Charging with a automotive charger

simmtronsimmtron Solar Expert Posts: 87 ✭✭✭
Has anyone used an automotive charger for charging their off grid system? I have been using the charger from my Xantrex Freedom 458 for 10 years now ( is 16 years old) and just smoked last week. I have it in MAYBE getting fixed (Mexico) so bought a Schumacher SC-1353 portable charger for temp use. I only need to use charger a couple times a month. It has 200 amo engine start, 40 amp boost and 6 amp normal charge. I thought I would ask their tech support about charging batteries in boost mode. The GUY told me boost would shut off in 10 minutes. I thought ohhh, it seems like a heavy battery charger to only use 6 amps. So had it charging yesterday morning, 8 - 6 volt golf carts, and yes it is 12 volts, and yes I know people don't like 4 parallel strings. Well it went to boost mode and stayed there for 1 hour untill I shut it off (solid 37 amps] . Wires were warm not hot , and unit wasn't very hot, and it's 90 f here. Any thoughts about problems using the charger in only boost mode.


  • mike95490mike95490 Solar Expert Posts: 9,089 ✭✭✭✭✭
    40A is not much for 800ah @ 12V,  you could put that to the batteries for many hours.   What was the voltage at the batteries when you terminated ?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

  • simmtronsimmtron Solar Expert Posts: 87 ✭✭✭
    when I terminated the voltage was 14.2. It was morning and I didn't need to charge because panel would do it that day, but wanted to see if it would shut out of boost mode after 1 minutes like their tech said. This is a temporary fix until I get my Xantrex back or can order one from the states. They are crazy overpriced in Mexico. The local place has Chinese 15OO watt inverters with built in chargers butt he charger is only 2O amps. We have lots of sun here all year {Playa Del Carmen} So even with the Xantrex 1OO Amp charger I only ever need to run it for an hour if bad weather , so only have to run this 2 or 2 1/2 hours. With the panels I can equalize when ever needed.
  • EstragonEstragon Registered Users Posts: 4,478 ✭✭✭✭✭
    Purely guesswork... the 40a boost may flip a breaker at some point if sustained, or maybe it fuses closed and the internal wiring becomes the fuse :wink:

    Personally, I'd prefer to use a charger rated for the current I'm likely to want to bulk with (~80ish amps with an 800ah bank)..
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • simmtronsimmtron Solar Expert Posts: 87 ✭✭✭
    Just found some info on charger , specs online show 40 amp continuous. 200 amp which is car start mode intermittent. So my guess is that using boost mode (40 amps) should be good. I will eventually ,maybe get a charger like a xantrex or iota, but this seems to work. The local inverter charges available here only have 20 amp chargers integrated, so I'll wait an see.
  • simmtronsimmtron Solar Expert Posts: 87 ✭✭✭
    One interesting thing when looking at other battery chargers, just comparing 40 amp chargers. The iota and xantrex chargers are 5 pounds the portable auto charger I bought is 29 pounds. My old xantrex Freedom was about 50 pounds.
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