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Need a tutor
I hate to betray my ignorance of electrical systems, but I know most of you are gentle teachers, so here goes. My prior two coaches were easy for me to understand. A bank of 12v batteries wired in series feeding 12v to/from the inverter/ charger. This was easy to tap for all the 12v systems. My new bus has a bank of 12v batteries in series/ parallel, putting 24v into the two inverters and charged either by the inverters or the 24v alternator on the bus engine. I understand that. But what I don’t get is where does the 12volt come from that powers my lights and other systems? Can you get 12 volts out of a 24 volt battery bank, or does it have something to do with these Vanner equalizers that have taps for both 12 and 24 volts. I always assumed that equalizers were for equalizing, but do they also halve the voltage for the house systems? I guess what I’m really asking, is what do these Vanner Equalizers do? Tracing the cables from the Vanners requires more contortions than I have have in me, so I’m looking for advice from the gurus in the hope that I won’t need to disassemble the whole battery compartment to figure out this basic question.
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12 Replies
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Ok, I answered my own question. I found the Vanner manual online and see that it works as I suspected.
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Glad I could be of so much assistance.
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Bryan,
First, the wiring looks great! It would appear that someone paid particular attention to detail in crimping, the use of heat shrink and neat running of the cables.
So, you now know these are mystery devices that ensure the each half of your 24V battery bank is sharing in the supply of the necessary 12V loads. Without an equalizer you would be draining one half of your bank much more so than the other and likely over charging one half over the other.
I’m surprised by the installed capacity of your equalizers. Having 2 100A units in parallel gives you 200A of 12V service. Given your inverter loads are not 12V, that’s a huge amount of 12V service!
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Thank you Gil. I believe the converter did a superb job on the systems, and since the bus was seldom used before I bought it, most everything is like new. Since American Coach is defunct, it is my challenge to figure out everything they did during the conversion, and why. I’m not sure why they provided 200 amps of 12 volt. The only 12volt loads I am aware of are for interior lighting and the water pumps. We have about 70 halogen ceiling spots and perhaps 200 feet of Tivoli lighting so that can draw a lot of juice, but I don’t think they use anywhere near 200 amps. I changed the halogens for LEDs in the bedroom and they work great, so now I’m doing the rest. After that is done our 12 volt usage will be substantially reduced.
Based on your suggestions and those of Jon and Les, I got the flat disk warm white LEDs to replace the halogens. I paid $8 for the ones that aren’t polarity sensitive so I didn’t have to re-wire any of the the fixtures like you did. I did have to remove the pot metal reflector from each light fixture though, as the resistors on the back of the waffer make the disk too thick to fit in the fixture without modification. Not difficult, but not plug-n-play either. Since I still have halogens in much of the bus to compare, I can see that the LEDs are ever so slightly more blue than the warm halogen light, but I don’t find it harsh or offensive at all.
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The 200A service is about right. If you have all 70 of your 12V halogens on, they’d draw 116A. Now if you have an aux air compressor and a view other 12V devices (radio, sat) you’ll be using most of you 200A. Replacing the halogens with LEDs will help a lot.
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I have those exact Equalizers as well. My question is……….do they handle house batteries AND chassis batteries, or just house batteries?
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Jerry, I don’t know about your Vantare, but on my system the equalizers are not connected to the chassis batteries. My house and chassis systems are totally separate. The only connections between the house and the bus chassis on mine is a battery charger that runs off the inverters to charge the start batteries, and the 24V input from the engine driven alternator to charge the house batteries.
Threegreens, I think you have nailed why we have 200amp 12V. In addition to what you mentioned, the Aquahot needs 12V to run the pump and fans to heat the coach.
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Jerry, you may have an equalizer on your chassis bank, I do. Not all chassis power requirements are 24V on my coach. Unless you have a 24V house bank, you will not have an equalizer on your house bank.
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Bryan,
Makes sense. I have a Boost switch to connect house and chassis batteries together if needed to start.
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Bryan,
Threegreens nailed it. It always blows me away to see someone install a 24V bank and then to install so many 12V devices. Lights, water pumps, water circulation pumps, and air compressors are all available in 24V. Although generally more expensive, some of that additional cost would be offset by installing smaller conductor cable given you only need half the amperage.
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Every Prevost Chassis will have 100 amps worth of equalizer. Early models had 2 50 amp Vanners, later models a single 100 amp.
Coaches with only 12 volt house DC service are not liikely to have an equalizer, but I am not aware of any conversion with a 24 volt house that does not have an equalizer.
I was pleased to see the remark about the electrical load caused by halogen lights. Few think about those lights or the tivoli (rope) lights when they dry camp for example. The lights look pretty all lit up, but they are sucking power out of the batteries at an alarming rate.
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I have 5 equalizers on my house system and it is all 12volts. I have never checked the amperage, they may be 50 amp ones and that is why I have so many.
Greg
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