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Topic: Roadside blues... Again (Read 1500 times) previous topic - next topic

Re: Roadside blues... Again

Reply #20 –
Brett,

If you put a battery disconnect switch between the house battery bank and the battery isolator, then you would have the advantage of not charging the house bank unnecessarily. And, you would have the advantage of the battery isolator separating the batteries when they were not being charged.

You would of course still have the possibility of a battery isolator failure. But, I think the failure rate of the battery isolator would be fairly low and it is easy to wire around it in case of failure.

Larry

Re: Roadside blues... Again

Reply #21 –
Thanks for all the suggestions... we made home a few minutes ago with no further drama from the charging system after bypassing the Isolator by putting the center post directly on the Chassis battery terminal on the Isolator as Brett suggested. According to VMSPC, the charging voltage was normal range all the way home. Too tired to respond more at the moment... except to say that I got a stop engine light three times on the way home that went away almost immediately two of the three times and within about 10 seconds the other time (that was a long 10 seconds!). The diagnostics page in VMSPC wasn't very helpful, and thus far I haven't been able to figure out what the fault codes correspond to. This also happened twice on the previous leg of our trip. Every time it has happened so far, it was going up hill under load. Coolant temperature staying around 182ยบ, Trans temperatures, oil pressure, et al. all within normal ranges. This was a Stop Engine light, not a check engine light... by the time I realized what the warning light was and was thinking about pulling over at the next possible spot, the light went away each time. Another head scratcher as if I haven't had my share... :-\
Well, hanging it up for tonight... back at it tomorrow. At least I am parked at my home base and can stay here long enough to get parts and figure out what is what. Neil, I will probably be taking you up on the phone call once I have had a chance to sleep and chew on this a bit... thanks for the offer. I will plan on rerouting the sense wire to the battery terminal as I decide what parts I need. I will definitely be changing how this system is hooked up. I had been planning on it all along, I just ran out of time before we had to leave for our 5 month trip to Canada.
Don

Re: Roadside blues... Again

Reply #22 –
On my sailboat, I installed Blue Sea 7700 and 7622 relays so I could isolate batteries and busses both remotely and manually.  I was considering doing the same to my 96 and I will likely do the same to my 2005.

Re: Roadside blues... Again

Reply #23 –
Needless complexity.  Install a manual battery switch or better yet tie everything together and don't worry about it.  Just about to install three new red tops in my sister's coach because the battery maintainer failed. (long term storage, plugged into bulletproof service behind a progressive surge protector)  Had they all been tied together and to the charger all would have been jake. 

When you think about it, the isolator is for the owner who doesn't think much about battery levels, just wants to make sure it goes vroom when they want.  Who among us doesn't monitor battery state when dry camping? 

Re: Roadside blues... Again

Reply #24 –
My guru buddy installed a non normally used outside battery equalizer. Much higher output than a trickl charger.  20 amps? Capacity.

If the house batteries are receiving a charge the chassis batteries get it also.

Brett wanted a picture or info a while ago.  Mounted externally he sealed the adjustment holes with sealant.

Seems to work well as my small solar 130 watt panel keeps the house batteries charged and when I try the coach the engine cranks perfectiy after a month stored

Re: Roadside blues... Again

Reply #25 –
Quote from: Chuck Pearson –
Needless complexity.  Install a manual battery switch or better yet tie everything together and don't worry about it. 

For storage, just hook up a jumper wire with alligator clips. Use thin wire, or install a fuse.

Re: Roadside blues... Again

Reply #26 –
Quote from: krush –
For storage, just hook up a jumper wire with alligator clips. Use thin wire, or install a fuse.

Or just eliminate the whole isolator mess, use a standard, self excited alternator available anywhere instead of Duvac, lose the diode voltage drop,  tie both battery banks together and enjoy a simple, durable electrical system. 

Re: Roadside blues... Again

Reply #27 –
Maybe I'm missing something here, but isn't the purpose of the isolator to separate the start batteries and the house batteries while camping? If all the batteries are tied together all the time what do you do when you run the batteries down to where you can't start either the generator or the big engine? On my coach, the house batteries start the generator as well as supply the house. The engine batteries start the engine. If I run the house batteries down to where I can't start the generator I can still start the Detroit, and the alternator charges both sets of batteries. If the start batteries are too low to start the Detroit I can start the generator or use the boost switch to start the engine. If all are tied together I'd be stuck.

Re: Roadside blues... Again

Reply #28 –
David,

Plan "B" using the KISS theory for alternator yet maintaining isolation if the batteries while dry camping:

Buy a Perko ON-OFF switch: PERKO Inc. - Catalog - Battery Switches - Medium Duty Battery Disconnect Switch

Wire alternator output (B+) and chassis battery cable to one lug.

Wire house battery cable to the other lug.

Either put the sense wire on the chassis battery terminal or to the B+ terminal of the alternator.

Re: Roadside blues... Again

Reply #29 –
The 7622 in my boat setup is a bistable automatic charging relay. It disconnects when batteries are discharging and connects when they are charging.

Re: Roadside blues... Again

Reply #30 –
Quote from: kb0zke –
Maybe I'm missing something here, but isn't the purpose of the isolator to separate the start batteries and the house batteries while camping? If all the batteries are tied together all the time what do you do when you run the batteries down to where you can't start either the generator or the big engine? On my coach, the house batteries start the generator as well as supply the house. The engine batteries start the engine. If I run the house batteries down to where I can't start the generator I can still start the Detroit, and the alternator charges both sets of batteries. If the start batteries are too low to start the Detroit I can start the generator or use the boost switch to start the engine. If all are tied together I'd be stuck.

Absolutely right.  That's the reason for the isolator, the Duvac alternator, the sense circuit from isolator to alternator, and the need for an additional trickle charger between battery banks (to keep the chassis batteries charged during extended park sessions while unmaintained). That said,  it would be extremely rare to find a forum member who doesn't keep an eye on battery charge while dry camped.  Everyone knows to limit house bank discharge to less than 50% in order to preserve the expensive coach battery bank life.  At that point, it's time for some shore power, generator power, alternator power or solar power to recharge. The whole additional layer of complexity and inefficiency is simply to compensate for blissfully ignorant management of battery banks. For the reasonably capable owner, though, it's a solution for a problem that does not exist.  It also introduces additonal points of mechanical failure previously referenced. 

A backup solution for someone who is worried about draining both banks would be to carry a small boost pack to fire up the genset.  Or, as Brett suggested, install a mechanical battery selector switch, common marine item. 
 

Re: Roadside blues... Again

Reply #31 –
Mine seems to work well as it was installed from the factory, no re engineering needed. I simply do a little preventive  maintenance, and inspection with a good meter once and a while and clean a terminal or 2 every year, keeps me from running out of something to do on the coach(ha).

Re: Roadside blues... Again

Reply #32 –
Quote from: bbeane –
Mine seems to work well as it was installed from the factory, no re engineering needed. I simply do a little preventive  maintenance, and inspection with a good meter once and a while and clean a terminal or 2 every year, keeps me from running out of something to do on the coach(ha).

Mine hasn't been any particular problem either though I have maintained it and if I were going to retain the system would relocate under the bed.  One other thing you could eliminate in addition would be the boost switch and solenoid, no longer necessary if banks are tied together.  Actually, Steve D's battery charger relay looks pretty intriguing, hadn't noticed it before posting.  Noting the warranty on the item it's either absolutely bulletproof or very failure prone! 

It has been proven to me without a doubt, though, that the present system puts an expensive bank of chassis batteries at risk depending on lifespan of a $50.00 trik-l-start or similar, and they seem to be pretty sketchy based on peoples comments of replacing them repeatedly.  Cost my sister three new red tops to replace fairly new red tops and me some embarrassment explaining why she needed them.  Her computerized engine apparently has significantly more draw on chassis batteries when parked than mine. 

But many ways to skin this cat for sure. 

Re: Roadside blues... Again

Reply #33 –
Quote from: Chuck Pearson –
But many ways to skin this cat for sure.

After removing the isolator, boost solenoid, etc. One could:

(1) Increase the size of the house bank and remove  the chassis bank

(2) Install manual transfer switches for shore power, generator and inverter/charger

Larry

Re: Roadside blues... Again

Reply #34 –

If you eliminate the isolator panel (and its associated 0.6vdc voltage drop) make sure you adjust your alternator downwards so you don't fry those expensive batteries. Or install a smart charger for the alternator side of things.

Our old U225 has two house batteries (8D) and one start battery (2 redtops in parallel). I am replacing my two 8Ds with new wet cells simply because I want to wait and see how the Lithium batteries shake out and when we start snow-bording in 3 years we'll have a better idea of which way to go.

The downside to connecting all the batteries in the system together is, of course, the issue of running the bank down to where nothing will start. Solar mitigates this issue to a certain extent; provided that one is in a spot where the solar system will work and also in a place where you can stay long enough for it to charge the system up to the point where you can get going.

Some time ago I ran across a review of a small lithium battery pack that was able to charge numerous Jeeps out on a 4-wheeling weekend. The batteries for people seriously into 4-wheeling with their Jeeps can take a beating what with air compressors that air up huge tires, run the differential lockers, etc. and it's not uncommon for them to have dead batteries. The editors of JP magazine swear that they used this little battery pack to start 4 or 5 dead Jeeps and were looking for more; they just ran out of dead Jeep batteries.

http://antigravitybatteries.com/microstart/

I bought the XP-1 from Amazon and we carry it with us any time we drive farther than 35 miles in any vehicle. I haven't had to use it yet but with a 400-amp peak power capability I suspect it can start the 5.9 Cummins. After all, regular car batteries do that job in my pickup. At the very least it should easily start the generator.

http://www.amazon.com/Antigravity-Batteries-639713373219-Battery-Booster/dp/B00I9HGMYO/ref=sr_1_5?ie=UTF8&qid=1418833406&sr=8-5&keywords=antigravity+battery

Holds a charge for a long time but I plug it into AC when we're home and into the solar system when we're out in the coach. I wait 'til the house batts are fully charged before I plug it into the coach's system.

I should probably test it. I think I'll wait for warmer weather.

Craig

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Re: Roadside blues... Again

Reply #35 –
This is an interesting discussion.  I have just installed a trik-l start on my 1999 U320.  The wires connected to my isolator are one from the house batteries to the house battery lug, one from the chassis batteries to the chassis battery lug and one to the center lug which I assume goes to the alternator. Mine looks just like the pictures in the Barry Beam description except there is no second wire on the chassis battery lug on the isolator.  There are no additional wires to any of the lugs.  Everything has worked well since I got the MH in 2009.  Are there alternative wirings that I should be aware of?
Richard Anderson
1999 U320 40' build 5586
 

Re: Roadside blues... Again

Reply #36 –
Quote from: wa_desert_rat –
If you eliminate the isolator panel (and its associated 0.6vdc voltage drop) make sure you adjust your alternator downwards so you don't fry those expensive batteries. Or install a smart charger for the alternator side of things.

Craig

Craig, 

Because of the external sense wire, no modification of the alternator is needed.

Said another way, the sense wire is on the chassis battery side of the isolator, so it reads voltage after the drop in the isolator.  If no drop, it will automatically not OVER volt from the alternator, but keep the battery at the exact same readings.

In fact one could take the sense wire off the chassis battery terminal and put it on the B+ terminal of the alternator (as many, many alternators are already wired).
I