Sealed Lead Acid batteries (SLA)
Sealed lead-acid batteries are used in many MIPRO PA units. They combine the best
available size, weight, power capacity and battery life available when the PA systems
were designed. However, they do require that the user follow some basic practices to
obtain maximum service life. Improper usage can cause damage to an SLA battery in as
little as 48 hours, or even ruin them in a few weeks. They are very similar to the standard
batteries in automobiles. (Excluding newer Electric Vehicles.)
Problems with batteries are by far the most common symptoms we hear about regarding
the MIPRO portable PA amplifier systems. Strictly speaking, dead batteries do not
necessarily qualify as a manufacturing defect under warranty unless the failure occurred
due to a defect in the charging circuitry of the system, or very rarely, a battery itself fails.
Dependent upon how the batteries are used, (frequency of use and depth of cycle) with
proper battery maintenance, you should have trouble free operation for two to three years
before you begin to have appreciably shortened play times. However, if improperly
maintained, they can fail in weeks!
Charging Your Batteries and Proper Maintenance
Batteries must be recharged as soon as possible after every use when operating your PA
system on battery power.
• Allowing a partially discharged battery to stand overnight can damage it.
• If, after using the MIPRO PA system, and anticipate that the unit will not be used
for more than 4-6 weeks, we recommend you fully charge the system overnight
after using it. Then plan to repeat with subsequent occasional overnight “topping
off” to insure that the batteries are not running down. e.g. Every 2-3 weeks.
o If you are to be away and no one can be on location to maintain/recharge
your batteries, connect your PA system to a timer as described below.
• To ensure optimum battery output performance and longevity, you may consider
connecting the unit’s AC power cord to an appliance/lamp timer for scheduled
charging/topping off.
o **Turn the MIPRO power switch off.
o Plug the MIPRO power cord into the lamp timer.
o Set the lamp timer to switch ON for its minimum time (usually 15
minutes) once every 24 hours.
o This will refresh the battery charge daily and keep it ready for service.
• Your diligence will be rewarded with long dependable service.
**Note; On the MA707 you must have the “AC power switch” pushed in while charging.
(Round Push Button Switch, located on the back panel about 2/3rd of the way to the top,
on the left side.) The other “Rocker style” power switch turned off.
Play Times On The Batteries
Any battery powered audio device will have its useful play/operation time vary
depending upon its use.
• If you play music and play it loud, your MIPRO system requires/consumes more
power than when it’s playing music at a lower volume level.
At high volume settings, it draws more current/consumes more power from the
power source. (Batteries])
If you are just speaking into a mic, the power consumption is less than if playing
non-stop music at the same volume setting.
o An auctioneer may tax the system more than just having a person speaking
for public address. .
If you are using the wireless mic’/receivers in addition to music, they too will add
to the power consumption.
Please keep these variables in mind when planning an event. If people are going to use
the systems for loud music, some will purchase an extra set of batteries to get extended
play times. (These extra batteries need to be properly maintained as per the previous
Extra backup power for extended play time;
All of the MIPRO portables are equipped with an auxiliary/external power source input
jack. In the past, all MIPRO portable PA’s had the correct external DC power plug
included as one of its accessories. If it becomes lost, bring your MIPRO PA unit and your
user manual to your local electronics supply store or Radio Shack. These are common
• Some models utilize the same DC input jack for charging the internal battery(s)
as well as to connect the “External Power Supply” plug to your MIPRO PA.
• A special cable with the appropriate connector can be constructed by an
electronics technician that can be connected to an external battery pack or
appropriate voltage source. (Use only the voltage and amperage recommended in
the user manual.)
• External/auxiliary batteries, dual (2) or single 12V SLA batteries, car batteries, or
even “Deep Cycle” marine batteries have been used to drastically increase the
play/operating times.
o Some MIPRO portable PA’s use external 12 volt power sources, and the
larger units use 2) 12vdc batteries in series to make 24vdc.
• Make certain that your technician consults the user manual and service manual for
those voltage and polarity details before constructing your cable. If still unsure,
you can request info from
• When properly maintained and charged, the batteries normally will not require
replacement for two or more years. However, if the unit operates only a short time
on battery power or if it does not appear to have power at all, the batteries are the
first item to test.
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