Hi Arv,

I intend to do just that. I don't know where it will lead exactly but
probably not very far from the commercially available charge systems.
Since fifth grade I have had the bad attitude "if I can't do it myself
it ain't worth having and I don't deserve it". That was more than a
month ago and I have made it stick all this time. Wait..it may have been
more than two months..or more.

73,

Bill  KU8H

On 5/14/20 2:17 PM, Arv Evans wrote:
> Allison
>
> Why don't technically savvy hams build their own lithium ion cell chargers?
> It doesn't seem all that difficult.  A voltage regulator for max-charge
> voltage
> and a shunt regulator to prevent over-charging seems rather easy for a
> single
> LI cell.  For multiple cells the voltage regulator and shunt charge
> limiter would
> need to be replicated for each cell.
>
> Arv
> _._
>
>
> On Thu, May 14, 2020 at 10:59 AM ajparent1/KB1GMX <kb1gmx@...
> <mailto:kb1gmx@...>> wrote:
>
>     While Lithum is more compact, much lighter and offers more charge
>     cycles
>     for their lifetime it comes with 3-4x the cost of commonly available
>     NiMh.
>     Safety requires using a proper charger.
>     Why higher cost?  Lithium requires a specific charger so buying that is
>     often part of the initial purchase and life cycle. Plus any battery of
>     known quality has a higher cost.  An example 3S1P (three series
>     1 parallel) 18650 cells (3x 2800mAH LG brand), about $6.50 each
>     (with solder tabs), battery protection board about 7$,  charger
>     suitable
>     for that pack 14$.  Up side is those cells should last for many years.
>     There are cheaper lithium but they are often junk or over rated,
>     use care. The pouch cells are susceptible to damage so use care if
>     damaged can catch fire.  The upside for those is often found cheaper
>     and offer lowest weight.  No matter the type battery protection board
>     must be used and fuses as secondary protection.
>     I am a long time user of rechargeable batteries, lead acid/gell/AGM,
>     NiCd, NiMh, and Lithium tech.  So of the old school NiCd and NiMh are
>     used because the radios and gear are already fitted and have suitable
>     built in charger.  Some I replaced with NiMh as upgrade.  In cases
>     where cheap and high power lead/gell/agm are used where weight doesn't
>     matter or its within acceptable weight. My favorite is the classic
>     7-8AH gell cell.  However where compact light weight power is desired
>     Lithium unusually in the form of 18650 cells with suitable protection
>     board is my preferred solution.  I also prefer them when I want the
>     battery to last through many use cycles.
>     Its why I suggested NiMh as for first time 2.2AH (2200 mAH) is plenty
>     to run the QCX for many hours.  Low entry cost and ease of acquisition.
>     They charge easily and often a 4 pack and matching charger runs
>     about 16$
>     But I also use non-rechargeable AA alkaline cells as they are easy to
>     find everywhere, generally cheap and offer easiest way to battery power
>     a radio up to the 5 watt region.  Even with these, fuse things please!
>     Cost to do that?  A 48 pack of AA alkaline cells that are not
>     rechargeable
>     is typically 16$  Bjs or similar.  Walmart has Energizer Max 48 pack
>     for
>     about 21$.   Either one is enough power at 9-10 cells each group for a
>     intense weekend of contesting. using a QCX.  Its by far the cheapest
>     way to go for an intro to portable.  For long term use they get
>     expensive,
>     However when your out in the woords recharging is unlikely or hard and
>     a spare set of cells may be easier.
>     The trade up is short term one use non-rechargeable cells.
>     Long term, high use, rechargeable cells.
>     Least weight, always Lithium.
>     Allison
>     -------------------------------
>     Please reply on list so we can share.
>     No Private email, it goes to bit bucket due address harvesting in
>     groups.IO
>
>

--
bark less - wag more

While Lithum is more compact, much lighter and offers more charge cycles 

for their lifetime it comes with 3-4x the cost of commonly available NiMh.
Safety requires using a proper charger.

 

Why higher cost?  Lithium requires a specific charger so buying that is
often part of the initial purchase and life cycle. Plus any battery of
known quality has a higher cost.  An example 3S1P (three series
1 parallel) 18650 cells (3x 2800mAH LG brand), about $6.50 each
(with solder tabs), battery protection board about 7$,  charger suitable
for that pack 14$.  Up side is those cells should last for many years.

 

There are cheaper lithium but they are often junk or over rated, 

use care. The pouch cells are susceptible to damage so use care if 

damaged can catch fire.  The upside for those is often found cheaper 

and offer lowest weight.  No matter the type battery protection board 

must be used and fuses as secondary protection.

 

I am a long time user of rechargeable batteries, lead acid/gell/AGM, 

NiCd, NiMh, and Lithium tech.  So of the old school NiCd and NiMh are 

used because the radios and gear are already fitted and have suitable 

built in charger.  Some I replaced with NiMh as upgrade.  In cases 

where cheap and high power lead/gell/agm are used where weight doesn't 

matter or its within acceptable weight. My favorite is the classic 

7-8AH gell cell.  However where compact light weight power is desired

Lithium unusually in the form of 18650 cells with suitable protection 

board is my preferred solution.  I also prefer them when I want the 

battery to last through many use cycles.

 

Its why I suggested NiMh as for first time 2.2AH (2200 mAH) is plenty 

to run the QCX for many hours.  Low entry cost and ease of acquisition.

They charge easily and often a 4 pack and matching charger runs about 16$

 

But I also use non-rechargeable AA alkaline cells as they are easy to 

find everywhere, generally cheap and offer easiest way to battery power 

a radio up to the 5 watt region.  Even with these, fuse things please!

Cost to do that?  A 48 pack of AA alkaline cells that are not rechargeable 

is typically 16$  Bjs or similar.  Walmart has Energizer Max 48 pack for 

about 21$.   Either one is enough power at 9-10 cells each group for a 

intense weekend of contesting. using a QCX.  Its by far the cheapest 

way to go for an intro to portable.  For long term use they get expensive,

However when your out in the woords recharging is unlikely or hard and 

a spare set of cells may be easier.

 

The trade up is short term one use non-rechargeable cells.  

Long term, high use, rechargeable cells.  

Least weight, always Lithium.

 

 

Allison

-------------------------------
Please reply on list so we can share.
No Private email, it goes to bit bucket due address harvesting in groups.IO

Hi Gwen.  Where should I be watching for your new system?

73,
James/KB7LJP

A good "starter" portable battery pack for QRP is one of the 12v Talentcell packs from Amazon. Here's one I got:  https://www.amazon.com/Talentcell-Rechargeable-6000mAh-Battery-Portable/dp/B00MF70BPU 

It's 6Ah at 12v, which is quite a lot. It gives you 12v at 3A max, and you can charge it while you use it with the y-adapter they provide, if you have mains power for at least part of the time. I have yet to run that one down more than one light in an afternoon's operating in the park.

I also have a more powerful one that also has 9v and 5v USB outputs, so I can make a battery cable for a 4SQRP "Cricket", or run another radio that uses 9v, and I can charge my phone if I've been using it for logging on QRZ or something. But they replaced that model with this one: https://www.amazon.com/TalentCell-Rechargeable-11000mAh-14500mAh-26400mAh/ It's similar to the one I have but has a bit more juice. Mine was 8.3Ah at 12v and a max of 6A. But this one is 11Ah at 12v and gives a max of 6A at 12v. There IS one bigger than this, but by that time you should be looking at a different form factor, and a new battery chemistry. I just got Talentcell's 12Ah LiFePO4 battery, which combines more capacity and more peak power (15A) with the lighter weight of Lithium Iron Phosphate. It can charge from a standard 12v charger that you'd use on a lead-acid battery (it has a management circuit inside), and will charge a lot of times before it starts to lose any capacity. I have a small battery box I'm going to mount it in, and a little Power Pole distribution board for connecting it to gear.

Beyond that, and you're talking some potentially complex stuff, and some serious cost, like battery banks and solar cells and portable generators -- more Field Day level of portable operation. But for near backpacker levels of QRP operation, I'm working on a new system that'll be lighter, potentially cheaper, and more flexible. I want to get it written up for publication before I start yammering about it, though.

-=-=-=-=-=-=-=-=-

73,

Gwen, NG3P

On Tue, May 12, 2020 at 5:36 PM ajparent1/KB1GMX <kb1gmx@...> wrote:

Try 8-10 AA cells for starters.  If you get into it and do it more then try
2200mah NiMH cells again 8-10 of them.

Either will be the easy and most common and everything else
will higher investment cst.

Allison
-------------------------------
Please reply on list so we can share.
No direct email, it goes to bit bucket due address harvesting in groups.IO

Try 8-10 AA cells for starters.  If you get into it and do it more then try
2200mah NiMH cells again 8-10 of them.

Either will be the easy and most common and everything else
will higher investment cst.

Allison
-------------------------------
Please reply on list so we can share.
No direct email, it goes to bit bucket due address harvesting in groups.IO