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Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
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Good Advice from Andrew there..
Keeping an eye on the end-of-charge voltage is very important as he mentioned, because most car alternators are set to put out 14.2 - 14.4v which is fine for a wet-cell, but will cause an SLA to gas when its full, which is a bad thing, since you cant just top up the electrolyte like a wet-cell..
Doing it with the car off will put *some* charge into the SLA, and it will be a nice smooth voltage so its good in that respect, but the car battery voltage will probably only sit around 12.5 - 12.8 volts under load, so you wont get a full charge into your SLA with the car off.. and you will get too much if you dont monitor it with the car running..
Bottom line is, if its a good quality SLA, charging it from your car alternator is a last-resort thing to do if you're desperate to get some power into it in a hurry.. but If your SLA having a long happy life is important to you, its not something I'd reccomend doing.. unless its a cheapy you dont care about. _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
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Mon Apr 25, 2005 10:15 am |
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Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
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While wiring up some battery charger leads, I thought I'd suggest another use for an idea andrew mentioned a post or so back.. a cheap SLA "Charging complete" indicator.
At the last event, a couple of people were plugging their SLA Batteries into my "Super Charger" (as someone called it - a 25amp power supply) to charge them up faster than their own chargers could manage.
Thats fine by me, but even although my charger has current indicator on it, it was also running my Tritons at the time, which made it impossible to tell whether the 10amps on the display was going into the Tritons, or the SLA's that were being charged at the same time, so they couldnt tell if their battery was sufficiently charged yet or not.
If you were to make up a "charging lead" that had a suitably rated light globe in series with one of the leads, then when the battery was drawing current, the globe would glow brightly, and as the SLA charged up and the current dropped off, the globe would dim and eventually go out, showing you the battery had stopped taking power and was (hopefully) full..
Something like a car interior light globe maybe, or perhaps a 6v globe would be better (since its unlikely your battery would be at 0v when you put it on charge). a bit of experimentation might be required to find the right rating of globe, since you dont want it to blow at full charge current, but you want it to go out once the current has fallen off to 100mA or so..
It would be good for people who charge multiple SLA's from a single charger as well, since if each lead had its own globe, you could easily see which batteries were full and which ones werent.
I cant think of any reason why it wouldnt work, and it should be a very cheap and easy indicator to put together a few of. I hope it helps people _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
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Mon May 23, 2005 12:51 am |
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