2003 Brave 30w house battery questions

[Rahdo]

Hey everybody. I've got some questions about the electrical system for our 2003 Brave. I'm very much a novice when it comes to all things electric, and I'm trying to figure out how things work. Here's my situation:

I've got a Bluetti AC180 solar battery and a 300w panel which I use for laptops, Starlink, etc. I've actually got it down in the RV's power bay, and I've got the shore power cable for the rig plugged into it in there. I use a remote control device to turn on or off the AC jacks on the bluetti from inside, when I want the outlets inside the rig to work for various things (like the laptops).

I've also got two 27dc Interstate deep cycle marine batteries from Costco, and their only real job is the house lights, the propane fridge, fans, etc.

It's been working great for the last few months, but unfortunately I was an idiot and didn't really pay attention to the water levels in the house batteries. I'd been noticing for the last week that when I'd wake up in the morning that they were lower and lower, and I was more having to rely on the onboard generator to top them up (because trying to charge them with the Bluetti would empty it out in no time). When I eventually realized "oh wait, I have to top them up with distilled water" and checked them out, several cells were below the plate line, and I'd been charging them and presumably driving them into the dirt. Lesson learned, argh!

So We're boondocking in Baja, Mexico right now and will be for several more months. I feel like I need to buy some replacements because it's getting untennable running the generator to pick the house batteries up every morning back into the mid 12v range from the high 11s that it's falling to now (and falling faster than ever in the past, which again makes me assume I've ruined them).

But, i don't really have access to Costco or Walmart etc. We will be getting to La Paz in a couple of weeks and I figured my options would be greater down there, but I'm wondering what option I should pursue.

So here come the questions:

1) are these batteries gone or salvagable?

2) if gone, should I just get replacement deep cycle 27dcs, whatever I can find?

3) should i instead try to get a couple of AGM batteries, if I can find them? If so, will I need to replace the on board charger as well? That's something I don't want to take on myself, nor try to hire a local mechanic. I am willing to pay more for lower maintenace and better performance, but the specter of having to install a new more modern charger is a bit much at this point I think. Is it necessary?

Also, I'm trying to figure out how to get by until we get to La Paz, especially because we're in an area where running the generator is frowned upon, so I tried something this morning:

Turned off the house batteries completely with the switch near the side door and used the Bluetti for EVERYTHING. It works pretty well, but my solar panels can't quite keep up with the demand, and I'm confused about the demand. With nothing plugged in and everything (like the fridge) turned off, I'm still drawing nearly 50 watts from the Bluetti. Using the circut breaker, I discovered that the "fridge/conv" circuit is the cultprit. Since the fridge is off, I assume the "conv" is what's drawing power, but what is this "conv"?

I'm assuming it's the house battery charger, and in fact, while that circuit is active, if I look at the cigarette battery voltometer, the house batteries are acting as if they're being charged (going above 13 volts), so I thought "hey, this is great... it's a less impactful way to charge the house batteries without running the generator, and without emptying my bluetti in a couple of hours", but after doing this all day, I've discovered that it didn't seem to have a lasting effect on the house battery charge, and they're still dangerously low.

So one more question (for now): what is the "conv" doing with the house batteries when they're turned off? Trickle charging them? Doing nothing?

Thanks in advance for any advice y'all can give, I really appreciate it! Constantly worring about this is really undoing the mellow laid back mind set I'd hoped to have on this trip!

 

[CharlesinGA]

The converter IS the battery charger, and also the source of all 12v power in the RV (assuming you don't have some sort of inverter/charger unit) The converter takes 120v AC and makes the 12v DC that powers the control circuits of the fridge, the control circuits of the water heater, all of the lights, the Fantastic or Maxx fans, the furnace blower and control/ignition circuits, ANDDDD charges the battery.

If the 120v circuit breaker for the converter is OFF as in you manually tripped it off or it overloaded and tripped off, then the converter is doing NOTHING as it has no power to operate it. It is quite common to find the fridge 120v (which is only the heating element for the boiler) and the converter on the same circuit breaker. Both are low enough draw that they can share the breaker.

Does the fridge operate properly on GAS? For your type of boondocking, it needs to.

Are you connecting the Bluetti via the shore power cord? The RV battery should show a standing/resting voltage after charge of about 12.6 to 12.8 volts. If it drops below 12.0 it basically is dead. It certainly sounds like the house battery has no life left in it. They do make deep cycle AGM batteries but they are not easy to find. You will probably end up with a standard deep cycle battery for a replacement and it will probably be fine if you keep the water serviced properly and keep it charged.

So you have a 2003 Brave (as in Winnebago Brave?) If you have the original converter, it may be failing. They are a single voltage unit that can do more damage to a battery than good sometimes. New replacement converters are multistage that ramp up to over 14 volts for bulk charging and 13.6 for top off of the battery but if you are not using the batteries much will drop to 13.2 where they keep the battery charged without cooking or boiling it.

So that I don't retype a bunch of stuff that I just did the other day, go to THIS POST and THIS ONE and tell me if this is the power center you have (Its about all Winnebago used in the late '90's and most of the 2000's) EDIT: see post below, it appears you have a stand alone deck mount converter.

The nice thing about the converter I recommend (Progressive Dynamics 46XX series) is that you can force it into bulk charge when you have the generator running to get the most charge in the least time. When on regular shore power, it don't matter, and the converter's own programming is quite good, but when you have limited generator run time, this charge wizard control allows you to force it into a mode that gets the job done quicker.

When you are running on the Bluetti, trip off the fridge/conv breaker. (but you need a good battery or this won't get you anywhere, as you have discovered) This will eliminate the converter and fridge heat element draw on the bluetti and it should work just fine on solar. (fridge heat elements tend to draw 300-400 watts so thats a hefty load on the Bluetti and on gas you will use very little LP.

I would consider a new MULTISTAGE converter, and certainly new batteries.

You might also consider hooking portable solar panels to the RV's battery (but again, a GOOD one).

Charles

 

[CharlesinGA]

I typed "RV batteries" into Google Maps for Baja Sur and it shows a place called Liverpool and a City Club in LaPaz and a Walmart (a Super Walmart) at the southern tip of the peninsula at Las Palmas.

Charles

 

[CharlesinGA]

OK, Something made me look into the Wiring diagrams for a 2003 Brave 30W and it appears you have a free standing power converter, under the fridge, behind the power center, screwed to the floor. In this case, I would recommend a Progressive Dynamics 9200 or 9300 converter, which are "deck mount" units. Best Converter is one source of these units. They will have the Charge Wizard with manual override available by a wired remote control to do what I suggested above in forcing the converter into bulk mode charging for best use of the generator time.

The 9 in a triangle is pointing to the converter, it is plugged into a dedicated outlet. There should be an access door to get into this area without having to remove the power center.

 

[Mark_K5LXP]

1) are these batteries gone or salvagable?

Agree with the notion that a vintage converter isn't doing you any favors. They ramp charge current down entirely too soon and your batteries are short cycled, so you end up consistently using only a portion of their capacity which is hard on them. Throw in going dry and these might be done.

2) if gone, should I just get replacement deep cycle 27dcs, whatever I can find?

Seems if your availability is that limited, you're bound to whatever you can find. If you can find them, a pair of 6V deep cycle will be better performers than a pair of 12V.

3) should i instead try to get a couple of AGM batteries, if I can find them?

AGM's obviate electrolyte maintenance but would fare no better in the event your converter, usage or both is compromising. Even a "better" battery like lithium can only deliver the amp hours you put into it, so part of this exercise is to review your charger and daily charge profile to ensure you're replenishing the Ah you're using. Doesn't sound like you have a battery monitor so that would be another issue to remedy.

Mark B.
Albuquerque, NM

 

[John Canfield]

Welcome to the forum. Excellent advice from Charles and Mark!

AGM batteries are superior to traditional flooded cell (wet) batteries of any voltage. They charge faster and and have very low self-discharge if they are just sitting -and- they are truly maintenance free. Another feature is they will far outlast run of the mill wet batteries (Interstate, WalMart or whatever) - they are more expensive but I consider them necessary for peace of mind in a marine or RV environment (and required in light aircraft.)

However. There are premiere quality wet batteries out there - Rolls and Surette are two that come to mind.

So to summarize in order of priority: Replace your converter (charger) with a good multi stage version, replace your house batteries with AGM.

 

[Tulecreeper]

Seems if your availability is that limited, you're bound to whatever you can find. If you can find them, a pair of 6V deep cycle will be better performers than a pair of 12V.

Mark B.
Albuquerque, NM

Everything being equal, for the same power supply the OP would need 2 pair of 6v deep cycle to replace one pair of 12v batteries.

 

[Gary RV_Wizard]

Everything being equal, for the same power supply the OP would need 2 pair of 6v deep cycle to replace one pair of 12v batteries.

A single Group 27 12v flooded cell battery is typically rated at about 100-115 AH, so 200-230 AH for the pair. A pair of GC2 flooded cell 6v will be 210-230 AH each, so 210-230 AH for the pair (voltage doubles but AH doesn't add). In other words, about the same AH capacity per pair.

AGMs are usually rated lower than flooded cells for the same case size.

For the lead-acid battery type, true deep cycle 12v are a specialty battery type and both expensive and hard to find, so the more common 6v GC2 "golf car" battery is the most cost-effective way to buy a lot of amp-hours. I think Mark's "perform better" statement is relative to the more common 12v marine/rv battery, which is a hybrid design rather than true deep cycle.

As for the OP's questions:

• AGMs are still lead-acid batteries and the same charger will work.
• AGMs will alleviate the need for water monitoring & filling, but won't yield any more capacity (amp-hours). Maybe even less capacity
• Another pair of Group 27's is the easiest replacement, but the common 24 or 31 sizes would work too. Group 24 would have about 15% less AH capacity than the 27's and 31's would have about 15% more, but the 31's are physically large and may not fit in the available space. A pair of 6v GC2 would require some wiring changes (series instead of parallel) but otherwise a good replacement. You will just have to see what is available.
• The converter is also a charger and will attempt to charge the house batteries as long as it was power to do so. From your description, you are converting solar DC to 120vac via the Bluetti and powering the converter, which then re-converts the 120v back to 13v DC for battery charging and house DC use. Converting twice is wasteful but it works.
• If you are seeing 13.3-14.4v from the converter, it is working OK. But if that voltage is not able to bring the battery charge up, then odds are the batteries are toast.

 

[Rahdo]

wow, thank you so much everybody for your incredible answers (especially charles going the extra mile to look up schematics!)
so since posting, i've switched to leaving the house batteries off almost all of the time to try to preserve them as much as possible, so they're only on when we go to sleep in case we need to turn the lights on or use the toilet during the night.
the rest of the time the bluetti is providing all power to the rig and things are working okay with it powered by the 300w solar panels. i still don't quite understand what's happening with the house batteries in this case as the voltometer does indicate that they are charging throughout the day, and i see a 50-60 watt draw at all times even if everything else is off, so i assume that's all going to the house batteries. but it doesn't seem to have much of an impact on their levels, but maybe that's because i've damaged them too badly, or maybe it's because 50watts an hour really isn't very much for recharging a wet battery?
so i'll limp along with this until we hit La Paz and maybe try to get some replacement batteries at the walmart there. Though if i can make do with things as they are now, i might just try to keep limping along, because it really seems that I should upgrage my battery charger before subjective new batteries to my ancient one, and that seems like something i should do when we get back to the States in late Feb.
Again, i'm blown away by the thoughtful and very useful replies here. You all are awesome!

 

[Gary RV_Wizard]

50 watts @ 14 volts (charging voltage) is only 3.5 amps, so not a lot for a Group 27 battery that should store 100+ AH each. But I suspect your problem is that the battery simply isn't accepting (storing) the charge that is being applied. Rather, the amperage is just generating waste heat overcoming internal resistance. Or possibly a cell is shorted and the voltage simply cannot ever reach the normal "full charge" (a battery with a shorted cell is effectively a 10v battery instead of 12v).