Z-20 Replacement Charger Question

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Overload
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Z-20 Replacement Charger Question

My Z20's second OEM charger died, and I was told to get a generic replacement. It looks like the XLR plug is a standard, so no rewiring will be needed.
My question is what voltage should I get a 60V or 72V charger. I would have assumed 60V as it's a 60V (12Vx5)system, but the local electric scooter shop told me 72V as the batteries are above 12v each when fully charged.

thanks for the help,
Overload in CO

PJD
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Re: Z-20 Replacement Charger Question

Absolutely do not use a "72 volt" charger.

Normally, it is understood that a charger's voltage refers to the nominal voltage of the battery pack it is intended for; not the actual charging voltage. So a "60 volt" CC-CV-float type charger will put out a peak voltage of about 72 volts(5*14.5) volts when the pack reaches fully-charged, then switch to float and the voltage will settle down to about 63 volts (5*12.6). Read the charger literature carefully to verify the proper voltages - including if the voltages are adjustable. You want a charger specifically for AGM-type batteries, and it is important to check these voltages whenever getting a new charger to be sure its voltages are set properly.

By the way, it is best to keep AGM batteries on float as much as possible.

Johnny J
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Re: Z-20 Replacement Charger Question

"Float" on lead-acid is more like 13.8V. :-)

Overload
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Re: Z-20 Replacement Charger Question

thanks for the answer. I thought it was strange.

My next question is what Amp rating should I get? The web site I'm looking at has 1.6, 2.5 add 5. The picture of the ElectriCruz® 60 Volt 5 Amp looks like what I have.
thanks again,
Overload in CO

Overload in CO

PJD
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Re: Z-20 Replacement Charger Question

johnny J,

Thanks for the correction; having gone over to LiFe PO4, it's been a while since I've dealt with Pb-acid.

Overload,

I think the maximum recommended charge rate for SLA's is usually C/3; i.e 1/3 of the ampere-hour rating, or about 13 amps for a typical 40AH pack. So the 5 amp charger will be fine, but a 10 amp charger would be a lot faster - probably much more expensive though.

marylandbob
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Re: Z-20 Replacement Charger Question

YES, a set of 5 series connected 12 volt lead-acid or lithium iron phosphate batteries DOES require a charge voltage of approximately 72 volts to properly charge! It is always a good idea to actually MEASURE the output/charging voltage with a good digital voltmeter, to be SURE it is correct! Many chargers have "Current Limited" outputs, so the measured voltage, when connected to a discharged battery, will not reach maximum voltage untill near the end of charge, when the battery is full. Chargers are not always MARKED with their ACTUAL output voltage, as many car type chargers say "12 volts", when they ACTUALLY provide 13.5 to 14.5 volts, (typically, close to 14 volts).

Robert M. Curry

marylandbob
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Re: Z-20 Replacement Charger Question

YES, a set of 5 series connected 12 volt lead-acid or lithium iron phosphate batteries DOES require a charge voltage of approximately 72 volts to properly charge! It is always a good idea to actually MEASURE the output/charging voltage with a good digital voltmeter, to be SURE it is correct! Many chargers have "Current Limited" outputs, so the measured voltage, when connected to a discharged battery, will not reach maximum voltage untill near the end of charge, when the battery is full. Chargers are not always MARKED with their ACTUAL output voltage, as many car type chargers say "12 volts", when they ACTUALLY provide 13.5 to 14.5 volts, (typically, close to 14 volts).

Robert M. Curry

marylandbob
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Re: Z-20 Replacement Charger Question

Yes, about 72 volts is required to charge 5 series connected 12 volt batteries.-It is always best to actually MEASURE the charge voltage with a good digital multimeter, to be sure! Many chargers are NOT properly marked with their ACTUAL charging voltage, as most automobile chargers are MARKED as "12 volt" when actual charge voltage is around 14 volts!

Robert M. Curry

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