# Eco Bike changing to sealed lead acid to Lithium



## Topfmine (26 Jul 2017)

Hi I live in Hampshire and have been mountain biking around the Woolmer forest area most of my life on a Fusion mountain bike I bought about 25 years ago, the bike is still going strong. I have been talking about with a friend for years about electric bikes and just bought on on eBay just yo have a play. The E bike I bought is an old Eco bike which I believe was used by some police forces up and down the country. It is a 36 volt powered bike that holds 3 12volt 12 amp batteries, although hardly used it does have slight rust on the chrome that's not an issue. Being lead acid sealed batteries they have now come to the end of their life, batteries show 12 volts but have lost its amps the 3 dial light just comes on at two and dies of to one. As for battery replacement I would like to go lithium as 3 12volt 12amp batteries are a huge lump. I thought I could buy three 12 volt equivalents in lithium as a direct replacement with the same terminals but not so. In the mean time I will buy the same old style batteries and will save for lithium until I can come up with a solution. Couple of questions. Can I get one for one 12volt 12amp batteries from lead to lithium, lithium being more efficient would I need less amps say from 12 to 10 or 8. Would I need to charge the bike differently and get a new charger for lithium. Anyone seen or had a Eco bike with full suspension, just wondered what you thought of them even though they are over 10 or 15 years old.


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## Dan B (26 Jul 2017)

You will need a new charger. I'm almost certain you mean "amp hours" not just "amps" and the answer is "no, you well still need just as many but the battery will be lighter"

Actually that's over simplifying a bit as the actual usable energy in a battery also depends on the discharge rate ("c rate") but it's a good place to start


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## raleighnut (26 Jul 2017)

Cheaper to replace the lead/acid ones, Lithium need their own dedicated/matched charger expect to pay twice the price for a comparable set up.


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## KnackeredBike (26 Jul 2017)

The biggest problem you will have is not sourcing the battery and charger, that is relatively simple nowadays from somewhere like www.pingbattery.com

However, most Lithium batteries operate at a higher voltage (or rather they are banked together at a higher voltage) than your 12V lead acid ones.

Unless you want to get into DIY solutions or are really concerned about the weight I would just stick with lead acid for the moment, enjoy the bike, then be aware when you come to upgrade that a Lithium-powered bike is likely to give you greater scope for service/upgrade in the future.


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## Topfmine (26 Jul 2017)

I thought I may need a dedicated charger for lithium and as for price I was expecting to pay about three or so times as much for the lithium route. I wonder what E bikers have done who have revived a perfectly good bike from lead to lithium. Did they go the diy way and make their own or buy a power pack of similar voltage etc and charger and retro fit it to their existing bike. What do you do if the company who makes your bike go bust or your model is out of date. These bikes are not cheap to toss aside and cough up for another.


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## raleighnut (27 Jul 2017)

KnackeredBike said:


> The biggest problem you will have is not sourcing the battery and charger, that is relatively simple nowadays from somewhere like www.pingbattery.com
> 
> However, most Lithium batteries operate at a higher voltage (or rather they are banked together at a higher voltage) than your 12V lead acid ones.
> 
> Unless you want to get into DIY solutions or are really concerned about the weight I would just stick with lead acid for the moment, enjoy the bike, then be aware when you come to upgrade that a Lithium-powered bike is likely to give you greater scope for service/upgrade in the future.


12v lead/acid batteries actually operate at around 13.5 volts when fully charged but this voltage tapers off as they are used so that won't be a problem (the wheel doesn't care what source the electricity is from)


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## KnackeredBike (27 Jul 2017)

raleighnut said:


> 12v lead/acid batteries actually operate at around 13.5 volts when fully charged but this voltage tapers off as they are used so that won't be a problem (the wheel doesn't care what source the electricity is from)


It is just above 12V to about 10.5V when under load, which is what matters. Although the motor will tolerate greater variances than the battery anyway.


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## Cycleops (27 Jul 2017)

The change to Lithium would make the bike much lighter and would be the way to go I'd have thought. Are they prohibitively expensive?


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## KnackeredBike (27 Jul 2017)

Cycleops said:


> The change to Lithium would make the bike much lighter and would be the way to go I'd have thought. Are they prohibitively expensive?


It is prohibitively expensive if you can't find one the same voltage as the existing ones.

Much easier to get lead acid ones which are cheap and readily available at 12V unless weight or range is a critical factor.


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## Topfmine (27 Jul 2017)

Looking at the ping battery site for what I need would be worth the money if I was going to use it a lot. Not a viable option if you were to use it once in a blue moon, I like the idea that you can specify a near fit size to fit in the old battery box, hopefully e bike batteries will be made to a standard size rather than a jumbled mixture. I think as electric bikes become more popular as time goes by especially with the bikes being lighter and more efficient if nothing is done to replace e bike batteries on old model's then there will be a glut of useless e bikes kicking around sitting idle. People will think twice about coughing up for a 1000 plus e bike with the batteries being a issue later on. In the mean time I will buy some lead one's until I get some extra shirt buttons in the kitty.


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## Phaeton (27 Jul 2017)

Topfmine said:


> Looking at the ping battery site for what I need would be worth the money if I was going to use it a lot. Not a viable option if you were to use it once in a blue moon, I like the idea that you can specify a near fit size to fit in the old battery box, hopefully e bike batteries will be made to a standard size rather than a jumbled mixture. I think as electric bikes become more popular as time goes by especially with the bikes being lighter and more efficient if nothing is done to replace e bike batteries on old model's then there will be a glut of useless e bikes kicking around sitting idle. People will think twice about coughing up for a 1000 plus e bike with the batteries being a issue later on. In the mean time I will buy some lead one's until I get some extra shirt buttons in the kitty.


Isn't that the whole issue with the move towards electric cars, buy a very expensive car now only to find in 5-10 years the technology has moved on so far what you now have is so obsolete the only option is to scrap it.


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## raleighnut (27 Jul 2017)

Topfmine said:


> Looking at the ping battery site for what I need would be worth the money if I was going to use it a lot. Not a viable option if you were to use it once in a blue moon, I like the idea that you can specify a near fit size to fit in the old battery box, hopefully e bike batteries will be made to a standard size rather than a jumbled mixture. I think as electric bikes become more popular as time goes by especially with the bikes being lighter and more efficient if nothing is done to replace e bike batteries on old model's then there will be a glut of useless e bikes kicking around sitting idle. People will think twice about coughing up for a 1000 plus e bike with the batteries being a issue later on. In the mean time I will buy some lead one's until I get some extra shirt buttons in the kitty.


The cases can have the individual lithium cells replaced.


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## keithmac (27 Jul 2017)

Quite a few 36v LiOn batteries about if you search hard enough


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