Battery expert help to assess Li-on vs Alkaline battery pack

Forums › Home Workshop DIY › Battery expert help to assess Li-on vs Alkaline battery pack

Hatch

816 posts

Ultimate Geek
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#251420 25-Jun-2019 09:57

Could someone help me assess the difference in run time that I would get from two batteries,

This is for a VHF marine radio.

The battery is all but dead and the option is to get a new li-ion battery pack or to buy a "pack your own" battery than could take alkaline batteries.

These are the stats that I have:

Li-Ion Batter 7.4 V / 940 mAh vs Alkaline Battery Pack which takes 5 x AAA

Radio info:

http://www.icomamerica.com/en/products/marine/handhelds/m34/specifications.aspx

Some interesting statistics:

Current drain (at 7.2V DC)
Tx (at 5W output)
Rx (at AF max.)

1.5A
200mA

Output power (Hi/Mid/Low)

5W (High),1W (Low)

2W (High, with alkaline cells)

Does the 2W output power on Hi with Alkaline batteries show a limitation and therefore a lower output vs the Li-ion pack (5w).

I wonder if there was any difference if I used lithium AAA batteries instead of Alkaline?

Just to explain I actually never use the VHF Radio in anger, its really just an emergency backup in case I have to call the coastguard etc, so in some ways I would prefer to use the "pack you own" battery pack as I can just have a pack of 5 AAA alkaline or lithium batteries to use when I need it and can replace these annually or 6 monthly etc.

wellygary

8813 posts

Uber Geek
+1 received by user: 5295

#2263927 25-Jun-2019 11:48

I think you have just answered your own question....

going down the Li-ion route means you will a some point in the next months/years need to take it out and charge it up after its been sitting there slowly discharging...

As its safety gear You will have to draw up a check schedule for it to determine if the battery has gone flat

Going down the AAA pack your own route means you can have a set of unopened Batteries sitting there just in case you find the current ones are dead....

With pack your own, you don't really need to check much, just that the set of spare cells are not too old...

DonH

231 posts

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Lifetime subscriber

#2264079 25-Jun-2019 14:22

Second the "pack your own" option. Fit primary (non rechargeable) lithium cells. High current capability, high capacity, never known them to leak, very long shelf life.

People hear what they see. - Doris Day

Hatch

816 posts

Ultimate Geek
+1 received by user: 57

#2264277 25-Jun-2019 16:16

Im interested in the runtime of AAA batteries including disposable lithium ones as I noted some reviews where the AAA alkaline's only lasted for a few hours.

Also note that the specs sheet seems to state that on Alkaline output is only 2W on high compared to 5w with the Li-ion battery pack.

Aredwood

3885 posts

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#2264353 25-Jun-2019 18:30

Alkaline batteries have much higher internal resistance than Lithium batteries. That means they have a lower max current output, and their terminal voltage sags more in relation to current draw.

How easy is it to swap over battery packs? Maybe have 2 swap your own packs. 1 with alkaline batteries, which will be for when you need to mostly operate the radio in receive mode. And a second pack of the Lithium primary cells for transmission usage.

Is this your only radio, or is it simply a backup for another radio? EG if your boat loses electrical power therefore your main radio won't work.

Goosey

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#2264526 25-Jun-2019 20:21

Aredwood: Alkaline batteries have much higher internal resistance than Lithium batteries. That means they have a lower max current output, and their terminal voltage sags more in relation to current draw.

How easy is it to swap over battery packs? Maybe have 2 swap your own packs. 1 with alkaline batteries, which will be for when you need to mostly operate the radio in receive mode. And a second pack of the Lithium primary cells for transmission usage.

Is this your only radio, or is it simply a backup for another radio? EG if your boat loses electrical power therefore your main radio won't work.

Id go for the two packs also, always have one fully charged and in the unit for when you are using the boat and a spare on hand.

At the end of your trip, take the pack out.

At least you have a faith in the radio working immediately when needed...whats worse than fumbling for batteries knee deep in water.

1101

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#2264882 26-Jun-2019 10:33

AAA batts

not in any way intended for high current draw .
So I wouldnt use them for this

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Hatch

816 posts

Ultimate Geek
+1 received by user: 57

#2264885 26-Jun-2019 10:38

Goosey:

Aredwood: Alkaline batteries have much higher internal resistance than Lithium batteries. That means they have a lower max current output, and their terminal voltage sags more in relation to current draw.

How easy is it to swap over battery packs? Maybe have 2 swap your own packs. 1 with alkaline batteries, which will be for when you need to mostly operate the radio in receive mode. And a second pack of the Lithium primary cells for transmission usage.

Is this your only radio, or is it simply a backup for another radio? EG if your boat loses electrical power therefore your main radio won't work.

Id go for the two packs also, always have one fully charged and in the unit for when you are using the boat and a spare on hand.

At the end of your trip, take the pack out.

At least you have a faith in the radio working immediately when needed...whats worse than fumbling for batteries knee deep in water.

I'm really curious how to rate the AAA Lithiums vs the Li-ion rechargeable pack. These things are expensive so I'll be going for one or the other.

This is the only VHF radio i will have as its only a small dingy really, not offshore game fishing for example. I have an emergency beacon as well.