Checking Batteries?

[skyking8]

My six house batteries are almost 6 years old. I have maintained them well, but I've noticed that my slides are slowing down when operated only on battery power. I don't want to replace all six at once unless necessary. I was wondering how I can check their serviceability without taking them out. Even tho it would be a chore, I can disconnect the leads from each separately.

[wolfe10]

At that battery age, I HIGHLY recommend replacing all at the same time.

The problem is if one battery fails (say, one cell dies) after replacing some of them, it will signal the charger (voltage will show low) to stay at full charge voltage which will well OVER-charge the new batteries.

Brett

[Guest BillAdams]

If you replace one, then you should replace all. With that said, unless you are having problems, you likely don't need to replace any of them just because they are "old."

You can check each cell in each battery with a Hydrometer. If you are seeing problems with one or two, then the time has come to replace them all. If they all check out as being OK (even if they are a bit weak), then you should not have to change any unless you have high dry camping needs that are not being met with your current bank.

[tbutler]

Our owners manual suggests that we move the slides when we have shore power hooked up. When we are boondocking we'll move the slides while the generator is running. There have been times when we move the slides on battery power but not many. If the only time you are noticing the batteries lagging this could be one way to keep them going a little longer.

On the other hand, I've had a set of batteries give up the ghost in short order and then you are faced with getting replacements on a schedule and in a location you wouldn't normally choose to do this. I'd say if you have six years on a set of batteries it is time to bite the bullet and replace them before your next planned outing.

[skyking8]

The living room slide is large so I rarely move slides without shore power, but that hasn't helped much. Here is the scenario:

1- Using battery power only, the big slide moves only about a third of the way in and then stops. Being connected to shore power doesn't help.

2- It won't come in without stopping a couple times when on the generator.

3- If I leave the engine on and use the generator the slide will retract.

4. I don't have any other apparent issues with my other DC systems, but most of that is small current draw.

Given those conditions, I just assumed that the batteries weren't putting out enough juice to move the large, heavy slide. I also assumed that the motor is working properly. I would think that it would either be good or bad.

I'll buy a hydrometer and do some checking. I agree that if more than one is weak then I need to replace all. (altho my wallet doesn't agree).

Appreciate the ideas and suggestions.

[wolfe10]

Generator or shore power should be the same in terms of effect on battery voltage-- both power the batteries through the same charger or inverter/charger.

Here is how I would proceed: With engine off, 120 VAC off (generator and shore power off), have someone activate the slide while you use a digital voltmeter to check at TWO PLACES.

Check at the battery.

Check at the slide motor.

This will help determine if the issue is weak batteries or a problem with an inadequately sized cabling from batteries to slide motor, poor connections, etc.

If the voltage at the battery stays good (12.0 VDC or above) but at the slide motor drops more than about .3 VDC below battery reading, check connections and/or cable sizing.

Brett

[pnixon235]

Tell us alittle more about your slides. Are they hydraulic or screw type? Do they get lubed or greased? I have hydraulic type and had to have a valve replaced when one slide started getting erratic.

[skyking8]

pnixon> I wish that they were hydraulic. Then we wouldn't be having this discussion. They are electric, screw, greased type and I keep them greased.

wolfe> Great suggestion about checking voltage at two places. If this isn't a bad battery issue then I could have a poor terminal connection somewhere. There are several aux wiring connections at several of the battery posts which could be an issue.the problem.

Since I am on the subject of batteries I have another question that is kind of out of the box thinking. I have always wondered why Alfa put six batteries in this coach unless it was to power the large living room slide. I have little use for six batteries since I don't do much dry camping and I could always use the generator when dry camping. Most people get by with 2 or 4 even if they dry camp alot. So the question is, why not get a professional installation of only 2 or 4 batteries when I go to replace batteries?

[wolfe10]

If you don't dry camp and don't use your inverter, then yes 2 (around 220 amp-hrs @12 VDC) or 4 (around 440 amp-hrs @12 VDC) will be fine.

But, it is the inverter, not the slide that requires a large battery bank.

The power to move the slide can be gotten from the alternator (if the engine is still running), shore power powering the inverter/charger or generator powering the inverter/charger.

Brett

[rosszie@me.com]

I would have them checked out by a professional, If you are un-easy. I had a 6 month old battery (one of my D-7 house batteries) with a bad cell it was hard to find.. I was having all kinds of problems with the appliances in my coach, refer was not working properly, same for Micro & Stereo

I charged it and it was fine, then I go to use it and/or problems were showing up.. I had a tester, I was informed to only test it fully charged, well here lying was the problem.. After a call for a jump.. I took the battery to Interstate Battery (the mfg.) they tested and found it was defective.

It was not a standard Interstate Battery, it was a Sam Club Battery made for them by Interstate. (not the same quality as the Interstate Corp Battery a cheaper version sold only to Sam's/Walmart (they want a cheaper model, So I was informed) But they Interstate changed it out for me for FREE.. And all is great in my Magna.. I hope this will help some of you. When in doubt have it check' you do not want to be stranded!!

[Guest Wayne77590]

You stated that when the slide will stop two times when being operated. What gets it going again? Do you have to wait 10 seconds or so and then retry, or is it instantaneously starting back up?

Reasons for my questions, which may have nothing to do with your situations, but is worth the discussion. Those large slides typically have two motors. They have to be in synchronous operation. If one gets to far ahead of the other, the one that has traveled the farthest will hesitate and wait for the one that is lagging to catch up. There could be something on the circuit board, and/or the sensor that controls all that.

If you have to wait 10 seconds or so, then push the button again, it could be that they have an automatic circuit breaker in-line to prevent over-current. If that is the case, and the motor is drawing to much current, finding the cause is the best solution. Most likely it will be low voltage which will cause a current increase. If the voltage is good, all connections are tight, it could be the age, or other problem, of the motor. If it does have an automatic circuit breaker in-line, finding one of the same size and placing it in parallel should keep the motor running continuously to operate the slide.

I'm just throwing all this out there as a "what if" scenario.