Mobility scooter batteries

jessmist

Hi,
I have two 75amp batteries on my mobility scooter.
The batteries don't seem to be holding charge anymore. The batteries are only 5 months old. So I am going to send them back to the supplier to test them.
The batteries are agm 75amp batteries. 
I have just purchased a new charger to rule out my original charger being faulty.
But when I connect the new charger the red light and green light come on. 
So it appears the batteries are fully charged. But I know they aren't as I have just used the scooter.
If one or both batteries are faulty could the charger detect a fault and this is why it shows fully charged? 
As it seems strange the charger isn't trying to charge the batteries.
Any advice? 
Thanks 

Baldytyke88

Can you use a multimeter and test the voltage of each battery?

FreeBear

Baldytyke88 said:

Can you use a multimeter and test the voltage of each battery?

The battery voltage needs to be checked with a large load. I'd suggest going to your local tyre & battery place (ATS or similar) and ask them to test both batteries.

jessmist

Baldytyke88 said:

Can you use a multimeter and test the voltage of each battery?

One battery was reading 13.5 and one was 13
I was just surprised the new charger doesn't seem to try and charge them. 
It just shows the red and green light. 
Could the charger be detecting a fault so that's why it doesn't try to charge.

ThisIsWeird

jessmist said:

Baldytyke88 said:

Can you use a multimeter and test the voltage of each battery?

One battery was reading 13.5 and one was 13
I was just surprised the new charger doesn't seem to try and charge them. 
It just shows the red and green light. 
Could the charger be detecting a fault so that's why it doesn't try to charge.

These no-load voltage readings suggest that the batteries are actually ok. But, as FreeBear says, they really need testing under load.

When you add in the fact the batteries are only 5 months old, my suspicion is that there's a fault with your scooter, and not the batteries.

Where would you go to have this checked? Who fitted the batteries for you - if not yourself?

jessmist

ThisIsWeird said:

jessmist said:

Baldytyke88 said:

Can you use a multimeter and test the voltage of each battery?

One battery was reading 13.5 and one was 13
I was just surprised the new charger doesn't seem to try and charge them. 
It just shows the red and green light. 
Could the charger be detecting a fault so that's why it doesn't try to charge.

These no-load voltage readings suggest that the batteries are actually ok. But, as FreeBear says, they really need testing under load.

When you add in the fact the batteries are only 5 months old, my suspicion is that there's a fault with your scooter, and not the batteries.

Where would you go to have this checked? Who fitted the batteries for you - if not yourself?

That's more of a worry if it's not the batteries.
I'm think the manufacturers do a home service. But would have to check on that.

FreeBear

jessmist said:

ThisIsWeird said:

jessmist said:

Baldytyke88 said:

Can you use a multimeter and test the voltage of each battery?

One battery was reading 13.5 and one was 13
I was just surprised the new charger doesn't seem to try and charge them. 
It just shows the red and green light. 
Could the charger be detecting a fault so that's why it doesn't try to charge.

These no-load voltage readings suggest that the batteries are actually ok. But, as FreeBear says, they really need testing under load.

When you add in the fact the batteries are only 5 months old, my suspicion is that there's a fault with your scooter, and not the batteries.

Where would you go to have this checked? Who fitted the batteries for you - if not yourself?

That's more of a worry if it's not the batteries.
I'm think the manufacturers do a home service. But would have to check on that.

Being less than a year old, you should be going back to the seller to get any fault fixed.

jessmist

FreeBear said:

jessmist said:

ThisIsWeird said:

jessmist said:

Baldytyke88 said:

Can you use a multimeter and test the voltage of each battery?

One battery was reading 13.5 and one was 13
I was just surprised the new charger doesn't seem to try and charge them. 
It just shows the red and green light. 
Could the charger be detecting a fault so that's why it doesn't try to charge.

These no-load voltage readings suggest that the batteries are actually ok. But, as FreeBear says, they really need testing under load.

When you add in the fact the batteries are only 5 months old, my suspicion is that there's a fault with your scooter, and not the batteries.

Where would you go to have this checked? Who fitted the batteries for you - if not yourself?

That's more of a worry if it's not the batteries.
I'm think the manufacturers do a home service. But would have to check on that.

Being less than a year old, you should be going back to the seller to get any fault fixed.

Yeah I'm going to send the batteries back to the seller for testing.
The scooter is quiet old but in really good condition..

ThisIsWeird

jessmist said:

Yeah I'm going to send the batteries back to the seller for testing.
The scooter is quiet old but in really good condition.

Surely costly to return the batteries?

The battery charger is 12V? And the batteries too? In which case, they are surely connected in parallel, so even if one battery was defunct, the other would still power the scooter? If your scooter is 'dead', then I suspect summat else.

Your scooter has a headlight? Does it work?! Brightly? If so, I'd turn it on, and leave it for a good hour.

See if the headlamp is still bright after an hour, and also check the voltage across the battery. Plug in the charger and see if the charger now 'works' to charge the battery - if so, everything battery-related would appear to be ok.

Make and model of scooter? I wonder if it has fuses and safety trips?

Albermarle

I think the types of batteries used in these scooters can be affected by the charging cycle ( although obviously I do not know exactly what the batteries are in your case) 
They should not be run completely flat.
They should not be regularly just topped up by short periods of charging after a short use period.
Ideally they should be used until they are quite low in charge, and then have a full recharge ( often takes many hours).

If the battery is faulty, knackered, it can confuse the charger into thinking they are fully charged when they are not.

jessmist

ThisIsWeird said:

jessmist said:

Yeah I'm going to send the batteries back to the seller for testing.
The scooter is quiet old but in really good condition.

Surely costly to return the batteries?

The battery charger is 12V? And the batteries too? In which case, they are surely connected in parallel, so even if one battery was defunct, the other would still power the scooter? If your scooter is 'dead', then I suspect summat else.

Your scooter has a headlight? Does it work?! Brightly? If so, I'd turn it on, and leave it for a good hour.

See if the headlamp is still bright after an hour, and also check the voltage across the battery. Plug in the charger and see if the charger now 'works' to charge the battery - if so, everything battery-related would appear to be ok.

Make and model of scooter? I wonder if it has fuses and safety trips?

The seller is paying for the batteries to be returned for testing. If they are not faulty I will have to pay for them returned back to me.
The scooter will run fine but only covers about 4 miles before the battery's are showing really low.