Topics

Battery Chemistry Discussion


Ryan - KJ7GIE
 

Howdy... On last Thursday's net there was discussion on batteries and what people do to maintain them so that everything has a healthy charge in case of needing to leave the grid. We ran out of time but I wanted to ask if we had a resident "battery chemistry" expert?

I know lithium ion is probably the worst chemistry for this kind of situation because it doesn't like to be stored at max capacity and the life of the battery is directly determined by how many times you fully charge it. Knowing that, I looked and found every single one of my HTs using Li-ion. So, some references would helpful as well as alternative chemistries, their pros / cons, for both HTs and portable rigs. Thanks!


Dan Pflugrath
 

This information source may be of help to you.  My experience is with portable radios.  Every radio I own now use lithiums except for the cheapo FRS radios.

https://mpoweruk.com/performance.htm     Make sure you check out some of the references noted within the article.

Lithium batteries might be what you are looking for.  They have a very low self discharge rate on the order of 2% per month and have no memory.  The depth of discharge is the variable for determining the number of life cycles.  https://mpoweruk.com/life.htm#dod    

Some lithium battery packs like used in the KX2 have built in circuitry that control the charging and discharge limiting temperature during charging and maximum discharge voltage.  This makes sure you do not accidentally damage the battery and shorten usable life.

Raw lithium batteries used for RC application must somehow be monitored remotely during use to prevent over discharge and special chargers are used to monitor individual cells to make sure the cells are properly charged. 

Dan KA7GPP

 


Mark Kenworthy
 

For radios, the LFP (Life, Lithium Iron Phosphate) have the best characteristics.  Most of the RC hobby batteries are LiPo (Lithium Polymer).  LiPo batteries do not like to be stored charged and lose charge and capacity fairly quickly if they are stored charged.  LiPo batteries are also quite volatile, can catch on fire if they are charged wrong, discharged wrong, or damaged.

 

LFP batteries are completely happy to store in the charged state, have extremely low internal resistance so the charge lasts a very long time, and are almost impossible to catch on fire.  The reason the LFP batteries aren’t very popular in the RC hobby is that they have slightly lower energy density and quite a bit lower peak current capability.

 

Mark

 

From: snovarc@snovarc.groups.io <snovarc@snovarc.groups.io> On Behalf Of Dan Pflugrath via groups.io
Sent: Monday, August 3, 2020 5:11 PM
To: snovarc@snovarc.groups.io
Subject: Re: [SnoVARC] Battery Chemistry Discussion

 

This information source may be of help to you.  My experience is with portable radios.  Every radio I own now use lithiums except for the cheapo FRS radios.

https://mpoweruk.com/performance.htm     Make sure you check out some of the references noted within the article.

Lithium batteries might be what you are looking for.  They have a very low self discharge rate on the order of 2% per month and have no memory.  The depth of discharge is the variable for determining the number of life cycles.  https://mpoweruk.com/life.htm#dod    

Some lithium battery packs like used in the KX2 have built in circuitry that control the charging and discharge limiting temperature during charging and maximum discharge voltage.  This makes sure you do not accidentally damage the battery and shorten usable life.

Raw lithium batteries used for RC application must somehow be monitored remotely during use to prevent over discharge and special chargers are used to monitor individual cells to make sure the cells are properly charged. 

Dan KA7GPP

 


Mark Kenworthy
 

Spell check got me there.  LFP batteries are also known as LiFe and (more correctly) LiFePo (Lithium Iron Phosphate).

 

Mark

 

From: snovarc@snovarc.groups.io <snovarc@snovarc.groups.io> On Behalf Of Mark Kenworthy via groups.io
Sent: Tuesday, August 4, 2020 7:06 AM
To: snovarc@snovarc.groups.io
Subject: Re: [SnoVARC] Battery Chemistry Discussion

 

For radios, the LFP (Life, Lithium Iron Phosphate) have the best characteristics.  Most of the RC hobby batteries are LiPo (Lithium Polymer).  LiPo batteries do not like to be stored charged and lose charge and capacity fairly quickly if they are stored charged.  LiPo batteries are also quite volatile, can catch on fire if they are charged wrong, discharged wrong, or damaged.

 

LFP batteries are completely happy to store in the charged state, have extremely low internal resistance so the charge lasts a very long time, and are almost impossible to catch on fire.  The reason the LFP batteries aren’t very popular in the RC hobby is that they have slightly lower energy density and quite a bit lower peak current capability.

 

Mark

 

From: snovarc@snovarc.groups.io <snovarc@snovarc.groups.io> On Behalf Of Dan Pflugrath via groups.io
Sent: Monday, August 3, 2020 5:11 PM
To: snovarc@snovarc.groups.io
Subject: Re: [SnoVARC] Battery Chemistry Discussion

 

This information source may be of help to you.  My experience is with portable radios.  Every radio I own now use lithiums except for the cheapo FRS radios.

https://mpoweruk.com/performance.htm     Make sure you check out some of the references noted within the article.

Lithium batteries might be what you are looking for.  They have a very low self discharge rate on the order of 2% per month and have no memory.  The depth of discharge is the variable for determining the number of life cycles.  https://mpoweruk.com/life.htm#dod    

Some lithium battery packs like used in the KX2 have built in circuitry that control the charging and discharge limiting temperature during charging and maximum discharge voltage.  This makes sure you do not accidentally damage the battery and shorten usable life.

Raw lithium batteries used for RC application must somehow be monitored remotely during use to prevent over discharge and special chargers are used to monitor individual cells to make sure the cells are properly charged. 

Dan KA7GPP

 


Paul Butzi (W7PFB)
 

I keep my SLA (sealed lead acid ) batteries fully charged. The ones not in active use get topped up once a month.

All my HT’s work on LIPO batteries. In theory the battery life is shortened when they are stored with a charge over 80%. The batteries in the get home bags in the car I store fully charged anyway. They get topped up every 2-3 months. This means their service life will be shortened. Ah, well, they’re cheap Baofengtech batteries, and basically the stuff in the get home bag is all considered overhead costs of being somewhat prepared. I just don’t worry about it.

I have fairly expensive batteries for the Kenwood HT’s at home. They tend to be kept fully charged. I know this is not optimal, but frankly the optimal thing is just not very convenient. My policy is that, if the battery on the HT is over 80% I don’t generally put it in the charger. But I have a bunch of batteries, I cycle thru them, and when they get charged, they get charged up to 100% and then put in the stack for use.

This is all in defiance of the best advice. Sometimes the optimal policy is just too much of a PITA for me to follow it, let alone care.

I have to say, I’ve used rechargeable batteries using NiCad, NiMH, and LIPO technologies. In terms of longevity and freedom from hassle, LIPO is the clear winner even with my staunch defiance of ‘best battery maintenance’ practices.

-p W7PFB
73, Don’t forget to smile and have fun!

On Aug 3, 2020, at 1:50 PM, Ryan - KJ7GIE <@KJ7GIE> wrote:

Howdy... On last Thursday's net there was discussion on batteries and what people do to maintain them so that everything has a healthy charge in case of needing to leave the grid. We ran out of time but I wanted to ask if we had a resident "battery chemistry" expert?

I know lithium ion is probably the worst chemistry for this kind of situation because it doesn't like to be stored at max capacity and the life of the battery is directly determined by how many times you fully charge it. Knowing that, I looked and found every single one of my HTs using Li-ion. So, some references would helpful as well as alternative chemistries, their pros / cons, for both HTs and portable rigs. Thanks!