Recelling NiMH battery to Li-On/range

[Mary Ferguson]

Hi All,
Ive been away for a while. Ive recently had my Giant La Free Twist Lite (2004) bikes battery recelled. I had the bike garaged for a long while. Im now back on it! . The 'new' battery is 24v 11amp. Ive noticed that even tho I am much lighter and only doing a couple of miles a day, the new LED strip says my battery has gone to half full. This is ridiculous as I used to weigh a lot more and did 14 miles a day. It can only be the battery hasnt been recelled properly or the motor on my bike is drawing a lot more power than it should. Can anyone advise, and tell me what I should do please?

 

[flecc]

Hi Mary, welcome back in the forum. Don't worry about the meter, you are fortunate that it gives any indication.

The meter circuit is matched to the characteristics and size of the cells fitted, so was designed for NiMh cells of 6.5 Ah. A number of us have found that even with new NiMh, changing to different cell capacities upsets the meter.

I've found 9Ah NiMh cells read somewhat inaccurately and another member, Chris, found that 10 Ah NiMh cells didn't leave the meter working at all. Commercial re-cellers have found the same and some subsequently refused to recell them due to this issue and customer complaints.

The resistances etc of lithium cells will be rather different from that of NiMh, so I think you will have to find the new range by experiment and then use the meter proportionally or just rely on mileage readings alone.

In practice you should find a greatly increased range, which could exceed 30 miles, depending on road circumstances.
.

 

[Deleted member 4366]

The meter works from the battery voltage. Nihm cells hold their voltage until nearly empty, then it drops right down suddenly. A lithium battery's voltage goes down steadily as you use it up.

Having said that, the Nihm pack, most of the time, runs at a lower voltage than a lithium one, so the meter should show the maximum for much longer. In that case, it does sound like there could be something wrong with your lithium pack, unless the guy that re-celled it used 6 cells instead of the normal 7.

You should get about 20 miles out of a 24v 11Ah lithium battery.

Did you get a new charger with your lithium battery or are you still using the old one?

 

[Mary Ferguson]

Hi Mary, welcome back in the forum. Don't worry about the meter, you are fortunate that it gives any indication.

The meter circuit is matched to the characteristics and size of the cells fitted, so was designed for NiMh cells of 6.5 Ah. A number of us have found that even with new NiMh, changing to different cell capacities upsets the meter.

I've found 9Ah NiMh cells read somewhat inaccurately and another member, Chris, found that 10 Ah NiMh cells didn't leave the meter working at all. Commercial re-cellers have found the same and some subsequently refused to recell them due to this issue and customer complaints.

The resistances etc of lithium cells will be rather different from that of NiMh, so I think you will have to find the new range by experiment and then use the meter proportionally or just rely on mileage readings alone.

In practice you should find a greatly increased range, which could exceed 30 miles, depending on road circumstances.
.

Thanks for this. Its reassuring to know that I can expect this. I just dont want to run out of juice on a long ride to have to push a 30kg or therabouts bike home! I'll try to use it at weekends close to home and see how far I get!

 

[Mary Ferguson]

The meter works from the battery voltage. Nihm cells hold their voltage until nearly empty, then it drops right down suddenly. A lithium battery's voltage goes down steadily as you use it up.

Having said that, the Nihm pack, most of the time, runs at a lower voltage than a lithium one, so the meter should show the maximum for much longer. In that case, it does sound like there could be something wrong with your lithium pack, unless the guy that re-celled it used 6 cells instead of the normal 7.

You should get about 20 miles out of a 24v 11Ah lithium battery.

Did you get a new charger with your lithium battery or are you still using the old one?

Thanks. I got it all recelled by Motorsavers in Corby. The chaps there seem decent and I wouldnt like to think they've put in reduced no of cells. At the moment the indicator shows 50% less after 3 miles. So Im not sure really what to do. I'll call them again tomorrow. thanks for your advice.

 

[Mary Ferguson]

Thanks for this. Its reassuring to know that I can expect this. I just dont want to run out of juice on a long ride to have to push a 30kg or therabouts bike home! I'll try to use it at weekends close to home and see how far I get!

sorry I got a new charger with the recelled battery.

 

[flecc]

As I've recommended Mary, try it out to see what range you get from a full charge. From my experiences of recelling mine and others Lafree batteries you may be pleasantly surprised.
.

 

[Mary Ferguson]

As I've recommended Mary, try it out to see what range you get from a full charge. From my experiences of recelling mine and others Lafree batteries you may be pleasantly surprised.
.

Ill keep you posted. !

 

[Mary Ferguson]

Ill keep you posted. !

Hi Flecc did you have the same problem as me exactly and you were confident that your bike wouldnt die? I am still looking for a shop/repairer who could service my motor as it was garaged and unused for 12 years. Although it worked straight away, the battery does concern me. The longer I use it the less likely the company is who recelled it will redo it! .

Does anyone know of a place near me, that is reliable and could do a proper diagnostic? In in Luton LU20PY. and transport is a problem is getting the bike anywhere as it wont go in the car!

I was going to start a new thread but perhaps you can advise?
bests
Mary

 

[Deleted member 4366]

You might or might not have a problem with your battery. There are some very simple tests that any dunderhead can do to determine the answer to that. You need a voltmeter, which costs a few pounds. There's no chance of electric shock or anything going wrong during these tests.

Voltmeter:
http://www.ebay.co.uk/itm/Universal-LCD-Digital-Multimeter-Ohm-Voltmeter-Ammeter-AVO-DT830D-Test-Lead-/263117717877?hash=item3d4309c175:g:KqgAAOSwBLlVUesE

When you have a voltmeter/multimeter, show us which one you have, and we'll show you how to check your battery.

 

[Mary Ferguson]

You might or might not have a problem with your battery. There are some very simple tests that any dunderhead can do to determine the answer to that. You need a voltmeter, which costs a few pounds. There's no chance of electric shock or anything going wrong during these tests.

Voltmeter:
http://www.ebay.co.uk/itm/Universal-LCD-Digital-Multimeter-Ohm-Voltmeter-Ammeter-AVO-DT830D-Test-Lead-/263117717877?hash=item3d4309c175:g:KqgAAOSwBLlVUesE

When you have a voltmeter/multimeter, show us which one you have, and we'll show you how to check your battery.

I have one at work. I will ask the tech to check it for me. Thanks. If no joy I'll buy the one in the link, thanks

 

[Deleted member 4366]

He won't know how to check it. See if you can borrow the meter.

 

[Mary Ferguson]

He won't know how to check it. See if you can borrow the meter.

Will do. Ill get back to you. Thanks very much.

 

[Mary Ferguson]

Will do. Ill get back to you. Thanks very much.

He won't know how to check it. See if you can borrow the meter.

Hi there
Sorry for delay. Ive borrowed the voltmeter. Its an ISOTECH IDM97 RMS. If you could explain to me how to assess the battery Id be grateful. thanks

 

[Deleted member 4366]

Hi there
Sorry for delay. Ive borrowed the voltmeter. Its an ISOTECH IDM97 RMS. If you could explain to me how to assess the battery Id be grateful. thanks

Geez, you couldn't have got a more complicated one. I'd need to have it in my hand to see how it works. Perhaps someone else knows how to set it, or you can get the guy that gave it to you to set it to read volts in your battery voltage range.

Basically, you need to charge the battery, then immediately measure the voltage on its main terminals. Without seeing a picture of your battery, I can't tell you how to do that. next, go out for a ride until the LEDs show that it's half empty and then measure the voltage again.

 

[Mary Ferguson]

Geez, you couldn't have got a more complicated one. I'd need to have it in my hand to see how it works. Perhaps someone else knows how to set it, or you can get the guy that gave it to you to set it to read volts in your battery voltage range.

Basically, you need to charge the battery, then immediately measure the voltage on its main terminals. Without seeing a picture of your battery, I can't tell you how to do that. next, go out for a ride until the LEDs show that it's half empty and then measure the voltage again.

Thanks. Ill google it and take it to work tomorrow.

 

[flecc]

It's autoranging, automatically selecting the right voltage range.

Plug the probe leads into the two right hand sockets, red to red, black to black. Then after fully charging your battery, turn the meter pointer knob two positions to the right to the red V and bar next to the Ohms "horseshoe" and take the voltage reading by placing the two probes on the two battery contacts. Then turn the pointer knob to Off again

Switch on and take the reading again when d8veh has said to, then report back here the two voltage readings.
.

 

[Mary Ferguson]

It's autoranging, automatically selecting the right voltage range.

Plug the probe leads into the two right hand sockets, red to red, black to black. Then after fully charging your battery, turn the meter pointer knob two positions to the right to the red V and bar next to the Ohms "horseshoe" and take the voltage reading by placing the two probes on the two battery contacts. Then turn the pointer knob to Off again

Switch on and take the reading again when d8veh has said to, then report back here the two voltage readings.
.

Hi Flecc..Ill do that! Thanks very much. Seems straightforward. Ive it on charge now for tomorrow. I did notice last week that the led hadnt moved at all after riding to and from work so perhaps battery is just bedding in. We shall see.

 

[flecc]

Hi Flecc..Ill do that! Thanks very much. Seems straightforward. Ive it on charge now for tomorrow. I did notice last week that the led hadnt moved at all after riding to and from work so perhaps battery is just bedding in. We shall see.

I didn't answer your earlier question since I didn't want to interrupt the discourse between yourself and d8veh.

The answer is that I've only recelled with NiMh, never with lithium, so I can't add anything relevant from experience.
.

 

[Mary Ferguson]

Hi Flecc..Ill do that! Thanks very much. Seems straightforward. Ive it on charge now for tomorrow. I did notice last week that the led hadnt moved at all after riding to and from work so perhaps battery is just bedding in. We shall see.

Hi Flecc and D8veh.. I did as you said. After charge battery before use was 29.34 v, and then after riding to and from work today where it now shows half full, it reads 28.24 v . I guess this means the LED is wrong and battery still has a high charge left?