I do a build on my own.

I'm going to check your link out for finding the converter, and I'll assume the seller you mentioned gives the best bang for the buck with his packs.

Thanks so much for taking the time for all that, Wturber.
Last edited by Kenny'sID on Oct 11, 2017 6:22 pm, edited 1 time in total.

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 11, 2017 4:37 pm

Wtrber, I checked out the link to your main post on this build, and see the single pack hooked up...did/can you actually run the bike on a single pack?

Either way, I'm sold, and think I'll go with just what you've done or recommended to be safe, then consider other possibilities/configurations later on, as in the 36v controller or what you mentioned here.. My 4/18ah lead acids, and pulling a trailer with both my two and 3 wheeler will only top out at 26 and 22mph on the flat respectively so, this will help a lot there as well, even if it's just what I gain from dumping nearly 50lbs of SLA's from the trailer. And my mileage is awful but I pull a very heavy trailer for half my usual trip...still I think these will make a big difference

Going to try to find the converter on ebay now.
Last edited by Kenny'sID on Oct 11, 2017 6:27 pm, edited 3 times in total.

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Re: couble of battery pack questions.

Post by Kenny'sID » Oct 11, 2017 6:09 pm

wturber wrote:The general advice here seems to be to tear the packs apart and rebuild them to suit. There are clear advantages to doing that. You can custom shape the battery pack for a better custom fit. You can customize the voltage and capacity. You can create very high voltages and amperage configurations.

But that's not what I did. I'm using a DC-DC boost converter - which is pretty non-standard. Bottom line is that it is working fine for me. I've been commuting 32 miles round trip through a hilly area with a 1000watt direct drive with no problems. I put about 540 miles on my bike in about a month. I use either five or seven packs wired in parallel. When I can stop working 12 hour days in a few weeks, I'll probably reconfigure into two groups of four packs in parallel. Five packs are enough to get me to work and back and then a few miles on one charge. But I've been using seven packs lately to put less strain on the batteries and to have more flexibility to take side trips and/or go faster on some days.

The boost converter hurts efficiency a bit - probably by 5-7%. I run mine set to a 54v output. Its real world power limit (delivered to the controller/motor) set this way is 1175watts (the battery draw peak is about 1250 watts). My 48v 13A controller pulls a maximum peak of 26A. When it pulls more than the converter can deliver, everything shuts down for about five seconds and then power self-restores. That's not good when accelerating through an intersection or beginning a hill climb. I resolved this problem by using my S-LCD3 display to limit the controller to 80% of its maximum output. I no longer get any shut downs from demanding too much power from the converter.

So the converter limits my max power by 20% and I'm losing about 5-7% of my battery capacity. But I like the modular nature of my system. If a pack misbehaves, I can just pull it out and test it (I can plug my 10s charger in and check the pack balance if I wire in a BMS bypass) and replace a pack if it isn't performing properly. On the road, I could just disconnect a failing pack and leave the others connected. As a newbie to ebikes, I've avoided the whole business of designing and welding or soldering packs together (weld or solder? Nickel strips or fuse wire? Make sure strips aren't just nickel plated. Solder or weld? Build a cheap battery welder? Holders or not? If holders, which ones? What about the BMS? It isn't rocket science, but it does take more time and effort than rigging up a wire loom for multiple pre-made packs and mounting a DC boost converter.

I think the DC boost converter is fine for a commuter ebike if the rider likes to pedal along a bit on hills and/or when accelerating from a stop. If you crave more performance, then you'll want more than the 20 amps and 1175 watts that the DC boost converter can deliver. I see there's a 50/30A converter that might deliver 1500 watts (more than my controller should pull). If that device is smaller, it might be better than the converter I'm using. But that converter will deliver about 4 amps more than my controller can handle. My bike will do over 30mph unassisted on the flats. It handles hills with up to about a 10% grade with only mild effort needed from the rider. I'm commuting 16 miles in about 45-50 minutes on the downhill run to work and in about 50 minutes to 55 minutes on the uphill run back home. I could probably go faster, but I've been tending toward conservative use of power.

BTW, perhaps the biggest negative with those 36 volt packs (from alarmhookup on ebay) is that they are based on 2150mah cells. You can get better energy density (size and weight) by using higher capacity cells or using LiPo packs in parallel. I'm intrigued by the 22.2v 10A LiPo packs. My main concern is the lower voltage (44.4v nominal vs. 48v nominal). I'd probably be inclined that direction before I'd build a battery pack myself. The 36v packs are economical, but do add a bit of weight if you want to go relatively long distance. The weight doesn't bother me a lot. After all, I could shed a lot of that weight by running four packs and recharging at work. But with a heavy hub motor, it can add up to be a fair amount of weight.
Pretty sure this is what you recommend so, if you get a chance to verify, I can get one on the way.

http://www.ebay.com/itm/1500W-30A-DC-Bo ... SwZKBZJSZ0

And the 200 cell count from the 36v pack seller you mentioned, looks like a good deal to start with. Did you go with the no brand, the Samsung's or the LG packs?

I should mention due to leg problems, I cannot pedal at all, the reason both my bikes include a gas drive as well. But from what I'm getting from you in a hilly area and me, far from it, I should still be ok just on electric power with this set up....right? Also I will look into what you did to avoid cut outs, as I've considered the messy situation too, of rushing through an intersection or whatever when we really need the go power....not a good scenario. Seems I almost never see bikes on the road around here, and just that fact scares me, so I need to do all I can to avoid trouble, as these are the times I use electric most, when I'm not cruising on open road, and I prefere to use it always.

Easy and economical, just what I was after. :)

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Re: couble of battery pack questions.

Post by wturber » Oct 11, 2017 10:03 pm

Kenny'sID wrote: Thanks all for the very helpful replies...this one really has my attention, I thought about the converter but after being shut down (rightfully so) on a few things over the course of this, I decided not to mention it for fear of looking stupid, but you give some very impressive feedback on using the packs with fairly few drawbacks. That might be just the thing for me. It would also give me some built packs to look at and as someone else mentioned, help me figure things out with hands on, or at least eyes on before I do a build on my own.
Yeah. That was my thinking. I figured I was only risking the cost of the converter and I could always re-wire the cells. As for looking stupid, at this point in my life I don't really worry much about that. Even if the converter had failed, I would have considered it a worthwhile experiment. There are a lot of smart people on this forum and most of them seem to want to help you so long as you are willing to put some effort into learning. Reasonable questions seem to be taken in stride.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couple of battery pack questions.

Post by wturber » Oct 11, 2017 10:06 pm

Kenny'sID wrote:Wtrber, I checked out the link to your main post on this build, and see the single pack hooked up...did/can you actually run the bike on a single pack?
I never ran the bike on one pack. I think I posted a picture with one pack to show relative size. I have run the bike on two packs, but would not recommend it for general use. I think it puts too much strain on the batteries. I'd recommend a minimum of five packs and will probably end up running eight in the interest of battery longevity and trip flexibility.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couble of battery pack questions.

Post by wturber » Oct 11, 2017 10:30 pm

Kenny'sID wrote: Pretty sure this is what you recommend so, if you get a chance to verify, I can get one on the way.

http://www.ebay.com/itm/1500W-30A-DC-Bo ... SwZKBZJSZ0
To be clear, I'm simply reporting what I've done and the results. I'm not suggesting that you do anything in particular. But yes, that looks like the the same converter that I used. But lots of people are selling them and I can't be sure that they are all the same.
Kenny'sID wrote: And the 200 cell count from the 36v pack seller you mentioned, looks like a good deal to start with. Did you go with the no brand, the Samsung's or the LG packs?
I only ever considered the LG batteries from seller alarmhookup. There seemed to be a lot of good information on them and it was pretty clear that they were new MF1 cells. I lucked into getting 10 packs for $200. Seemed like a no-brainer. If the converter didn't work I could disassemble and rewire.
Kenny'sID wrote: I should mention due to leg problems, I cannot pedal at all, the reason both my bikes include a gas drive as well. But from what I'm getting from you in a hilly area and me, far from it, I should still be ok just on electric power with this set up....right?
You are asking me to give an opinion regarding things I can't really know. But if I wasn't able to bring my legs into the mix, then I'd probably err toward a system that has more off-the-line torque than my current system has. I'd probably lean away from using the converter and toward getting perhaps a 40A controller or larger controller. Either that, or I'd lean toward a geared rear hub. I'd want that extra torque to get through intersections fast or to quickly get up to speed to more quickly traverse sections of my route where I'm less comfortable with the traffic. That said, if I had easy paths with little concern for traffic, then acceleration would be less important to me.
Kenny'sID wrote: Also I will look into what you did to avoid cut outs, as I've considered the messy situation too, of rushing through an intersection or whatever when we really need the go power....not a good scenario. Seems I almost never see bikes on the road around here, and just that fact scares me, so I need to do all I can to avoid trouble, as these are the times I use electric most, when I'm not cruising on open road, and I prefere to use it always.

Easy and economical, just what I was after. :)
Well, if you still think you'd like to go with the converter, you might want to consider this one (which I have not tried).

http://www.ebay.com/itm/1500W-50A-DC-Bo ... 0033.m2042

It costs more, but the specs suggest it will deliver 1500 watts with the 36v packs (vs. the 1175 watts that my converter delivers). I hadn't seen this one when I began my project.

Given your situation (bike with trailer - no leg assist) and assuming a direct drive hub motor, I'd lean toward feeding the motor a LOT of amps. You may find that running 10 of those packs and a 40A controller at 36v is simpler and plenty fast at about 23 mph top speed. What is the total weight of you, your bike, and your trailer?
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 11, 2017 11:06 pm

To your first comment...I understand, and what I do is all on me. :)

You've given me a lot to think about and I think I actually got all my questions in there, and answered for now. It's definitely still a go.

$200 was a pretty good deal but even at $250 or so and knowing the worse that could happen is I'd tear the packs apart and use them for a high drain pack as opposed to the low drain laptop batteries, I can't really lose. Plus it will likely work out fine for at least one of the 2 bikes. Also, there is only one intersection in my little town, and when I think about it, I can avoid it altogether if I must. I think I was just recalling a few weeks ago when I was in a semi panic trying to find gas for my generator before Irma hit, and it got a little dangerous, as I got a little cocky with my trike. Point being, not that big a deal on the speed here, I just need to be careful, but I will have to do something about the cut outs no matter what I do.

Thanks man, and I'm bound to have a few more questions but for now I think I can get started.

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Re: couple of battery pack questions.

Post by wturber » Oct 12, 2017 1:58 am

There are three devices in the power chain that can cut off power: the motor controller, the DC booster, and the BMS in the battery packs.

I'm using an S-LCD5 like that available at BMS Battery - though I bought my kit on ebay. I changed two settings. I changed C setting 5 to a value of "6". That limits the power draw to 80% of the controller's maximum, or about 21 amps. 21 amps * 54 volts is right around the 1175 or so limit of the DC booster. I think this setting is the key to avoiding having the system shut itself down. I then set the LCD5's C value 12 to a value of "0". That changes the motor controller's voltage shutoff from about 40v to about 38v. The BMS in the battery packs will shut the packs down at about 28-29volts. So I set the DC booster voltage cutoff to be well below that value. That effectively eliminates the DC converter from causing a power shut down.

So the BMS is the ultimate protection for the battery packs. No matter what you do, they'll stop any significant draw before you can damage the cells. But if the batteries get near empty (but still above the BMS cutoff), and you put a high drain on them, you can still get a temporary power cutout because the DC converter's output voltage will sag under the high current load. (You can monitor the DC booster's output voltage on the LCD display.) If the sag drops below 38v, the motor controller will cut out for a moment if the voltage drops below 38v. If/when that happens, this is your warning that the batteries are on their last legs. You have about 15% of their capacity left. They'll still give you cruise power on level ground or slight inclines, but there isn't much left in them. This occurs at when the packs are delivering about 35v. At around 34 volts, the packs will start to rapidly lose voltage. When running 7 packs, I no longer ever hit that low voltage situation with my normal commute cycle.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couble of battery pack questions.

Post by Kenny'sID » Oct 12, 2017 11:53 am

wturber wrote:
Kenny'sID wrote: Thanks all for the very helpful replies...this one really has my attention, I thought about the converter but after being shut down (rightfully so) on a few things over the course of this, I decided not to mention it for fear of looking stupid, but you give some very impressive feedback on using the packs with fairly few drawbacks. That might be just the thing for me. It would also give me some built packs to look at and as someone else mentioned, help me figure things out with hands on, or at least eyes on before I do a build on my own.
Yeah. That was my thinking. I figured I was only risking the cost of the converter and I could always re-wire the cells. As for looking stupid, at this point in my life I don't really worry much about that. Even if the converter had failed, I would have considered it a worthwhile experiment. There are a lot of smart people on this forum and most of them seem to want to help you so long as you are willing to put some effort into learning. Reasonable questions seem to be taken in stride.
This board has been the best by far for helpful folks. I won't mention where I got the somewhat bad vibes from because it wasn't that big a deal, but do want to mention it wasn't here.

The more radical the idea the more stupid we might look to some, however, some stupid people end up making stupid things...like airplanes.

Anyway, ordered with no regrets, and the batteries and converter has already been shipped.

I should ask about charger/charging. What's the best bet there for the charger, and do I charge them together or separately? Might as well get that on the way too

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Re: couble of battery pack questions.

Post by wturber » Oct 12, 2017 2:22 pm

Kenny'sID wrote: I should ask about charger/charging. What's the best bet there for the charger, and do I charge them together or separately? Might as well get that on the way too
I'm using an iCharger 1010B+ that is fed by a 600 watt or so computer power supply. I charge to 41.0 volts, not 42.0 to extend the life of the cells.

My original plan was/is to be able to use the 10s charger to check each pack for proper cell balance from time to time since they are pre-wired with balance leads to feed the BMS. The problem I ran into was that I found that I couldn't just unplug the multi-wire connecter from the BMS. I I have to also bypass the BMS's main power leads. That is relatively easy to do, but requires cutting a couple wires and soldering in bullet connectors or something similar - for each pack. This was further complicated because some of the packs having a different, smaller multi-pin connector that isn't so easy to find (Though I think it has been found with the help of some folks here). So I haven't fully implemented that part of my plan yet.

My current routine is to charge all the packs in parallel (not balance charge) after letting them "rest" a minimum of 30 minutes after I get home. So far, the packs seem to be staying balanced. I just did a "storage" charge on Sunday since I knew I wouldn't be able to ride most of this week and then unplugged and individually measured the voltage of each pack. They were all within four one-hundredths of a volt of each other. So they seem to be staying in balance after about a dozen or so cycles and about 400 miles of riding. If I had all the packs re-rigged for balance charging/testing, I'd have checked the cell balance on each individual pack during this downtime.

Anyway, that's my plan. Routinely gang charge in parallel and occasionally do a maintenance check on the balance of the packs and cells. Time will tell if it is a good plan or not. I should probably work out some kind of pack rotation so that all the packs age at about the same rate so that a "replacement" pack will behave much like all the others.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 12, 2017 3:29 pm

I'll have to reread some of the posts, and try to understand what going on, but I figure I have a couple of weeks to do so, and in the mean time I also want to post a vid, once I find/upload it, of the noise this two wheeler motor is making. I think it's normal but I should get opinions. The three wheeler with the silver striped motor (as opposed to the black noisy motor on the two wheeler) has never given me a noise problem.

It was never that bad until I put my first big load on the back, and it may have just been too much tongue weight pushing the back of the bike down, lifting the front, and the lack of weight allowing the wheel to resonate...or something. I'll work on getting that up here now.

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 12, 2017 5:50 pm

Here is a link to the noise and FWIW a couple of pics here.

https://youtu.be/H4YJ145qCyE
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Re: couple of battery pack questions.

Post by wturber » Oct 14, 2017 12:55 pm

"Video is unavailable"
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 14, 2017 3:26 pm

Sorry bout that, and thanks. It should be available now, and please let me know if it's not.

Also upon watching the vid, I noticed the sound got a lot quieter once it hit the road from the grass, again suggesting a resonance problem, or no big deal. I guess the question is, should it be that loud to begin with. This is just after my trailer came off for the first time due to all the weight. after thinking more about it, this was a kind of loud wheel anyway but not terrible, but this is the first load I've had on the back so, I'm thinking it's as I mentioned, and to much tongue weight lifted the front, making an acceptable but already noisy wheel way noisy. Might just be a matter of getting the weight adjusted and/or just living with the extra noise when there is a load. But don't let that color opinions, it could be something wrong with the wheel. It runs at about 26mph on the flat w/an empty trailer, and a bit over 200llbs of me, so the wheel seems to work fine.

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 14, 2017 6:17 pm

Turber, most of what you mention there on the charger is over my head. Can I just get a Li-on, 36v charger and plug it up, and do them separately? Or is there something more to that? And if I want to do them all at once, say I want to do 8 at a time, do I just buy a 36v li-on charger, one that charges that many amp hours? If we talked about it I forgot how many AH 8 of those packs are?

I'll go try to find one and maybe get you to ok one to be sure, and that should get me well on my way.

And while I have you here, I purchased around a 14 AH or very close to that/48v charger recently, not knowing the AH's were an issue as the firsts charger I got came with the kit so I never paid attention. Can I use that on my 48V 18AH SLA?. I gather I can but just barely, however I want to be sure.

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Re: couple of battery pack questions.

Post by wturber » Oct 14, 2017 7:34 pm

Kenny'sID wrote:Turber, most of what you mention there on the charger is over my head. Can I just get a Li-on, 36v charger and plug it up, and do them separately? Or is there something more to that? And if I want to do them all at once, say I want to do 8 at a time, do I just buy a 36v li-on charger, one that charges that many amp hours? If we talked about it I forgot how many AH 8 of those packs are?

I'll go try to find one and maybe get you to ok one to be sure, and that should get me well on my way.

And while I have you here, I purchased around a 14 AH or very close to that/48v charger recently, not knowing the AH's were an issue as the firsts charger I got came with the kit so I never paid attention. Can I use that on my 48V 18AH SLA?. I gather I can but just barely, however I want to be sure.
The charger setup I'm using is a bit clumsy, but it is versatile. The main thing I'd recommend from it though is that you don't charge to 42.0 volts, but to 41.0 or even 40.5 volts. By all accounts, this will help your batteries last a longer time. My setup makes switching from 4.1 to 4.2 or to a storage level pretty easy. It also allows me to balance charge each individual pack - which may or may not prove to be useful over time.

The simpler approach would be to get a "regular" charger that doesn't do balancing and open it up and adjust it's output voltage to 41v. Search these forums for info on doing that. I haven't done that, but it is commonly suggested. It is probably best to get an actual charger rather than a simple power supply. Though a simple power supply of the right kind will work. The reason is that Li Ion batteries are ideally charged with varying amounts of current. Proper chargers do that. But apparently some power supplies (Meanwells?) effectively do something similar. Again, search these forums for more specifics.

Each pack is 10s 2P. That's 10 18650 3.7v Li Ion cells in series and 2 in parallel. 20 cells per pack. 2lbs weight per pack. Each cell is a nominal 3.65v and 2150 mAh per the LG spec sheet. So that makes the packs 36.5 volts (10s = times 10) and 4300 mAh (2 * 2150) or 4.3 amp hours per pack.

The spec sheet gives a standard charge rate of 1075mA (.5C for this pack) per cell. They allow a max charge rate of double that. But faster charging probably reduces pack longevity a bit. So for each pack, that's a 2150mA standard charge rate or 4300mA max for a fast charge. For simplicity, let's just call that 2amps and 4amps respectively. So if you wanted to charge 8 packs at the same time, you could charge at up a 16 amp (or 656 watt - 16amps * 4.1v) rate. A fast charge would double that. Because the standard charge is .5C, it should take about two hours to fully charge your packs from a near empty state if you use this standard rate. But you may have to do some searching to find a charger that will charge at that rate. Even the Grin Technologies Cycle Satiator will only deliver 360 watts. To go much

I charge at a much lower rate of 6 amps or about 240 watts because my more complex and fiddly setup has a maximum charge rate of 300 watts. But with the right charger, I should be able to charge at more than double that rate and get much faster charging and not hurt the cells one bit. However, I suspect that one reason my packs have stay so well balanced (all charging to nearly the same exact voltage) is that the slower than allowed charge give the cells more time level each other out. And since I probably use up a little bit more than half of my pack's capacity for a round trip commute, I'm not charging the packs from empty. So charge times aren't horrible even at the relatively low rate I'm using.

Anyway, to sum up. You should look for a 36V charger that can deliver up to 16 amps (656 watts) or a little bit less - assuming pack longevity is a goal. And if it is, you should make sure the charger you buy can be adjusted to different charge voltages, such as 41v. A charger like this one seems to offer a good balance between simplicity, capacity, flexibility and price. https://lunacycle.com/luna-charger-36v- ... e-charger/

Charge the packs in parallel and make it a point to spot check them to make sure none of them are misbehaving.

Note that if you are going to charge an individual pack, you may need a separate, cheaper lower amperage charger.

I have no idea if it is a good idea to use your 48v 14a charger on an SLA.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 16, 2017 12:08 am

Thanks for all that, I realize it took some time. I don't really want to get into something too advanced like the first recommendation for a few reasons...one being I don't understand a lot at this point and learning this type thing from scratch is one of my weaker points, plus I don't want to be a pain with all the questions when I can pick it up eventually. Also, between that, the expense that I really don't mind under some circumstances, and a fact I didn't mention, that I only need this every few weeks at most, at least for the most part, then that coupled with the fact I'm just not sure yet if I'll eventually be tearing these down to go 48v or not (probably not but who knows), would it be too terrible for me to just get the $10, 1.5 to 2A 36V charger?

I would prefer I could do as you say and open the charger and set the voltage so I'll check that out as you recommended. Plus $10 or so is pretty much nothing in the scheme of things and I can always upgrade to something like the Luna or even the first setup you mentioned once I'm more advanced and sure of what type system I'll be running. IOW if that is doable, another "little to lose" situation. What do you think?

One reason I asked about charging an 18AH SLA with a charger designated for a 14AH battery, is because I don't understand why AH's matter there. I mean don't these all just run until the battery is charged/until they reach proper voltage? Yet all the chargers are labled for specific AH's. And I don't even see one for as few AH's as these individual packs I'll be getting are.

So, if I can go that route, just buy a charger that is designated at the lowest AHs possible as long as it is above the 4AH or whatever of the pattery packs? or can I go with a much higher AH charger as long as it's more than the 4 AH's of the pack? Or do the AH's of the charger have to pretty much match the AH's of the pack? See my confusion here? This really should be a siple buy but I can't even order the charger until I understand what's up with this.

See, with 12 volt LA batteries/all my life, I never had to worry anout amp hours of the charger or the battery, but unless I'm missing something it's an issue with Li-ions and they have to be matched either somewhat or exactly.

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Re: couple of battery pack questions.

Post by wturber » Oct 16, 2017 1:19 am

I agree. Rating chargers with amp hours makes little sense to me. IMO they should be rated by voltage as well as by amps or watts. Note that the charger I linked to is rated as a 36 volt charger 300 watts. If you look at the specs they also mention 7 amps. 7 amps at a 42 volt charging voltage is 294 watts (7 * 42 = 294). Simple.

Ebay can be a great place to get deals, but not such a great place to get technical info.

If you get a 1 amp charger, expect very long charge times. The general recommendation is that you should monitor Li Ion batteries that are being charged. Things can go wrong. The more you move away from a pre-made solution from a well known vendor, the more important that probably is (like if you built your own battery pack). With only 1 amp, it could take days to charge a pack that uses a bunch of those 36 volt packs. Charging one pack would take about four hours. Ten packs ... forty hours. So at least try to get a 2 amp charger.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 16, 2017 2:16 pm

So just get the two amp and don't worry about the AH ratings? Or at least as far as you know? I'm not holding you to anything at all.

I doubt it'll work but I'm going to look into adjusting the new/cheap 48V 14AH I have to the proposed voltage limit we want these to stop charging at. It at least makes some sense they would make them all the same to a point, and just readjust the voltage to make them 24/36/48V chargers, but I shall see....maybe not. And thanks for the formula, that should help me in getting the right one.

I do sometimes use ebay for info but those people have tendencies to lie, Take the "Hi definition" TV antenna we assumed we all needed when they did the change over to HD, when it turns out, the old antenna's work fine. So, right or wrong, I smelled a rat in the AH ratings on these chargers but didn't want to mention it because I wasn't sure. They do stand to make much more money by rating them, but I could be way off base, so no solid conclusion.

Just got the packs... half the weight, better than twice the power, and a much longer life cycle. I cringed every time I put this heavy SLA in my trailer.

Got more questions I'm sure, but will leave it at that for now...thanks again.

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 16, 2017 4:17 pm

OK, no adjustment on either of my chargers.

I'm looking at adjustable step down/up modules...

https://www.ebay.com/sch/i.html?LH_BIN= ... =400&rt=nc

...I can add to my 48v chargers either inside the charger box (they seem to be very small) or outside it in the output line but I question whether that will mess up the chargers ability to stop when the battery is charged? Would you happen to know about that? Unless they really jump in price by the time I get to some that will take a 48v input, this will cost me 6 to 8 bucks each and just make my charger or even chargers more versatile. It's a thought anyway and just wanted to run that by you.

At worst, I'll still just buy the cheap 36V charger, and my cheap two are 1.8 to 2.4A so, cheap is fine, at least for now to get me going while I get a little more knowledge on this.

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 16, 2017 4:43 pm

Oh, not sure what I was thinking, or if I was at all, but I already have the system converter I ordered.

Question, can I simply run my existing 48v charger directly into the input on the converter we are using, and charge them all by adjusting the output to stop at 40.5V or whatever voltage is best? I do understand it will take forever to charge them all, but at the moment, that's ok.

Also, and I know these may be a lot of dumb questions or q's you may not know the answer to, so again, I can still just go the easy route, but should ask anyway to cover all possible cheap options and reduce wait time for materials. Can I possibly run both chargers together for a total input of around 5A?

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Re: couple of battery pack questions.

Post by wturber » Oct 16, 2017 5:46 pm

You should get a charger made for charging 36 volt Lithium Ion batteries. End of story.

There are certainly other ways to do it, but you don't seem to be the guy who will take the time to understand all the details and "gotchas" of doing it some other way. So save yourself the grief and get a "for purpose" charger from a reputable source. Preferably an e-bike supplier of some sort who will stand behind their products.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: couple of battery pack questions.

Post by Kenny'sID » Oct 16, 2017 10:16 pm

It's not so much that I won't take the time but like I said, I don't want to get anyone here irritated with all the questioning, and I will figure it out eventually, but I need to get these on the road shortly, hence the last fire off of questions.

Thanks again, and I'll decide what to do soon enough..

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