Maybe, maybe not.

Charging Information For Lead Acid Batteries - Battery University

I guess it depends on the charger types....I have seen quick chargers for 48v golf carts up to 120amps........ I would call the charger manufacturer for advice, because it is likely that the chargers will trip the voltage indicator circuit in each other reducing charging voltage....Now there might be some way to rewire the chargers, but easier just to acquire a more powerful charger....

http://www.powerstream.com/8000-watt-lead-acid-charger.htm

If by "dry" you mean sealed gel type or AGM then you need to excercise caution.

Even if you connected both of these chargers in parallel the charge rate will not change.

Charge current is increased by increasing the charging voltage.

Have you actually measured how much current your chargers are pumping and the voltage they're presenting to your battery at different times in the charge cycle? Battery temperatures are good to know too.

The charge time you quoted can be reduced but probably not with the chargers in your possession.

More details of all your kit would help us come up with a solution.

Yes, you definitely can use your second charger to drastically reduce the time you have to wait for a charged battery.

It does require an additional investment. A second battery is needed so that it can be charging while the other is in use.

Waiting time V charging time....

....that's one way of looking at it.

You don't mention what the battery charger output voltage is. Commonly (and keeping it simple) these are 12V for standard lead acid batteries, with higher voltages for ones specially designed for battery packs.

If you have two 12V chargers and a 48V battery pack made up of a number of 12V battery cells (or blocks), AND you can disconnect the batteries into 12V cell (or block) multiples then you can use two 12V chargers to halve the recharging time.

If however you have two 48V chargers then it MAY be possible to link them in parallel to reduce the charging time but I STRONGLY suggest against this in your case as if it is not done correctly AND the battery chargers are not designed for it AND you don't carefully monitor the recharging process then the battery chargers and/or batteries could be damaged.

Perhaps just getting a second battery would be best.

The simplest answer is yes you can parallel two 9 amp chargers that are the same to make a 18 amp charger. It will give you a higher initial current capacity but in the end they will still follow their end of charge cycles just the same.

I have done it many times to get faster charging of large battery sets from what I considered under sized charging systems.

That only works if the single charger is working at current limit which it probably isn't in this case given the charge time quoted for this Ah battery capacity.

More data from the OP would work a treat right about now.

The charging/recovery rate for any battery is dictated by the applied voltage (pressure) of the battery charger and the impedance/resistance of the battery which is dependent on how far down the battery has been discharged and battery plate material composition/makeup.

The amount/magnitide of current the battery charger outputs at any one time during the charging cycle is regulated by the battery recovery state and the capacity of the charger.

Paralleling the two chargers will not decrease the charging time of the battery pack since the voltage output of both chargers is most likely the same level as the current output rating is the same. (9 amp)

Consult the battery OEM documentation and identify the maximum allowable applied voltage.

Verify the voltage output of your charger(s) (measure with VOM while connected to a battery and charging).

If the charger is not capable of meeting the OEM recomended/allowed maximum charging voltage, you will have to purchase a charger that can meet the specification in order to shorten the charging cycle time.

CAUTION!! Applying an equalization or high rate of charge (higher voltage) can and will damage the equipment the battery is providing power to if the level is above the equipment rating. Be sure to remove the battery from the circuit during fast rate charging if this is the case.

you can but only if you pulse the power a regular charger will hurt the battery.

if its pulsed in the battery properly you can do it in a hour we have a charge system here that charges a battery in that time frame we built it for lithium but does lead acid batteries as well

Richard

ok,itseems that more information about the chargers will give you guys a clear picture and you can help me with the answers....

the chargers are scheduled to be here in a couple of weeks,ill put the specifications on the forum thread once i have them..

thanks to everyone who answered.will get back to you soon :)