Drycamp question

[Cedar41]

I read some post about drycamping but we have never done it and have questions.

We have 6 deep cycle batteries, Residential Frig. How long would you estimate you could go between generator charging?

How long do you have to run the generator (on average) to get charged?

If we wanted to buy the gel battery how much would we expect to pay?

Thanks,
John

[Cedar41]

I read some post about drycamping but we have never done it and have questions.

We have 6 deep cycle batteries, Residential Frig. How long would you estimate you could go between generator charging?

How long do you have to run the generator (on average) to get charged?

If we wanted to buy the gel battery how much would we expect to pay?

Thanks,
John

[Mac and Chris]

Hi John,

You've correctly identified the residential refridgerator as an issue. But it can be overcome.

The specific answer to your question about how long you can go on the batteries between charges depends on how many amps you pull, and how much power you're using with all appliances, lights, etc. So you'll need to determine this. Here are two ideas:

1. You could experiment.

Just turn off shore power and "dry camp" at your hookup site. Make note of the time, and of each item that is being used (tv, etc). When your battery monitor system tells you the batteries require charge that's your time. (For those without a reliable battery monitor, measure battery voltage. Turn everything off and check with a good digital volt meter. At 12.2 volts you want to charge.)

How long do you need to run the generator to charge?

Similar situation. Your coach charges the same on generator as on shore power. So plug back in to shore power, and check the battery monitor to see when batteries are charged. Then repeat above again.

2. Do an energy audit (I'll give you a link to my web site for this topic, it's long).

Figuring power needs for refridgerators is problematic, because they don't run constantly, and they don't run for consistant time periods. You can estimate, or use a Kill-a-Watt meter to determine power needs of the frig. This Link will give you more info on dry camping electric issues in general.

If you find generator run time is more (or more frequent) than you can tollerate, you could get a more powerful charger (if the batteries will take it), you can also add batteries. But another idea would be a small, quiet, portable generator that you could run all day, and just go on batteries at night (assuming they'll make it through the night). Lots of options.

Concerning AGM batteries. Several reasons to have them, but direct replacement of same size batteries usually won't give you more available power. Expense depends on what size your batteries are, but expect to pay a good bit more for them. The link above includes battery information and further links to other web sites with more detail.

Hope this helps!

Mac

[EngineerMike]

John, IIRC when the res fridge was added, so was Auto-Gen-Start. I've got the Xantrex inverter/charger/AGS system & by simply cycling thru the screens on the control panel to the right of the TV, I can reprogram the AGS If I want. The '06 comes from WRV set for AGS @ 11.5V on the house batt's (which is about right IMO for good deep cycle batts), quiet time (non-start so you don't turn your boondocking neighbors into late night terrorists working out detailed and creative plans for a firey, pyroclastic display wiping your noisy, inconsiderate existence from the face of the earth) from 8pm to 8am, and some default for stopping the gen after charging (I assume that's a variable based on reaching float charge, but that could be overreaching).
You may have an Onan inverter, but I believe whichever you have, you have programmable AGS. Check your docs for specifics, or scroll thru the control screens for a quick overview, and to avoid alienation of neighbors.

[1peddler]

We have dry camped for 3 to 4 days at a time. We have the res refridg. We have the auto start system. The system is auto off from 9:00pm to 7:00am. Most mornings the auto gen will not start until after coffee and my wife stars the blow dryer.

Can not tell you how long it takes to fully re-charge. So far it has not shutoff after 1 1/2 hours. At this point I termanated the gen.

[Snuggery]

We have the Xantrex system on our Alpine 2005 FDTS - the menu settings are very confusing to me. I have spent hours studing the instruction manual and pushing the little buttons and still feel anxiety while dry camping.

Is there a source somewhere to suggest good default settings for the RS2000 and AutoGenStart? Can anyone suggest a good strategy while dry camping to have the batteries last all night and be ready for peak demands - usually in the early morning and in the evening?
Does this monitor and display battery state of charge (SOC) somewhere or do you have to depend on DC voltage to indicate what percentage of charge the batteries are?
If so, what is a good lower voltage setting to indicate they need recharging?
How long does the generator need to run to fully recharge the house batteries? While the generator is running the meter seems to show the charging voltage being applied rather than any indication of how well charged the batteries are.

[APEXMAN]

I had a 40'w/ res.fridg.I could go 24 to30 hrs.before I had to recharge the batterys.I found by not letting the batterys go below 12.2 I would run the gen 1 hr in the morning and 1 hr a night

[Mac and Chris]

I can only make suggestions for some of your questions.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Can anyone suggest a good strategy while dry camping to have the batteries last all night and be ready for peak demands - usually in the early morning and in the evening? </div></BLOCKQUOTE>

If you plan to set your system to NOT auto-start overnight, say 10:00 pm and 7:00 am, then toping off the batteries for evening may be a good idea. You could manually start the generator and run it for an hour just before bedtime.

Using the "trial and error" method. In the morning, if you find that batteries are lower than 12.2v without load, you may want to increase the evening run to 1.5 hours.

On the other hand, if you're camped in the middle of nowhere, and nobody else around to disturb, you might just leave the autostart set and let it crank up overnight as needed.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">How long does the generator need to run to fully recharge the house batteries? </div></BLOCKQUOTE>

I believe the RS2000 has a 100 Amp charger. I'm also assuming your battery bank is 600 AH. (you said it was a 6 battery system, so that would be typical)

If you're 50% discharged, a 100 Amp charger should get you to around 85% in about 3 hours.

It would take another 2 to 3 hours for the final 15% of charge. But you really don't "need" to charge them to 100% every single day. If you're only dry camping 1 to 5 days at a time it's fine to manage them to the 85 or 90% level.

If you're going to dry camp more than 5 days at a time, solar panels are helpful. During the day solar can finish the charging cycle so that you have 100% fully charged batteries going into the evening.

The reason here is, if you only recharge the batteries to 85% all the time you'll greatly shorten their lives, and eventually reduce their capacity. But a few days a month is of no consequence.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">While the generator is running the meter seems to show the charging voltage being applied rather than any indication of how well charged the batteries are. </div></BLOCKQUOTE>

Most of the time, you won't really know how "full" the batteries are while the charging is taking place. For this you'd need a meter like "Trimetric" or "Link" brand that measures current flowing in each direction. It's essentially like a "fuel gauge" for your batteries. It's nice to have, but not essential.

Someone more familiar with your system may be able to tell us if a similar capability is built in.

Mac

[Snuggery]

I finally got a good answer on this question from Xantrex. We were confused about State Of Charge (SOC) which is in the Xantrex manual and on the Xantrex System Screen settings, but apparently was never a part of the Xantrex system??????

They said: "The SOC settings are not present because that is a feature that was not developed, as there is no way of measuring Ahrs. The Start V should be set for 11.3VDC @ the 30 sec setting, and the 2 hr setting to 12.0VDC, all the rest should be "off" except "stop float", which should be "on". This way the gen will start when the batts drop to 11.3 due to a significant load being present, enough to pull down the batt volts for 30 secs, and if they stay @ 12.0VDC for 2 hrs, that is probably their actual steady state voltage and will mean they are approx 50% discharged. When the batts are charged and reach the float stage, the gen will turn off."

[EngineerMike]

For those who want to pinpoint appliance usages, you can try the AmWatt Appliance Load Tester. It is a 120V, 18" extension cord that you plug in-line where your appliance cord plugs in, and it reads amps or watts directly (reading to 0.1A or 1W). With your total appliance usage (amps x hours), and the inverter's efficiency rating you could calculate battery draw down per hour. The residential fridge takes some additional observation since it is on/off based on its demand, so you need to do a time study to estimate its % of run time.
My toaster = 7.8A running, 0.05A± idling.
My toaster oven = 8.1A running, 0.0 idling (fully analog)
This Dell laptop charger = (1.5A running (per rating)), 0.35 idling.
27" CRT type TV = 95 watt running (vs 122W rated), 2W idling
TV & Stereo will have idling draws as will any digital stuff plugged in, which will add to the fridge's periodic inverter draws.
My guess on battery charge time is that it will vary meaningfully depending on condition of batteries (age, electrolyte level, # of times non-distilled water was added, # of times charged to electrolyte level below top of plates, etc.).