| Author |
Message |
Steve Fessenden (63.25.54.52)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 04, 2001 - 12:20 pm: | |
I read one post on a board suggesting that we use only one voltage and converters to to run 12 volt equipment. I believe I can do that with 12 volts for only for the car stero system (100 to 160 watts) the clocks, compartment temp gauges and refrigerator electronics. I have a 1992 Dometic 3801. I do not run it on 12 volt power other than to run the 12 volt control board. It runs either 110 volts or gas. The 12 volt heating unit is inoperable, apparently burned out. The only other 12 volt items I have are lighting items which can be run in series or changed.
I have obtained several Vanner DC to DC converters: 22-32 volt 20 amp to produce 12 volt 25 amps. Not very efficient. I also have one marine/aircraft Newmar converter with the same specs but much bigger and heaveier. The thought of not having a separate 12 volt system is very appealing. I have two alternators so I could change the 12 volt alternator to 24 volt and have completely separate house and bus systems.
The only remaining 12 volt system would be the generator, and I could start the generator off a centertap on the 24 volt system on the rare occaision when its own 12 volt battery fails. As soon as the generator starts, it would be powering an inverter charger to recharge the 24 volt house system.
Any advice. My coach can never have an all 12 volt house system. Too much 24 volt stuff. This sounds like a good way to simplify. I will have spare converters on board in case a critcal one burns out.
By the way, skycraft surplus has 4.3 amp 24 to 12 volt DC to DC converters for around $10, new and easy to find replacements.
Any thoughts.
Steve Fessenden |
Paul M (216.244.20.11)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 04, 2001 - 6:51 pm: | |
Steve,
We solved the 12 & 24 volt problem very simply.
First we have two 8Ds in series dedicated to starting the engine. Second we have two Rolls deep cycle 8Ds as house batteries hooked up in series to provide 24 volts. We then tapped into the first battery for 12 volts. with the use of a Vanner 50amp 24/12vdc equalizer, we can charge with the engines alternator(24vdc). We have hi amp switchs to isolate both banks when desired. We have been running this system for three and a half years with absolutely no problems. I also check water & specific gravity regularly, with no excess use of water and both of the house batteries are always charged to the same level. Another benefit is that you can charge the whole mess with a 24volt inverter/charger when you're plugged in.
Hope this helps
Paul M |
Steve Fessenden (63.27.89.92)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 05, 2001 - 2:30 pm: | |
I talked with a Vanner tech about the difference between a converter and an equalizer.
A DC to DC converter supplies a very constant voltage, not affected by the charging system etc. Good to use where you need a precise voltage. A Vanner 20 Amp 12 volt converter has a standby current draw of a tenth of an Amp. Of course no standby current draw if the input 24 volt to is switched off.
A Vanner equalizer has three leads. It hooks up to the 24 volt terminal, the 12 volt terminal and ground. It feeds current from the 24 volt terminal into the 12 volt battery as needed to keep it equal in voltage to the upper (24 to 12 volt) battery. Up to the limit of the equalizer. If you briefly exceed the equalizers capacity, the equalizer will catch up when the excess load difference ceases. Providing the difference is not too much for to long. No equipment current flows through the equalizer.
So it is possible to have an equalizer that is only sized to your average 12 volt load. They come in 10 Amp, 20 Amp, 60 Amp, 80 Amp and 100 Amp models.
Pricing: I checked five distributors for prices:
Three were almost the same. Florida was much higher. These are selling prices to a business. I just gave them my business name.
60-10B 10 Amp $195.00
60-20A 20 Amp $250.00 to $262.50
60-60 60 Amp $386.90
60-100 100 Amp $703.50
So you see, we can afford a Vanner equalizer in our conversions. Cost is comparable to the cost of putting in a separate 12 volt alternator.
Lighting does not need to go through an equalizer. Bulbs can be run in series. A balance center tapped system can be run for bulbs that are always on together.
A center tap is required with a Vanner equalizer for 12 volt. If you already have a center tap for 12 volt on a coach, like I do, and it is creating problems, the easiest fix is just to add a Vanner equalizer. Three wires and it's fixed.
Hope this parroted information helps someone.
Steve Fessenden |
Steve Fessenden (63.11.118.173)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 05, 2001 - 10:47 pm: | |
I just got an Email question that I'll answer here.
ON THE VANNEER EQUALIZERS THE RATING 20 AMPS, 60 AMPS, ETC IS FOR CONTINOUS DUTY ALL DAY LONG AT THAT RATE.
I just ordered a Vanner 60 amp equalizer today for $386.90. That is a business price. I'm no expert but I believe that Vanner is the number one name.
Steve Fessenden |
Steve Fessenden (63.27.89.195)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 06, 2001 - 6:15 pm: | |
All Electronics has DC to DC converters 24V to 12V, 1.67 amp for $3. Should be good for running the refrigerator electronics if the 12 volt heater is not enabled.
Their Part number is: DC-34
DC-DC CONV, 12V @ 1.67A (USED)
They also have: PS-9505 for $2.50
a 17W POWER SUPPLY 120V AC input, 12V 1A and 5V 1A output. I plan to use it plus a relay to run the refrigerator on 120 VAC with out battery. Does anyone else get annoyed when their battery goes down and the refrigerator shuts off even though you are tied to a 50 amp post?
Their web site is allcorp.com
Steve Fessenden |
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