is it bad to charge 12v sla @ 3.0 - 5.0 amp

[DanSFIV]

hi,

i just got this to charger my 12v batteries individually.

http://www.canadiantire.ca/AST/browse/4/Auto/3/Batteries/BatteryChargers/PRDOVR~0111518P/MotoMaster+Eliminator+Intelligent+Battery+Charger+12%2B8%2B2A.jsp?locale=en

when i use optimal charge setting it starts from 2.0 then goes to 3.0 then 4.0 then 5.0.

is it ok or should i just use 2.0a rate

i noticed when i used my regular bulk charger i only got 80v from 72v charger -which is only 13.3v

is 13.3v low??? this was probably the cause of my poor range

whats volt should it be @ 13.8 or is higher still safe - like 14.2

how much voltage should i get with 72v? 88v?

 

[Ykick]

We don't know your setup so unless you input that information such as battery size/capacity, # in series, it's gonna be hard to offer detailed advice.

IMHO 9-12Ah SLA can become stressed above 2A charge rate.

Why do you wish to charge them individually? Balancing every once in a while?

 

[DanSFIV]

yeah i got the charger to do that. this is the first time charging them one by one.

12v20ah 6 in series

i normally charge them all in series (been doing so for 8 months)

i also have 12v18ah 4 in series

i think ill just use 2a to be safe.

was hoping it could fix my 12v18ah batteries hold a better charge. and to desulphator them and got it for a decent price

how much voltage should a 12v20ah sla battery be to be 100%?

how much voltage should a 12v18ah sla battery be to be 100%?

also to check to see if i have any bad sla i got 12 for 2 electric scooters

 

[Xanda2260]

yeah i got the charger to do that. this is the first time charging them one by one.

12v20ah 6 in series

i normally charge them all in series (been doing so for 8 months)

i also have 12v18ah 4 in series

i think ill just use 2a to be safe.

was hoping it could fix my 12v18ah batteries hold a better charge. and to desulphator them and got it for a decent price

how much voltage should a 12v20ah sla battery be to be 100%?

how much voltage should a 12v18ah sla battery be to be 100%?

also to check to see if i have any bad sla i got 12 for 2 electric scooters

Voltage will be the same, regardless of capacity (so fully charged 20ah will be same voltage as 18ah) and its 13.4v fully charged IIRC.
Each battery should not be charged at more than 0.1C regularly (thats 2A for the 20ah and 1.8A for the 18ah)

Bad SLA will not hold a charge (voltage drops lots in a few days without use). A good indicator is low voltage (less than 10v ish)

Hope that helps

 

[Russell]

A fully charged SLA battery IS 13.2 +/- 0.1V and is based on the chemistry. During the charging process an SLA charger will go as high as 14.8V and when the charging is completed it should go into a "maintenance" mode of 13.5+/- 0.3V. 13.8V does NOT represent a higher state of charge, it is only used to keep the battery "topped off". When the charger is removed the battery will settle back to 13.2 +/- 0.1V.

Often times the battery will have the specs on the side regarding the recommended charging rate, or look up the model at the Manufacturer's web site.

Lower than expected range with lead-acid batteries often is because people go by the advertised Amp-Hour rating which is for a 24 hour discharge. When used in a typical EV situation the discharge rate will often be an hour or two. At this rate of discharge an SLA can be expected to deliver 50 to 60% of the rated Ah capacity.

That said, it is very important when charging batteries in series to make sure the batteries are identical, of the same age and that each starts at the same state of charge. Before putting batteries in series each should be fully charged and each battery should be checked periodically to make sure it is at the same voltage as the others. A simple zener shunt can be made and installed on each battery to help keep them balanced if it is a problem.

-R

 

[amberwolf]

Regarding the actual question in the title of the thread, considering 18Ah-20Ah batteries: Usually marked on the side of those batteries is the charging rate for different situations. Cyclic use is typically 4-5A for that size, but it depends on how they are made. So best is to check the side markings.

 

[ZOMGVTEK]

13.3V charge termination is very low. If you are saying thats about the voltage the 12V pack sits, after the charger terminates, thats about right. Generally, chargers run 14.2V termination on a 6 cell PB.

Anything above around 1/5C charge rate generally is towards a 'quick charge' for lead. It won't really be THAT hard on the battery until you near 1/2 or even 1C, but it won't be as charged as if it charges slowly and floats a while on the termination voltage.