Boon Docking battery capacity

[bbillp]

2016 Sunseeker 2500TS with the stock pair of group 27 batteries under the stairs. I'm preparing for some boondocking, no external AC power and my neighbors don't like generators so right now testing in the driveway. The run time from battery seems very short, only a few hours with no lights, no TV, slide outs are in. The only thing on are the little indicator lights. Is this normal or are the batteries sick???? I ran 3 tests, The batteries were charged 100% prior to each test and .my previous motor home with similar batteries would easily run 2 days.

[JLeising]

Sounds way to short - our 2012 Solera will easily do three days +.
Are you sure your batteries are fully charged? Indicator lights will show "full" with a minor surface charge. Takes a day+ on shore power to fully charge the batteries.
I'd pull a battery cable and check current draw at the batteries. Under conditions you described, should be quite low.

[bbillp]

Thanks, The batteries measure 14.7 while charging, then drop back to 13.5 when charged then I turn the main DC power switch on and in a few hours the batteries read 10.5 volts. I am new to the SunSeeker and all of its electronics so I hope its just poor batteries and not an electrical problem.

For this test the solar panel fuse is removed, I just want to know how long the bare batteries will power the rig lights and maybe a few hours of TV or radio and in the winter the heater will be needed for those cold winter nights.

[lugoismad]

Sounds like your batteries are toast. You may have left a load on them and ran them all the way down and ruined them. I did that last year, I accidentally left a light in our camper on for a few weeks, and it ruined an almost brand battery.

[gizmo98]

check your water levels in the battery I had a similar issue and the 2 batteries for my forrester class c 3051S were dead . I replaced them and added a solar panel no problems

[270S]

No matter what anyone says, ... The ONLY ACCURATE way to test a battery is with a Carbon Pile Load Meter! Inexpensive ones may be purchased at HF or similar. The slightly higher priced 500 amp version does a better job than the 100amp version $50 vs $22 - Don't forget a 20 or 25% Coupon.

(https://www.harborfreight.com/500-am...ter-91129.html)

(https://www.harborfreight.com/100-am...ter-61747.html).

[Wandering]

Still on my stock batteries and can get a few days with charging.

[Bluepill]

The best tool for determining true battery condition is still the tried-and-true hydrometer. It gives you indisputable information on each cell's state of charge. As cheap as 5 bucks.

http://www.arconequipment.com/article_0995.html

[TSman]

I have a 2014 2500TS and struggled with the battery life for a year. Not quite as bad as yours but the propane alarm going off at night due to low batteries. I finally replaced the stock batteries with the largest 12v deep cycle batteries from Sams Club and now have reasonable life. I do not remember the size but think they were slightly larger than the stock ones. The stock ones were apparently a hybrid battery that would deep cycle but also designed to for starting. The pure deep cycle ones seem to last longer.

[ActionJackson]

Originally Posted by gizmo98

check your water levels in the battery I had a similar issue and the 2 batteries for my forrester class c 3051S were dead . I replaced them and added a solar panel no problems

Originally Posted by Bluepill

The best tool for determining true battery condition is still the tried-and-true hydrometer. It gives you indisputable information on each cell's state of charge. As cheap as 5 bucks.

Using the Battery Hydrometer

Lots of batteries are sealed so no water level checking or hydrometer. On a set of good 12v batteries, you should easily last 48 hours with minimal use and no heat. I'd say your batteries are shot. Best to replace as a set.

[Skip51]

If you're voltage drops to 10.5v, you're batteries are toast. You need to replace the batteries and do a load test to see what the parasitic load is. If it's normal then either the batteries came defective or you placed a large load on them when they where low. When battery voltage drops to 12.0v the battery is at about 50% and is in danger of overheating and warping the plates under load. 11.3v is 10% of capacity.
I have the same batteries in my MBS and probably about the same parasitic load. After 5 weeks of non use the batteries where at 12.3, the longest I've boon-docked without running the engine or generator has been 2 days and was at 12.4 (you're results may vary)

[pmsherman]

A hydrometer is a very accurate way to measure the SOC (State of Charge) of a liquid filled battery. Carbon pile testers give an accurate measurement of a battery's starting capacity. Unfortunately, for RV use, you're not interested in starting capacity and are more interested in the 10 or 20 hour discharge capacity. These are measures of how much current you can draw from the battery at a constant rate for a specific amount of time before the battery is fully discharged. A rating you'll find on the batteries that's related to this is the "reserve capacity" measured in minutes. Reserve capacity for 12V marine (hybrid) batteries, what's usually found in many Forest River products is measured at a 25A load. A golf cart battery's reserve capacity is measured with a 75A load.

When I suspected that the house batteries in my 2011 Georgetown were toasted, I tried to get them tested. The hydrometer showed a full charge and a load tester indicated a good battery. I took one of them to the local outlet store for a battery manufacturer and asked them to test them for me. The clerk was very apologetic and explained that they only had one technician trained to use the $10k deep cycle tester and that tech was off that day. I ended up building a deep cycle tester to test the battery.

The test I ran showed that the battery had less than 50% of its rated capacity. When I showed the test results to the dealer, they were accepted as proof that the batteries were bad and they were replaced as a warranty item. I also reminded the dealer that the batteries had been run flat and allowed to sit for over a week fully discharged twice at this point, both times with the rig sitting on his lot.

Phil

[duradiesel]

When we bought our used 2012 Wildcat They were pulling the emergency brake switch to park it. The 2- 6 volt batteries were completely dead . I got it home charged the batteries & have used them to this day with no problems. we dry camp for 2 t0 3 days with out any problem. We are going for 6 days in August dry camping . WE will use a generator then or a portable solar panel. I Have tested the batteries & they tested O.K.

[Pacostaco]

For sure Hydrometer is the best tool but not the easiest way to maintain your batteries in the long run. I installed a trimetric 2025 after I killed my original batteries the RV shipped with. I also replaced them with 2 AGM Lifeline batteries and have been fine ever since. They are expensive but if boon docking or even for just traveling from place to place they are wonderful. You don't have to worry about discharging them too far because they are designed to go below 50% discharge. Mine were almost 500.00 a piece. The dummy light for the battery is garbage. It is not accurate and if you show 2/3 you are already on your way to killing your batteries. invest the money and don't look back.

[camaraderie]

1. Everyone telling you they are toast is correct.
2. Get some good TRUE deep cycle batteries ...not anything that talks about cranking power on the label along with deep cycling. Trojan or Deka DC series batts would be my choices
3. Sounds like group27 is what will fit so you will have ONLY about 100 amp hours usable with a new pair. Suggest a true battery monitor so you can tell WHEN they are fully charged (you CANNOT with a voltmeter!!) ...tell how many amps you are using NOW, Tell how long your batt will last at the current use rate, tell actual capacity left (which you can't with a voltmeter) and more. Trimetric or my favorite...the Victron 702. If you don't boondock...you don't need one...but if this is something you continue to do it will pay for itself in battery life and recharging time.

BTW...if you don't get a battery monitor...get a clamp on AC.DC meter so you can trace down the parasitic drains on your battery that put you in this situation in the first place.

[mnoland30]

I have a 100 watt solar panel on my roof with a Trimetric controller and monitoring system. In my opinion, well worth the investment. Your batteries are done. It is hard to find true deep cycle batteries in 12 volt at a reasonable price. When my current batteries die, I'll go with 6v golf cart batteries in series from Costco at $84 each. Your batteries should last two days without charging. Look on the forums on how to disconnect the heater in your refrigerator door. It draws about 1/2 amp constantly. It keeps condensation off the outside of the door. I've had surprising drains on batteries from time to time. With the monitor, I can glance at it and know what is going on. We can go indefinitely here in the southwest. In Montana when it was raining, I added a small portable solar panel to keep up. The life of your batteries will be reduced if you go below 50%, but if you stay at 80%, they will last a long, long time. My batteries seldom go below 80%. Recharging your batteries daily with solar will make them last much longer.

If you want more info than you can ever use, read this:
https://handybobsolar.wordpress.com/...ging-puzzle-2/

[robbdrell]

Will running my Honda 2000 plugged in to rig with adapter charge my batteries?

[Flybob]

There are parasitic loads on the battery that are always there when the battery is connected. CO/Propane alarm, Radio, Fridge control board and possibly door heater ( if fridge is on). If the batteries were drawn down to 10 something a few times, it is likely they will charge but not support any load. See chart below.

[kcmusa]

Originally Posted by robbdrell

Will running my Honda 2000 plugged in to rig with adapter charge my batteries?

Yes, it will take time, hours to get a full charge.
the converter should bulk charge then float charge. some people report the cheap converters never go into bulk charge.

[bbillp]

Good information, thanks everyone. Using both solar and shore power the batteries were charged for weeks (DC switch off) while in storage. I ordered a AC/DC clamp on ammeter from Sears that should arrive Friday and also bought a Hydrometer to test the electrolyte well it seems one of the group 27 batteries was very low on water, the other was dry. Since this is a new rig I think someone messed up pretty bad and I just sent a letter asking for replacements. In the past I have used DEKA DC27 batteries and will try to get another pair for this rig. I did my battery test at night after the sun was off the panel for a few hours but its obvious without battery water and having sunk to 10.7 V maybe multiple times at the dealer that the batteries are toast.