Icom A4 Sport

[Morph]

Anyone using one of these radios in their microlight? I have one running purely off the battery pack and this irritates me particularly on longer jouneys when your batteries run flat.

I see there is a Charging socket on the side. The manual says you can connect a 12V source to this point but you should not charge and run the radio at the same time. I connected the 12V to this point and tried to run the radio without the battery pack and it powers up but switches off as soon as you key the mike. With the battery pack installed and the external power connected it works fine. I am using nicad batteries and am worried about having the power source permanently connected. Will this stuff the batteries up?

Is there anyone running one of these in their microlight permanently connected to the external 12V. Have you had any problems.

The alternative is to remove the battery pack completely and connect a rectified 9.6 V DC to the two battery pack connection points.

[John Young]

I connected the 12V to this point and tried to run the radio without the battery pack and it powers up but switches off as soon as you key the mike.

Morph, sounds like you are using the wall charger – this will never support TX without the batteries.

Is there anyone running one of these in their microlight permanently connected to the external 12V. Have you had any problems.

I have seen several A4’s on M/L’s . If you only use it when flying and use the A/C to power the A4 @12v, you should have no problem [except for the obvious but curable ignition noise].

Morph, did I correctly understand your post?

[Microwave]

Hi Morph,

If have an A3, with a charging socket on the right hand side. I had no problem for a while and it was great to carry on flying and talking without having to worry about the battery going flat. However, one day the radio burned out for an unexplained reason. The Icom agent said that it had been hit by a surge of power. He reckons that the voltage from the plane charging circuit is far from clean and does have the occassional bad spike.

He also advised me that you should never remove the battery pack from the radio if you're charging from an outside source as the internal battery acts as a buffer for some of the smaller spikes. So beware!

Since that incident I have added in a voltage surge protector and I have never looked back. This device also has a filter system which has completely removed the charging/ignition hum that John Young was talking about.

I got the regulator at a place near east Rand Mall, it works really well.

I will dig around and see if I can find you the details of the place and you can contact them if you're interested.

[Morph]

Morph, sounds like you are using the wall charger – this will never support TX without the batteries.

Nope I connected to a 12 battery. I measured the battery voltage and it was just on 13 V. I plugged this power into the radio charging socket and took the battery pack off. I measured across the two connectors for the battery pack at picked up the 13 V. So it seems to pass it straight through, albeit at a reduced current. Trying to key the mike or even press squeltch cut the radio off without the battery pack. Since the radio passed this 13V through to the connectors I tried connecting the battery voltage straight there.and the radio powered and worked fine. However I only did this for a second or two as I was not sure whether the radio would burn out.

I have seen several A4’s on M/L’s . If you only use it when flying and use the A/C to power the A4 @12v, you should have no problem [except for the obvious but curable ignition noise].

What I am concerned about is whether the continuous 12-13.5 V coming from the A/C power will damage the NICAD's

[Morph]

I will dig around and see if I can find you the details of the place and you can contact them if you're interested.

Would appreciate it, thanks

[Microwave]

Morph,

I must admit that the NiCads on my hand held are really badly shot now, I doubt that they will give me more than a minute or two of charge. I am not sure whether this is the result of connecting it to the plane circuit or just old age. However, I must admit that I never have any reason to use the radio other than in the plane so it does'nt really worry me.

[John Young]

What I am concerned about is whether the continuous 12-13.5 V coming from the A/C power will damage the NICAD's

Morph, a continuous trickle charge at 12v [while flying] will not damage the nicad’s.

However, bear in mind that charging nicad’s before they are fully flat results in a “memory” being formed, meaning that if the nicad is usually charged when 60% depleted, eventually only 40% of capacity will be available for taking a charge [caused by the “memory”].

I am sure you have seen / heard many cases of people saying “My battery goes flat after a few minutes”, or “My battery won’t take a charge”. This will result from “charging for 2 hours before we go flying” etc.

The “memory” or crystal build-up can be broken down to some extent by applying a much higher than usual voltage to the battery in reverse – but generally, a developed “memory” means chuck away.

If you are going to use the A/C to charge the battery while flying [like I do], then just accept that although functionality [while flying] will be retained for many years, the battery will eventually not perform very well as a stand alone.

Hope that this helps you - regards

[Morph]

Thanks John,

Does the same stand for NiMH. I understand they don't suffer from the memory problems of Nicads.

[John Young]

Does the same stand for NiMH. I understand they don't suffer from the memory problems of Nicads.

Nickel-Metal Hydride (Ni-MH or NiMH) and Lithium Ion (Li Ion) rechargeable batteries are amongst the most advanced rechargeable battery systems commercially available today. They offer several advantages over ordinary nickel-cadmium batteries, including up to 40 percent longer service life.

Ni-MH batteries don’t need to be completely discharged before recharging. Only NiCd rechargeable battteries do as they have a “memory effect”. To try and avoid this effect, you can discharge the battery fully in your radio every few charges. Please note that this is a “stop gap”. Without completely discharging “almost every time”, the memory effect, [which can be described as cumulative] will eventually cause a permanent “memory” to be developed.

For info, Lithium Ion (Li Ion) rechargeable batteries are used in cell phones and can take much more abuse. Except for the recommended initial charge of 16 to 24 hours, the Lithium Ion (Li Ion) rechargeable batteries can be charged at will.

Morph – hope this helps – kind regards

[ACE]

Regarding Nicads memory problem, connect the battery to a torch globe or similar and let this drain the battery completely - it will give you some extra life but these batteries are only good for a certain number of cycles.

[John Young]

Morph - you OK with this now?

Regards

[Morph]

Morph - you OK with this now?

Regards

Cool,

I have your circuit for the RF Choke and 12 V regulators. I'll build it this weekend and test.

Thanks :D

[John Young]

I have your circuit for the RF Choke and 12 V regulators. I'll build it this weekend and test. Thanks

Morph, one final tip - when you have the regulators soldered in place, apply a little silicone - the terminals are quite close and you will eliminate vibration on the points at the same time.

Regards

PS: When purchasing the "stuff", get 6 grommets for the wire as well.

[Oddball]

I have had a similar problem with my Icom A-23 radio which has never been able to hold charge for more than an hour or so since I have used it; some 6 months after I bought it.

It has a Ni-MH battery and I simply connect the radio battery to my trike battery via the relevant plug. So far this works but the filter/ regulator sounds like a good idea.

I have not seen the contact details for the East Rand spot where one can get these- does anyone have the details?

[Morph]

Oddball,

I am quite pleased with the little circuit, radio and intercom coms are clearer plus you don't have the risk of loosing the radio due to voltage spikes. Look in your local yellow pages for Electronic Components. Give them a call and ask them if they stock 30 to 40 mm toroid coils, 12 V voltage regulators and capacitors, I guarantee they do.

The entire lot cost me R70 and it works like a dream. The circuit is


1. Toroid coil (approx 40mm diameter) - cost R 45 (or ask a Ham Radio mate to find you one for free).
2. 2 X 12v voltage regulators - cost R 4 each. Ensure that the radio requires 12v and not 11v)
3. 1 X 16v 2,200 uF (micro farid) capacitor - cost R 2.
4. 2 X small electrical boxes (one to house the toroid and the other to house the voltage regulators) - cost R 4 each.
5. 1 metre of 6 amp twin power cable (red & black - approx 3mm in diameter) - cost R 3

The circuit is simple. Connect to ignition switch (the fuse is normally located between the battery and the ignition switch, meaning that the circuit is already protected). Wind power cord around the toroid about 20 times and fit the capacitor in parrallel after the toroid winding. Split the power cord into two and route each through a voltage regulator. Connect each of the two cords to the power jacks normally provided on the instrument pod for the radio and intercom. (Thanks to John Young)