So we went to Assateague for a long weekend (Thurs-Monday) and lived off the house batteries. I have two a 27 and a 29. Both were fully charged via my battery tender before we left. We used propane for the fridge (only power was for the operation of the fridge control and then random lights (all led replacement bulb with some electronic device charging. No lights left on overnight or when not in use. Both batteries would after a night off the charger before we left would read 12.6-.7 on a volt meter. The batteries control on the barth would read fair most of the time so I would run the generator about an hour to hour and a half a day. Would that be normal for 2 deep cycle batteries or are they or one of them on the way out. The one usually reads about .1 higher when charged then the other. I have a trusty starter alternator shop that I would think could test 'em but I wasn't so sure how you test load on a deep cycle. Barth ran great for the 300 or so mile trip. Averaged 8mpg with lots of stop and go traffic with my 500lbs motorcycle on the back(didn't include the portion where I had the generator running). Speeds under 65mph highways but lots of lights and 55mph secondary roads. I did screw up with the water though. Have had filled the fresh water tank about a month ago and it was nasty sulfur smelling. In the process of bleaching the tanks now. Finaly question is I lowered the pressure to what Barth recommeded max for my 16"x6" wheels 50 rear and 60 fronts if I remember right. PO had the tires about 10 over for each axle and it seemed to drive a bit better that way. For anyone with 16"s what do you run? I did scrape the hitch carrier in the driveway so I know it is riding a bit lower then when I tested the carrier out.

Sounds like those batteries are doing pretty well. 12.6 is not a deep discharge so you must be doing OK.

Check the load specs for your tires and get your coach weighed. Based on weights I have seen, the pressures that Barth assigned were on the low side. I think they were leaning toward lower pressure and softer ride.

OTOH, most coaches are run at or near their max weight. A few extra pounds in the tires keep them running cooler, farther from being overloaded. As a bonus, the higher pressures may improve mileage, handling, less sway.

I ran about 10 psi more than Barth called for in the 86. (80-85 psi)

The 98 has new larger tires I am still playing with inflation: currently about 110 psi.

Check the coach weight, you may be surprised. Once you know that, the tire tables can give you minimum safe pressures for that load. A little more gives you a safety margin.

Side note... little known fact: GM P30 19.5 inch steel wheels are rated for 95 psi maximum. Most 19.5 tires are rated 110 psi and tire shops often inflate them to that. Be careful.

The 12.6 was fully charged. Would be down around 12.3-4 in the morning. Will be pushing max weight easily on our trip so will go back up closer to what he had. Thanks.

quote:

Originally posted by benebob:
The 12.6 was fully charged. Would be down around 12.3-4 in the morning. Will be pushing max weight easily on our trip so will go back up closer to what he had. Thanks.

12.4 won't hurt them either. Stay above 12 volts and recharge promptly, no problem.

Far more tires have been damaged by underinflation than overinflation.

Have a good run!

It isn't so much about hurting them, just it seems they are dropping quicker then I would think they should. Overnight with very little stuff on.

Good point. They may have lost some of their capacity. Tough to test without a controlled discharge current and measuring with a hydrometer.

If you have access to a known good similar battery you might try to substitute and watch its behavior.

quote:

they are dropping quicker then I would think they should

How old are the batteries?

4 years or so. They tested fine but they can't do a load test on deep cycles there so not a huge help. Guess I will run with 'em and see. I'm just curious though what others get out of the batteries without needing a the gen. Only a couple days at a time without electric then to a park with electric for our trip aside from a week at Mount Hood while my daughter has ski race camp but it will just be me for most of the week til my wife flies out. I don't need much in terms of power.

Since your power consumption is low try isolating one battery or the other. One may be shorting the other.

---

If you are not ready to replace batteries you could try this fix? When I tried it on my two D8 batteries, I got a one to come back, the other did not. The batteries were 5 years old.

I have two size 31 batteries on the 86. Running just LED lights, pump, etc we can usually do 2 or 3 days no problem. In the winter when we are running both the furnace blowers, about 2 days. I have a digital voltmeter on my panel, I keep them at or above 12v.

If we need any appliances we start the generator for a while. If we do this once in a while, the batts stay happy for several days.

The 98 has four size 24 coach batteries. I have not been off the grid much so I can't say much for them. Good for two days anyway.

On our 93 Breakaway a significant parasitic electrical load is from the solenoid that connects the batteries to the house circuit. When we are "off-grid" it is likely our largest draw
on the batteries as we mostly use LED lights.

Bud

I agree with Bud. There can be parasitic loads that are a constant drain, even though you think there is no load, it is there. Relay coils are the single big one. Refer, water heater, furnace, anything that is connected to the house power will draw power even if it is shut off. Anything that is "on demand" may have a wake up circuit that is always on.

12.6 VDC (specific gravity=1.265) is considered to be a full charged with no load connected to the battery. 12.1 VDC (specific gravity=1.170) would be considered to be 35-40% charged. 11.9 VDC (specific gravity=1.12) is discharged. Specific gravity on sealed or AGM batteries can not be measured

Again this battery voltage is measured with NO load attached to the battery. AH, or amp/hours capacity is highly dependent on battery age, temperature, stratification and usage over time. It would not be hard to have a 10 amp parasitic load which is 120 watts. Over night, battery voltage could very well be 12.3-12.0 VDC.

Finding battery loads can be a PITA. Measuring DC loads would require an ammeter in series with each wire from the distribution panel or an expensive clamp on meter designed for measuring DC loads without disconnecting wires.

Our trailer has a CO detector that will drain the two house batteries within weeks. I have installed a battery disconnect for time in storage.

My problem isn't the voltage dropping but rather the control module saying that the batteries are fair not good almost immediately. Both have been sitting at 13.02 and 12.81 for about 24 hours now after trickle charging up. I did take to my local alt shop and they couldn't do a load test on Deep cycles but felt everything was up to snuff on 'em. Guess we will leave in a week with the originals and hope that should we need some Walmart resupplies itself with deep cycles.

My Crown, Advanced Glass Matt Batteries are performing very well so far. I also now have Crown standard lead acid for the engine batteries. Just incase you are thinking of changing out your batteries.

---

Have a safe trip Bob

---