Which Lithium Power System

[cruising7388]

Originally Posted by booster

I would agree that it can be iffy with wet cells, but disconnected they can still do it quite often, I know that from personal experience.


Disconnected, so no drain, AGM batteries will nearly always start you in the spring. 3% a month loss for 5 months in an AGM in good shape, is not much. Lots of winter stored cars with Optimas in them just get disconnected in cold storage and start in the spring without issue. We also have done that, when our hotrod was stored offsite in unheated space.

For a disconnected AGM, don't frigid temperatures act to reduce the local discharge to even less than 3% per month?

[booster]

Originally Posted by cruising7388

For a disconnected AGM, don't frigid temperatures act to reduce the local discharge to even less than 3% per month?

Yes, AFAIK, it does, and 3% is on the high end for good AGMs also.


I picked 3% as a very conservative number for the comparison and it still was easy.


The biggest risk to the AGM would be if it somehow got too far discharged near spring, and then it got very cold out and froze it, but that should not happen.

[VanFan]

Originally Posted by booster

How does your dual system handle turning off the charging when the batteries get full? The big question has been if the output of the alternators is turned off, you could get a big spike...

I'm not an electrician or electrical engineer and I'm not sure what you mean by "field," so this answer may be incorrect or incomplete, but if I understand your question correctly I believe the regulator controls surges from the alternators. As for the alternators, I was writing from memory having not seen the specs in several months so I just went back to check and sure enough I was mis-remembering. The amps I mentioned are the maximum. The actual output at idle speed is about 200 amps per alternator, 400 amps total for both. That's at 2250 RPM's at the alternators, which is about 750 or 800 RPM at the engine.

[VanFan]

Originally Posted by gregmchugh

If you go to the Volta website you can find descriptions and specs for all of the system components. In the system used in the Travato you have a 48v inverter/shore charger to get 120v AC and charge the batteries on shore power. There is a 48v to 12v DC to DC converter connected to the 48v battery bank to power the 12v loads. And the 48v battery bank and 48v auxiliary alternator.

https://voltapowersystems.com

That's everything I wanted to know. Thank you.

[Reed]

Reread Battery University and you can trickle charge at 0.02 C.

We left fifth wheel at son’s place at 7500’ in northern NM. We disconnected battery since even winter sun would be 0.1 C

Noted earlier that son had installed blower in 2002 Roadtrek to warm battery compartment. Talked with him on this. The fan pulls air from compartment and expels it to outside. This pulls in warm cabin air to battery compartment aka space under bed

Reed and Elaine

[booster]

Originally Posted by A. A. Dickson

I'm not an electrician or electrical engineer and I'm not sure what you mean by "field," so this answer may be incorrect or incomplete, but if I understand your question correctly I believe the regulator controls surges from the alternators. As for the alternators, I was writing from memory having not seen the specs in several months so I just went back to check and sure enough I was mis-remembering. The amps I mentioned are the maximum. The actual output at idle speed is about 200 amps per alternator, 400 amps total for both. That's at 2250 RPM's at the alternators, which is about 750 or 800 RPM at the engine.

Those are very likely the Nations 280amp alternators that most use for alternator charging.



Those alternators (one of ours is that model) will usually give about 165 amps average when fully hot and heat cycling back and forth between full output and 50% when the Balmar sees they are too hot. The range is about 145 amps when turned down and 185 amps when they are at full output, and at full output speed. Most vehicles these days won't spin them fast enough for full output unless the pulleys are changed or there is a fast idle switch. The 330amps continuous average is going to be a push for a single 4/0 cable, so hopefully you have two cables for them.


The Balmar will turn down the charging to a lower voltage when it thinks the batteries are full if programmed right, but current recommendations are to shut off the charging completely when full. Especially if there is no other battery in the circuit, like the starting battery, just using big switch can be harmful to electronics, but even with the starting battery in the circuit suddenly shutting off 330 amps might be an issue, if they are doing that. Shutting off the field refers to stopping the output by stopping the smaller current that the Balmar sends to the alternators, which will stop output without any hazard.


Does you alternator charging stop completely when the batteries get full

[Cannuck]

Camping in the cold, and I’m talking within 10 degrees of freezing, is not uncommon for anyone out for a trip is the transition seasons. For us, some of the best camping is in the transition seasons.

We have a Roadtrek with the Ecotrek solution. It’s a dated 12 volt system that has crazy phantom loads that have been well documented on this site. As much as I’d like to strangle the Roadtrek designers sometimes, those phantom loads do keep the batteries warm. We’ve camped at -10C without issue - as long as we keep the battery systems on.

The Fit RV site demonstrates a 400 amp hour solution they developed themselves. Their battery is inside the coach. They have no phantom loads. Yeah!

My possibly obsolete advice would be to look for a solution that is inside the temperature regulated environment of the coach that has evidence of reliability and has limited phantom loads.

[Oliver2017]

Originally Posted by Cannuck

Camping in the cold, and I’m talking within 10 degrees of freezing, is not uncommon for anyone out for a trip is the transition seasons. For us, some of the best camping is in the transition seasons.

What is your source for heat? Do you have a recommendation for an electric source to use to avoid a fuel based heat source?

[fratermus]

Originally Posted by Davydd

... if you don’t have a method of heating lithium batteries anyway you are some kind of fool or planning to stay in south Florida.

Or chasing 65F wherever it is.

[Davydd]

Originally Posted by fratermus

Or chasing 65F wherever it is.

Good luck with that. I have camped down to 0F in Gallup, NM and if you live in most of the USA you will experience freezing temperatures and you do have to store your B when not in use.

[gregmchugh]

Of course, if you live full time in an RV then avoiding freezing weather is not that much of a challenge if that is your goal.

I would still go for battery heating pads if my batteries were not in the heated portion of the RV. The only thing in our RV that would freeze in very cold weather is the grey tank and it has a electric heating pad to use if needed.

I personally have a goal of avoiding hot weather and don’t worry much about occasional freezing weather. That is a little easier to do since you don’t have to go quite so far south in the winter months and there are many options for keeping cool in the summer.

[Cannuck]

Originally Posted by Oliver2017

What is your source for heat? Do you have a recommendation for an electric source to use to avoid a fuel based heat source?

We have the Alde hot water heating system which uses 800 or 1600 watts of 120 Vac electric heaters or propane. With the pathetic 20 lb tank (supposed to be 30 lb tank per Roadtrek specs), we still get 8 nights of heating off a propane top up. The Alde is unbelievably efficient and quiet.

Perhaps I’m biased but I don’t think you can realistically heat with battery power. We can and have run the heating boiler from shore power but we almost never get a site that had power or water.

[fratermus]

Folks following good weather wouldn't stay at 6000'+ when it's cold.

This past January I was running around in shorts in January.

[Davydd]

I run around in shorts in January as well. In fact the next day after camping in Gallup, NM in 0F weather I was running around in shorts in Arizona. However, I know something about lithium ion batteries having gone 62,000 miles in 3-1/2 years with them.

I mostly try to follow the 65 degree weather in our travels but being home based in Minnesota and not being able to predict the weather in our travels, or more accurately, not have weather dictate our plans once underway, you can’t avoid situations. Besides, I like the challenges such as Mike Wendland’s Winter Freezeout rally on Michigan’s Upper Peninsula in January with 3 feet of snow on the ground.