increasing battery capacity

[JamesW]

Ok this is a dangerous question for an unskilled person to be asking, but I will ask it anyway on the understanding that I will wait to learn more before I act on this info... It is food for thought for the next 9 months.

Can a battery, say 36V 10AH be taken to a greater voltage capacity in the same way that an "normal" one would in a childs toy. i.e. by the addition of extra cells in series (I'm assuming they would need to be of a similar spec and could be sourced from BMS Battery).

I keep reading something about "balancing" - would this need to be done.
- would the existing BMS cope?
- would the next stop after 36V be 48V (another 3 or 4 cells if they are rated at 3.7Vea)?
- What would be the implications on this from a charging perspective? - could the existing charger be used or would a new one be required?.

Or am I just in cloud cuckoo land thinking it might be possible to move from a 36V battery to a 48V battery for a significant amount less than buying a new one?

I rather the side effect of getting this wrong is a quick trip to the local hospital to the burns unit and maybe the loss of whatever building was being worked in!

James

 

[OldBob1]

Hi Jame my advise at the moment if you have a 36 volt system is to use it and enjoy it, at the same time get your self a good multi meter and learn how to use it and try to under stand Ohms law which is the basic to electrics.
Like most things its horses for courses, speed or grunt.
Bob.

 

[JamesW]

Thanks Bob,
I have a dmm and soldering iron at both home and office. Am familiar with Ohm's laws and did GCSE electronics a long time ago. This does not mean that I class myself as knowledgable enough yet to mess around with batteries. I am familiar with the principles of the.battery from A level chemistry (how they work and that to charge them you apply a voltage across them the wrong way to move the chemical ions back from cathode to anode - unless I have got my poles mixed up). I am also aware of the fact that shorts can cause overheating and overheating ( also a soldering byproduct if care is not taken) causes batteries to explode and the person who got it wrong to have to deal with a fire and chemical burns.

Hence my question to ensure I have the correct info and don't get hurt!

James

 

[Geebee]

Search for booster pack, there will be a few threads.
There is a chance of blowing your controller as it might exceed component voltage.
Charging, you charge it seperately and you will need a different charger for the booster pack which is connected in series with the main pack to supply more voltage when using the bike, you preferably need to use batteries with similar capacity and also preferably a similar C rating as the main battery so that the booster pack doesn't get drained to far or inhibit power delivery.

 

[JamesW]

So Booster Pack is the only way?
I way hoping to avoid have to charge more than 1 thing (even if that means replacing the controller). I'm looking into integrating my lights into the system as soon as the warrantee expires, so I don't have 3 batteries to charge each day, adding a booster pack would be a step backwards after doing that!

I was hoping it might be possible to tack more cells onto the existing battery to increase the voltage or something.

James

 

[KirstinS]

A turnigy accucel or an imaxb6 charger will charge your booster battery. And just very useful too. I've used mine to charge everything from a range rover to a Kindle battery. Very useful for capacity testing too

A ku65 can take 44.4v nominal with minimal danger of blowing

So that's a 7.4v booster battery

I put mine in a saddle bag

 

[KirstinS]

Do remember that your lvc will no longer work as well

 

[JamesW]

A turnigy accucel or an imaxb6 charger will charge your booster battery. And just very useful too. I've used mine to charge everything from a range rover to a Kindle battery. Very useful for capacity testing too

A ku65 can take 44.4v nominal with minimal danger of blowing

So that's a 7.4v booster battery

I put mine in a saddle bag

(Next Post:
And do remember your lvc will no longer work as well)

And that was where someone started to speak Chinese!!

I'm ok with Chinese, but speak slowly, write it down and give me an interpreter!!!

James

 

[JamesW]

Ok, I've had a little look at booster pack threads - they've confused me a bit.
I've also spent the afternoon rewiring a 6-60V DC converter that is stepping down an input voltage to 5V to allow me to charge my phone and run my EL wire (be seen from the side at night.) The eventual idea is to have all lights on the bike coming off the main battery, but as this is not working at the moment I have broken them out to come off a battery pack for my front light the case of which got smashed up so I have been unable to mount it in wet weather on the bike.

anyway... getting to the point...
I see that this battery pack contains 4x18650C Li-ion batteries wired in 2 pairs to give 7.4V nominal output.

When I get my main battery back up and running is it just a case of connecting these in series with the other battery to increase the voltage to 43.4V - is this basically what a booster pack is? (and if it is what extra fuses might be required.)

James

 

[patpatbut]

Theologically yes but 4 cells would not be enough. Of course it depends the capacity of your main pack. You need to match the Ah

Pat

 

[JamesW]

Theologically yes but 4 cells would not be enough. Of course it depends the capacity of your main pack. You need to match the Ah

Pat

So if I doubled the numbers of cells in parallel ( or whatever figure is required to match the Ah) would my light charger still be able to charge it safely?

 

[patpatbut]

Your light battery should have a small bms to charge the 4 cells. You might need a new bms to charge more cells at the same time or you can get a balance charger to balance charging every time.

Also, you need to check the max amp out of the cells you have. Just make sure don't go over it.