RV Inverter / Charger Opinions?

System

Greetings -

I am looking to have the 12V converter / charger in my new 17' Oliver replaced with a combination inverter / charger.

This is a small RV, so I don't have much space to work with. The area where the current converter is located is roughly 26” x 15” x 9”.

My AC requirements are pretty minimal - two laptops and a second LCD monitor are the key loads. Being able to handle higher occasional loads for a blender or microwave would be nice too.

I do value the convenience of an automatic transfer switch, and I want the charger to be able to top off the battery bank as quickly as possible if I ever have to resort to generator.

The battery bank will be either 220 AH of Lifeline AGM's, or 300 AH of Trojan flooded lead acid.

Here are the inverter / chargers I have been researching. I would love to hear opinions and experiences with these:

+ Xantrex Freedom HF 1800 -- 1800W Inverter, 40 amp smart battery charger. Comes with a remote control for checking battery status and turning the inverter off. 30Amp transfer switch for passing through AC shore power. Size: 4.2" x 9.5" x 18.0" x 12.8lbs. This is perhaps the cheapest and smallest option.

+ Xantrex Prosine 2.0 -- 2000 watts of true sine wave AC, 100 amp smart battery charger. 30A transfer switch. Remote control and battery temp sensor included. 17.7" x 11.2" x 5.7" x 24lbs. The 100A charger on this would be very useful for quick recharging via generator.

+ Xantrex Freedom 458 -- Comes in various combinations of inverter sizes from 1000W to 3000W, with 50A to 140A charger built in.

+ Xantrex MS2000 -- Potentially too big to physically fit.

+ Magnum ME2012 -- 2000W Inverter, 100Amp charger. They have a range of other models / sizes / shapes too. All are "PFC Corrected" for more efficient generator charging.

+ Magnum MM1212 -- 1200W Inverter, 70A charger. 16.6" x 8.4" x 4.7" x 20lbs

+ Tripplite RV1250ULHW -- 1250W Inverter, 55A charger. They also have larger and smaller sized models. 7" x 8.75" x 9" x 23lbs.


Are there any other models or brands I should be checking out? Any recommendations of products to avoid?

Thanks for the collective wisdom!

- Chris // www.technomadia.com

crewzer

Re: RV Inverter / Charger Opinions?

The battery bank will be either 220 AH of Lifeline AGM's, or 300 AH of Trojan flooded lead acid.
The 100A charger on this would be very useful for quick recharging via generator.

The 100 A charger may well be overkill -- in both charge current and in cost -- for your proposed battery bank size.

AGM batteries like the (Concorde) Lifeline can handle very high charge current. However, charge current of ~30% of bank capacity may be the practical upper limit for AGM batteries. Trojan recommends a charge current of between 10% and 13% of battery bank capacity.

Assuming 85% efficiency, a 100 A charger would require a generator rated at (100 A x 14.4 V) / 85% = 1,700 W continuous at sea level. A higher rated generator would be required at higher elevations.

Another issue is that the charger will only deliver full charge current during the bulk charge stage. Once the charger reaches the absorption stage, it will begin to limit charge current in order to maintain battery target voltage.

Therefore, a charger rated for between 30 A and 66 A may be a good choice for your proposed battery bank.

An option is to consider a separate charger and inverter. For example, the Xantrex Truecharge 40 is a very good 40 A charger, and Exeltech makes fine true sine wave inverters (“XP” Series).

See: http://www.xantrex.com/web/id/69/p/1/pt/7/product.asp
And: http://store.solar-electric.com/xaprbach.html
And: http://www.exeltech.com/ (go to “Products”, then to “XP Series”)
And: http://store.solar-electric.com/exsiwain.html

Yet another option might be two inverters: one small one to regular small loads and the periodic medium load (i.e., a 600 W model), and a larger inverter (or just the genny) for the occasional big load.

HTH,
Jim / crewzer

System2

Re: RV Inverter / Charger Opinions?

crewzer wrote: »

The 100 A charger may well be overkill -- in both charge current and in cost -- for your proposed battery bank size.

AGM batteries like the (Concorde) Lifeline can handle very high charge current. However, charge current of ~30% of bank capacity may be the practical upper limit for AGM batteries.

Checking Lifeline's online FAQ, they claim "no input current limitations" - which seems to imply that a 100A charging current would be fine. I haven't found any documentation suggesting otherwise. Hmmmm....

crewzer wrote: »

Assuming 85% efficiency, a 100 A charger would require a generator rated at (100 A x 14.4 V) / 85% = 1,700 W continuous at sea level. A higher rated generator would be required at higher elevations.

The generator we are leaning towards is the 2000W Honda or 2400W Yamaha. These are the smallest generators that would be able to run an air conditioner. It would be nice to take maximal advantage of them for shortened charging times too. A 100A charger seems like a good fit.

crewzer wrote: »

An option is to consider a separate charger and inverter. For example, the Xantrex Truecharge 40 is a very good 40 A charger, and Exeltech makes fine true sine wave inverters (“XP” Series).

We have fairly limited space, so two boxes is not ideal. I also want an inverter with a built in AC transfer switch so that it can be permanently wired into the RV's electrical system. I don't want to deal with having some outlets only functional on shore power, and other outlets functional via the inverter.

crewzer wrote: »

Yet another option might be two inverters: one small one to regular small loads and the periodic medium load (i.e., a 600 W model), and a larger inverter (or just the genny) for the occasional big load.

This is an intriguing idea. The 300W MorningStar pure sine wave inverter might be more effificient for our small and sensitive loads. And then I could use something like the Magnum MM1212 for larger AC loads, DC power, and charging.

Thanks for the advice,

- Chris // www.technomadia.com

niel

Re: RV Inverter / Charger Opinions?

as to concorde agms i was told by concorde that the charge rate max is an amp for every ah of battery capacity for 20hr rates. this is indeed high and not normal for most batteries to the point i never heard of any other battery with this ability, but nice to know concorde believes the batteries to be that good to allow such a charge rate. for solar and most other charge sources it would be rare to feed the batteries at such a high rate of charge. for example, how many could feed 104a into say a pvx 1040 from solar and few would do so with an ac charger either, but they told me it will take it. although it would take it at a high rate, i believe that some charge efficiency would be sacrificed like many other secondary batteries on a fast charge suffer from and i agree with crewzer that up to about a 30% rate may be better and more realisticly encountered. going higher than 30% won't void any warrantees with concorde.

crewzer

Re: RV Inverter / Charger Opinions?

Quote:
Originally Posted by crewzer
The 100 A charger may well be overkill -- in both charge current and in cost -- for your proposed battery bank size.

AGM batteries like the (Concorde) Lifeline can handle very high charge current. However, charge current of ~30% of bank capacity may be the practical upper limit for AGM batteries.

Checking Lifeline's online FAQ, they claim "no input current limitations" - which seems to imply that a 100A charging current would be fine. I haven't found any documentation suggesting otherwise. Hmmmm....

I agree that there are several Concorde / Lifeline statements that suggest their AGM batteries have virtually no charge current limitations:

http://www.lifelinebatteries.com/marinefaq.php#d

Absorbed Glass Mat (AGM) batteries include lead plates packed between silica-glass mats, which hold electrolytes in suspension. They have no input current limitations…

http://www.lifelinebatteries.com/marinefeatures.php

Faster recharge; no current limitations with voltage regulated recharging.

http://www.lifelinebatteries.com/marinesizing.php

AGM Batteries are not harmed by high amperage charge and discharge so long as the input voltage is carefully regulated.

But, there’s more to the story than just pushing Amps. The first notion to dispense with is that battery charging is a linear operation. Specifically, you can’t take 100 Ah out of a 220 Ah battery, hook up a 100 A charger, and recharge the battery in one hour (assuming 100% recharge efficiency).

Concorde / lifeline also says to “Charge 1 with voltage-regulated (constant potential) charger.” See: http://www.lifelinebatteries.com/manual2.php

This type of charge delivers full current in “bulk” charge mode until the battery voltage reaches the target absorption voltage, at which point the battery is ~80% to 90% fully recharged, depending on charge current. Ironically, while a high current charger will achieve the absorption target voltage rather quickly, the battery is less full (i.e., closer to 80% full than to 90% full) due to the high surface charge.

The charger then switches to absorb mode, which hold the battery voltage constant by slowly reducing charge current. The absorption stage for AGM batteries can last anywhere from 2-1/2 to 4 hours or more.

Here’s a somewhat simplified comparison of using a 100 A charger vs. a 40 A charger:

Starting at 220 Ah – 100 Ah = 120 Ah remaining, a 100 A charger would take about an hour to recharge the 220 Ah battery bank to 80% SOC (176 Ah). Assuming another 2-1/2 hours for the absorption stage, the 100 A charger would take ~3-1/2 hours to put 100 Ah back into the battery bank.

Starting at 220 Ah – 100 Ah = 120 Ah remaining, a 40 A charger would take about two hours to recharge the 220 Ah battery bank to 90% SOC (198 Ah). Assuming another 2-1/2 hours for the absorption stage, the 40 A charger would take ~4-1/2 hours to put 100 Ah back into the battery bank.

So, is the extra 60 A charge current -- and its attendant size and cost (don't forget BIG cables and a BIG DC breaker) -- worth it?

The 30% charge current “rule” for AGM batteries is used by several manufacturers. MK (East Penn) says to “Maintain Current <= 30 A per 100 Ah C20”. See: http://www.mkbattery.com/images/AGMBatteryCharging.pdf

Exide suggests something in the 30% range for their Marathon AGM batteries (i.e., 37 A recommended max for their ~105 Ah battery). See: http://industrialenergy.exide.com/exidepdfs/Section%2092.30%202005-09.pdf

But, going the other way, Concorde, Lifeline’s corporate owner, recommends a “conditioning charge constant current charge rate” of 11 A for their Sun-Xtended 220 Ah AGM battery. 11 A is just 5% of capacity. See: http://www.sunxtender.com/xtenderservice.php

I hope this additional information is useful to you.

Regards,
Jim / crewzer

wild01

Re: RV Inverter / Charger Opinions?

if you go with the prosine be prepared to shell out $$$$ on battery cables. they go ape shite on inductive loads if you don't have really big cable {think 4/0)

I really regret buying mine. I ended up spending as much on copper as I would have spent upgrading to a sw series. my neighbor runs 4 gauge cables on his sw2412, (no longer avail) and it hums along fine

Windsun

Re: RV Inverter / Charger Opinions?

wild01 wrote: »

if you go with the prosine be prepared to shell out $$$$ on battery cables. they go ape shite on inductive loads if you don't have really big cable {think 4/0)

I really regret buying mine. I ended up spending as much on copper as I would have spent upgrading to a sw series. my neighbor runs 4 gauge cables on his sw2412, (no longer avail) and it hums along fine

If he ran #4 wire to a 2400 watt inverter, he is way undersized on cable.

wild01

Re: RV Inverter / Charger Opinions?

yup he is. however he's fused for it (150 amp slo-blow) and he doesn't max his inverter. my point is, the sw series will run that way. my prosine wouldn't start loads that my 750 watt msw walmart thing started. (until i put 4/0 welding cables on it) I have thought about installing a high amp capacitor @ the battery b-c it's the initial draw that seems to upset the prosine. as long as I had a big enough resistive load already on the prosine started inductive loads just fine. but my house is actually energy efficient and when I turn everything off everything turns off.

InverterExpert

Re: RV Inverter / Charger Opinions?

Forget the Freedom 458, they are modified sine. Not good for you laptops and LCD monitors. Prosine's are ok to do the job considering your space requirement. Magnum ME2012 seems a good choice too, but too over loaded with features and need for extra remote and cabling.

Check out the Xantrex Freedom SW 2000. Retails between $850-1000, comes with transfer switch, simple to configure and needs no extra remote to be bought.
http://www.xantrex.com/web/id/302/p/1/pt/7/product.asp

Dont confuse it with Prowatt SW 2000.

Kamala

Re: RV Inverter / Charger Opinions?

Windsun wrote: »

If he ran #4 wire to a 2400 watt inverter, he is way undersized on cable.

I have a ProSine 2.0 and am very pleased with its performance. It is overkill for my application. But the appeal of TSW, charger and Xfer switch in one box was just to great to ignore. I have none of the problems sited by wild01. But I run no "highly" inductive loads. Just a 1KW microwave. But the price is a big hit. :grr

I'm very happy that I followed this post because I have learned that my cabling/fuse combination is wrong.

The ProSine manual directive for cable size was only given in MCM, not AWG. Erroneously, I decided that 250 MCM (recommended by Xantrex as the cable size for runs of less than six feet) was equivalent to #4 AWG. Turns out that 250 MCM is more like #0000, or 5.7/0..

So I am way undersized on cabling. That being said. the system has worked very well.

For that cable size, Xantrex recommended a 300A fuse. I now plan to replace the 300A fuse with a 125A one. Might need a new holder. I really can't see/justify replacing all the cabling. I have used Ancor #4 cables of relatively short lengths in small spaces and the flexibility is essential.. 0000+ is not reasonable in this tight space.

For the OP... The ProSine 2.0 is highly configurable. I have to be in prone position to work on/or see mine (link to My Camper in my sig) so I don't use it often. I have set the PS2.0 max charge to 40A and when AC is delivered to it by my Honda 1000eui it takes about 4 to 6 hr to recharge (no insolatiion.) But if the sun is out... it works without said genny!

Cariboocoot

Re: RV Inverter / Charger Opinions?

Kamala,

Isn't that a 2 kW 12V inverter? If so, I should think 000 (3/0) wire and a 200 Amp fuse should suffice (2000 Watts / 10.5 Volts = 190 Amps). I could be wrong - it happens several times a day!

Yes, 4 AWG is too small for max current and you did size the fuse wrong. Naughty! Tony & I were just discussing this in another thread too - talk about coincidence!

I think in your app 4 AWG would be good for 70-80 Amps, and therefor a 100 Amp fuse would suffice.

And I already know I'm going to be told I'm wrong - did the math wrong again - something. Go ahead, guys!

Kamala

Re: RV Inverter / Charger Opinions?

It is indeed a 2KW 12V unit. My design calculations indicate that if all loads are on simultaneously, the current draw will be 110 amps. If the microwave is off, then the total current drops to about 27A. This design prediction is supported, loosely, by what I have seen on the battery monitor. Normal use is around 8A. If the microwave is powered up the current rises and fluctuates between about 80A and 105A. Operation of all devices and appliances has been flawless. (Except for the load sensing feature of the inverter. No matter what value is used for the threshold, the unit cycles on and off. Hysteresis. The manual suggests that this can happen when "phantom" loads are present. In my case the microwave and TV. Yes, I know about using a power strip on these devices. It is not needed in this application since the inverter is remotely shutdown (<2mA) most of the time. It is on, usually, for only 4 to 6 hours at night. So load sense is disabled.)

So the plan now is to downsize the fuse. And find an answer to the question, "What is the maximum size fuse that can be used with 4 AWG cable?"

Or I could ditch the microwave. I didn't want it in the camper to begin with, but it was not an option when I ordered it. The microwave was standard. It can removed removed easily and, if it was, it would free up badly needed stowage space. But if there is a hamburger or potato left over from the night before, it sure is handy. Interestingly, this is only my sixth largest load. 2.5 minutes of use is about 42WH. And it is rarely used. 12VDC motors are the largest loads.

LP fridge fan = 9W (24/7 in summer = 1.5KWH)
Roof vent fan = 21W (12H/weekend = 0.25KWH) might be higher Jun-Aug
Furnace blower = 43W (???KWH) only used Apr/May and Sep-Nov

K

Cariboocoot

Re: RV Inverter / Charger Opinions?

I know what you mean about microwaves. We have one and it mostly collects dust. But every now and then it's just the thing to have. Wreaks havoc with the power for a couple of minutes, then goes back to collecting dust. We only use it mid-day, when the sun is shining and the batteries are charged.

From memory (which isn't very good anymore) I think 4AWG is good for 135 Amps, possibly 150. So that would be a 110 Amp fuse, which there probably isn't one, to 125 Amp fuse, which is what you already figured out!

Don't mind me; I just prattle on.

niel

Re: RV Inverter / Charger Opinions?

from this chart
http://www.okonite.com/engineering/nec-ampacity-tables.html
you can use that as the max fuse rating. i'd go by the 3 conductor figure as few would be a single conductor in open air.

Cariboocoot

Re: RV Inverter / Charger Opinions?

Thanks, Niel!

It also explains how I managed to get confused about with my initial "70-80 Amps" and my second "135-150" post, which is wacker-jawed. Fog in the noggin, you know.

Always best to err on the side of caution with fuses.

Although this does indicate that Kamala needs to install larger wires.:roll:

Kamala

Re: RV Inverter / Charger Opinions?

Thanks 'Coot & Neil. I'm going with #1 cable and a 125A fuse. I solicit your opinions on two related matters.

1. Stud diameter of lugs. The #1 cable will connect to both 3/8" and 5/16" studs. Should I be concerned about using a 3/8" lug on a 5/16" stud. My sense is that I don't need to be concerned.

2. Fuse holder termination. Options are lug or cut cable. Seems that cut cable would be one less failure point. My concern is, will the #1 cable fit in the cut cable termination. I think it will.

My original #4 cable is marine grade purchased from a western vendor. I'll miss this great cable, individually tinned fine strands. But I'm not really marine. Unless the river rises... alot.:p

Same vendor also sells #1-5/16 lugs for the same price as their #1-3/8" lugs. At $65 per 25. NAWS sells the 3/8" for $17 per 25. Unbelievable!

I'll sleep a little better (but only a little) this summer. Not that sleeping is a problem. Spouse doesn't understand this stuff very well, yet. She's supportive and mildly interested but puts her trust in me. So now I will have become more trustworthy.

And sorry for the hijack. I hope some of it is helpful to the OP.

Craig

niel

Re: RV Inverter / Charger Opinions?

1 i don't think that will matter too much as long as the connection stays tight with no movement of the lug. someone who would try say a 1/2in lug on a 1/4in post would experience movement as well as issues with contact area so some washers (possibly locking) could come into play in such a case, but in this case i don't believe you'll have any problems as it's only a 1/16th inch difference.

2 not to sure what you're driving at here. are you concerned that the wire is too big to make the connection to the fuse block?

Cariboocoot

Re: RV Inverter / Charger Opinions?

I agree with Neil. Not only about the lugs, where it is the surface that makes the contact, but also about not understanding the fuse holder question.

I think it means you have a fuse holder which can either clamp down on bare wire or bolt on a lug.
In which case I'd favour the lug.

Kamala

Re: RV Inverter / Charger Opinions?

Two different fuse blocks. One has studs on to which lugs are bolted. The other accepts bare cable, much like what is found in a combiner box, I imagine.

Cariboocoot

Re: RV Inverter / Charger Opinions?

Kamala wrote: »

Two different fuse blocks. One has studs on to which lugs are bolted. The other accepts bare cable, much like what is found in a combiner box, I imagine.

Six of one, half dozen of the other.
Some might say that putting lugs on cable and then attaching to studs adds up to more connections and therefor more chance of connection problems.
Others might say the clamp-down type is more likely to come loose and cause the same connection problems.

Me, I like lug connections.

System2

Re: RV Inverter / Charger Opinions?

The New ProCombi Q from Sterling Power USA is fantastic. I bought the Q as i run non-thyristor appliances (practically every appliance except washing machines). Get the ProCombi S for non-thyristor and thyristor, it will run everything. It costs a little more tho.

http://sterling-power-usa.com/procombi-s-puresinewavecombiinverter-12volt2500w230vac.aspx

http://sterling-power-usa.com/sinewaveinverter.aspx

dwh

Re: RV Inverter / Charger Opinions?

Oooh....a new term for the glossary; QSW (Quasi-Sine Wave).

They have some interesting products on that site - such as a DC powered battery charger in various voltage combinations like 12v-12v, 12v-24v, 24v-12v etc.

Also an alternator powered battery charger that installs in place of an isolator. Neat.

vcallaway

Re: RV Inverter / Charger Opinions?

Q is short for square.

The Sailing Today comparison they brag about shows the waveform. Looks pretty square to me.

More pork products in a can.

Cariboocoot

Re: RV Inverter / Charger Opinions?

Big on hype, small on facts.
How do they get those massive 130+ Amp outputs from those "alternator chargers"? Kind of neglect the fact you need a 150+ Amp alternator in the first place, don't they?
As for DC-to-DC chargers ... Wouldn't you need significantly more Amp hours in the source battery in order to ramp up the Voltage to charge levels and put some appreciable amount of power back into the destination battery? I didn't see any explanation of "how it works" there either.
Not saying any of it doesn't work; just that they could be a bit more factual in their presentation.
I like data. Lots of relevant data.

dwh

Re: RV Inverter / Charger Opinions?

Cariboocoot wrote: »

Big on hype, small on facts.
How do they get those massive 130+ Amp outputs from those "alternator chargers"? Kind of neglect the fact you need a 150+ Amp alternator in the first place, don't they?
As for DC-to-DC chargers ... Wouldn't you need significantly more Amp hours in the source battery in order to ramp up the Voltage to charge levels and put some appreciable amount of power back into the destination battery? I didn't see any explanation of "how it works" there either.
Not saying any of it doesn't work; just that they could be a bit more factual in their presentation.
I like data. Lots of relevant data.

I never saw them before today, but in their defense:

They do sell the high output alternators.

The DC-DC chargers can apparently be wired so they don't come on until the engine charging system is up and running.