Two Letters Re: A Simple Off-the-Shelf Solar Power System and Off-Grid Power Tools

James,
Your readers recently bring up good points about the advantage of battery powered tools with solar recharging. The advice to use an inverter connected to a 12v deep cycle battery and regular corded AC tools was good advice also, since the batteries may not last very long.

Having just recently purchased a set of Ryobi one+ tools myself, I found a seller on ebay selling an adapter for the one+ tools. It plugs into the tool in place of the battery then you can plug an AC DC power supply into it. This will give the best of both worlds. Use of the Ryobi batteries, then once the batteries no longer hold a charge, you can connect an AC/DC power supply to your 12v deep cycle battery and basically have a corded tool.

Search eBay for “EX-One use AC adapter replace Ryobi One+ P103 Lithium” or seller “lcdpayless”. The adapter is only $20 but doesn’t come with the AC/DC power adapter. I am not the seller and I haven’t ordered one of these yet. I just thought your readers with Ryobi One+ tools might be interested to learn of this possibility for backup power for their tools. – D.L.

Sir:
A clarification for your readers on the article titled: A Simple Off-the-Shelf Solar Power System and Off-Grid Power Tool., The “Bill of Materials” for this project included; “Interstate Marine/RV 12 volt battery #27DC-1 ($68 from Sam’s Club)” I spent some time on the internet trying to find exactly what this battery was, given that there aren’t any Sam’s Clubs nearby.

A search of Interstate’s web site leads me to two conclusions:

1) The part number cited is a Sam’s Club number and not likely to be useful elsewhere.

2) Interstate only makes (in Group 27) Start Only duty or Start/Deep Cycle duty batteries for marine use, neither of which is optimal for this application.

The best type of marine/RV battery to use for this application is one rated for true “Deep Cycle” duty. Deep Cycle batteries tolerate more frequent and deeper (more than 10%) discharge without early failure. These are not often found in warehouse stores. My local BJs had one this week, but this is the first time in over two years that I’ve seen one there and I live in a “seaside community”. Deep Cycle only batteries are not often found for under $100.