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Message |
Chuck MC8 (207.69.11.21)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 6:17 am: | |
I'm planning on using a bank of Golf Car Batteries for "house" system on my MC8. I've seen
very nice and clean additions of 12V alternators on the 8V71 to charge the house batteries.
But, as I look at the massive 24V alternator that I already have, It seems a shame to have it only charging the starting batteries and running the lights ( no factory bus a/c, anymore).
Here's the question....I can connect my house batteries to make 24V...There are 24V inverters available, I already have the "big dog" charging system..What would I need (an isolator?) to charge
the house batts along with the starting batts?
And how to reduce the voltage from the battery bank to 12V final product for my "final" needs? |
Steven Gibbs (12.148.43.7)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 6:47 am: | |
Chuck,
You can draw your charging current right off of your starting battery bank if you install an equalizer. You may already have this if your headlights have been converted to 12v.
You simply tap off 12v from the 24v bank then run this through an isolator relay that makes the connection when your engine is running only.
Check the Archives on this board since detailed threads on both equalizers and charging are located there.
HTH,
Steve G.
MC9 |
Richard Bowyer (Drivingmisslazy) (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 7:28 am: | |
I seriously question the need for a separate bank of house batteries. Boy, is this going to start some controversy.
Many months ago, Gene Rochester made a very convincing argument on a post and it was sufficiently detailed and with good enough reasons to convince me that if I ever built another conversion, I would not have two separate banks. Unfortunately, I cannot recall all the details. I have not seen him post for a few months, but maybe if he reads this, or if somebody saved to post, it could be re-posted. Ace may have it or remember it and or contact Gene directly to repost it.
Some thoughts of mine are that I am not convinced that you really need deep cycle batteries. The newer inverters will cut out when a low voltage is sensed. I think this may be adjustable, but is in the 11.5-12 volt range. This voltage should not harm regular starting batteries, in my opinion. Also, the newer chargers have the capability of being programmed to start the genset automatically when the battery voltage drops to a certain level. They can also be programmed as to time of day to start so that the genset does not start at 0dark30.
The main bus alternator will keep the bank charged while driving and the inverter will keep them charged when plugged in to the PP. When dry camping, the genset would be utilized to re-charge the batteries as needed.
Starting batteries generally have a much better warranty than deep cycle batteries. Something like two or three years free replacement and six or seven years pro-rated.
The one mandatory item would be a separate start battery for the genset. If the main battery bank ever got discharged to the point of not being able to start the bus, the genset would start automatically, or it could be started manually and the high rate recharge capability of the inverter, running off the genset, would recharge the bank in a matter of minutes to provide enough energy to start the bus. I have done this in the past and the time required was less than 15 minutes to get enough charge to start my 8V92.
Just my thoughts.
Richard |
Don Ripley (66.53.73.173)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 7:41 am: | |
I agree with Richard.I set my coach up using four 8D batteries for starting and house use.I use a seperate battery for my gen set. I have a 24 volt system and use a 4024 trace inverter which has beeen great so far. |
Stan (65.59.7.137)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 9:23 am: | |
I never used a separate battery for the genset. A bank of 8D's will crank the small engine even when pretty low. As a last resort use the toad battey to start the genset (I never had to use it in many years of travel). If your genset uses an internal winding to charge its own battery then you have to put a large diode in the cable from the 8D's to the genset battery so that there will not be a connection between the AC powered battery charger (Inverter) and the genset charging system. If the genset uses an external alternator, just remove it and not use the diode. |
Bus Jock (198.81.26.174)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 10:10 am: | |
Chuck,
You will get a lot of conflicting answers to this question. What this indicates is there are a lot of ways to solve this problem. It will depend a lot on how you plan to use your bus. Do you plan a lot of boon docking with no electricity, or will you mostly be staying in RV parks with full hookups?
I have tried to aproach this problem from an engineering standpoint, and have written an EE note showing one aproach that has worked extremely well for us. Its posted at:
www.purplebear.com/busnuts/bus_elec.html
Jock Fugitt |
Chuck MC8 (207.69.81.179)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 2:17 pm: | |
Mostly , what I have in mind is, as we travel, that our family (of 4) would "boondock" at the usual locations, nights, instead of campgrounds. Then when we arrive at the destination, that we would book into a campground and plug up for the desired length of time, probably a few nites, and then move on.
We also like College Football, so we plan to attend games where we will arrive Friday afternoon and stay till Sunday AM with no hook up. |
Keith Kroeker (Keith) (65.33.37.243)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 5:07 pm: | |
This is a good thread... I also dont picture dry camping more then 2-3 days max without hookups and this would not be regular for the next few years.... Now I'm wondering if maybe a larger 24 volt bank would be better than 2 banks and a second alternator??????..... If you used say 4or 6 8d's hooked series parralel for 24 volts, couldn't you add a cut off switch similar to this used on RV's to cut power to one part of the bank (primary starting batts) if voltage dropped below a certain point or is this making a simple thing harder? |
Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 7:01 pm: | |
I plan on having a complete separate system from the "chassis" vs the "house". Will keep the two (2) 8D starting batteries and alternator alone and have.....
Anywhere from 12 to 16 L16 batteries as the house bank. Diesel electric coach-no propane. One (1) large SW invertor will run the house with maybe...
A small SW backup to keep the reefer running if necessary. This arrangement solves more problems for me than making them. Planning on around a 7500 Watt...
Or soosssss diesel gen set and around a 2000 Watt Outback Invertor (right now) with the correct sized charger to do the batteries. The main heat....
Will be some sort of hot water boiler system with some small induction backups run off shore power or the gen set. Three roof AC units are planned.
Suppose there are many ways one can do their coach---in my situation, I have decided to do it this way. Plenty of chassis capacity with the....
Crown 40-foot 3-axle 10-wheeler with a GVWR of 47,160# and a stripped shell weight of 23,950# Even with 400 gallons of fuel, 400 water and holding ...
It will even be close to the allowed road weight. More like a logging truck chassis than a coach. Ex schoolie from the LA area. Thanks. |
Tom Caffrey (Pvcces) (64.114.233.137)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 25, 2002 - 10:50 pm: | |
Chuck, the main differences between starting batteries and deep cycle batteries are plate thickness, separaters and the amount of antimony used.
Starting batteries have much thinner plates, more porous and thinner separaters and very little antimony.
Deep cycle batteries are just the opposite. And then there are hybrid batteries, with properties in between the other two.
The starting batteries should not be discharged more than 20% before they are recharged if you do not want to hurt them. At that level of charge, they will still show over twelve volts unless heavily loaded.
Deep cycle batteries are designed to tolerate discharging to the 50% level many times before they are hurt. They will show voltages down to around 11.5 or 11.6 and still be going strong.
If you use deep cycle batteries for boondocking, for a given usable capacity, you will only need 40% of the batteries that you would need in starting batteries.
Since the AH per pound is similar, you will only need to pack and pay for 40% of the batteries. The weight and space and cost needed for batteries makes this something worth considering.
Regarding 8D batteries, I believe there are quite a few hybrids out there, so finding them shouldn't be too hard. The difference is in the ratings.
If you find only CCA, assume it is a starting battery, because that is what they are bragging up. If you find only AH and they say it is a deep cycle, it might actually BE a deep cycle.
If they give both ratings, expect a hybrid at best.
One other thing. So far, all the inverters that I've looked at say the cutoff voltage is around 10.5 volts. At that point, your starting batteries are hurt. The deep cycles will recover much better.
Something that helps you with the deep cycles is that they will not be as deeply discharged in most cases when they hit the cutoff. This is because of their lower operating voltage.
We went with several 8Ds ourselves, but that was only because we had a bunch of them setting around not being used. When I run out of free or nearly free 8Ds, we will change over to colf carts.
The voltages mentioned are for 12 volts. Halve or double them, as required, for other systems. Also, I know of people who have found the 220 amp golf cart batteries for little over $50. If you are using new batteries, that makes them hard to beat.
HTH
Tom Caffrey PD4106-2576
Suncatcher |
Phil (204.89.170.126)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 26, 2002 - 7:57 am: | |
I am running a factory coach (Monaco) and use two 12 volt, not 8d, for starting batteries (only have to start a 5.9 liter Cummins)and four 6 volt golf cart batteries for the house. I dry camp for 10 days at a time. We operate with a 1500 watt inverter to run TVs, sat. receiver and the normal 12 volt stuff, lights, furnace (propane). We run the generator for 45 minutes to an hour in the morning to make breakfast and any time we need AC. We try to park where the gen (Onan 7500QD)won't bother anyone. The inverter (70 amp charger)seems to keep the batteries well charged. Works fine for us. Been doing this for three years with this coach and are still using the original batteries. FWIW |
Mike Eades (Mike4905) (206.148.166.121)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 26, 2002 - 8:46 pm: | |
I run 4 8D's Two for coach 24 volt and two for house 12 volt with two vanners. one is a 25 amp unit and one is a 60 amp unit. Seperate batt for the genset. wirco 8 kw with seperate fuel tank in my 4905. I do this for about 35 k miles a summer and dry camp at motorcycle shows and I haven't had any problems. |
FAST FRED (209.26.115.225)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 27, 2002 - 4:55 am: | |
For folks that prefer to use the start batts as combined house batts , the use of deep cycles will usually work out better than real starts.
The truckers that do this purchase a low voltage disconect.
The idea is they can use juice only to a certain point , the point where there is JUST enough juice to get restarted.
One such device ( there are many) can be found at
www.copelandengineering.com 800.357.7514
another is called the Power saver from Intra Tech.
no address.
MUCH CHEAPER is a marine "low voltage alarm" which is only $15 or $20. These have the downside if sounding when the volts drop under load , so it might alarm every time the inverter is used , as that would kick the volts lots lower.
Best would still be a Bogart or E-meter that learns the batt system & displays the % of discharge , so YOU can decide when you have depleated the batts enough for YOUR wallet.
And will have the advantage of actually showing how much refill the gen set does , also in % of charge.
FAST FRED |
Don KS/TX (67.210.119.74)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 27, 2002 - 9:32 pm: | |
I think Richard has it right. If I build another, I will do it that way. I used the L16 bank of deep cycle, lots of stuff mainly because everyone else was doing it that way. Less batteries and a auto start on the genset is the way to go for most uses I think. Even if you shorten the battery life, with the longer warranty you can just get new ones. |
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