Iota 55 amp converter questions

[GlennWest]

As some know I have issues since putting in the 48/70 amp chinese  converter. My stock Iota 55 has ran everything fine by itself. For now I am unhooking the chinese converter and connecting up my Iota. My Iota has a plug on it for charge controller option. Iota makes a lithium one. $18.99. Charges bulk to 14.7 volts. floats and maintains. I am considering getting a 20 ah 12v lithium battery. Out of work right now and money is limited. Sound like a game plan?

Edited October 13, 2021 by GlennWest

[GlennWest]

Well little more research and that won't work. I would have to use a 100ah battery to handle the 55 amps. Most the small battery will take is 20 amps. 

Edited October 13, 2021 by GlennWest

[Lou Schneider]

Nothing wrong with that.  Batteries will only draw as much charging current as they need.  A 55 amp converter won't overcharge a small battery.

Think of electricity in water terms.  Voltage is pressure, amps is flow rate (gallons per minute).  You can have a large pump or a small pump but as long as the pressure is right, you'll only get so much flow out of a garden hose sprayer.

Same with your battery.  As long as the voltage is right (14.7 volts) it will only drink as much current as it needs.

Edited October 14, 2021 by Lou Schneider

[Randyretired]

Lithium batteries are rated for the maximum charge amps.  Typically .5c to 1c but it varies.  A BMS will also likely restrict the amount of current allowed through it.  Many times it will just open the circuit for charging or even stop all current in or out for a period of time if that value is exceeded.

[GlennWest]

Interesting. Plainly states 20 amps max charging. Has a bms and the way i understand a bms won't allow overcharging.

[Randyretired]

1 hour ago, GlennWest said:

Interesting. Plainly states 20 amps max charging. Has a bms and the way i understand a bms won't allow overcharging.

Most BMS's have a maximum amount of current that will pass in or out and typically act like a circuit breaker.  If that current limit is exceeded the BMS will open the circuit.  Over charging to an unsafe voltage is also limited with most BMS's but as long as the cells are balanced and the charger is set to the correct voltage the BMS will not restrict the charging as the battery will only charge to the chargers set voltage.  One BMS 2 different functions.  Another function of many BMS's is to maintain safe voltages, to high or to low in each cell.  If these voltages are outside of the limits the BMS will also open the circuit.

[GlennWest]

My Iota is a 55 amp charger. Will it put out less? I don't know. Have to research this. Well I did and states will put out as much as 55. That I understand as put out just as much as needed up to 55 amp. Module to add to it changes to lithium profile and 14.7 volts. https://www.amazon.com/gp/product/B087JKQGJB/ref=ask_ql_qh_dp_hza?th=1      This is the battery considering. Just something for water pump and led lights when needed traveling. And aid in slide outs.

Edited October 15, 2021 by GlennWest

[Randyretired]

That battery specs 20 amp charge rate and maximum voltage of 14.5v.  My thoughts are if this battery is depleted to any significant degree the converter will provide up to 55 amps and try to charge to 14.7v.  

[GlennWest]

https://www.donrowe.com/iota-iq-lifepo-smart-charge-controller-p/iq-lifepo.htm?gclid=Cj0KCQjwqp-LBhDQARIsAO0a6aJqEsSKWDJUuK59b89QKGMKk46Qq_XWh6Oo1No_ErG-GiVsQTH-CIcaAu4wEALw_wcB. This link to lithium module

[Randyretired]

There is a note that seems pretty important in this case but this is your choice.  I am only giving you my opinion.  My experience with LifeP04 batteries makes me wonder why these charging parameters are offered on this converter but that is another story.

[GlennWest]

Read that note too. Sounds like they covering themselves if it goes south.

[GlennWest]

Think I will can that idea. Just wait and when money coming in again get 2 30 amp Victron Orions. The Iota converter run slides fine. Anything in our Teton. Just no DC power until plugged in. Oh, side note, played with the chinese converter some. It is supplying 12.3 volts until high load and it drops to 10ish. It was good on all but the slideouts. Truly it is not what it rated at. That unit has good reviews too. It was worth a try though. Those 2 Orions $430.00. 

Edited October 15, 2021 by GlennWest

[GlennWest]

Just researching 100ah lithium batteries. Most of them limit charging to 50 amps max. Battle born was the exception but they don't mention it. Some rvs have 90 amp converters in them. Are we not looking at this right?

[Kirk W]

1 minute ago, GlennWest said:

Are we not looking at this right?

Not really. When you open a 1 liter bottle of wine, you do not have to drink all of it.

16 hours ago, Lou Schneider said:

Think of electricity in water terms.  Voltage is pressure, amps is flow rate (gallons per minute).  You can have a large pump or a small pump but as long as the pressure is right, you'll only get so much flow out of a garden hose sprayer.

Same with your battery.  As long as the voltage is right (14.7 volts) it will only drink as much current as it needs.

 

[GlennWest]

31 minutes ago, Kirk W said:

Not really. When you open a 1 liter bottle of wine, you do not have to drink all of it.

 

So are you saying I should be good with my 55 amp converter with the lithium module and the 20ah battery? I don't know of any who has one. 

[Kirk W]

While that converter can supply more than the battery needs, it will not force it on the battery. That is a function of applied voltage. But when you have a converter that can supply more than the maximum current needed by the battery it can supply current to other loads at the same time as the battery is being charged. Remember that your converter is more than just a battery charger, but it supplies all of the 12V power to the RV at the same time as it is charging the battery. 

[GlennWest]

Think I will give it a shot. Won't be out of a lot if it kills it. Thanks. Been researching batteries this morning. Lots of batteries that people use are just car batteries, cheap. And I hear no mention of then boiling acid out or anything. And their chargers are way more than batteries rated for.

[Randyretired]

One might want to look up the charging profiles of a lithium battery.  Because they have little internal resistance these batteries charge at very high rates until charged.  This charging is very different than lead acid.  If I were to even consider what you are thinking about I would NOT purchase the lithium addition for the converter.   First it charges to 14.7v.  None of the batteries you are looking at are rated for that voltage.  Lithium batteries do not need to be charged 100%.  13.5 to 13.6v is a fully charged battery and unlike lead acid given time the battery will reach that voltage even if without a higher voltage charge.

[GlennWest]

51 minutes ago, Randyretired said:

One might want to look up the charging profiles of a lithium battery.  Because they have little internal resistance these batteries charge at very high rates until charged.  This charging is very different than lead acid.  If I were to even consider what you are thinking about I would NOT purchase the lithium addition for the converter.   First it charges to 14.7v.  None of the batteries you are looking at are rated for that voltage.  Lithium batteries do not need to be charged 100%.  13.5 to 13.6v is a fully charged battery and unlike lead acid given time the battery will reach that voltage even if without a higher voltage charge.

I was just on their site and max voltage is 14.8. Recommend charging at 14.5. I should be good. It may shorten life some but this not permanent situation unless it works better than I think it will. Intend to be on inverter power later and will still need 12v somehow. I could just use as is without module. Just will never reach full charge. I don't have a lot of ah to start with though. 

Edited October 15, 2021 by GlennWest

[Randyretired]

13.3v is 40 to 90% SOC on these batteries.  There is no need to go higher in most cases.  13.4 is up to 99% SOC

[Star Dreamer]

We have a 90 amp converter in our trailer. I think you are misreading what it does. The larger converters allow more 12 volt circuits, or larger amp circuits, to be handled by the converter similar to how a larger alternator (or multiple alternators) are used for vehicles with large stereo systems.

 

When you are plugged into shore power, your converter then provides more amperage to power the 12v accessories and provides enough power to charge to batteries with the maximum they will take. You might notice that when you are not connected to shore power and running off of battery power that lights dim when using high power items like the water pump or inverter but didn't do it when hooked to shore power. If you have a smaller converter and are powering 12 volt items in your RV, you may not be able to have enough amperage to recharge the batteries at their maximum thus taking longer to recharge them. 

Edited October 16, 2021 by Star Dreamer

[GlennWest]

Actually my 12v load is light. Residential fridge, all led lights, mini splits are our heat until freezing temps. Recently checked it and if I remember correctly 3or4 amps. 

Edited October 16, 2021 by GlennWest

[Star Dreamer]

30 minutes ago, GlennWest said:

Actually my 12v load is light. Residential fridge, all led lights, mini splits are our heat until freezing temps. Recently checked it and if I remember correctly 3or4 amps. 

What about water pump, awnings, propane furnace fan (you may not have one now that you have mini splits), leveling system, slide outs, stereo, 12v TV if you have one, etc...? What 12 volt fuses to you have in your fuse panel? Obviously many of those loads are only when needed. 

[GlennWest]

My 55 amp 120v stock converter will run everything. We only use our furnace if it get real windy and freezing temps.  My slideouts is the highest draw. Just stating that in a normal usage 12v is very low.