Others have posted several good ideas that I am building on. This post would be my approach. You mentioned your interest in learning EVs, so the following is also applicable to a highway speed EV. -1st ensure you have a way to charge the batteries, begin with the charger. As posted, you need a 240VAC 30A source (I assume that is available in your garage which is where the lift will be stowed& charged).
I found a charger that might be similar to yours, see: http://www.ebay.com/itm/HOBART-BROTHER-BATTERY-CHARGER-MODEL-NO-1R12-550-/220766216900 If you want to contact the manufacturer, see: http://www.hobartbrothers.com/contact-us.html -Next work on knowing the status of the batteries: are they still usable (they just need charging and watering), or do they need replacing? I suggest opening the battery case and measuring the cells to know their health. As mentioned, take a look to see if each cell's plates are covered with distilled water. You can charge them if the plates are covered, but do not fill the cell to its fill ring level until after the charge cycle (if you make the mistake of pre-watering them, and then charge the cell, the electrolyte will expand in volume and over flow, spilling acid everywhere = not good, prevent this). In my former S-10 Blazer conversion EV with a new 132VDC pack of 22 6V T125's that were allowed to rest for an hour after a full charge, each battery would usually read ~6.4VDC (if this seems low or high then it might have been my volt meter/DVM). That means if I could have measured each 2V cell, they would have read 2.14VDC. In my College chemistry courses they taught the potential of each cell should have been 2.2V, thus a 6.6V battery (of 3 cells). But in practice, the static surface voltage always read lower for me. While you figure out how to get a charge on the bank of cells, you should measure them to know what SOC (their health) before you put a charge on them. Here is a table that gives the SOC voltages, see: http://modernsurvivalblog.com/wp-content/uploads/2013/06/battery-state-of-charge.jpg According to the above table, a fully charged 2V cell will read 2.12V . And a fully charged 24V pack will read 25.46V (you may want to also find out how accurate your DVM is: does it read low or high?). When you do charge your 24V pack of 2V cells, spend extra time to monitor the charge cycle (baby it) so that you know/familiarize-yourself on how the charger and your pack's SOC correlate (work together). Years ago, Otmar showed his way of charging his Porsche EV's pack. He set the dash mounted e-meter to read out like the pack (no mater what actual voltage it was) was one 12V battery. Thus, he would only have to follow standard wet cell voltages: 13.8VDC for a float voltage, 14 to 14.4V for a finishing charge, etc. I instead set my e-meter to read the actual voltage, and remember what each voltage would be for my particular 132VDC pack. i.e.: when my pack reached 151VDC I knew it was 95+% charged (but the pack may not be balanced). Pushing the charge longer to balance it would raise the pack voltage to 156VDC before the smart charger would shut off. An hour after the charge cycle had completed, my 132VDC pack would settle down to a 141VDC reading. If you find the 24V pack of 2V cells needs replacing, as posted, for an hour's use, that is 1/8 the 400Ah capacity of those 2V cells (400+Ah * 1/8 = ) four 100 minute 6V batteries in series to give 24V would be a minimum replacement pack configuration. Trojans are best but are costly http://www.trojanbattery.com/pdf/datasheets/T105_Trojan_Data_Sheets.pdf You should be able to find ~100 minute 6V golf/traction batteries for near the prices shown at: https://www.google.com/search?q=L16+6v+batteries&tbs=vw:l,p_ord:p&tbm=shop You also mentioned keeping a charge on the pack so it would always be ready for use. I suggest after use, you put the lift on a charge, afterward use two 12V battery maintainers, see: https://www.google.com/search?q=battery+maintainer&tbs=vw:l,p_ord:p&tbm=shop I have been using one (12V 1A maintainer) similar to http://www.ebay.com/itm/like/172241881686?lpid=82&chn=ps&ul_noapp=true for over a year: it still works good. But a 12V 2+A maintainer would be better. I would not just leave the lift on the large charger all the time (a waste of power, and likely hard on the batteries: will dry them out). Once the charger and pack are up and running, measure throughout a charge cycle to know what it is doing. Being an old transformer type charger (like my 30A Bycan was), it likely uses a rectified half-wave design. This means the secondary winding of the transformer is center tapped and each (leg) end feeds a power diode. In my Bycan, I put a switch to disable one leg (one of the waves), to provide a half power setting. From a design perspective this is considered hard on the transformer, but I never found it to over heat or damage the transformer (my Bycan was a lower amperage charger though). It did allow me to draw less power for a longer slow-charge cycle. If plan to copy what I did, you would need a higher rated switch than I used because of your 24VDC charger's higher output current. The charger ratings mentioned 115A output. I have charged at this high rate with no problems. This type of transformer charger design uses the AC sine wave to taper the charge. Meaning: in the beginning, the charge current is high, but as the pack voltage rises and approaches the ~50% SOC point, the charge current has already tapered to a lower charging current. This is why this type of charger is slower than today's smart chargers that push maximum current until a specified taper voltage or cut off point. So, the ratings may state 115A max, it won't always push that much into the pack. As far as later disassembling the lift and trying to use its low voltage motor in an EV, it possible, but I do not recommend it. Those that I have read about having success, had a low voltage system, which translates to less top speed (it was more of a nEV, than a lsEV, and forget about highway speeds). Also, the lift motor was loud and noisy by design, so it was OK at low speeds, but not a fun ride at high speeds. Meaning, while it can be done, you may not want to use the e-motor (plan for a nice 144+VDC system voltage using an AC e-motor so you have regen, etc.). I hope this post has been f use to you. 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