Time for new house batteries

[Neal]

When you know you know...as I was wondering when the time would be to do this. Over 5 years with these flooded lead acid batteries. While I have 1800W solar, I rarely use it and my boondocking at the EAA AirVenture airshow worked great last July. Last night at my Harvest Hosts I had a significant SOC drop, woke up to 64%. I didn't see where I was at gen stop / bed time 10 PM last night. I did leave my PC running which does have a 850W power supply in it but that shouldn't have caused this much drop, I don't think. It is time for water to be added, been meaning to service the batteries, but it's time. Winter project will be battery replacement, had Freightliner Custom Chassis do the chassis batteries last years' visit just to be safe. I'll probably go with AGM's and nag @Chuggs again, it's been a while. Not sure I'm ready for Lithium's but will review and see how @Richpatty's are working out. As I'm on shore power 99% of my RV time the house batteries haven't been needed much but that may change as I'm planning on longer trips starting next year to dabble into near fulltiming mode and when out west hitting more BLM lands, doing Quartzsite again, etc. and putting the solar to good use.

 

[TheLooks]

If that is your plan, go with Lithium. No comparison at all, if you intend to use them.

 

[Neal]

Which ones? I'll be looking for Black Friday sales as I think that's how @Richpatty captured them. My only concern is the down line items affected such as the BIM? I don't want to be fighting the system but if people have it figured out I'd entertain it.

 

[Neal]

Looking at my Victron VRM data it appears I had a constant 31A draw. I have to think where that draw is coming from. Refer is on, Dometic cooler in basement, and computer. Home theater stuff was powered off as I know that's always a big drain. No heating/cooling was on, windows were open.

 

[TheLooks]

I am not familiar with your coach systems as far as battery maintenance. In the solar class here at the NRVTA we used the batteries being built by the Head Tech at the school Tod Henson. His are almost 300 Amp hour batteries but are pricey. The plus to his are they can be taken apart and fixed if there is a bad cell. I was not sold on lithium until I saw the numbers they produce and the anticipated lifetime of them. As I said, it it worth it if you are going to use them. None of the Lithium's are cheap, and they require a different charger. The batteries have their own management system built into them. In the fiver we did the install in, the lead acid batteries stayed in place and we ran the Victron system into the ATS, like a generator install.
Tod's batteries are about $1700 each, they fit in the footprint of a 27 series battery, They are a bit taller then a 27. Again, serviceable and powerful.
The install we participated in had almost 3000W on the roof and 8 of Tod's batteries. They can run everything in that monstrous Solitude.

 

[MemoriesByTheMile]

Which ones? I'll be looking for Black Friday sales as I think that's how @Richpatty captured them. My only concern is the down line items affected such as the BIM? I don't want to be fighting the system but if people have it figured out I'd entertain it.

When we bought our coach, it already had lithium installed by the prior owner.
They had to install a different battery charger to output the slightly higher voltage for the lithium charging.
After we purchased the Coach I changed out the BIM as it wasn’t functioning properly with the lithium. That was a pretty simple swap and now the engine charges the batteries while going down the road.

 

[Richpatty]

Hi Neal.

I do like the lithiums even though I have not been able to really test them out as we just don’t get out as much as we would like. I have “tested” them while parked in full hookups and I really like the way they perform. I would still do it again…even if you don’t boondock that often. Here are my thoughts:

• I really like that they take a charge so quickly, especially with the solar. This is also helpful when charging from generator as it cuts down the generator run time to get charged back up.
• No more corrosion! I know AGMs probably won’t either, but I like the idea of no water in my batteries to think about.
• Yea, they are pricey, but they should last a very long time. If you figure the lifetime and usable capacity vs AGM, they are competitive.
• Less weight! I replaced my 8 LA with 8 lithiums and cut the weight in half while doubling the usable capacity.
• And if you really want to go apples-to-apples with capacity, you really only have to get 400ah of lithium to replace you LA batteries.
• I have found that I no longer have to leave the magnum charger on at home…as the lithiums do not discharge very much at all, even with the slight vampire draw. I do put the chassis batteries on trickle charge after a few weeks, but that is a very low draw. I have even thought of using a separate small inverter from the lithiums to run the trickle charger…. This way the RV would not have to be plugged in but everything would be charged. Have not tried that yet.
• They work real well when running the one AC unit from the inverter and I don’t have to worry about voltage sag.
• I found the cabling to be much simpler….since the lithiums are 12v. It really simplified it all in my mind.
• If you do bookdock, your solar paired with the lithiums is a really sweet setup. Especially if you want to start going to Harvest Hosts or Bookndockers Welcome spots…
• Lastly, I think they are really cool….

I would change your BIM to head off potential issues with the alternator. Not hard to do.

And yes, I did get mine in CyberMonday for only $709 a piece. Hopefully they repeat that again this year.

Of course this is all from my point of view and I am sure that others will differing opinions.

Hope this helps.
Rich

 

[Richpatty]

FYI….Here was my thread on my lithium install….

Move to Lithium

So as I get ready for my Lithium project, I began to think about the best way to wire them. I will have 8 100ah GC2 sized battleborns. I know many of you use the wiring method on the left (see below). I have seen articles that say the diagram on the right pulls power from the batteries...

rvforums.com

 

[Neal]

Thanks @Richpatty - which model battery did you get? I haven't looked at the above thread yet, just settled into a new CG.

As to my discharge last night and the "when you know you know" is now an "I'm not sure I know." If my amp draw is in fact 31A continuous then the SOC this morning was expected. It's not a battery issue, it's a draw issue, and I have to figure out what's calling for the 31A's and I think it's the computer setup (2 computers, switches, NAS, monitor) etc. I turn all this off when boondocking but didn't this time. I did not have issues at the airshow in July. But the time is coming near and I'll watch the sales. I'd rather go smaller first, i.e. try the 400aH and then add if needed. I'd hate to waste money just throwing batteries in when they may not be needed. Then again as my mirror shows I'm a man of excess, so then there's that!

Which BIM did you use by the way? Again, I need to read your thread if all that's documented.

 

[Richpatty]

Hi Neal,

I bought the GC2 drop in replacement…

100Ah 12V GC2 LiFePO4 Deep Cycle Battery

This 100Ah 12V GC2 LiFePO4 Deep Cycle Battery by Battle Born Batteries delivers superior and long-lasting performance, with long-term lithium battery use.

battlebornbatteries.com

And I purchased/installed the Precision circuit Li-BIM.

Amazon.com

Rich

 

[JRW-NAW]

These folks (from Nappanee) were at Rock Springs this year:

Solar Energy Systems - Solar Installers - Nappanee, IN

Solar Energy Systems is a leading solar installation company in Nappanee, Indiana, providing solar energy solutions for residential, commercial, farm, and RV's.

sesindiana.com

I looked seriously at the 120Ah Elevation LIFEPO4 they sell until I got distracted by bright, shiney new coachs...

Safe Travels.

 

[Dona40]

Look at it this way. A LIPo battery lasts 3-4 times as long, is half the weight and twice the usable rated capacity. IMO, they are worth the cost.

 

[Neal]

You're not helping!!!! My poor credit card!

 

[Dona40]

You're not helping!!!! My poor credit card!

Just think of you credit card a couple years "down the road"

 

[Neal]

When you don't know....test!!!

Last night I performed a test of my house batteries which are now going on 5 1/2 years old. I use the flow-rite watering system to keep batteries topped off and perform this quarterly. I also perform an equalization at least twice a year. As per this thread I did a Harvest Host recently and had a surprising drop in state of charge (SOC) which is a battery percentage remaining instead of a voltage reading available by upgrading to a Magnum ME-ARC50 control head and installing a Magnum ME-BMK (battery monitoring kit) which is a shunt that measures electrical flow.

To perform the test I decided to use the feature of the ME-ARC50 that allows me to tell the inverter when it should use shore power (pedestal). This feature is commonly used when you have to pay for electricity and you want to maximize your solar setup (or generator) to avoid electricity fees. You can use different methods such as a time window or by battery state of charge (SOC). I elected to use the AC IN SOC option telling the system not to connect to shore power until my SOC goes down to 65%. It would then charge up to the high end value of that setting which is 100% and then disconnect again and run on house batteries.

Figure 1. Evening check after PC and other loads turned off​

I started the test with everything running as usual. My PC was finishing up some work so I couldn't shut it down for a period of time which was a little bit of a bummer as I was seeing AMP draw on my BMV-712 upwards of 50 amps! I checked my PC power settings and it's on high performance so it's going to not be power friendly. I also have a power hungry video card in this PC (Nvidia 3080 Ti) and of course a 27 inch monitor. I was finally able to shutdown the PC and monitor and start turning off items to see what the loads were. I turned off my computer components under the dinette, the Dometic CF-80 cooler in the basement, night light on the Microwave, and that was about it. Loads came down to around 12-13A draw via the BMV-712 which was nice. If I wanted to go even further I would disconnect the Amazon Echo (Alexa) devices. My concern was the amount of power the PoE switch was pulling so I unplugged it, it was 1A so I reconnected it. If I really needed to conserve I could turn the Inverter off but I never do that, I want the refrigerator always on and never power cycling as I believe that's when things go wrong.

It seemed warm enough as I had windows open here in TN but was concerned about needing to run the furnace as it is a power draw. I did turn the OASIS burner on prior to going to bed so it would be available if I needed to turn the furnace on via my phone using the Micro-air smart thermostat via Wi-Fi or Bluetooth.

I watched TV for a bit prior to going to bed. the 32 inch TV and Apple TV connected drew 4 amps. At 1 AM I woke up due to it being cold and turned on the furnace, was happy to see the SOC was only down to 93%. The furnace with both zone 1 and 2 running I believe was pulling 12 amps. Front blower remains on high which doesn't help.

I woke up at 6:30 and checked the BMV-712 on my phone and it showed 84% (12.14V) which was great.

Figure 2. Morning check of battery SOC​

Conclusion: Batteries are perfectly fine and amazingly healthy. I attribute this to remaining on charge and in float while in storage, the battery watering system, and performing equalizations.

 

[Neal]

I forgot I also had VRM data available. Click for full screen if desired.

 

[Rich W.]

This brings up a lot of questions but for starters, why do you have both the 712 (I have a 700 and shunt on the shelf) and the ME-BMK. Don’t they do the same thing?

 

[Neal]

I removed the ME-BMK shunt and installed the one with the BMV-712 and piggy backed the wires for the ME-BMK on it.

 

[Rich W.]

So did you mount the 712 in the same cabinet with all the other power stuff? Got a pic of it?

Also since your LA batteries are still healthy (veering back on topic) are you going to just stick with them until they get weak? I’m guessing your coach is all electric with 8 batteries and a 2800w inverter?

 

[Neal]

So did you mount the 712 in the same cabinet with all the other power stuff? Got a pic of it?

The shunt is in the back of the battery bay, the BMV-712 display is in the pass through bay wired to the solar equipment with its wires going through the wall with other wires.