anyone made their own generator?

Submitted: Saturday, Jun 21, 2003 at 20:42
ThreadID: 5583 Views:2285 Replies:4 FollowUps:4
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Hi
I'm curious to see if anyone has made their own generator (like the Christie one)? Any tips appreciated.

thanks
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Reply By: Eric - Saturday, Jun 21, 2003 at 22:04

Saturday, Jun 21, 2003 at 22:04
Shaky.
Yes I built a unit like the Christie and found that the normal alternators are very ineficient, the best I could get was about 20%. I started reading up on alternators and eventualy realized they are not suitable for this application. the unit that works best is a 24volt dc motor made by davis criag for use in a truck radiator fan, using it as a generator gives 5 amps at 1000 revs which is quiet and very cheap to run. the maximum amps the unit is capable of putting out may well be twice that but I dont want to find out the hard way. If you can get a slightly larger 24 volt motor you would get more power, the unit I have is about the size of a cricket ball and has a permanent magnet that gives it its high eficiency, the unit that may be best is a blower motor from a 24v truck air con. Eric.
AnswerID: 23170

Reply By: Will - Sunday, Jun 22, 2003 at 13:39

Sunday, Jun 22, 2003 at 13:39
Yep I made my own using a Lucas 22 amp generator and a 3 barrel regulator
Much quieter than Christie and does not wreck your batteries like the Christie
Generator charges batteries much better than an alternator
AnswerID: 23200

Follow Up By: shaky - Sunday, Jun 22, 2003 at 14:07

Sunday, Jun 22, 2003 at 14:07
Hi Will,
thanks for the reply. Do you (or can you ) post some pics?. I need as much info as possible. I need to charge a gell cell battery as quickly on camping trips, so I'll probably look at a 55 amp unit I thought your comment of the ready to buy unit was very observant.
thanks

Steve
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FollowupID: 15401

Follow Up By: phil - Sunday, Jun 22, 2003 at 14:24

Sunday, Jun 22, 2003 at 14:24
gel battereis hate being charged too fast or, worse, overcharged.
55 amp would be much too high!
Phil
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FollowupID: 15403

Follow Up By: Will - Sunday, Jun 22, 2003 at 18:04

Sunday, Jun 22, 2003 at 18:04
Phil charging batteries especially deep cycle batteries at 55 amps is the quickest way to ruin batteries. Anybody that knows anything about charging batteries would recommend no more than 15% of battery capacity. 10% of battery capacity used to be the standard, but modern deep cycle batteries will comfortably take 15%.

My camper lives down at a lockup and don't have a picture. It is mounted on the front of the camper in a small roll over frame I made at work from aluminium that. It is padlocked on and can be easily lifted off once the padlock is removed. I used a Honda GX100 motor that direct couples to the motor using a low cost rubber metal and rubber spider coupling. On the engine shaft I put a 2.5" pulley with a mounting bracket above the generator to run a small high pressure water pump. All I have to do is put the belt on. I made the guard so it keeps the belt out the way while the pump is not being used. We normally always park next to dams or streams and the kids go through heaps of water in the shower and washing dishes and it is easier to pump it up than struggle with buckets.
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FollowupID: 15416

Reply By: Joe - Thursday, Jun 26, 2003 at 11:17

Thursday, Jun 26, 2003 at 11:17
Well there you go , the breeding ground for the backyard professional strikes again. Thats the drama with these forums, people are very willing to splatter about 'opinions' with no back up as no one can be held accountable. Its unfair considering it can easily ruin the reputation of a perfectly good product.

The Christie charger is a REGULATED charging system that will only allow 55 amps input if the battery can take it(ie. flat). As the battery becomes charged the input current reduces accordingly to the point where the built up internal resistance of the battery blocks further hazardous charge from boiling the battery. Therefore it is impossible to overcharge your battery using the christie.

Keep it tidy boys.
AnswerID: 23557

Follow Up By: shaky - Thursday, Jun 26, 2003 at 16:29

Thursday, Jun 26, 2003 at 16:29
From the research I have done on batteries, my understanding of the charging process is as follows. Normal cranking and deep cycle batteries should be charged at C/20 up to a maximum of C/10 according to the battery manufacturers. The exception to this rule is AGM batteries (such as Optima) and Gell Cell (such as the Sonnenschein Sportline range), which will accept very high charge rates. Now, if you have a very flat, high capacity auxiliary battery and charge it too quickly, the heat generated will damage the lead plates. Doing this repeatedly to the battery will shorten the life of the battery.
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FollowupID: 15755

Reply By: Mick - Thursday, Jul 03, 2003 at 18:25

Thursday, Jul 03, 2003 at 18:25
Hi guys,
Mick Christie here from Christie Engineering.. just letting you know that the chargers we build use a standard Australian made Bosch alternator and on the low setting will regulate to 14.2 volts no matter how flat the battery is and is the standad setting for motor vehicle charging circuits world wide, however there is a high setting that will set the regulator to 14.8-15 volts (also regulated) and over a short pereod will not harm a lead acid battery. This is means of "boost" charging a battery which is ideal for campers who don't like sitting around for long periods with a noisy generator charging a battery.
Before the product was put on the market Battery world, and other auto elecs tested and trialled the charger on their computerised tester and highly recommend the product.
AnswerID: 24116

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