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Clean sheet design: inverters, batteries, etc.
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Chad, same here on the batteries! I have been following those videos for a while now. Although I would consider using a different BMS, or at least make sure the alternator will shut off if the built-in BMS decides to disconnect.
Jerry, I have considered a lead-acid and lithium combo, but for simplicity I would prefer a single type of battery. In the design you suggest, can I assume the inverter/charger is connected directly to the lithium batteries, and the lead-acid is only a buffer for alternator charging?
However, I should give the lead-acid buffer a little more consideration: given that there is already another 24-volt lead-acid battery system (chassis batteries), I wonder if there’s a opportunity to sort-of combine the two systems, house being lithium, chassis being lead-acid, and all alternators charging lead-acid, and BtoB chargers “carrying over” charge from the alternator, through the lead-acid, to the lithium batteries.
With Victron, the BtoB chargers should be able to be controlled by the inverter, and you could stack these chargers in 70-amp increments. So getting to 200-450 amps should not be too difficult, as long as there is not a problem pulling that current from the lead-acid batteries. There’s also some opportunity to have chargers in the other direction, in case your lead-acid chassis batteries are drained after sitting a while. I am really liking the sounds of this…
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Leaving some LA and using BtoB chargers addresses three issues simply and easily.
The first is protecting your alternator from overheating while trying to charge Li batteries at the high amp rates Li batteries will draw if they can. The BtoB charger limits amp draw to their rated output.
‘the second is absorbing any voltage spike that might occur when the Li battery BMS shuts off at full charge while the engine is running.
the third is eliminating the need to alter anything about the existing alternator or voltage regulator. The BtoB charger takes care of that for you. You do need to alter the charge profile of your inverter/charger to the charge profile required by your Li batteries.
A side benefit is being able to greatly extend the life of your existing LA batteries. Once freed of trying to run 120vac appliances through an inverter they will last much longer. This also allows you to do the conversion with somewhat fewer Li batteries as they never see any of the 12vdc loads carried by the LA batteries.
so, you get many benefits with far less re-engineering than you need if you go all Li. Be very careful if you start changing your existing set up as you might do if you try to use a BtoB charger from your starting batteries to recharge your house Li bank. All kinds of other considerations may come into play.
jerry
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
Jerry, do you know of any B2B chargers that are 24v->24v that are designed for Lithium, have high current, and are reasonably priced? The Victron buck-boost charger, 50A (with 24v) is about $1150 each. If you wanted 200A, that would put this at over $4k. I actually though that Victron might have had the Orion branded chargers for 24v->24v, (which are much cheaper) but that does not appear to be the case.
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Just thinking out loud here, but could the Victron converters be used in series to achieve that? The documentation mentions parallel installations, but not series. I only found one post in the Victron Forums for someone looking to add a 24v and a 48v output in series.
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Sterling BB242435 is one choice. You can add them in parallel for faster charging. No need to go overboard as most drive four to eight hours in a day which provides a lot of amps available to the batteries even at the relatively low amp out rating of most BtoB chargers.
jerry
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Jerry have you considered putting your reference article in the article section of this website?
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I mentioned earlier that it would be a wonder if I ever finished this project. Well, I have since decided to completely gut the interior of the bus and start from scratch. I was becoming less enthused about doing so much work on a bus with such a dated interior. Despite the significant added work involved, I’m excited to have a true “clean sheet” going forward.
In doing this, I was able to completely remove the OTR ducting and coolant/refrigerant lines from the interior floor-to-wall junctions. I have also completely removed the three Cruisairs, and they will not be going back in. I also removed the Espar hydronic heating system, which simplifies the rebuilding process. Those radiators on the walls were really in the way. I also am able to re-prioritize my use of space, sacrificing the washer/dryer, dinette, oven, and ice maker to add needed size to the bedroom, shower, and kitchen storage.
I’ll post a new thread on the rebuild, but thought I’d update this one for now. The only guaranteed result is that I can no longer call this a Liberty Coach. It will be unrecognizable as such!
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Please post pictures as you go along, my washer/dryer was the first thing thrown in the scrap heap when i brought my bus home. We now use that space for Trash and storage. I am a big believer in making the bus a space to suit your needs not a future owners needs.
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It’s certainly a case of different strokes for different folks. One of the biggest reasons we bought this coach was the stacked washer/dryer! We full time so a W/D in the coach vs. using laundry rooms where ever we travel makes owning a W/D a no-brainer for us.
2005 XL Thompson Coach
Rarely tow anything behind us.
Sold: 1993 Liberty that we loved for 12 years. -
In our trailer days when we didn’t have a W/D and sat in the laundry rooms doing our clothes and bed sheets we quickly decided to bring enough clothes and linens along to NEVER have to use a public or camp ground laundry facility ever again from what we saw.
Poppy baby clothes (that had not been pre cleaned) put in the machines, dog beds with heaven only know what was on them put in the machines, bath towels with stains that I don’t even want to know what was on them put in the machines…….
Add in the extra sanitary issues that have come about in the past few years and I am afraid to even walk close to a laundry faculty.
To each their own. As for our house on wheels, we will never be without our own W/D because you can never un-see what you have seen.
Chuck
Jeff and Lindsay
91 Marathon XL -
The washer/dryer removal was an easy decision for me. It was a combo unit that performed pretty poorly. Even before committing to the remodel, I decided that turning the space into storage for more clothing would offset any loss of convenience. I’d love to have a stacked combo, but that’s tough in a 40′ bus that’s only 96″ wide.
Interestingly, I discovered that the combo unit had a large concrete block on top of the drum, I suppose to dampen the vibration. It was surprisingly heavy.
Jeff and Lindsay
91 Marathon XL -
Nice update, Chad.
1999 XLV X-6872, liberty #440 -
I can’t wait to see Chad start the new thread. This should be very interesting to watch is all come together. Good luck and God speed!
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Bill, I thought of you as I pulled out the last CruiseAir!
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I’m not quite ready for a new thread, but I wanted to provide an update. I somehow managed to go further down the rabbit hole by completely rebuilding the rear electrical junction above the engine. Have you ever tried to put a plate of cooked spaghetti back in the box? I’m very happy with the way it turned out though. I just hope the bus starts. I’m still in the middle of some other projects back there, so we’ll have to wait to see how good my wire labeling was.
Then (and this was a real treat) in order to dismantle the rearmost part of the interior, I had to completely remove the engine air box to get to screws that were installed through the firewall into the interior framing above the engine. That meant that the coolant reservoir and the engine oil tank also had to come out. Might as well soda blast and paint all of that. New stainless steel screws throughout, as well as new foam between the metal pieces. I just about pulled the engine and tranny to keep refreshing the engine compartment, but then I remembered that I don’t really know what I’m doing. That was enough to refocus my attention!
I thought I’d replace my Delco voltage regulator while I had easier access. The new unit required a slight wiring change on the 50DN, so I of course broke a field wire internally while loosening a stuck nut. You may have seen my posts where I’m considering deleting the 50DN. Well, today I finally pulled it and cracked it open to see what the damage was. It’s a lot less intimidating than I expected, so I think I’ll do a minor overhaul and throw it back in for now.
Once the engine is running again, I’m going to start on the interior and the electrical. I’ll create a new thread then. Thanks again for your comments over the last year and a half.
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