How i can increase max speed of my bike?

[crazymaster]

so maybe thats why i am not getting x2 more range with 15a sla compared to 8a li lon ?
I get just about 50% more i think

edit:
i currently nlown up my li lon battery, so now i have only sla. and li lon charger...
but i wonder if i have to buy sla charger or i can continue using li lon charger for my sla batteries

 

[Nealh]

Your SLA's are 12v you need 12v car battery charger it is as simple as that.

 

[anotherkiwi]

A LiPo charger can charge many other different chemistry batteries including SLA which MUST BE CHARGED AT 0.1C If you try to charge it faster bad things will happen...

 

[Deleted member 4366]

A lithium charger will over-charge SLAs, not under-charge them.

 

[Woosh]

A lithium charger will over-charge SLAs, not under-charge them.

each SLA cell (nominally 2V) can take 2.75V before you kill it, 12V SLA has 6 cells, 3 * 12V SLA have 18 cells.
18 * 2.75V = 49.5V
if you charge at 42V, you won't kill the SLAs

 

[Deleted member 4366]

each SLA cell (nominally 2V) can take 2.75V before you kill it, 12V SLA has 6 cells, 3 * 12V SLA have 18 cells.
18 * 2.75V = 49.5V
if you charge at 42V, you won't kill the SLAs

That's not right. I think you've confused SLAs with wet lead batteries. SLAs start gassing above around 2.5v per cell, which will kill them eventually.

 

[Nealh]

The OP hasn't indicated how he is charging his SLA's.

 

[wheeliepete]

The situation here is that i charge SLA batteries with li lon charger.

Best just use the right charger for the right battery. 12v car charger will be fine for SLA, but you can get a 24v or 36v SLA charger fairly cheaply on ebay.

 

[Danidl]

SLA batteries are more robust than Li Ion or the more exotic chemistries. A single 12 Volt battery 6 cell should be charged to 13.6 V , therefor a set of three , should be charged to 39.9 or 40 V. Any voltage in excess of that will prior to the battery being charged, cause a little heating and a tiny amount of hydrogen gas release . And when the battery has charged, to any excess voltage above 13.6 ..or appropriate multiple, there willbe a lot more outgassing as the water decomposes . In a Wet battery, the water can be replaced, but in sealed batteries it is an nightmare, as one has to break open the seals ... or just leave it and hope that the oxygen and hydrogen recombine.
Your Li Ion Charger is satisfactory for charging the SLA types provided
1. You disconnect when the overall voltage gets to 39V . The charger will have been working in constant current mode , so will be charging slower than would a normal SLA charger.
2. You insert a few power silicon diodes in series with the positive from the charger. Each one will give you a drop in maximum voltage of 0.7 to 0.8V, so 3 in series will stop any current getting into the battery over say 39 V.

 

[Woosh]

That's not right. I think you've confused SLAs with wet lead batteries. SLAs start gassing above around 2.5v per cell, which will kill them eventually.

It does look like it.
Thank you for correcting me.

 

[crazymaster]

UPDATE

Finally i put 36V(3x12V 15AH SLA) batteries and and i get max speed around 35km/h which is enough for me now.

The range is 25-30km, which is not very good...

I have one more 12V 15AH battery. Do you think that it worth connecting it to gain more range? And what you suggest about connecting?

Today when the 3 batteries finished, i just disconnected one of them and connected the 4th fully charged 12v battery... but the result was not very good. i expected to get enough power, just to be for less range, but power was close to zero(or very low)

What you think that its better for me to do right now?

1. To connect 4th battery just parallel to one of the other 3rd batteries
2. To connect 2 of the batteries in serial connection to get 24V and to make additional switch/button for connecting the other 2 batteries(connected in parallel) connected serial to them to get 36V and to use only when needed(60% of time)
3. To buy 2 more batteries and to have 3 in serial + 3 more in serial like second battery. In this case it will be hard with the space with the bike... and i have to add 10 more kg which is the weight of 2 batteries.


The price of 2 12v batteries is just 40 pounds

 

[Deleted member 4366]

Get yourself a lithium battery. You can get a 36v one for about £160, which will give you double the range. It will also be light enough to ride your bike safely.

 

[Danidl]

UPDATE

Finally i put 36V(3x12V 15AH SLA) batteries and and i get max speed around 35km/h which is enough for me now.

The range is 25-30km, which is not very good...

I have one more 12V 15AH battery. Do you think that it worth connecting it to gain more range? And what you suggest about connecting?

Today when the 3 batteries finished, i just disconnected one of them and connected the 4th fully charged 12v battery... but the result was not very good. i expected to get enough power, just to be for less range, but power was close to zero(or very low)

What you think that its better for me to do right now?

1. To connect 4th battery just parallel to one of the other 3rd batteries
2. To connect 2 of the batteries in serial connection to get 24V and to make additional switch/button for connecting the other 2 batteries(connected in parallel) connected serial to them to get 36V and to use only when needed(60% of time)
3. To buy 2 more batteries and to have 3 in serial + 3 more in serial like second battery. In this case it will be hard with the space with the bike... and i have to add 10 more kg which is the weight of 2 batteries.


The price of 2 12v batteries is just 40 pounds

If a battery is empty or discharged putting another battery in series with it will do no good as the empty battery will not conduct current through it. That is why it waa no improvement.
When the bike is going faster the wind resistance increases rapidly so it takes 8 times the power consumption to double the speed that is why at 35km the range dropped.
Even though the batteries are cheap their lifetimes are very limited. .... that and the fact that lead is heavy is why d8vh is recommending you change to lithium
The math and physics is simple. If you want more range put batteries in parallel if you want more speed increase voltage by putting batteries in series. If you want both then the number of batteries increases very fast and very heavy....

 

[Nealh]

If 35km/h isn't enough get a petrol moped.
Use the 3 in series and be happy with the increase, 3 more in series then both used in parallel will increase range but then you have the extra weight to consider. Far better as d8veh has said get a lithium battery of a similar ah for much more range and save weight.

 

[crazymaster]

Yeah but its becoming very expensive and above my current budget to buy lithium batteries, because i am leaving the country after 30 days, so not enough time to work and make enough profit from the big investition

 

[Danidl]

Yeah but its becoming very expensive and above my current budget to buy lithium batteries, because i am leaving the country after 30 days, so not enough time to work and make enough profit from the big investition

Well that's fine then as your lead acid batteries will be showing significant deterioration after the 60 or more charge discharge cycles they will have been subjected to. But will last the 30 days... Happy days

 

[Steven Halle]

Does anyone have any idea how I could unrestrict a Lectro Urban City bike:

https://www.leisureoutlet.com/electric/bikes/outdoor-pursuits/117090-lectro-urban-city-19-mens-electric-hybrid-bike?gclid=EAIaIQobChMIz-Wl5ZCC2gIVbbHtCh1Tqg-1EAQYASABEgKO4_D_BwE

There doesnt appear to be an magnets on the wheels, so I guess it maybe a change of the controller, but I am new to E-Bikes so I know little about whether this is possible or not.

Any feedback will be appreciated, unless it is about the legality of riding this bike in the UK...I am aware of the UK laws but I still want to know if this is possible?

 

[Nealh]

Does anyone have any idea how I could unrestrict a Lectro Urban City bike:

https://www.leisureoutlet.com/electric/bikes/outdoor-pursuits/117090-lectro-urban-city-19-mens-electric-hybrid-bike?gclid=EAIaIQobChMIz-Wl5ZCC2gIVbbHtCh1Tqg-1EAQYASABEgKO4_D_BwE

There doesnt appear to be an magnets on the wheels, so I guess it maybe a change of the controller, but I am new to E-Bikes so I know little about whether this is possible or not.

Any feedback will be appreciated, unless it is about the legality of riding this bike in the UK...I am aware of the UK laws but I still want to know if this is possible?

The battery is a bit weedy at 8.8ah, unrestriciting (if possible) will drain it and hasten it's demise quicker.
The display is led so speed will be pre-set and most likely non adjustable as is..

 

[Steven Halle]

Thanks for your reply....here is my display (Attached)

 

[Deleted member 4366]

The controller is normally in the frame above the battery. To get at it, you have to remove the battery holder/tray thing, then you can pull it out. Sometimes, there's a pair of wires which restrict it, and if we knew what controller it is, we could give better advice.