Power supply?

[Cheech]

I was wondering is it posible to hook a voltage regulator to power supply and use it as battery charger and power supply kinda like what they have in RVs? I know you can do this with a battery charger but the power is not filtered and its ment more for charging a battery than runing dc electronics. I already have an optima 34 yellow top that I used to run my 25 before I got my astron. If I could conect it all together that would be great! It would also save the time of charging the battery! Thanks!!!

 

[bob85]

if the power supply is a good quality one yes you can use them to charge batteries, if its a cb power supply then i would not go over 1/5th its rated max continuous current to charge a battery, i never use the propper cheapass chargers that come with most gear, i use a 5 amp farnell psu in the garrage to keep my spare batteries in good shape, its set to 13.85 volts and 2 amp current limit, in the shack i use two variable voltage/current psu's to charge all my other batts, you must limit the current either internally or with a big resister othewise an average quality cb power supply will burn itself up in no time at all, for a 12v car type battery i use 14.45v to regular charge and 13.85v for long term maintainance charge, been doing it for years and had no probs with sulphated batts or overchaging and no burnt up psu's.

 

[Cheech]

So it would take more than just a voltage regulator to a alternator I take?

 

[bob85]

the power supply already has a regulater in there, you just need to set the voltage to what you need for charging the batt, and some way of limiting the current, simplest way is a high power resister in series with the battery to limit max current, but be aware that no cb or ham power supplys i ever saw are capable of doing what it says on the front continuously, i have smoked a motorolla power supply charging batteries without current limiting it, the farnells i use now are way over engineered when compared to any cb/ham supply, i set an old 10/15amp cb supply to 14v at 2.5 amps for my dad years ago before automatic car chargers were available here, he uses it almost everyday for his old tractors and van without any problems yet.

 

[Cheech]

I was thinking that maybe the voltage regulator to an alternator would kinda serve as the current limiter and make it a automatic charger. My power supply is rated at 35 amps but only 50% duty cycle so I can see burning that thing out without a limiter. I eventually plan on geting an Iota power supply thats rated at 100% duty and ment for battery charging. There actually ment for RVs but they say you can use them for power supplys or a power supply and batery charger.

 

[nomadradio]

Umm, the "RV" power supplies that are MEANT to be used with an auxiliary battery have one important thing MOST regulated DC power supplies dont: ISOLATION.....

If the battery is connected to the output posts on your regulated power supply with the AC OFF, a reverse-polarity situation can arise with the regulator circuit. I have clobbered one or two small supplies this way, charging gel-cells, not being careful.

Any power supply meant to be used with a battery will contain isolation diodes that prevent this. Most DC supplies do not include isolation, and can be damaged by 'back-feeding' juice into the output posts from a battery with the AC power turned off.

73

 

[Cheech]

Yep I thought that may be a problem. Anyway it looks like Im going to have to wait for the Iota power supply just wish they made a charge controller for gel and AGM batteries.

 

[bob85]

a diode is a good idea, i have not blown my supplies in that way charging batteries but i have smoked a 30a psu running it in parallel with another identical supply set to the same voltage because i neglected to use isolation diodes and in a momentary lapse of concentration turned just one of them on when they where still connected together, not a difficult repair but i could have kicked myself in the nuts when i realised what i had done.

 

[Cheech]

Ouch! I have 3 power supplys and two of them are the same and I was told I could hook them in paralell but I never did try it. I was thinking something bad may happen.

 

[nomadradio]

Some industrial-type power supplies are meant to be placed in parallel for higher current capacity. Mostly you will find one of the screw terminals marked "slave", or a jumper joining a terminal marked "sense" to the one marked "output".

A supply designed for this kind of service will not be damaged this way, but you have to hook them together the way the manufacturer intends. There is usually more to it than just tying the output terminals together.

73

 

[Cheech]

Yep dont think my power supplys could handle being hooked up that way. Thanks for all the help everyone!