Old Urban mover UM44 charger

[Funky]

Hi Everybody,
Here's a challenge.
I have an old Urban mover UM44 usprite stepthru type. I was given it, and have never ridden it as there was no charger for the battery. It's a waste just sitting there, and every now and again I get the urge to do something positive about it.
The battery on these old things is a 26v, (not 24v, not 36v) 9ah lithium type.
It has a 5pin socket. I have no idea whether it will hold a charge, but it currently has none as I tested it for output using a circuit tester.
I have contacted urban mover via their website email address, but I've got no reply yet.
While I'm waiting for that, I thought I'd get on here and pick other folks brains.
I am not able to find any 26v chargers. So, does anybody have one that works from years ago?
Does anybody have a clue as to a genuine place to look, Ebay has come up with nowt every time I've tried.
Can anybody with proper knowledge tell me if a 24v charger would work?
Any help would be much appreciated, it would be a genuine shame if this bike went unused.
Many thanks, Funky.

 

[Funky]

Hi Everybody,
Here's a challenge.
I have an old Urban mover UM44 usprite stepthru type. I was given it, and have never ridden it as there was no charger for the battery. It's a waste just sitting there, and every now and again I get the urge to do something positive about it.
The battery on these old things is a 26v, (not 24v, not 36v) 9ah lithium type.
It has a 5pin socket. I have no idea whether it will hold a charge, but it currently has none as I tested it for output using a circuit tester.
I have contacted urban mover via their website email address, but I've got no reply yet.
While I'm waiting for that, I thought I'd get on here and pick other folks brains.
I am not able to find any 26v chargers. So, does anybody have one that works from years ago?
Does anybody have a clue as to a genuine place to look, Ebay has come up with nowt every time I've tried.
Can anybody with proper knowledge tell me if a 24v charger would work?
Any help would be much appreciated, it would be a genuine shame if this bike went unused.
Many thanks, Funky.

EDIT.
I found a thread on this site which gave a link to an email address for urban mover and have had an immediate response.
Sometimes I love the internet!

 

[Deleted member 4366]

26v is 24 v. That's why you can't find a 26v one. Most people would call them 24v, though they're actually 29.4v chargers.

7 cells that have a nominal voltage of 3.7v and a maximum of 4.2v, so nominal of 25.9v and maximum of 29.4v.

 

[Funky]

Hey d8veh,
Many thanks for that info. I looked at your 'Bikes I've built' page and note that you must love 'tinkering' with these things and clearly have a far superior knowledge base to me. So, can I pick your brain?
An update on the bike is this.
I talked to a elec bike shop guy who said if I connect the bike to a 24v power supply it would show whether the bike electrics work.
I only have a 22v 0.5amp power supply which I hooked up.
It seems to work so I have confidence the project is worth carrying on with.
The UM44 battery is too old and has had no charge for years so I am told it just wont charge, no hope.
I assume this is just a problem with the cells themselves.
A new battery is prohibitively expensive.
How easy/difficult is it to replace those cells but retain all the other stuff in the battery?
You say there are 7 x 3.7v cells. Are 3.7v cells of the same ah ratings basically all much of a muchness?
What would I need to do to make sure I get the right replacements?
Could I find them on the internet?
I have removed the battery top and bottom carefully so I think I should be able to get access to all of its inner components.
I'm not an eletrician or an electronics whizz kid, but I'm fairly good with my hands and am very patient when I need to be.
If you think you can help me resurect this old steed, let me know.
Many thanks in advance.
Funky

 

[Danidl]

Hey d8veh,
Many thanks for that info. I looked at your 'Bikes I've built' page and note that you must love 'tinkering' with these things and clearly have a far superior knowledge base to me. So, can I pick your brain?
An update on the bike is this.
I talked to a elec bike shop guy who said if I connect the bike to a 24v power supply it would show whether the bike electrics work.
I only have a 22v 0.5amp power supply which I hooked up.
It seems to work so I have confidence the project is worth carrying on with.
The UM44 battery is too old and has had no charge for years so I am told it just wont charge, no hope.
I assume this is just a problem with the cells themselves.
A new battery is prohibitively expensive.
How easy/difficult is it to replace those cells but retain all the other stuff in the battery?
You say there are 7 x 3.7v cells. Are 3.7v cells of the same ah ratings basically all much of a muchness?
What would I need to do to make sure I get the right replacements?
Could I find them on the internet?
I have removed the battery top and bottom carefully so I think I should be able to get access to all of its inner components.
I'm not an eletrician or an electronics whizz kid, but I'm fairly good with my hands and am very patient when I need to be.
If you think you can help me resurect this old steed, let me know.
Many thanks in advance.
Funky

I have attempted to rebuild the battery pack with mixed results however before you go there there are a number of steps you can try. The battery pack in the earlier urban movers running at 26v were are MeH types at 1.2v not the Li ion cell 3.7v as used in later units. There is therefore a lot more of them and they look like the standard C cell as used in a flashlamp. They are spot welded together in sticks in both series to increase the voltage to 25.2 and in parallel to increase the current rating to 8 9 AmpHrs . These batteries do not need as much protection as the Li ion which need cell balancing electronics . The good news is that the cells probably are OK. . These older battery's are controlled by temperature. They are charged at the standard charging voltage until the temperature starts torise dramatically at the full charge level. The additional terminals on the power connector are to connect a thermistor in the battery pack to a sensing circuit in the power supply. I attempted to rebuild the battery pack by purchasing D type cells and soldering them together. It worked after a fashion. I later just replaced the full pack by buying a" frog " type Li ion pack from China on eBay and rewiring it in. I t is pretty simple for any diy person to do and this has given me an extra 3 years service.

 

[AlexBlue85]

Hi can you please tell me if you did rebuild the battery pack or just got a replacement one?I have one Urban mover UM33X and I think I have the same battery. ..only problem is that it shows 27.3 V and if I ride the bike for 1 mile it cutting off but,like the lights from the battery are off..like someone is switched off ...after I press the button and the battery is on again works for 30 sec/1 min..and goes again off...no lights on the battery. ..what can it be?

 

[Fat Rat]

Hi can you please tell me if you did rebuild the battery pack or just got a replacement one?I have one Urban mover UM33X and I think I have the same battery. ..only problem is that it shows 27.3 V and if I ride the bike for 1 mile it cutting off but,like the lights from the battery are off..like someone is switched off ...after I press the button and the battery is on again works for 30 sec/1 min..and goes again off...no lights on the battery. ..what can it be?

Hi

The OP hasn't been on here since October 2016
So I feel you may not get an answer anytime soon

 

[AlexBlue85]

Oh..well..done.my best..thank you anyway for your reply. How's your bike?