Battery help

[rgh]

Hi All. I'm hoping someone can help with this. the battery I have is a 48v 15ah
and its starting to lose power .I have been using it for a couple of years.
I'm after a 48v 20ah battery but wondered if there is a way I could make one myself as
the prices are way to expensive to buy one ready done. ?

 

[Alan Quay]

Hi All. I'm hoping someone can help with this. the battery I have is a 48v 15ah
and its starting to lose power .I have been using it for a couple of years.
I'm after a 48v 20ah battery but wondered if there is a way I could make one myself as
the prices are way to expensive to buy one ready done. ?

That's a lot of battery you are after, give or take 1kWh. Its always going to be comparatively expensive.

If you are willing to learn how to use them safely (or reckless/brave/stupid) then lipo is cheapest, but a bit of a faff.

Sent from my HTC One_M8 using Tapatalk

 

[rgh]

That's a lot of battery you are after, give or take 1kWh. Its always going to be comparatively expensive.

If you are willing to learn how to use them safely (or reckless/brave/stupid) then lipo is cheapest, but a bit of a faff.

Sent from my HTC One_M8 using Tapatalk

Hi Alan

Thanks for replying.I cant afford the price that was quoted at me from the seller who built the bike. I'm more than happy to try any suggestion or help you can give me as I don't want to stop using the bike.
how do you go about with the lipo ones please.?

 

[Alan Quay]

I haven't read all of it, but it looks like as good a place to start as any.....

http://www.instructables.com/id/Lithium-Polymer-Etiquette/

 

[Fordulike]

Are you sure it doesn't just need balancing?

You could trying leaving it on the charger for a day or two, to see if it improves the performance.

 

[rgh]

I haven't read all of it, but it looks like as good a place to start as any.....

http://www.instructables.com/id/Lithium-Polymer-Etiquette/

Thanks Alan. it looks complicated but I will read it more in depth later see if I can grasp it.

 

[rgh]

Are you sure it doesn't just need balancing?

You could trying leaving it on the charger for a day or two, to see if it improves the performance.

Hi Ford.
I just normally go out on the bike and charge the battery when I get home until the charger states it completely recharged.I could give that a go as its worth a try.

 

[anotherkiwi]

Thanks Alan. it looks complicated but I will read it more in depth later see if I can grasp it.

It isn't complicated it just requires a bit of discipline and common sense. You have to be there during the charge, but charging doesn't take long. Choosing the right charger(s) is very important and the most expensive bit of kit.

Will 20 Ah fit there where there are 15 Ah at the moment? Because to get a usable 20 Ah you will need to fit 25 Ah of battery, you can only use 80% for various reasons (charge 12S to 49.8V and discharge to 43.8 V for example).

Probably best you ask Intersat for a quote on a custom Li-Ion battery.

 

[rgh]

It isn't complicated it just requires a bit of discipline and common sense. You have to be there during the charge, but charging doesn't take long. Choosing the right charger(s) is very important and the most expensive bit of kit.

Will 20 Ah fit there where there are 15 Ah at the moment? Because to get a usable 20 Ah you will need to fit 25 Ah of battery, you can only use 80% for various reasons (charge 12S to 49.8V and discharge to 43.8 V for example).

Probably best you ask Intersat for a quote on a custom Li-Ion battery.

Thanks but on checking the site a custom seems to be about £400/500.

 

[Alan Quay]

Thanks but on checking the site a custom seems to be about £400/500.

Batteries are pretty much costed on capacity. 1kWh is a very big battery, £400 is a good price.

For example, a 36v x 10ah will set you back around £240. That's 360Wh.

Perhaps a more pertinent question is why do you need so much capacity?




Sent from my HTC One_M8 using Tapatalk

 

[rgh]

Batteries are pretty much costed on capacity. 1kWh is a very big battery, £400 is a good price.

For example, a 36v x 10ah will set you back around £240. That's 360Wh.

Perhaps a more pertinent question is why do you need so much capacity?




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I agree the £400 price tag is good compared to the £750 I was quoted from Frank the person I bought the bike from for £1200.who seems to be a bit of a con man.
As for the capacity my old battery which was with the bike is a 48v/15ah so obviously I need to keep to that sort of power .

 

[anotherkiwi]

I keep repeating myself but the battery isn't where you want to be saving money. On my dream bike there is a 17 Ah HL Li-Ion battery with internal controller at over 600€ but I can't buy it right now. So I have a LiPo pack which cost so far 180 € for 8 Ah usable at 37 V soon to become 16 Ah usable.

An example 48V 15.8 Ah battery pack (12S - 44.4V nominative, 49.8 V hot off the charger) made from 6S 6.6 Ah multistar (3P2S). This pack will be able to provide 18 Amps to the controller all day long as it is rated for over 180 Amps constant. You will have tenths of a volt sag on steep hills:

275€ for 19.8 Ah nominative, 15.8 Ah usable - 758 Wh
366 € for 21.1 Ah usable - 1013 Wh

Then you add in...

128€ for 2 x 300 W 20 A chargers. Each can charge 2 batteries in parallel at just under 1C don't make the mistake I did and buy an 80 W charger which struggles with 10 Ah 6S packs at 3.4 Amps charge rate.
80€ for a couple of 350 W power supplies (notice the power supplies provide more current than the charger requires). I have a PC power supply which provides about 250 W which I got for free.
50€ Wires, plugs, sundry...

528€ total investment for 15.8 Ah, a 2 hour charge time instead of 5-7 hours etc. etc.

 

[rgh]

I keep repeating myself but the battery isn't where you want to be saving money. On my dream bike there is a 17 Ah HL Li-Ion battery with internal controller at over 600€ but I can't buy it right now. So I have a LiPo pack which cost so far 180 € for 8 Ah usable at 37 V soon to become 16 Ah usable.

An example 48V 15.8 Ah battery pack (12S - 44.4V nominative, 49.8 V hot off the charger) made from 6S 6.6 Ah multistar (3P2S). This pack will be able to provide 18 Amps to the controller all day long as it is rated for over 180 Amps constant. You will have tenths of a volt sag on steep hills:

275€ for 19.8 Ah nominative, 15.8 Ah usable - 758 Wh
366 € for 21.1 Ah usable - 1013 Wh

Then you add in...

128€ for 2 x 300 W 20 A chargers. Each can charge 2 batteries in parallel at just under 1C don't make the mistake I did and buy an 80 W charger which struggles with 10 Ah 6S packs at 3.4 Amps charge rate.
80€ for a couple of 350 W power supplies (notice the power supplies provide more current than the charger requires). I have a PC power supply which provides about 250 W which I got for free.
50€ Wires, plugs, sundry...

528€ total investment for 15.8 Ah, a 2 hour charge time instead of 5-7 hours etc. etc.

I'm sorry you need to keep repeating yourself. but to put it mildly I don't have a clue what your saying. I'M a novice and know nothing about what a battery can do or cant do.that's why I always asked Frank for advice because I didn't know who else to ask..

 

[anotherkiwi]

Not repeating to you, sorry, there are many questions about batteries with the OP trying to save as much as possible.

It isn't a good idea, a powerful motor connected to a substandard battery becomes a sub standard motor. Though on a shoestring budget when I bought my first kit I got a Samsung celled battery and I am not regretting that decision a year later.

 

[D8ve]

The battery is the fuel tank for your bike.
You can get cheaper lighter batteries but unless you know what you are doing. Bad things happen. Like burning your house down. Google lipo fires for that.
I have a 16ah battery that cost about £120 but I need to watch it carefully or the wife will kill me if I burn the house down.
The bigger the battery the better is another thing. As refuelling takes so long etc.

 

[rgh]

Not repeating to you, sorry, there are many questions about batteries with the OP trying to save as much as possible.

It isn't a good idea, a powerful motor connected to a substandard battery becomes a sub standard motor. Though on a shoestring budget when I bought my first kit I got a Samsung celled battery and I am not regretting that decision a year later.

No need to apologize.I know your trying to help.but as I said I don't know anything about e bikes and certainly not the batteries.I asked the question in the hope that they might be a cheaper way to sort the battery out as I don't have the kind of money that's been quoted.

 

[rgh]

The battery is the fuel tank for your bike.
You can get cheaper lighter batteries but unless you know what you are doing. Bad things happen. Like burning your house down. Google lipo fires for that.
I have a 16ah battery that cost about £120 but I need to watch it carefully or the wife will kill me if I burn the house down.
The bigger the battery the better is another thing. As refuelling takes so long etc.

I agree Dave. as stated I know nothing about the battery side of things .I'm just trying to find a cheaper way to keep the bike going.

 

[soundwave]

 

[rgh]

Thanks for that..looks as easy as pie. you do it and there will be a £120 smackers in your pocket.

 

[soundwave]

i dont have the equipment to do it buy the time i bought it all be more than a bought batt.

https://bmsbattery.com/