Tweety

Well, marginal wire gauge plus solder, and you get tin in the wrong places...

Basically, the type of gauge you need to carry the correct current, you cannot crimp to a connector small enough to fit between two cells... It's physically too large... So you are better of using copper bars, or even the bars that the sellers will ship with the cells...

wolfgun

LiFePO4 38120P (M size) Cell: 3.2V 10 Ah, 100A Surge Rate, 32Wh with 6M screw Terminal - UN Approved (3.0)

This from Google after entering 38120.

Tweety

Why would you pay more to buy from another vendor if the manufacturer is selling on eBay? This is $17.75, so cheaper...

38120S (10Ah) LiFePO4 cell | eBay

skokievtr

Markus,

Would this battery be good for the VTR and if so, would I need 4 or 8?

Was not sure if you were referring this battery for a cage.

House done yet?

Tweety

This is the correct battery size to snugly fit 4 into the VTR's stock battery bay, with the cells "lying down" like the one in my pictures... The only thing you need to do then is to extend the stock battery connectors since they wont reach on one pole, with both poles on one side of the bike...

However, just FYI, this is seriously overkill for the VTR... This is kind of right for a big BMW adventure bike with the same amount of ligths as a big rig... But, for all weather riding with extra lights, and heated gear, it might be the correct choice to have "reserve power"...

This is also usable for a car, if you use 8 cells... But you can just as well go for larger cells, it's more what you can fit into the battery box that's the limit...

Have a look here for more options... 8-10-12-15 Ah cells... The larger they are, the longer, so the 12 & 15 doesn't work very well for bikes, but for cars it should be fine...

headway-headquarters | eBay

I'm hoping to move all the stuff into the house by next-next weekend... Perhaps if nothing goes seriously wrong, I'll start the move next weekend... X-mas in the new house... 2 acres for X-mas decorations... Yay! (Albeit the SO says I'll never notice the difference, as I probably won't be leaving the workshop until next year...)

wolfgun

I didn't know that Headway was selling on Ebay , after reading your post I just googled the Lifepo4 and the site I was referred to had some description of the type of battery that you had built. I'm not an electrical engineer and do not know how to put 4 3.2V batteries together to form a 12.8V unit. I wouldn't know whether to connect pos to pos or pos to neg.

Tweety

Well... It's described in the thread you posted in... So sorry, but you aren't getting off that easily...

Basically, this whole thread has turned into a Q&A where I tell how to build one from the cells... Read through it, and you will likely be able to build a battery yourself... Otherwise, just ask and I'll fill in the missing pieces...

7moore7

I'm more of a positive person myself, so I don't touch the negative ones...

E.Marquez

I found shipping to be a bit cheaper by going to the Headway home site Electric Bike Batteries | Headway Headquarters | LiFePO4 Battery

I saved $ on the first order,,, going direct to the store front vice Ebay.

I machined up some copper bus bars and derlin holders today.... just waiting on the cells to arrive now.

smokinjoe73

Marquez, make sure to post up pics of your creation with results.

skokievtr

Instead of making Delrin spacer blocks, what about using 4 of these (2 at each end)?

2 HOLE SPACER BLOCK 38120S, 38120P & 38140S

And Headway also sells bus bars (nickel coated copper, thickness unknown; 2 (series) & 4 (parallel) battery app)

Product List

For the Anderson connectors, should we get 30 or 40 amp (for 12 versus 10 gauge wire), and "unassembled" or "bonded" plastic housing (unassembled seems more versatile as they can be oriented for polarized mating)? However, the bonded housings "Powerwerx now offers Red/Black Powerpole sets that have been ultrasonically welded together which creates a permanent bond between the red and black housings. This can save assembly time, guarantee correct configuration, eliminate the need for a roll pin and enable the use of Powerpole accessories such as retaining clips or block-lok clamps."

Also, is the Power Werx TriCrimp tool worth getting (it seems so for $39)?

45 Amp Unassembled Red/Black Anderson Powerpole Sets

Anderson Powerpole & SB Multipole Series Sets: Bags of housings and contacts in different sizes

Tweety

Well, if you look at the pictures in my original post, you will see that I have indeed used those... They make a good pack in so much as they keep the pack stable... But the point of the delrin plates is to isolate the poles of the cells, not to keep it together... If you touch the frame on the bike with the pole screws or plates there will be fireworks, and you might loose a hand at worst, the pack at best...

With the delrin plates, you can't accidentaly short out anything beyond the two end screws, and you have to make fair mistake to accomplish that, or to stick something down the holes, so it's safe for normal use, albeit not idiot proof...

So if you do use only them, you will need to figure out a way to safely and securely isolate the pack anyways, and the delrin parts can be made with cheap handtools if you have a decent hand really, it's just a whole lot easier if you have a full shop (like I will have) like I borrow at work...

The nickel plated bus bars work well for an application with (relatively) low amperage, like on a bike (The VTR peaks at around 25-30A starting current)... But for usage in a car, you should probably use thicker bars... They are really intended for high voltage packs, in electric cars, bikes and such, where the amperage drops as a result of the higher voltage, so they aren't ideal for this usage, I made thicker ones in raw copper...

The connectors I use on the bike packs are the Anderson SB50, which are good for 50A... That should cover most cars as well as bikes for peak starting current... I'd say 10 gauge is marginal, I'd use that or preferrably better... If you have a car with a higher starting current, the SB120's should be plenty overkill, I used that on the few packs I made for big V8's...

That tool seems decent for the money, but I wouldn't know really... My "cheap" tool costs three times that, and it still annoys the hell out of me compared to the tools I use at work, which is freakishly expensive, but smooth as butter to use...

E.Marquez

The HDPE works very well to both locate, secure, and insolate the cells.. and is cheap to buy in 1" thick plates......

You bore a pocket in it deep enough hold and locate the cell....and leave enough material to leave the terminal recessed and protected.

skokievtr

For $39 its worth a shot, eh?

Tweety

What I did was to be "lazy"... I hold the pack together with the orange plastic holders, and then I drilled holes for M3 screws to hold the delrin and holders together, and just countersunk the nuts in the delrin and tightened it together... The result is a very sturdy endpiece... But as Eric said, it's easy to buy 1" thick delrin and make the endpieces instead, then you really don't need the holders, as the endcap will be thicker...

Doubling up on the bars work, but again it's not ideal... Making thicker copper bars isn't really much work, all you need is a drill, a handsaw and a file...

30A is enough in terms of what the VTR would normally draw on startup... But as a general rule, I make things one size larger than what is needed... If you need 30A, make it 40 or 50... Then it won't break... If you make it 30, and you draw 31, it might... Besides, the SB50 connector is one solid piece, and I liked the feel of it compared to the others, so I choose that one... I'd say the 45A rated ones are plenty, just choose something with margin to 30A....

Definetly, worth $39...

skokievtr

Markus, because I can be thick as a brick and unfortunately run on 4~5 hours sleep a day or less, I'm now not sure of the orientation of the connections for the 4-battery "pack" for the VTR. Could you please (once again?) provide a schematic (preferably color coded) of the battery pole connections using the KISS principle? Thx

BTW, you in the house and getting unpacked?

7moore7

They are each 3.2V, 10Ah batteries. So you just line the batteries up in series for all four of them (+) to (-).

If you want to know more out of my basic understanding:

Lining them up in series (+) to (-) increases their voltage while keeping amp hours.

Lining up in parallel (+) to (+) or (-) to (-) increases amp hours while keeping voltage.

So if you want a 12 V, 10Ah battery out of those, you line them up in series to get 3.2*4 V, or 12.8V and 10Ah

If you were to put them all in parallel, you would get a 3.2V, 40Ah pack. Aaaaand that's about the extent of my knowledge...

Tweety

7moore7's got it...

Nope, not yet... But getting there... An emergency installation/service trip to Stavanger got in the way, so right now I'm operating on half an hour of sleep (on the plane) for the last 32 hours... Gonna go pass out now... Nighty nite...

xeris

Any reason why these wouldn't work for a Hawk with a bit more load demand (heated gear, etc) in a 4 pack configuration?
H-38120HP Headway LiFePO4 Cell

7moore7

Or use two of them for 16Ah? Those things are huge! I'd like to hear if there are any draw backs as well...

Tweety

The two of you kind of haven't read the discussion have you? Those are the cells we are discussing, besides a bit spec difference...

Well... No, besides the fact that the H-38120HP is suited to a high power output configuration, like an electric car...

If you where to read what has already been written, the H-38120S cells are the largest one's I have crammed into the stock battery bay... The difference is that you get 10Ah instead, and they are better suited to the low ampere draw that our bikes subject them too (relative terms, but)...

Ie, it's been done... More than once... Lookie here what I have in my hand as I write this...



But for the VTR in normal use, I still recommend the small 8 pack, it's going to have a longer lifespan...

The downside to having a 4 pack is that you are more likely to deep discharge or overcharge the cells, and reversing one that with an 8 pack, where two cells always equal each other...

xeris

I have read the entire thread at least twice and individual posts more than that. So maybe it's my comprehension that is at fault. To make sure I'm on the same page, the cells that you are using are the 38120S, blue exterior, 6mm screw at each end, 10Ah, like this H-38120S Headway LiFePO4 Cell
The other cell 38120HPH-38120HP Headway LiFePO4 Cell has a lower 8Ah rating but capable of higher discharge rates, correct?
When I made my post I did not notice the lower Ah rating on the 38120HP
So what you are saying is that the higher discharge rate isn't a benefit for the type of use, and the lower Ah rating is a negative issue related to deep discharge and cell reversal? Is that also the reason that you're recommending an 8 pack (more reserve before the low voltage knee is reached)? Also I don't understand reason for possible over charging with a 4 pack vs an 8 pack.
You're building 4 packs, I'm assuming for resale. Is cell reversal from deep discharge and overcharge really that big an issue?
Just trying to educate myself, thanks

Tweety

Now, wait a minute... Your mixing a lot of things together in one lump now...

One, I'm not selling much on the forum, since I'm overseas... But I am selling locally, to other riders in my area... I can sell to the US however, but not too cheap since shipping eats it up... With that cleared up, lets move forward...

In general, an 8 pack, where you have the cells configured in pairs, + to + and - to -, the pack is essentially just an 4 pack in the end, but you gain the fact that those two cells keep each other in balance, vs a single cell, so less prone to killing the pack from overcharge, or undercharge... This has nothing to do with Ah rating in specific, all to do with how cells behave relative vs each other in a pack...

But yeah, going to a higher Ah total for a pack also reduces the risks of accidentally damaging the pack, but that should kind of be figured into the sizing of the pack for it's use to begin with... Ie why I would recommend an 8 pack of 26650 A123 cells for a VTR in normal everyday usage... It's best suited for how the bike is using the battery...

But, if you do use stuff like a heated vest and similar things, and need more Ah for a buffer, it becomes complicated to make the 26650 cells into larger packs adding them in pairs and strings over and over, so then you go to a larger cell... Ie the headway H-38120 cell size...

Now, higher discharge rate means that the cell can supply up to 200A instead of 100A... Since the VTR at worst will need 25-30A to whack the starter motor over, the difference is pointless...

I'm making 4 packs of the larger cells, yes... And they work just fine... An 8 pack would not come close to fitting anywhere near the battery box or any other place on the VTR... So that's not an option... But it would be more robust against stupid mistakes...

Now, that's answers to your specific questions...

Tweety

However, to make it clear what I'm talking about... Let's get some background...

No, the packs or cells aren't susceptible to deep discharge or overcharge... The user is...

An SLA type battery is very resilient, and takes effort to kill... An LiFePo4 cell is a bit less soo... Overcharging it is hard to do on a bike, so as long as you leave well off using stupid "intelligent" chargers it's fine... Deep discharge however is an issue that's more likely to happen...

The bike usually drains a battery slowly if it's left sitting... So doing that over extended periods is plain stupid... Design the battery pack to have a quick disconnect, like an Anderson connector, and unclip it for storage and every things fine... I have done that for years, on several packs I have been "testing" pretty hard, ie I have done my best to use them had, but not intentionally kill them... Apart from the one I accidentially left discharged in a -10C garage a month, none of them have died...

But that's mostly down to me knowing how to ressuect them, and having the tools... For the "average user", the rules are simple... Pick a pack size that you are unlikely to discharge below the knee in normal usage, and rarely topcharge, never, ever connect a charger to it, and it will outlive you... Anyhting else, you need to "baby it" and make a conscious effort to maintain it to some point...

If you want more, do a search, I have discussed this in ahalf a dozen threads so far, and I'm to lazy to repeat all the info about how to balance and chage the cells, IF you decide to do so... Best practice, don't fix things that aren't broken... You don't need to charge the pack unless you have done something stupid... Even running it flat, you don't need a charger, just run the bike until it starts, and go around the block a couple of times and the pack will be charged enough to start the bike...

xeris

Thank you for the explanation.
over the course of the last few months I have read and re-read all of the other threads on this subject (elsewhere on the net as well) that I could find. I appreciate you extensive input on this subject.
I'm still putting the info to work in my head. How I understand it as it relates to the discharge, is one of the pair of cells will charge its buddy keeping it from dropping below the voltage knee and if you don't do anything stupid the weaker cell won't reverse polarity. This, I think, is where I was having trouble understanding.
From your reply it seems that the 26650 cells are a better candidate for a SH daily driver.
Again thank you for your time.

7moore7

I just have extremely selective attention, haha!

Tweety

Yep, you got it right...

The 26650 cells in an 8 pack is a better candidate, since you are then measurably discharging the pack for a start, making it cycle below a topcharge even if you ride a short ride... The larger cells won't even start to drop before you start topfilling them again unless you are actually using heated grips or a vest or whatever... As a result, you will end up topcharging them, and the lifespan is reduced...

superman_006

Pretty good info, I would think the 8 cells @ 200 amp would be better. I think the gel and AGM YTX12-BS batteries are only 180 amps. But going with this would be great for those doing custom tails or wanting more room, you could stack 8 cells like 50 different ways to fit how ever. It will be neat to see these in someone's finished out tail.

Tweety

Well... IF you think that, you are either not reading the specs, or not understanding them... Yeah the smaller cells in an 8 pack is better, but not because they are rated at 200A...

The 200A rating is burst rating... Ie they can supply that in a very short burst... Their total storage rating for an 8 pack is 4.7 Ah... The other version is burst 100A, and storage 10 Ah for a pack of four... And the VTR needs about 25-30A burst for starting... So how does having 250A burst higher than you need turn into something useful?

And no, there are no SLA in the world that's going to fit into the bike that's giving you 180 Ah... That would be a truck battery... Yeah, I know the numbers are that high on paper, but it's also a number attained by discharging the battery at almost no current (like the bike sitting with a dashclock running) for a very long period... The burst rating on a SLA is abysmalically low, which is why it basically can't start the bike more than 2-3 times when it's cold outside, where as the LiFePO4 pack can do it a couple of dozen times on 4.7 Ah...

SLA = high storage, low burst, high voltage drop on load...
LiFePO4 = low storage, high burst, low voltage drop...

The reason they are a better option is that, like I said, the 4.7 Ah can start the bike a dozen or more times, but it will be noticably discharged by doing it only once, making the battery cycle properly, where as the SLA doesn't need to cycle, and the larger LiFePO4 pack doesn't cycle and suffers from it...

The reason behind thi is that an SLA can be "maintainance charged" where as the LiFePO4 has a limited amount of charge cycles, and maintainance charging builds up internal resistance, making the cell fail...

So IF you go for a big cell pack, you need to use a vest or whatever to make it work, otherwise it will start to slowly fail... Otherwise just select an 26650 8 pack and ride as normal, every day...

E.Marquez

Some thoughts.
Battery's are just storage devices... (no **** marquez, really?)
the idea from Tweety is valid, the larger cells need to be discharged enough in use that the bike has a chance to charge them...more then then just a top charge.

BUT, using a "vest or whatever to make it work" ie using more current then the stator can provide, thus pulling from the battery pack,,, only works if that excess use stops at some point so the charging system can completely recharge the battery before stopping (not a long time)

So yes, if your using the larger cells in a 4 pack.... when you turn on the bike, let the headlight burn while your putting on gloves and helmet (this actually "warms up" the cell pack and will make easier starting in cold weather) If you have a heated vest and gloves, better, let um warm up and pull some power as well.... start the bike, and ride off......if what your using for power draw , creates a delta in usage vs stator output, just stop using the stuff before you end your ride.

With LiFePO4 Cellls it is a balancing game (pun intended)
On the one hand you want the extra capacity they offer ready and available to start the bike,,, as many times as needed to get you going down the road...
On the other hand, you can not treat LiFePO4 Cells like a SLA battery and in the event the bike starts immediately and uses hardly any stored energy, just let the system top off the battery and then "maintain" the rest of the ride.

I agree with Tweety, for most, the better choice is a 8 cell pack of 26650, it is much more install and forget.

IF a rider is willing to understand and take the time needed to use the 4 cell 38120S pack as needed, it is a better option if it fits in your desired location.

Just make sure to discharge it before or during the ride, with enough ride time left to recharge it.