Updating a previous thread:I have a 2012 Chevy truck with a 2012 Four Wheel slide in camper. The camper is equipped with a Iota DSL30 converter and I recently added a Iota IQ4 battery plug in smart charger to it. Works great at keeping my two camper AGM batteries charged. I also want to keep my truck battery charged. I have a Battery Tender Plus that I use on the truck starting battery. My question is, do you see any problems in using the two charging systems together?I know that when using the Battery Tender Plus on the truck battery that it also sends a charge to the camper batteries, although not very effectively. Because of the battery separator, the Iota can not charge the truck battery, correct?Do you see any issues in charging with both the camper/iota and truck/Battery Tender Plus at the same time, i.e.: camper batteries getting charged by both chargers?

Not sure about the actual correct answer, but first--can't you just unplug the camper from the truck? You aren't driving at the time you want to do this.

BFL13 wrote:Not sure about the actual correct answer, but first--can't you just unplug the camper from the truck? You aren't driving at the time you want to do this.That would be the easy answer, but my camper is on full time and the plug can't be accessed.I suppose I could install a cut off switch to the camper if I HAD to.

rottidawg wrote:I know that when using the Battery Tender Plus on the truck battery that it also sends a charge to the camper batteries, although not very effectively. Because of the battery separator, the Iota can not charge the truck battery, correct?Personally, I don't know if this IS correct. I am pretty, old-rig centric and not up on your fancy-pantsed, new-fangled stuff. What your describing would basically require some kind of diode(s) to allow energy to pass only one way.On my rig, the 2 banks are either tied together or they're not. It's a pretty good system. When the rig is running a switch can tie them in order to charge the house bank with the alternator. With the chassis engine off, the power to the solenoid is cut and the two are no longer tied, so you can't run down the chassis battery with house usage. However, you can override this with a spring-loaded switch in the cockpit. The idea here is to put the two banks together in order to start either the chassis engine or the generator if one bank or the other is weak.But I digress...Regardless... it doesn't matter. If your tender can send power from the chassis battery to the house bank, it can work in conjunction with the IOTA. The IOTA will virtually always be doing all the work, though.I run a positive jumper between my two banks so the converter can keep the chassis battery floated. Works very well.BFL sometimes runs like 17 or 18 (I think it is) chargers on one bank at a time, so we know it can be done. :)Bottom line?You're on the right track. Your batteries are happiest when they're fully charged and with a float charger on them. A destratification stir now and then is a bonus.

Hi,I would have dealt with the chassis battery using a trik-l-start. (and I did) If so the Iota will charge the chassis battery.

Easy. Connect them ALL to the strongest in the herd. Monitor voltage over a period of a week. If it droops then you'll need to fall back five and punt.Personally I do not like tandem-ing high frequency devices. Like coupling an oboe with a cello. Even though a waltz may start, pretty soon they both regress where they don't belong - into jazz, and you in a heap o trouble. If you are a technocrit you can try adding a .47 uf capacitor - sort of like a midget conductor to the symphony.

Any problem in using two battery maintainers at once?

21 Replies

mena661
Explorer
Oct 04, 2013
KendallP wrote:
Perhaps I'm just not quite as skilled. Hope I don't need another 50 years to get that sarcastic!
MEX was being sarcastic?
KendallP
Explorer
Oct 03, 2013
smkettner wrote:
...Both (or all 18 :) )... will just drop out as the voltage meets or exceeds the set points.

Think if you had 18 chargers rated one amp each and voltages set at 12.5 to 14.1 at 0.1 volt intervals. You get 18 amps until battery voltage hits 12.5 and then 1 amp drops out. Then at each .1v another charger drops out until the last charger holds the battery at 14.1 volts. The other chargers just drop out of the process. And no harm to any as all these voltages are in spec.

LOL!!!

Glad you were able to make good use of my "18" quote, there, SMK. :)

I guess I'll have to add my sarcasm emoticon from now on. Ol' MEX seems to get away with it. Perhaps I'm just not quite as skilled. Hope I don't need another 50 years to get that sarcastic!
time2roll
Nomad
Oct 03, 2013
Horsedoc wrote:
Ya'll lost me there, but I would just wonder if there were two charging units and both are feeding current to a pair of connected battery banks, would not these chargers read the current from the other charger as 'full' and start cutting back before the battery bank(s) were fully charged? Seems I had that problem as a kid trying to charge a battery in a hurry using two separate chargers
Each charger will just output maximum design current until voltage hits the max specification.

Both (or all 18 :) ) will just drop out as the voltage meets or exceeds the set points.

Think if you had 18 chargers rated one amp each and voltages set at 12.5 to 14.1 at 0.1 volt intervals. You get 18 amps until battery voltage hits 12.5 and then 1 amp drops out. Then at each .1v another charger drops out until the last charger holds the battery at 14.1 volts. The other chargers just drop out of the process. And no harm to any as all these voltages are in spec.
BFL13
Explorer II
Oct 03, 2013
The secret is the different spreads between each charger's voltage and the battery's voltage. The charger with the biggest spread will run the longest while the others drop out as their spreads disappear in turn as the battery voltage rises.

The battery can only accept so many amps at any voltage, so the chargers will only add amps more than one charger can do, if the battery can accept that many. Otherwise you will get the same total amps with several chargers as with that one charger. In that case each charger will do a few amps and they will add up to that total. How much each charger does of that total is in proportion to its "spread"
Horsedoc
Explorer II
Oct 03, 2013
Ya'll lost me there, but I would just wonder if there were two charging units and both are feeding current to a pair of connected battery banks, would not these chargers read the current from the other charger as 'full' and start cutting back before the battery bank(s) were fully charged? Seems I had that problem as a kid trying to charge a battery in a hurry using two separate chargers
rottidawg
Explorer
Oct 02, 2013
pianotuna wrote:

Yes, but when you say 18 chargers at once, some poor guy is going to "take you at your word" and try it.

I would be that poor guy. :)

I did pose my question to Iota tech support and their response was:
"Should not be problem"
mena661
Explorer
Oct 02, 2013
pianotuna wrote:
Hi KendalP,

Yes, but when you say 18 chargers at once, some poor guy is going to "take you at your word" and try it.
No PT. Most people are going to see that as an exaggeration. It's pretty obvious that it was.
pianotuna
Nomad III
Oct 02, 2013
Hi KendalP,

Yes, but when you say 18 chargers at once, some poor guy is going to "take you at your word" and try it.
KendallP
Explorer
Oct 02, 2013
OK, I got the harmonics reference, Grandpapa. It just sounded funny.

BFL's stuff seems to keep going and going and going. Is it because they are all a Vector design with the same frequency, perhaps?

MEXICOWANDERER wrote:
...It has to be pulse width modulated...

Why?

It's only putting out an Amp and a quarter. Visually, it looks more like classic tech.

Here's a photo...
KendallP
Explorer
Oct 02, 2013
pianotuna wrote:
Hi KendalP,

I think BFL13 used up to 5 chargers

Well there goes that boisterous, Canuck sense of humor again.

Thanks, PT. I think I had a pretty fair handle on BFL's MO. I may have exaggerated just a whisker. :)