I'd have to say I concur with Jzawacki. Even if your unit is out of warranty the new batteries will have a warranty. There is a fine line between charging and destroying your batteries. That is a lot of money to risk when all you need to do is ship off your charger. A thin layer of corrosion cause several 10th's of a volt error on your meter reading and if your meter is not accurate you add even more error and list goes on and on.
Also, it is my opinion because of reason's listed above, 29.5 volts is too high of a number. Unless I missed something, 29.3 should be the factory unloaded output and that is where I would start but regardless, I would rate myself at a fairly high level in electronic theory, testing and troubleshooting to the component level and I would not set my own charger if I where in whitey shoes. Also some industrial lithium battery packs contain not only a low voltage shut down circuit (required by the Feds) but also protection for over charging. 1/10th of a volt per cell too much can trigger circuit protection. Most lithium ion batteries will over charge when more than 4.2 volts per cell is applied. The battery pack will last much longer when 4.1 volts per cell is applied for charging. That is assuming these batteries are lithium Ion. Lithium Iron is altogether different. If I remember correctly that max charge per cell for lithium iron phosphate (LiFePO4) is like 3.6 volts per cell. I do not know how many cells are in the Lawnbott batteries. I'm suspect they compensate for voltage drops from the wire length and connections so its difficult to know with just their charge voltage. However I don't mean ANY disrespect to Jerry, he probably does know what he is doing. Like I said its only my opinion and we all know what opinions are like.... everyone has one.
