help please - battery confusion w cb612 rechargable battery

I just bought a used elec scooter for the kids which did not come with the charger for the battery. The scotter only came with one battery, though looking at the manual in the internet, I see it should have had two.

The battery is a CB612. Looking at the internet, I see that these figures usually imply 6V 1.2AMP thoughg the battery shows in brackets

12V6AH/20HR). Does this mean it is a 12V 6AMP battery, or what does the 20HR imply? Also the battery shows 14-15V cycle use, 13.5-13.8V standby use, and less than 1.8A initial current. I believe the cycle use implies the max voltage to charge it at, and since it shows 14-15V that I believe implies a 12V battery (2.4V per cell) - is this correct?

Or could this battery be a 6V, and the reason it shows the 12V stuff is perhaps because this scotter is suppose to have two of these battery connected in series which would make 2 6V batteries into one 12V?

By the way, I am currently charging this battery with a standard converter which outputs 12VDC @ 800mA - I assume this is OK since the battery does show 14-15V cycle use?

One last confusion - the manual on the net said the scotter was suppose to come with a 29V 1A charger - I believe this is because when two of these batteries are in series, the total cycle use is doubled allowing for a max charge of 30V. Is this correct.

Thanks

Reply to
dna_alexov
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A 12Volt 6Ampere-Hour battery. Amp-hours is a measure of capacity.

That means '20 Hour Rate', and relates to the (6AH) capacity. It means if you discharge the battery at 6/20 amps, it will last for 20 hours. If you discharge the battery at a higher rate (more amps) you'll get less useful energy out of it, due to losses in the battery. You might get slighly under half of the nominal 6Ah if discharged at 6/10 amps, and perhaps only 3/4 of the nominal 6Ah if discharged at 6/1 amps.

The 'cycle use' voltage refers to when you use the battery in an applicaition where it gets drained significantly, then recharged fully - it gets 'cycled', as in an electric vehicle. Lead acid batteries are sometimes used like this, but they are also often used in standby applications (computer UPS systems etc.) where they spend most of their time on charge, waiting for infrequent use (when mains power fails, for example). The higher voltage specified for cycle use recharges the battery quickly, but would damage it if charged at that voltage constantly for weeks or months. The lower voltage specified for standby use charges the battery more slowly, but it is safe to leave it on charge at that voltage for the entire lifetime of the battery - many years.

You need more than 12V to charge a '12V' lead acid battery. If you want to use a general-purpose power supply it should be set to somewhere between 13.5V and 14.5V and should be limited to less than 1.8A. More than 13.8V and it'll charge faster, but you'll have to remove it from the charger after a couple of days to avoid overcharge and damage to the battery. At 13.5 to 13.8V you can leave it on the charger for ever (this is a 'float charge' ), but it'll take a few days to charge from flat. At less than 13.5V it'll never fully charge. 12V would barely charge it at all. The better dedicated lead-acid battery chargers automatically switch from the higher voltage 'bulk' charge to the lower voltage 'float' charge, which gives a rapid charge to nearly-full, then a more gentle charge to 100% capacity and won't damage the battery if its left on the charger indefinitely.

If by 'cycle use' you mean 'recharge voltage specified for cycle use' then yes.

It sounds like you need two batteries to make the scooter work, and that these batteries will be connected in series. Thus, you need one more battery than you have to make the scooter work. It is inadvisable to connect 'unmatched' batteries in series, so you should buy *two* new, identical batteries and the single existing battery should used for something else or recycled. The new batteries would need to match the specifications of the existing one - 12V, 6Ah (the '20HR' bit is pretty standard; most batteries of this type are specified at that rate as it gives a bigger number). The type you'll be looking for will be called SLA (Sealed Lead Acid) or VRLA (Valve Regulated Lead Acid) and should mention being suitable for 'cyclic' applications. The place you buy the batteries from should also sell a suitable (specified for SLA/VRLA) battery charger. These are usually rated by the types of batteries they can recharge. You'll want one that can charge 12V 6Ah batteries (to charge them one at a time), or 24V 6Ah batteries (to charge them both together in series). A charger specified only for higher capacity batteries (>6Ah) may charge your batteries too fast (more than the 1.8A initial current specification), which can shorten the life of the battery and release explosive gasses.

Tim

Reply to
Tim Auton

Have a read here:

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John Riley

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