5 Amp Smart Battery Charger

Read reviews of our chargers at: eHam.net1 or eHam.net2 or eHam.net3

Proudly made in the U S A

Effective 01 OCT 2013
All versions of our 5A Smart Charger have been DISCONTINUED
5A Smart Charger data shown here for information purposes only
We will continue to support our products for at least the next 5 years
A & A Engineering is now a part time business
***** We are easing into retirement *****
After 41 years, no more 12 hour work days

Please allow extra time to process all orders
We have moved
Our new address is: 7970 Orchid Drive, Buena Park CA 90620-1930

Effective NOV 2014, company phone and FAX lines have been discontinued

The best way to contact us is via EMAIL to:


The A & A SMART BATTERY CHARGER is for use with any GEL-CELL or LEAD ACID battery. Sometimes these batteries are refered to as DEEP CYCLE, VRLA, VRSLA or AGM batteries. The design is based on the Unitrode UC3906 battery charging chip. It has three distinct operating states. Initially the charging current is limited to a pre-set bulk value and when the battery voltage reaches a specific level the charger enters the absorption mode and tops off the battery with an elevated voltage. After top off, it enters the maintenance mode where it maintains the battery at a precision float level value.

5 Amp Smart Battery Charger Operation/Notes download (5AChargerOperation.pdf)

A very important feature of this charger is a precision temperature tracking voltage reference. This reference is specifically temperature compensated to track the temperature characteristics of lead-acid cells.

If a load is applied to the battery while the charger is connected, the charger will contribute its bulk current to the load. If the load discharges the battery sufficiently, the charger will repeat the three state process described above when the load is removed. This charger can be connected to the battery indefinitely, it will not overcharge your battery.

This Smart Battery Charger circuit presents a DC load of only 175 µA when the AC is off or not present. A very important feature which prevents the discharge of the battery by the charger if the AC input is interrupted for long periods of time.

Excellent for larger batteries (automobile type 80 - 120 Ampere-Hour) which are not used very often. Both input and output are rear panel fused. Output is reverse polarity protected.

Many Ham Radio Operators maintain an Emergency Battery Backup System for use during power outages. Quite often Ham Radio is the only source of communication following a disaster. To be prepared, HAMs practice for these events during RACES exercises or the annual ARRL Field Day. Many HAMs depend on our 5 Amp or 1 Amp Smart Battery Chargers to maintain their Emergency Battery Backup System.

Trailer Boater (Bass Boaters) or Sunday Sailor, who usually only use their boats on the weekends, can be assured of a fully charged battery if they have a SMART BATTERY CHARGER working 24 hours a day.

Repeater sites, burglar alarms, etc. can use this charger to maintain back-up battery systems. For items in long term storage such as trailer boats, travel trailers, 5th wheels, RV Trailers or RV Motorhomes, motorcycles, wave riders, motorhomes, etc. all benefit by using this Smart Charger as a BATTERY TENDER. For Battery Tender applications, custom cables are available, please call or email with your requirements.

Our standard unit is 115 VAC input, 5 Amp Maximum output. Although we commonly refer to a battery as a 12V battery, meaning a battery having 6 cells at 2.0V per cell (12.0V). The actual Lead-Acid battery voltage is closer to 2.3V per cell (13.8V).

Attention RV'ers and boaters: this is a linear charger, NOT a "noisy" switching type charger. We have quite a few customers who have their boats and/or RV's parked at home and have had TV and Radio interference while trying to use a switching type charger. They solved their interference problem, and once again have happy neighbors, by changing over to a "noise free" linear charger. Although NOT water proof, and intended for indoor use, many trailer boaters and RV'ers use this charger in the garage or driveway.

This is a low RF noise linear (not a switching) charger, well suited for radio use. Ham Radio Operators have used this charger in many applications. Both standard (everyday) use or in emergency backup power applications. A 5 Amp Smart Charger, in conjunction with a deep cycle battery, provides the power for many Ham Radio Stations. If switching regulated power supplies are a problem, consider this method of powering your RIG(s).

The complete charger weighs 10 pounds and measures 7" W x 8 1/2"D X 4 1/2"H. Input is a six foot AC cord. Both input and output are rear panel fused. (Rear View Click Here)

See the SHORT TAKES review by Joel R. Hallas, W1ZR, ARRL Assistant Technical Editor in the MAR 2004 QST. For full details click here: (QSTArticle,pdf)

SOLAR PANEL USE: Both our 1A and 5A Smart Battery Chargers have Auxiliary DC input capability via pads on the circuit board. This auxiliary input can be used with a solar panel. For details see Solar Panel Notes

Various output cables are available, see details via Charger Price List or the price chart below.

Chargers awaiting shipment , is yours one of these ?

We have quite a few satisfied customer worldwide, here are a few unsolicited comments; TESTIMONIALS

For an assembled unit, Order #155-ASY

Sorry, not available in KIT form


Build your own version with blank circuit board, 155-PCB, $29.95 (click for details)

Build your own version with assembled circuit board, 155-PCA, $74.70 (click for details)

Shipping cost via UPS insured to US 48 is $16.50

Shipping cost to Alaska or Hawaii is $20.50

California Residents must add 8.00 % sales tax

Shipping cost via mail to CANADA is $34.35

Want to add ANDERSON Power Pole, Order #155-PIG, $5.95 (click for details)

Need a LIGHT DUTY cable, Order #155-LIT, $10.95 (click for details)

Need a DIRECT CONNECT cable, Order #155-BAT, $12.95 (click for details)

Need a HEAVY DUTY cable, Order #155-HVY, $14.95 (click for details)

Need a HEAVY DUTY cable with Anderson 30 Amp Power Pole connector
Order #155-AND, $16.95
(click for details)

Optional AUX DC input - can be used for SOLAR PANEL input
Order #155-AUX,
(click for details)

Foreign orders require special treatment, please contact us for details

For options, blank boards, cables and parts, see Charger Price List

For 230V 50/60 Hz options, see Charger Price List

We NO LONGER accept checks, money orders, Visa or MasterCard directly (see ordering information)

We now only accept PayPal

PayPal, American Express, Discover, MasterCard or Visa through (see PayPal information)

A & A Engineering 7970 Orchid Drive, Buena Park, CA 90620
Phone (714) 952-2114 FAX (714) 994-1104

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