Which is the better state for rechargable Batteries!!

When I moved house about five years ago, I stupidly left my motor mower
in the shed!! Stupid Me! So, over the last five years, I've been getting
a 'Jim's Gardening' guy in to mow and clean up the garden every three or
four months, at $75-$100 a go!
A while ago, I learned that one of my sisters had brought a Ryobi
Battery Mower, so this week, I've borrowed it and mowed my lawns. It did
a good enough job for me. The Battery takes about two hours to recharge.
Back in a previous life, I was an Electronic Technician, and, at the
time of Ni-Cad batteries being introduced, the recharge story was that
Ni-Cads should be fully discharged occasionally, otherwise they
developed a 'memory' such that if they were regularly used/discharged to
a particular amount, whenever they got to that level, they would stop
working.
They then had to be 'manually' flattened by continually being turned on
.... and turned on .... and turned on ... Until they were 'flat', so
that they could then take a full charge and be 'right-as-rain'!!
With that in mind, and remembering that it supposedly only takes two
hours to fully recharge the Mower Battery, would it be better, after
use, to leave the battery 'Flat' or 'flatish' or should the battery be
fully recharged ready for use .... even though that use might be a month
or two hence??
TIA
--
Daniel
Reply to
Daniel65
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Forget everything you know about Nicads. Almost all modern battery tools use Lithium batteries. I believe the Ryobi ones (like many others) have smart charge circuits in each battery, that takes care of balancing, etc.
Lithium prefers not to be flattened fully, and the optimum charge for long-term storage is 60-70%, not empty or full. The self-discharge rate is basially zero compared to anything previous.
Reply to
Clifford Heath
It doesnt matter with current Lithium Ion batterys.
Reply to
Rod Speed
========================
** And I was Napoleon.
** 1960's ?
** Mostly myth.
** Not true.
** There are no NiCds in your mower.
...... Phil
Reply to
Phil Allison
Ah!! So much the same as Ni-Cad, then. Thanks
--
Daniel
Reply to
Daniel65
No, if you treat them like Ni-Cads you will destroy them, even the new smart ones with charge/discharge limiting circuitry built in to them.
Charge it up, use it, and if it gets low charge it again, other wise leave it on the shelf until you need to use it.
If you know you are going to use it a lot tomorrow, charge it up today if it's not full.
Cheers, Gary B-)
Reply to
Gary R. Schmidt
=============
** A bind man once met an elephant. He grabbed the animal by the tail and exclaimed:
" Ahhh .... elephant just like snake "
....... Phil
Reply to
Phil Allison
No. One area NiCd differs is that it can withstand continuous low-level overcharging. NiMH and Li batteries die from that kind of treatment.
CH
Reply to
Clifford Heath
=================
A bl=================
** However, trickle charging is OK.
Most NiMH cells suffer from high self discharge rates. Only 1 month and they are almost useless. ( Eneloop ones are far better)
Trickle charging at about the 30 to 50 hour rate is OK.
...... Phil
Reply to
Phil Allison
Sorry, should have mentioned it is Lithium-ion.
If I were to "leave it on the shelf" for a month or so (How often do people mow their lawns?? Often in Spring, not so often rest of yer??), would the Lithium-ion battery still be holding a charge??
Yes, that's always an option as it only takes a couple of hours on the charger to be fully charged.
I was just wondering .... for the long-term good on the Battery.
Thanks to all for their responses. ;-)
--
Daniel
Reply to
Daniel65
Also, if a NiCd ever gets totally flat, you can just charge it and use it, sometimes even many years later (if it doesn't develop shorted cells, or if you succeed in blasting away the shorts with a high current pulse, which I have sometimes). If a lithium battery ever gets totally flat (or even below about 2.3V per cell I think), the electronics in the pack may prevent you from ever charging it again, (perhaps for safety reasons). If storing a lithium battery for a long time, it is best to charge it to maybe 60% so that it won't get too flat by self-discharge, and then store it in a cool place. Charging it to 100% before storing it is not a good idea as that causes faster degradation.
This is interesting, though I can't vouch for its correctness:
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Reply to
Chris Jones
[SNIP]
Yes, we realise that.
My jump-starter is LiFePO4 - Lithium Iron Phosphate (supposedly the latest and the greatest :-) ) - it says check every six months and /if/ it's dropped below 70% top it up.
The Bunnings Ozito PXC batteries say they lose 5-10% a month, but they don't appear to specify a trigger point for re-charging. I haven't noticed any of mine going low enough to worry about, I just charge them after use and toss them back in the bag when they've cooled down, they get used once a month or so.
Don't leave them on charge, don't let them get and stay low, store them where the temperature is fairly stable, that's about it.
Cheers, Gary B-)
Reply to
Gary R. Schmidt
Daniel65 wrote
Right thru spring, summer and autumn. Not much in the winter.
Varys with the tech. No problem charging it before use with mowing tho.
Reply to
Rod Speed
Thank you. ;-)
--
Daniel
Reply to
Daniel65
Charge and leave them that way they will be ready for use when you need them. Forget NiCads, not relevant here.
Reply to
Clocky

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