James-
Thanks for the interesting article on the Ryobi 12v solar setup.
Just wanted to chip in some advice on Ryobi batteries: Of the name brand cordless tools, Ryobi seems to have the worst NiCd battery quality. When used carefully, they will work well for a couple of years. If pressed hard, they will die a much earlier death. I have found that some packs will have a bad cell, dramatically shortening the entire pack’s life after only a few months. I’ve experienced this with 9.6v, 14v, and 18v Ryobi setups. Even the healthier packs, when pushed hard, particularly with a high drain device like a circular saw, die a quick death. To maximize the useful life, do not push them to the point where the battery pack gets hot and is completely drained. Such hard use guarantees the pack will lose capacity and cease to hold a charge for extended periods of time.
Ryobi’s latest 18v sets (“ONE+”) can be powered by either their lithium or NiCd packs. If the purchaser can afford the lithium setup, it is a better investment, as the lithium packs last longer in use, hold a charge longer, and have much better shelf life. If you cannot afford the lithium battery packs with the initial purchase, consider adding them later, as the same 18v charging setup you describe will work with either type of battery.
Also, Home Depot’s Rigid cordless tool line currently come with a lifetime warranty that includes the lithium battery packs, and they will replace the batteries if they fail to hold a charge, regardless of the reason. The Rigid line may be a good alternative for those purchases who intend hard use for their cordless tools. The Rigid line is typically twice as costly as the Ryobi line, but they do occasionally go on sale and represent a better value for people who wear out their battery packs. Regards, – Rich S.
Sir,
With regards to A Simple Off-the-Shelf Solar Power System and Off-Grid Power Tools, I must object to a portable tool solution based on short (“2-3 years”) rechargeable batteries which are fundamentally non-replaceable after TSHTF as opposed to a contrasting setup using inverters to operate 117 VAC-conventional power tools – all other parameters being identical. Just skip the 18 volt rechargeable tools and batteries and DC-to-DC chargers and stick with regular AC tools.
In order to prolong the deep-cycle lead-acid batteries into the “unlimited” range: stay within the top 10% of the battery capacity. Not only will you not have to worry about replacing high-technology 18volt portable batteries every three years, but you won’t even have to worry about replacing deep-cycle lead acid every seven years neither. – R.S.
JWR Replies: I agree with the simplicity of your approach.
Sadly, there is no such thing as a “forever” or “unlimited life” lead-acid battery. Even if they are kept fully charged, they will eventually sulfate. That chemical reaction is inevitable, and can at best just be delayed. One evidence of this telephone companies spending millions of dollars rotating their deep cycle batteries that they they use for backup at the Central Offices (COs). IIRC, they are replaced once every eight years. And those batteries only rarely get drawn down. (“Cycled.”) If there were some way to make lead-acid batteries have unlimited life, the phone companies would have implemented it long ago.