# motorcycle battery pack conversion



## frodus (Apr 12, 2008)

I assume the motorcycle is Gas Powered still.

How many amps do you pull while starting the engine? How many do you pull with all lights on with the bike running?


----------



## LincsTM (Aug 23, 2013)

frodus said:


> I assume the motorcycle is Gas Powered still.
> 
> How many amps do you pull while starting the engine? How many do you pull with all lights on with the bike running?


This is the problem as the battery is housed in the frame and there is no access to the battery to take readings and the way the bike is built I no way of taking any thing off to take any reading. So I was hoping that there may be some way of building something like the original values of the lead acid battery.

I will try and get the reading over the next couple of days.

I know this is not much help.

Tim


----------



## LincsTM (Aug 23, 2013)

frodus said:


> I assume the motorcycle is Gas Powered still.
> 
> How many amps do you pull while starting the engine? How many do you pull with all lights on with the bike running?


Sorry forgot to say yes the bike is still gas powdered.


----------



## frodus (Apr 12, 2008)

Well, what does the battery say it's CCA is?

Also, some places say 20Ah and you say 25Ah. How many Ah is it really?

Why switch the original Lead Acid to Lithium?


----------



## LincsTM (Aug 23, 2013)

frodus said:


> Well, what does the battery say it's CCA is?
> 
> Also, some places say 20Ah and you say 25Ah. How many Ah is it really?
> 
> Why switch the original Lead Acid to Lithium?


Hi, 
To answer your question which you have raised:-
The stock battery according the makers manual is rated at 20Ah, however the battery that is on the bike at the moment is rated a 25AH, (why the difference I have no idea as the battery was on the bike when I got it) with a CCA(-18°C):285[A].
The reason for the switch is because I am having to make this bike into a trike due to a motorbike accident back I had in February and as a result of the accident I lost the my right leg from the knee. So whilst building the trike I am making a number of changes so that 1) I can ride with one leg and 2) I have to change the frame to take an axle at the rear and this means that were the large lead acid battery would go has the be moved and if I could make/buy (would rather build my own as this would then go with the whole ethos of a self built trike) a smaller battery I would be able to position it under the air box/ seat frame.
I hope this answers your questions and makes what I am trying to do a bit clearer for you.
Thanks,
Tim


----------



## frodus (Apr 12, 2008)

I don't think you'll be able to make it much smaller than the stock battery for 20Ah or so. To get high cranking amps (which lets just say you only need 200A for a few seconds to turn over the engine), you may need several headway batteries in parallel, and 4 in series. 8 of the 10Ah at a minimum I'd guess or maybe 4 of the 8Ah batteries. Having those in an enclosure that is sealed may be larger in size than the original 20Ah battery. If you used A123 M1 cells, you may need 12 of them to get the amps high enough to turn over a 1000cc engine. 

Lithium may be much lighter than SLA, but I don't know how much space you'd be saving.... maybe 1/3 the volume over lead acid.

Maybe start this way:
How much space do you have in the trike for the battery?


----------



## LincsTM (Aug 23, 2013)

frodus said:


> I don't think you'll be able to make it much smaller than the stock battery for 20Ah or so. To get high cranking amps (which lets just say you only need 200A for a few seconds to turn over the engine), you may need several headway batteries in parallel, and 4 in series. 8 of the 10Ah at a minimum I'd guess or maybe 4 of the 8Ah batteries. Having those in an enclosure that is sealed may be larger in size than the original 20Ah battery. If you used A123 M1 cells, you may need 12 of them to get the amps high enough to turn over a 1000cc engine.
> 
> Lithium may be much lighter than SLA, but I don't know how much space you'd be saving.... maybe 1/3 the volume over lead acid.
> 
> ...


Hi Again,

Under the seat frame which is the largest space has the following dimensions:- 
150mm long x 70mm high x 160mm wide. This would put it at the back of the trike and well out of the way of any fabrication changes needed.

Tim


----------



## LincsTM (Aug 23, 2013)

LincsTM said:


> Hi Again,
> 
> Under the seat frame which is the largest space has the following dimensions:-
> 150mm long x 70mm high x 160mm wide. This would put it at the back of the trike and well out of the way of any fabrication changes needed.
> ...


Just a follow up to my last posting

Just to make things a bit clearer as to my plans (if it is possible).
Position 1 as marked on the drawing (attached) is were I would like to put the battery, I plan to make a fibreglass moulded box to fit into the rear frame mould it to the curved shape, so the battery would either fit in as a block or thinner and follow the shape of the moulding.

Would it be possible to have 6 headway cells in series and then connected them to another 6 in parallel, thus allowing me to follow the moulded box. Would this give me the required Amps etc. bearing in mind that the trike would not be ridden in the winter and is stored in a heated garage so starting would only happen in relatively warm periods? 

Tim


----------



## frodus (Apr 12, 2008)

The problem is, just throwing batteries at it could either be over or under what you really need. 

Is it possible to remove the battery and use cables to make it "remote" so you have access to measure the battery current while starting the engine, and also while it's just running idle with all accessories on?


----------



## LincsTM (Aug 23, 2013)

frodus said:


> The problem is, just throwing batteries at it could either be over or under what you really need.
> 
> Is it possible to remove the battery and use cables to make it "remote" so you have access to measure the battery current while starting the engine, and also while it's just running idle with all accessories on?


Hi,

Yes I have been looking at this today, I will do this but I am afraid that it will have to be next week as I have to go back into hospital tomorrow to get the wound on my leg revised as I am having a prosthetic fitted next month.

How ever I will ask if one of my mates will do it for me while I am away.

Thanks for all your input into my project.

Tim


----------



## frodus (Apr 12, 2008)

No problem. I hope everything works out, health-wise, for you.

You can also email me if you feel like it. Go to my website in my sig and email me at that address. I do some consulting/parts sales, but for small stuff like this, I can point you in the right direction.


----------



## LincsTM (Aug 23, 2013)

Thanks again.

Once I get the reedings you have asked for I will forward them onto you at your sales E mail address.

Regards,

Tim


----------



## Malevolence (Jun 5, 2013)

I successfully used 4 series A123 batteries taken out of a DeWalt battery pack as on a Kawasaki ZX-6R (600cc) for about a year before I got rid of the bike. This was several years ago. Even though they should only be hit with about 50 or 60 amps (IIRC), the bike started it up no problem; better than the stock ~8Ah 120 cold cranking amp battery. At the near full voltage the lithiums provided, it took no where near that to turn over the 600cc engine. I won't bore you with the technical details, but CCA are read with a lot of voltage sag which you won't have with the lipos, so you need far fewer amps than you might think based on the specs of the battery. It might struggle or significantly shorten the life of the batteries to start your much larger displacement engine. I would think doubling that would work (two four series packs in parallel). Handily, I happened across a website (not mine) that pretty well details how to do exactly that: http://www.ypedal.com/Skidoo/Index.htm

As much as it's stressed on the website, the Ah capacity really isn't important in your application, other than to have enough to get a couple of starts without killing the battery, since as soon as the machine is started, everything should run off the generator/alternator and recharge the battery. The main thing is to not kill the cells because you're trying to pull too much out of them too fast during start ups. And the simple physics of that is that to get more amps for startup, you'll end up with more amp hours too. 

I'm not sure why he cut those batteries all up and soldered them back together one by one; I simply took 4 off the "end" of the 10 cell string and voila, a 12V battery. I guess he wanted "buddy pairs" but I'm not sure the extra complication is worth it without a battery management system (BMS). If you plan your cuts right, you can get two 4 cell cubes and two individual cells left over. 

There are a few manufacturers that have started making "12V lithium ion" batteries designed to be a drop in replacement for lead acid batteries, but I don't think I've ever seen anything in a format small enough for your purposes. Valence, for example, makes drop in replacements for car batteries. 

The bad thing about the DIY solution is that you could run into cell balance issues if you don't have a battery management system, which is probably way out of the scope of this project. For your application, you will want to make sure all of the cells are individually "top balanced" before you use them, or all have the same matching fully charged voltage to prevent any single cell from being overcharged and damaged. 

Hope that helps and doesn't completely confuse you!

-Brendan


----------



## LincsTM (Aug 23, 2013)

Malevolence said:


> I successfully used 4 series A123 batteries taken out of a DeWalt battery pack as on a Kawasaki ZX-6R (600cc) for about a year before I got rid of the bike. This was several years ago. Even though they should only be hit with about 50 or 60 amps (IIRC), the bike started it up no problem; better than the stock ~8Ah 120 cold cranking amp battery. At the near full voltage the lithiums provided, it took no where near that to turn over the 600cc engine. I won't bore you with the technical details, but CCA are read with a lot of voltage sag which you won't have with the lipos, so you need far fewer amps than you might think based on the specs of the battery. It might struggle or significantly shorten the life of the batteries to start your much larger displacement engine. I would think doubling that would work (two four series packs in parallel). Handily, I happened across a website (not mine) that pretty well details how to do exactly that: http://www.ypedal.com/Skidoo/Index.htm
> 
> As much as it's stressed on the website, the Ah capacity really isn't important in your application, other than to have enough to get a couple of starts without killing the battery, since as soon as the machine is started, everything should run off the generator/alternator and recharge the battery. The main thing is to not kill the cells because you're trying to pull too much out of them too fast during start ups. And the simple physics of that is that to get more amps for startup, you'll end up with more amp hours too.
> 
> ...


Thanks for this info Brendan, I will look into this when I get out of Hospital next week.

Regards,

Tim


----------

