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House Battery Problem
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Your battery voltage is not 13.3 at rest. It is being charged by a charger. A fully charged 12 volt battery will be 12.6 to 12.8.. so there is a charge source. solar?
The amp draws you are quoting, are they from the coach gauges or a clamp on amp meter? All loads may not go thru the coach gauges. They also may not be accurate.
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I will try to answer all questions. I did not buy the batteries locally and they do have a one year warranty. I had hoped to know clearly what was happening before dealing with the warranty. The batteries have been disconnected for 48 hours now and they are still at 13.25, all of them. They are not connected to anything. The amp draws are from a clamp on meter that I am checking from the two main power lines leaving the batteries.
Is it possible that the batteries are quickly producing a surface charge rate that is high, fooling the inverters to not fully charge the batteries?
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If they haven’t lost power when disconnected for 48 hours I strongly suspect the current draw is in the coach.
This is unlikely your issue but illustrative of stuff purchasers of used coaches can encounter. On my first coach the House #1 batteries were depleted in a short period of time, like two days, while House #2 remained fully charged. I went nuts trying to trace the load until I found the previous owner had gotten creative and had connected the heater in the Racor fuel filter to the House #1 batteries. It took a long time to find that load because I never suspected a chassis component would be connected to the house batteries.
The wiring was not apparent which made looking for the issue more difficult. Good luck in your search.
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I just want to update everyone on what has occurred since my last post. The company that supplied my batteries sent out a representative to my home. He tested all of the batteries and said they were all bad! He said he had never seen this before and could not explain it. They are replacing all 8 batteries at no charge and are coming back to my home to deliver them and install them (except the wiring which I will do).
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Before you consider the problem solved, make certain you carefully monitor the charging protocol of your inverters to insure they did not damage the batteries. Every type of battery has specific values for the various stages of charging. Over charging or undercharging is going to damage batteries and shorten their life.
Once you have verified your coach inverters are set and working properly then any further issues can be attributed to the batteries.
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Eric,
If you get frustrated with those Chinese batteries, get your money back and contact me, I’ll fix you up with Lifelines.
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What Tom said. Don’t remember the name but Bought 4 Chinese 8D AGM’s off a Marine shop down outside Houston a few years back and they didn’t last till the water got hot. All dead over a couple months. Went with Lifelines, have had no problems.
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I have had a lot of battery experience and I learned two very important lessons.
The first is to stick with Lifelines. No other battery seems to have the quality and lifespan of those batteries.
The second lesson is to maintain the batteries properly. By that I rarely permit a discharge lower than around 50%, and I make absolutely certain the charging voltages for the three stages are exactly as c alled for by the manufacturer.
At the end of five years I replace my batteries because I just do not want the problems associated with aging batteries, but a lot of members have gotten more life than that from a set of Lifelines.
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As a marine electrical guy just reading this thread, I will add a couple of thoughts:
1) If it was a 100A, not 1000A carbon pile battery tester, 100A is way too small to test an 8D battery.
2) It is possible to identify a failed battery with a carbon pile tester, but a good result does not always mean the battery is good. For a starting battery OK, but not deep cycle.
3) The only true test of a deep cycle battery is a load test. The easiest way to load test is in the coach using something like this:
https://www.victronenergy.com/upload/documents/Datasheet-BMV-700-series-EN.pdf
There are other similar battery monitors, but this one is incredibly accurate for less than $200. Even if the path to the electric panel is a nightmare, this can go in the battery bay for occasional reference. It will give you a measurement of the energy consumed in Ah from full charge to no charge. This should be within about 80% of the new rating to pass muster. It’s also a terrific test of the quality of “new” batteries when installed and establishes a baseline.
Note that this test should not be run in its entirety very often. As stated by someone else, maximum life of batteries is achieved by keeping them between 50-100% SOC.
4) Lifeline are terrific batteries. We’ve also had good luck with Northstar Blue+ AGM Thin Plate Pure Lead:
http://www.northstarbattery.com/blue-plus-battery
The drawback is these are not conventional sizes. The advantage is the chemistry is slightly altered to allow for partial recharge cycles, like while boondocking a few days without the AC and generator running full time, something usually not so good for AGM. While Northstar is now marketing conventionally sized batteries, no direct experience with those yet.
5) All batteries are finicky to get the maximum life. Charging profiles are critical and should be set to the manufacturers recommendations. This was already stated, but the devil is in the details. The charging device must sense the voltage at the battery, and all flooded or AGM batteries must be temperature compensated. Too high a voltage or too low a voltage during charging will prematurely age batteries. It’s not a trivial range, Lifeline says float 13.7V at 50F, 13.13V at 90F. Multiply by 2 or 4 for 24V or 48V systems. Small variances, say 1/10 to 2/10 of a volt are OK, but float at an extended 13.7V in southern summers is gonna kill the batteries. There are similar variations in the numbers for charging voltages.
Don’t forget to look at the alternator controller charging profile if you have one on the house bank on the road. This device must “float” when appropriate, or long road treks can cause the same problems as an improperly configured inverter/charger. Haven’t dug deep enough into many coach conversions, but bet this may be often overlooked. No so important with the AC running on the inverter because of the constant demand. But worth examining if experiencing short battery life. Seen this on lots of boats with AGM batteries.
6) I like flooded batteries for bang for the buck. They do require periodic (usually monthly will do it) maintenance of water levels. They are also far more forgiving of abuse than any AGM. A set of Trojan T105 golf carts will last as long under equal conditions as AGM for about 1/2 the price, but are harder to kill (other than watering). I have read that there are some issues with locating them on a coach, they certainly need to be in a cabinet that can contain and be impervious to acid spills and vented such that the hydrogen generated during charging is appropriately vented to the atmosphere. If the conversion wasn’t designed for this, it may not be practical to retrofit costing more than the battery savings. But if AGM was king on cost…all the golf courses would be using them.
7) Many of the coaches I’ve looked at (1995-1999) have inverter/chargers designed in the Jurassic Park era. The technology has come a long way since then. Primarily in sine wave (SW) versus modified sine wave (MSW) power. I wonder as other equipment in the coach is modernized if it could be sensitive to MSW power? Think of new electronics, refrigeration and air conditioning systems. But more related to this topic, the charging systems are completely programmable to match the charging function to the specific battery installed on the coach. There are also inverter features like load sharing…say you need more than the 50A the cord set can deliver, run 4 air conditioners and cook dinner without popping shoreside breakers or running the generator, the most modern devices will use battery power as makeup during peak demands and go back to charging when demands are less.
Hope this helps someone!
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Just to add to Bob’s excellent post, The coaches equipped with a 50DN alternator have an adjustable external voltage regulator which according to the Prevost service manual should be set at 27.7 volts which is slightly over the likely Lifeline float voltage. The AGM batteries will never get a full charge if all that was relied upon was the coach alternator, but with inverters and shore or generator power they will be properly charged.
Ditto on the temperature sensing. It is important.
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Balmar makes some good external alternator regulators which are 3 stage and temperature compensated. This is what we normally install on large alternators, but large for us is normally 150-200A. I think some of the converters use close to 300A alternators, perhaps at 24V, and I’m not sure what the field current requirements are for these. Have to check for compatibility. While nice, may not be worth the investment. Depends on how you use your coach.
300A at 24V is almost a generator, not an alternator!!! Still wrapping my head around this.
Depending on where you operate your coach, I would set the max no load voltage on a basic one stage alternator regulator to the battery specification for the float voltage for the highest temperature where you normally operate the coach. This way it will carry all loads when on the road, but never overcharge. At this setting, it might not do much charging either, but that’s what the inverter/chargers or solar controllers (if applicable) can do.
Unless you boondock constantly, there isn’t a requirement for the coach alternator to do more than trickle charge the house and carry all loads moving down the road.
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I noticed in one of Eric’s post that the voltage (12.9) dropped with use (75 amps for 1.5 hours) to 11 and then came backup to 12.75 after turning off the load. Isn’t this normal?
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Battery voltage is always going to read less when loaded, and as soon as the load is removed it will go back to its resting voltage based on the percent of charge remaining (for wet cell, Gel and AGM)
That is why a low voltage reading will not initiate auto-start unless the voltage has been at the generator start voltage for a period of tme.
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