Questions on whether to replace converter or not.

I'm working on a 73 RoadCruiser Class C rv and was wondering how should handle the old converter.  Right now it has a 30 amp converter with a built in battery charger, this is 70s tech and I'm betting the cheapest they could find so I figure the charger is as likely to charge the battery as it is to boil it out.  Here's my question, should I buy a stand alone battery charger and somehow disable the one in the converter or should I just bite the bullet and get a new converter/charger??

I was looking a an Iota converter, http://store.solar-electric.com/dls-30.html , with the add on smart charger and shipping to me the price is a 161.22. 

I guess my question really is can I get away cheaper with just a 3 stage charger tacked on or will that cost me close to what I'd spend on a new converter?

If I can get away with just a charger can anyone recommend one or a brand I should look at.

Final question, will the charger or converter handle the chassis battery??  I'm not sure how mine is hooked up presently, I think there is some kind of battery minder device under the hood between the chassis battery and the house battery but I'm not a hundred percent sure.  Right now without plugging into electric I have no house lights or power but that might be a switch I'm missing.  I did see something in the manual for the converter about a switch on it to change from AC to battery so maybe thats why but I haven't remembered to try it when I'm around the RV.  Too much time and too little to do......strike that and reverse it  ;D



Bill

Did some digging on ebay and found the same converter with IQ4 charger for 135 bucks with free shipping!!!  I was also able to find the 45 and 55 amp versions for about the same price as my original post had the 30 amp version at.  If I have either a single 12v deep cycle or two 6 volt golf cart batteries will I get any benefit from the higher amperage during charging??  I'd be happy with the 30 amp version but if 25 bucks more gets me a big change in charging times I just might spring for it.

Bill

Not so fast...

    Some of the older converters rated at 30/45 etc amps, have a separate charger inside that delivers a limited current.
The 30/45 etc refers to the current available for house accessories, i.e. lights,fridge, pump etc.

For example, my old Magnatek unit (now deceased) was rated at 45 amp, yet the charger current at max was only 9 amps.

    You may want to double check the unit you have in mind. Most of the more modern converters have an integrated charger and will deliver full charge current, when required by the battery's state of charge.

carson FL

The bulk stage in a 3 stage charger is a constant current mode, so a higher output charger will charge the batteries faster.  Once the charger goes into acceptance mode, it won't make any difference.

Carson's point is good, check to see how much of the converter capacity is actually used for charging.  However, more is almost always better.

Digging around on Iotas website I found this in regards to the DSL-30 series converter/charger.

"As a battery charger, the converter will maintain
the battery, delivering its full-rated current when the
battery capacity falls sufficiently low. The voltage is set to
deliver its maximum current for the necessary period of
time that minimizes undue stress to the battery caused by
heating of its cells."

Looks to me that the system will indeed charge at the highest current available so I guess I should spring for the bigger amp model, but........

Let me see if my thinking is correct on charging times.  If I have 2 6volt Trogen T-105s with a rated 225ah and I figure on recharging at 50% then at 55 amps it should take roughly 2 hours for a full charge.  If I charge them at 30 amps it will take roughly 3 hrs and 45 minutes.  Am I anywhere in the ballpark with these figures??

Thats not a whole lot of difference in the real world, even using a generator to do an emergency recharge.  Most of the gensets I've looked at have a 5-7 hour runtime so at the least I'd be able to recharge in a resonable time and still have gas left in the genset.

My budget is VERY tight so maybe I'll just get the 30 amp one.  Like was mentioned, my old converter probably has a very small charger in it anyway so anything would be an improvement.  I do know the charger was an 'add on' option to it so I'm sure it was even cheaper designed than the converter itself.


Bill

As a battery charger, the converter will maintain
the battery, delivering its full-rated current when the
battery capacity falls sufficiently low. The voltage is set to
deliver its maximum current for the necessary period of
time that minimizes undue stress to the battery caused by
heating of its cells."

Click to expand...

    I'm not trying to be picky... The above statement "can be" interpreted" in several ways. If I were researching it I would still like to know the actual maximum "Charging current in amps" that the unit could deliver. (In print).

 
  carson FL

   

I just emailed Iota to find out if its max rated amps or limited for the charging side of things.

I'll let you know when I hear back from them.

Bill

The math isn't quite that simple.  The bulk mode, constant current, is only maintained until the batteries reach a set voltage (typically 14.4V) then absorption mode is applied at a constant voltage (again, typically 14.4V) until the charging current drops to a set level (typically 2% of battery capacity).  So charging isn't a linear function.  That's why experienced boondockers start charging when 50% depleted and stop at about 80% of full charge.  This makes maximum use of the bulk mode while not causing extended charging times.

All this assumes a well designed 3 stage charger.

Ok, can you give me an idea what charge time for two 6 volt 225ah bats would roughly be then??


Bill

Ok, here is what I got back from Iota.

"Hi William,
Our converters are a power supply with a rated maximum amperage output.  The DLS-30 will put out a maximum of 30 amps.  That is it?s current limit.  If it?s connected to a load higher than that, it will fold back the DC voltage output to protect itself.

As a battery charger, the current output is what ever the battery is pulling.  As the battery charges, the current draw goes down.

I hope this answers your question.  If not please let me know,
Thanks,
Jay"

So I guess the real question is, what can a deep cycle battery draw as a charging current?  Is it the rated amp hour, if possible, or is there a upper limit do to the construction and chemistry of the battery.

Bill

Bill, Good going, looking forward to the reply.
  Would you mind telling us where you are located? State?

carson FL

I'm in Eastern Pennsylvania, just outside of the cesspit, I mean city, of Reading.

Bill

That does not sound like a 3 stage charger, just a simple constant voltage charger.  The kind that can, and usually does, boil batteries.

No, if you add the IQ4 option, which is on the ones I've looked at, it is a three stage charger.  I think he meant that there is no extra limit placed on the charging output.

Bill

What was described in the email you quoted is not a 3 stage charger.  It doesn't describe the IQ4 option, assuming that adds the 3 stage charging feature.

I emailed and asked about the IQ4 option.

"William,
The IQ4 increases the voltage output, not the amperage.  The higher voltage causes the battery to boil which charges faster and more efficiently.
Stepping up to a 45amp or 55amp means you will have more amps available if your battery pulls that much and the higher amperage will charge faster.  There is usually only a $20 or $30 additional cost for the bigger units so it could be cost effective.
Jay"

So I'm back to asking, what kind of amperage will a charging deep cycle draw if it can draw all it wants??

Bill

Bill, I feel your pain.

  How about asking him what the maximum current the converter/charger will provide to "THE BATTERY" if it is in need of a heavy charge. We understand the tapering off in current when the battery reaches full charge. The IQ4 will probably do a good job on that.

carson

The IQ4 doesn't appear to be a 3 stage controller either.  Boiling a battery is never good practice.  I would find another converter/charger with a true 3 stage controller if you want your batteries to last.

I emailed Jay and asked him if he knows what a couple of Trogen T-105 in series could draw to charge.  I explained my problem with deciding on getting a 30 amp vs a 55 amp, my budget being in the negative right now and all and I wanted to know if they knew how much of a charging time difference the increased amperage would make.  I figure that they ought to have some notion or can point me in the direction of that info.... I hope  ???

Bill

Here is the documentation off Iotas web page concerning the IQ4

"The IQ Controller allows the DLS Charger to operate as an automatic 3-stage "smart charger." This gives the customer the benefit of Bulk, Absorption, and Float stage charging, increasing the charging capacity of the DLS charger and decreasing charge times, insuring proper and safe battery charging and minimizing over-charging. This "smart" technology monitors the battery at all times. If the DLS voltage remains in the long term stage for more than seven days, the IQ will automatically deliver a boost charge for a predetermined time, then automatically return to the normal float stage."

They are calling it a 3 stage charger.  Can anyone look at this and tell me if it's not ???

Bill