On the Home Front: Ryobi and Batteries

Back in 2004, Diane was looking at getting a reciprocating saw. Despite the indications that one simply should get the Milwaukee Sawzall and be done with it, we instead got a kit of Ryobi power tools that included a reciprocating saw. Ryobi is the Home Depot’s own brand of power tools, and occasionally Home Depot marks down kits deeply. In 2004, they had a pretty deep discount on the Ryobi 18V kit that included a reciprocating saw, 10″ chainsaw, circular saw, jigsaw, drill-driver, flashlight, and handheld vacuum. We found the purchase relatively disappointing, though, for one specific reason: the batteries and charger that came with the kit made the tools practically useless.

The Ryobi batteries circa 2004 were of one chemistry type, nickel-cadmium (NiCad). NiCad batteries are rechargeable, sure, but they are prone to a number of defects and do not yield high amp-hour figures. One of the most serious problems with NiCad batteries is a memory effect. If one does not completely discharge a NiCad battery each and every time it is used, it will tend to decrease in maximum charge capacity over time. It is really tough to do this well enough to keep NiCad batteries in top condition, so despite the fact that one can theoretically discharge and recharge a NiCad battery about a thousand times, its useful life tends to be a small fraction of that.

But the proximal problem we had was that the NiCad batteries didn’t have much in the amp-hour capacity department, and Diane would find that she would get perhaps half an hour’s work out of one battery used in the reciprocating saw. The battery would then need about 90 minutes to recharge, which meant that even with the two batteries that came with the kit, she was limited to perhaps a bit over an hour of useful work with the reciprocating saw before she had to simply let the first battery used recharge for another hour or so.

This problem with the power source colored our views of the Ryobi gear quite negatively. This contrasted sharply with our experience with 12V Makita power tools. We got our first Makita cordless drill sometime in the early 1990s, and while it used NiCad batteries as well, we didn’t get left with the feeling that the batteries would leave us high and dry with a lot of work left to be done. Of course, a drill may not have the power requirements of a reciprocating saw, but our impression of the comparison between the two brands was strongly shaped by the poor performance we got out of the Ryobi tools matched with their NiCad batteries and charger.

Recently, we had a task to accomplish. We had a survey done on a parcel of land, and the survey company said something about needing the area where a marker would be placed cleared, and needing line-of-sight to a position where their GPS instruments could be used for a high-precision fix. One corner of the land, though, had some heavy brush, including the invasive Brazilian pepper, that would need to be removed. By experience, we had come to the recognition that the Ryobi chainsaw was generally more efficient at cutting than the reciprocating saw. But the batteries made this only a partial solution because we had a lot more than an hour’s work to be done, and not enough time to be taking hour to hour-and-a-half breaks for every half hour of work.

We had resisted investing more money into the Ryobi toolset thus far, so while we knew that Home Depot had introduced an improved battery system, we had passed on buying into it. We decided to give it a try. We stopped by a Home Depot and bought two of the high-capacity 18V Lithium Ion batteries ($89.95 each) and a matching charger ($27.95). That turned out to make a huge difference in how well the Ryobi power tools performed.

We were able to work pretty much continuously with the Ryobi chainsaw. By the time we had discharged one Lithium Ion battery, the charger managed to have charged the other. The fact that we had to remove the cleared brush as well as cut it probably helped a lot there; I’m not sure that someone doing chainsaw sculpture, as a neighbor of ours in Galveston used to do, would have the same experience. But I’m confident that they would find the newer battery technology a huge improvement over the NiCads, as we have.

While we’re not so happy at having had to invest about $210 plus tax to make the stuff work like it should have to begin with, we are pleased with the performance so far of the Ryobi Lithium Ion batteries with the Ryobi power tools. If you have a Ryobi power tool gathering dust because trying to use it with the NiCad batteries is just too painful to deal with, getting the Lithium Ion batteries does seem to be a possible alternative to buying new tools in a different brand. If you are considering buying new power tools, the Lithium Ion batteries should make Ryobi far more competitive when comparing the different brands head-to-head on performance. Just make sure that if you do buy Ryobi, get the tools packaged with the Lithium Ion battery system. Home Depot still sells NiCad batteries for Ryobi (and apparently rather a lot of them, based on the number I’ve seen carried in stock in the stores), but I’d recommend strongly against trying to get work done while dependent on those.

I may have to disassemble one of the old NiCad battery packs and see what sort of cells are used in it. It might be possible to physically replace the cells with nickel-metal hydride (NiMH) cells. NiMH offers much higher amp-hour capacities than NiCad and reduces the memory effect almost entirely. NiMH does have higher self-discharge rates than Lithium Ion, which may be why Home Depot decided to go with Lithium Ion and not offer NiMH-based batteries in the 18V line. Back to the DIY battery modification, though; if I did upgrade the cells in the 18V shell, would I be able to charge it with the new Ryobi charger? I think the charge profiles for NiCad, NiMH, and Lithium Ion may all be different, and certainly the Ryobi One 18V charger was not designed to handle NiMH. Any advice from battery aficionados out there?

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Wesley R. Elsberry

Falconer. Interdisciplinary researcher: biology and computer science. Photographer. Husband. Christian. Activist.

14 thoughts on “On the Home Front: Ryobi and Batteries

  • 2010/03/17 at 12:20 pm
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    If it is any consolation, I have had the same discharge-recharge problem with my DeWalt cordless drill. I’ll have to look and see if they have an improved battery set.

  • 2010/03/18 at 6:19 pm
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    Here’s the deal: The Ryobi NiCad/NiMH chargers kill the batteries. It’s not intentional I suppose, it’s just that they do a piss-poor job of regulating the charge cycles and preventing overcharging.

    It’s possible that the Ryobi tools also allow users to over-discharge NiCad/NiMH batteries. Lithium-ion batteries come with extra circuitry to protect the cells and because of safety issues, their chargers have to be “smarter”. The downside of lithiums is that they can have a shorter lifetime. Even if you don’t abuse them, they die of “natural causes” after a few years.

    That said, you can replace the spent NiCads in your battery pack with NiMH. Just make sure to transfer all the safety components (fuse & etc) to the new pack. There are companies out there that either sell pre-configured battery inserts or offer replacement service. Personally, I think it’s hardly worth rebuilding Ryobi packs unless you’re able to get a great deal on NiMH cells.

  • 2010/03/24 at 9:47 am
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    I know this is not the answer for all. But I have found that basic tools work best. Gas chain saw, electric power tools, air tools. I leave the battery operated stuff for the simple little jobs, hanging pictures, mounting a light fixture.

    The regular jobs, siding a house, building a deck, taking down a tree, framing a garage, etc need real tools with reliable power.

  • 2010/05/07 at 8:46 am
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    NIMH are far more sensitive to be knocked around and also do not take a charge as fast as NiCad. NiCadís if treated well (charged gently and conditioned) can last years I have some that are over 10 years old. The Ryobi charger and the like tend to charge too fast and heat the batteries up. With these chargers there is no way to condition the batteries save perhaps manually using them until your power tool doesn’t function because of low battery. What a pain!

    Lacrosse(SP) has a few battery chargers for AA and AAA types that run batteries through a conditioning cycle and charges them slowly. It makes a huge difference in how the batteries perform. I wish there was such an animal for my 18V NiCadís.

    The LiIon batteries are great for a few years and simply die off. Think of your cell phone battery how long does it last? Probably roughly 2 or 3 years. Heat including room temperature heat kills these guys off. I suppose you could store your 89 dollar batteries in the fridge and get them to live much longer. Google Battery University for more info.

    Meanwhile, any one seen an 18 volt charger that will automatically condition the batteries and do the charging in a slow gentle manner?

  • 2010/05/19 at 6:25 am
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    The Ryobi Lithium Charger is supposed to charge the NiCad batteries. Does anyone know if it does a better job of managing battery life?

  • 2010/08/22 at 10:45 pm
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    NiCads do have no significant “memory” losses. Research the facts if in doubt of my statement…

    It’s not recommended to replace the NiCad cells with NiMH. Not unless you intend to use a charger that is designed to charge the NiMH’s.

  • 2010/08/22 at 10:47 pm
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    I apologize, I meant to type “NiCads don’t have any significant “memory” losses”.

  • 2010/08/23 at 10:10 pm
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    OK, Bleep, I went and found the FAQ. My bad… I guess the Ryobi NiCd batteries aren’t suffering from “memory” problems, but rather from a charger that overcharges and thus reduces the charge capacity. Yes, we routinely deep-discharged the NiCd batteries, and no, that did not restore them to full capacity.

    Unfortunately, whatever you want to call it, it means that the devices run out of juice way too soon to make them useful portable tools when using the NiCd battery packs.

    Thanks for the tip on NiMH replacement. I’ll probably just stick to the lithium ion batteries.

  • 2010/09/06 at 7:09 pm
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    “deep discharging” nicads ruins them. They should never be sischarged below 20% charge. They should never be lef ton the charger for extended periods. If used infrequentyly, they discharge around 1% per day (check this, I’m going by memory) so need to be recharge every 60 days or so. NEVER EVER EVER let them drain completely. DO NOT “deep discharge” them EVER. When they get low, stop using them.

  • 2011/11/09 at 10:36 am
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    Ok. So my reason for resurecting this thread is to help anyone else who stumbles across this site (hopefully not at 0230hrz like me… cant sleep…)

    Ok, first id like to correct a few things that were posted…
    Ryobi is not a Home Depot brand. They are actually owned by the same company that ownes the “Milwaukee” brand.

    NI-CAD batteries do have a “memory”. But in cases like this its the least of the problems.
    There are two reasons that you are having problems (other than using the wrong tool for the job)
    The first problem is that the first gen (ni-cad only) charger is charging the cells way to fast. The cells that Ryobi chose to use in the batteries are rated for a 1/4C charge over 5 hours (1/4 cell capacity for 5 hours) Most if not all consumers would find waiting 5 hours for a recharge to be unacceptable. They could have used higher spec batteries… but the the packs would be $60 each insted of $50 for two.
    I
    The second relates to the chosen cells again. This time its the discharge rating. These cells are rated for a 3C discharge rate. This means it is rated to discharge in constant use no faster than 20 min. Or a constant 4 1/2 amp draw for 20 min. There are only 5 tools in the line that pull less than 4 1/2 amps right now. The work light, the staple gun (just barely), the hand held vac, the caulking gun and the new radio/charger (im not counting the old radio as its being phased out).
    As you pull more current than rated, you start to loose capasity (the lost energy is generating heat). If you pull a largs enough current the battery will start to get over-heated. This causes even greater loss in capacity, and could lead to total failure of one or more cells. This cant really be avoided other than going with a 10-15% duty cycle.

    Also, as someone has already said, Dont store your ni-cads completely discharged. Anything over 70% and you should be fine. Also the 1% a day is a good rule of thumb.

    Now for the li-ion packs. They so have some Major advantages… but a few down sides.
    The first good thing is the capacity upgrade to 2.4Ah (over the ni-cad’s 1.5 AH). Second is that the li-ion cells maintain the voltage over a longer period of the discharge cycle, unlike ni-cads that start loosing voltage as soon az the current draw starts (starting the power tool).
    Also, since the battery pack is current limited and has a built in under voltage shutoff you dont have to worry about hurting the battery by use.
    Also due to the charge profile of the li-ion chemistry, they can charge the first 75% of the capacity in 15 min (or less in some cases) as long as the temp is kept under control.
    The one down side to li-ion (other than the cost) is that you CAN NOT store them fully charged for an extended ammount of time.
    If you dont plan on using your tools for a while, dis-charge them to 50-70% total capacity. This is due to the cathode mesh breaking down.
    This is also why your lap-top batteries die so quickly (by leaving them in the computer charging all the time). Yes, li-ion batteries do self-discharge. But it will take over a year for it to discharge from 70% toa point where it is in danger of damage.

    One point to remember though is that the current limiting on the li-ion batteries is a blessing and a curse. If you are doing something that requires a LOT of power like driving 1/2″ lag bolts (with the hammer drill). The li-ion ‘s over current protection will kick in. So the way I avoid that problem is keeping 5 li-ion and one Ni-Cad pack (yes, i really do need that many batteries).

    One final note ( i dont know if he was kidding or not)… DO NOT store your li-ion or ni-cad (or ni-mh) packs in the fridge! If you do, let them set outside the fridge for at least half a day to allow tbe inner cells to warm back up. Using a very cold rechargeable battery in anything that pulls more than the work light WILL damage them. It could take as little as a few min to completely destroy the battery pack if you go straight from the fridge to the canister vac or the sawz or the trill under heavy load.

    On a side note, with the charger that was just released… it IS safe to leave the ni-cad in the charger. That only applies to the 3rd gen chargers (not the ni-cad charger or the first green charger or the 6pack charger)…
    It is also compatible with Ni-mh cells). It not only use cell temp, but also current draw too (thats why it is also safe for ni-mh)

    I appologize for the grammer and spelling … its now 0300 and im typing this on a cell phone :-(

  • 2012/05/22 at 11:28 am
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    Fool me once, shame on you, fool me twice, shame on on me. Ryobi did not solve the problems with the new lith batteries. Do not be fooled twice. Run wires out of the battery pack to a 12v car battery if you refuse to trash them. But do not get suckered into buying any solution from Ryobi. They should be sending free replacements and apology letters. Its a national issue…read post anywhere! Check yourself on the web. There is no solution using Ryobi batteries. Do not invest another dime in Ryobi stuff or you will be fooled again!

  • 2012/05/22 at 10:12 pm
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    Well, both of the lithium batteries I bought are still working fine and driving the Ryobi gear we have. Maybe they will die tomorrow, but I’m willing to feel better disposed toward the Ryobi gear with lithium batteries than I ever was with the NiCd batteries. For someone who hasn’t yet invested in the tools, considering the experience I’ve had may well shift them to something else. The Ryobi battery-powered chainsaw in particular has been worthwhile to us, though, and I’m not sure what alternatives might be available.

  • 2012/08/04 at 3:41 am
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    Hi has anyone had a problem with the Ryobi One Plus Lithium Ion batteries dischargeing contantly to the point where when one places them in the charger the lights indicate that the battery is half charged thereby meaning that one is only useing half a battery before needing to recharge.

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