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Reviews Categories | Power Supplies | MFJ-4416 Battery Booster Help


Reviews Summary for MFJ-4416 Battery Booster
MFJ-4416 Battery Booster Reviews: 12 Average rating: 4.1/5 MSRP: $139.95
Description: Battery voltage booster
Product is in production.
More info: http://
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KI6DKC Rating: 4/5 Feb 22, 2010 07:55 Send this review to a friend
MFJ-4416b  Time owned: 0 to 3 months
I picked up one of these units for my new FT857d and Deep Cycle Battery. I noticed when I was running 100 watts on battery the radio really drew down the volts. So wanting to keep the voltage more steady and use the battery longer I began researching different battery boosters. The reviews for this particular booster were not spectacular but they were all for the earlier version, not the "b" model.

I have only used it in the full time operation mode not the RF sense mode and do not use it in a vehicle for mobile operation. For what I have used it for it works fantastic. It works just as advertised and keeps the voltage strong and stable even running the full 100 watts. I had a nice 15-20 minute QSO with a guy with no problems. The unit worked great. Then after ending that QSO talked another 10 minutes with another ham. So about a half hour of jaw yacking with two different hams and the unit worked great. I'm pleased with it's performance and can't wait to use it for field day or some other field operations.
 
W0SJ Rating: 2/5 Apr 29, 2008 07:06 Send this review to a friend
Design problems  Time owned: 0 to 3 months
My newly purchased MFJ-4416 was connected to a 12 volt 24 Ah gel lead acid battery and my Icom 7000 transceiver. A "T" connector was used on the 4416 RF sensing input, connected between the transceiver and a 50 Ohm load. The transceiver was operated in CW and SSB (microphone and two tone test) at power levels of 100, 75, 50 and 25 Watts.

Within a two hour span, the 30 amp fuse between the battery and the 4416 blew three times. After the first time, a scope was connected to monitor the voltages. A Tektronix P6302 (with AM503 amplifier) DC to 50 MHz current probe was connected to monitor the current. While looking at the transients, the input 30 amp fuse blew 2 more times. The input 30 Amp fuse blew one time when the transmitter power was set to 50 Watts and blew another time when a two tone test signal was connected to the microphone input.

I replaced the input fuse with a 40 amp, only to have the 30 amp fuse internal to the MFJ-4416 blow about 10 minuets later. This meant that the MFJ-4416 dumped a 30 Amp plus transient into my Icom 7000. This was very disturbing and further testing with the Icom 7000 as a load was discontinued. When the MFJ-4416 thirty amp internal fuse was replaced, the battery booster went back to working, so it was a transient and not a hard failure.

The Icom IC-7000 was tested monitored for problems. None were found. It appears that it survived without damage (Good job Icom). In subsequent use, it has never drawn more than 21 amps.

With the test equipment connected to the MFJ-4416 I was able to observe a number of transients. When RF sensing turned the booster on (while sending a series of dots), voltages greater than 1 volt above the 13.8 volt set point could be regularly observed. In the SSB mode using the microphone, I saw the scope trace go off the top of the screen on two occasions.

I believe the problem is related to RF from the 4416 sensing input getting into some of the regulator circuitry but I can not be sure of that. This product has great potential but it is still a work in progress. The MFJ-4416 was returned for a refund. My recommendation is delay purchasing one of these until the design is finished and properly tested.

Email from MFJ indicated that they are aware of the problem.
 
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