Alfa primary battery and charging system redesign after catastrophic failures

[davecampbell]

New to Forum, looking for information/feedback on a problem.

A friend handed an 03 Alfa over to me to fix, with horribly destroyed battery banks (house and inverter). The cases exploded from overheating.

Turns out there are some serious design flaws in the system, and having an engineering background, I'm redesigning the whole system instead of just sacrificing more batteries to the gods of Smoke, Fire and Corroded Battery Trays.

Anyone seen the burned circuit board trace on the BD-2 board? (batt. disconnect board)

The root problem of destroyed batteries was easy to see, its not that any component was 'bad' (the invert/charger is fine, good batteries, solenoids, wiring etc) the overall system design is not correct.

QUESTION(s)

1.) anyone particularly with an Alfa, similar failures?

2.) "If you could have the system redesigned, to either work as is with improvements or to add features, what features would it have or not have?"

Thanks, both the owner and myself will greatly appreciate any feedback.

please respond here, PM or email me gl1200harness@yahoo.com

["007"]

This link will cover most anything to do with a RV by Cruzer in detail.
Here is another that has to do with RV's.
While not a ALFA should be of help for you. Most system basics are a like do not think Alfa would be any different.
Sounds like the batteries may have been over charged by converter or inverter combination.

[jackrobinryan]

Just to satisfy my curiousity, what were the design shortcomings or mistakes that you found?

jack

[davecampbell]

Quote:

Originally Posted by 007";751564][B][URL="http://www.rvtechlibrary.com/electrical.htm This link[/URL][/B] Sounds like the batteries may have been over charged by converter or inverter combination.

Links no help, Im not a rookie looking to understand the system, Im an engineer redesigning it from zero. Overcharging, yes, exactly. Extremely badly overcharged

[davecampbell]

Quote:

Originally Posted by jackrobinryan Just to satisfy my curiousity, what were the design shortcomings or mistakes that you found? jack

Severe overcharging of batteries that could, under some circumstances, be hazardous. There are circuits missing (nothing wrong with the components there already, they all work) that can be added to accomplish proper charging and complete system automation. I just would like to know if there aer other problems that need solving, or other functions that could be added to make operation more convenient to a user, especially if they dont have technical know-how.

The inverter/charger is connected to both charge the inverter batteies and power the house, but it cannot possibly supply that much current. The max house load is about 150A and the charger max is 100A, but can not supply it continuously according to Xantrex. They say it is not acceptable to use the charger as a power source.

There apparently is a problem with one of the Xantrex chargers overheating, but im not sure that the chargers are the root problem. Ive seen switch-mode power supplies go up in a cloud of smoke due to excess current draw.

The RV power systems are somewhat manual now, Im going to redesign it to be completely automated so all the user has to do is plug in shore power or start the generator and every circuit is properly powered to the max and batteries are correctly charged according to the manufacturers required profile. Plus a few other neat features...

[jackrobinryan]

["007"]

From this list of Alfa owners it seems they have other pressing problems not batteries.
That web site of owners may be able to help you.

[RV Wizard]

Alfa's motorhomes are a nightmare when it comes to this area. There is also some irregularity of the design of different years and models. I had one, I counted 13 solenoids involved in the three battery banks. The problem is basically the original engineers were trying to charge three different size battery banks from two different sources; alternator and inverter/charger. The three banks in my opinion are not necessary. The same goal can be accomplished with two banks like most all other manufactures have been doing successfully for years. I also believe that when all components, batteries and wiring is correct that the smaller of the battery banks (house) is going to be charged at too high a rate if the inverter/charger is programmed for the size of the inverter bank. Then you through into the mix, the charging of the chassis batteries and the charging of all from the alternator. It is way to complicated and has a high potential of failures.

[davecampbell]

Quote:

Originally Posted by 007";752013][B][URL="http://www.rvinteractive.com/alfa/crean.html From this list of Alfa owners[/URL][/B] it seems they have other pressing problems not batteries. That web site of owners may be able to help you.

thats EXACTLY what Im looking for (the type of info, not necessarily for Alfa or any certain mfgr) - repeated complaints that arent addressed by simple repairs (headlight out, replace headlight). Now Alfa is a moot point since they are out of business.

Often times seemingly simple problems have much more complex root causes, and this particular Alfa is just that. I.E. a good deal of corrosion on a set of relays 3 feet above the house batteries. Looks like just normal water exposure, except it looks like years of water exposure, and that area is designed to be competely dry. It must have been corrosion from battery off-gassing (H2SO4 or HS) which must have been severe since thats a very ventilated compartment.

I want to make sure I have all the roots uncovered before taking a working MH apart and doing major surgery, especially since there are significant safety questions. Its not a light matter to manipulate energy in a large box in which people sleep!

Would I want to sleep in it after working on it? Similar question to airplane mechanics flying the plane after working on it.

I presume the slide motors (etc. as a general case) are a lack of maintenance, Im seeing a gross problem in used RVs of no/lack of maintenance and something buried in the works like a slide motor is usually forgotten till it goes bad. That presumption is based on the fact that companies like Alfa probably do not make motors, inverters etc and buy from reputable sources (one can do that with the momentum of making $200K to $1M motorhomes) but the system design level seems to be the problem, especially in the electrical systems.

[davecampbell]

Quote:

Originally Posted by RV Wizard Alfa's motorhomes are a nightmare when it comes to this area. There is also some irregularity of the design of different years and models. I had one, I counted 13 solenoids involved in the three battery banks. The problem is basically the original engineers were trying to charge three different size battery banks from two different sources; alternator and inverter/charger. .

EXACTLY the problem. Whats worse is that im not sure engineering was involved. It looks as if an assembly unit just took systems and strung them together without really understanding all the implications. For example, there are SEVEN charging sources in this particular Alfa (solar panel added, but lets consider that "factory" as that is a common addition at the factory level).

Part of the reason I say "engineering may not have been involved" is the observation that heavy, CRT type televisions (30-75 lbs) are placed in an overhead compartment where, if it falls out and hits the driver, may cause inury/ vehicle accident. I mentioned this to my wife (a nuke engineer) who said there may not have been any P.E. (enginering) review involved and that may be normal. That is just beyond my understanding. I realize they didnt have flat-screens back then, and that it's a convenient place to put a TV, especially with a backup cam connection, but its inherently dangerous. Maybe not often, but once is all thats needed to hurt or kill someone.

From a system engineering/safety standpoint, its even risky to arrange the coach with the entry/exit as a "bus door" (front right) with the high powered electrical system surrounding it or near it. If there are occupants, a short or other fault might start a fire at or near the only convenient egress point. "Might" is the key word. Yes, it "might not" and "probably wont" happen, but where does one exit if it DOES?

Out a window, 6 feet down on the pavement. Not a situation I want to be in...

The root problem with the electrical system is that they crowbar ("dead short") two battery banks together (a fully charged one, and a discharged one) which in no case is permissible (unless one accepts the risk of explosion...) and I avoid it like the plague, because Ive seen a battery explode in my face for something I did to it. Something that seemed innocent! Same with the chassis /inverter knife switches, fine idea, except one cannot tie two banks at a different state of charge together - the "dead" bank must be disconnected, then properly recharged or replaced. Theres no point in running down chassis batteries, not being able to crank the diesel engine and crow-barring the house batteries to them, because much of the house batt. charge is dumped into the chassis batteies, and FAST. To put it crudely, connecting two batteries together, one with "zero" charge and one with "100 pct charge" leaves both at 50%. Not exactly, but you see the point? What we want is ONE battery bank at 100% to crank the engine. ITs easier on the starter, too.

Worst case, crowbarring banks together might generate hundreds of amps or more and possible exploded battery. A dead short on a 12 volt source with 0.001 ohm internal resistance is 12 / 0.001 = 12,000 AMP. It probably wont be that high, but, again, you get the idea. "Worst case" might seem insignificant because "it doesnt happen often" but we have to realize that personal safety is involved. Being blinded from an exploding battery is an extremely serious matter, even ONCE.

There isn't enough electronic circuitry in this particular Alfa to properly manage all 3 banks with all 7 sources (7 brides for 3 brothers?) and the goal is to use what's there (no one wants to spend $5000 to throw a system out and start over)(and theres nothing at all wrong with the quality of whats there) with a minimum of mods/parts/rewiring to fully automate the system.

[davecampbell]

Quote:

Originally Posted by RV Wizard The three banks in my opinion are not necessary. The same goal can be accomplished with two banks like most all other manufactures have been doing successfully for years..

Generally, yes, it just depends on how much load is divided up where. In this Alfa, the inverter bank is 6X 4 solely to power the microwave oven, it draws 1500W on full power (asduming a 1000 watt oven at 50% efficiency on the magnetron) and thats a HUGE 12v power drain. However, the house bank is 6 X 2 with much more load (130-150A peak, 50A lights, maybe a max average of 72A). Were going to add more capacity to the house by adding 6 x 2 in parallel, but again, what about the safety factor? needs a fuse between pairs in the bank.

It gets back, ultimately, to

1.) the fact its bad to connect banks in parallel to supply power. What if one bank shorts?
2.) the engine batteries must be a different type than the house/inverter because the discharge is different

[TechWriter]

Quote:

Originally Posted by davecampbell New to Forum, looking for information/feedback on a problem. A friend handed an 03 Alfa over to me to fix, with horribly destroyed battery banks (house and inverter). The cases exploded from overheating. Turns out there are some serious design flaws in the system, and having an engineering background, I'm redesigning the whole system instead of just sacrificing more batteries to the gods of Smoke, Fire and Corroded Battery Trays. Anyone seen the burned circuit board trace on the BD-2 board? (batt. disconnect board) The root problem of destroyed batteries was easy to see, its not that any component was 'bad' (the invert/charger is fine, good batteries, solenoids, wiring etc) the overall system design is not correct. QUESTION(s) 1.) anyone particularly with an Alfa, similar failures? 2.) "If you could have the system redesigned, to either work as is with improvements or to add features, what features would it have or not have?" Thanks, both the owner and myself will greatly appreciate any feedback. please respond here, PM or email me gl1200harness@yahoo.com

Start here: Office of Defects Investigation (ODI), Flat File Downloads and download the flat file on vehicle defects. Split the text file in two (it's 85MB of defects) and load each part into Excel and sort by manufacturer. You'll see extensive info on reported defects and mandatory recalls (Holiday Rambler and Norcold are two of my favorites.)

Before I bought an RV, I used this list to exclude some manufacturers. You'll find issues similar to what you've found plus a house of horrors of others.

I love your expert outrage. It's refreshing.

[davecampbell]

Well, its not exactly outrage, I dont own it!!!!! Im outraging vicariously for a friend who bought it.

I can go raging after I buy one... LOL

And of course, Im planning to probably buy an Alfa, so... glutton for punishment?

Ill look at ODI, good source. I want to avoid little luxuries like windshields popping out.

Youd think a $200,000 rig wouldnt have these problems??

Well, I understand it, I've done production engineering.

The latest query turns up a potential solenoid failure turning the headlights off...

So how long DOES that freightliner take to stop when the brake button is pulled at 60 mph??