Battery novice needs help

[BryanToyFWC]

I’ve been reading everything on this forum regarding batteries. You all sound beyond knowledgeable.

I’m not an electrician, so you all are making my head spin. Im handy in a way that I can take stuff apart and figure out mostly anything, but electrical stuff has never sunk in.

I recently scored a 2017 Hawk, side dinette, solar, Zamp controller, 2xAGM 12V batteries (group 24), big fridge (non propane). Well cared for rig, super sweet. I have not changed or updated any of the components of the Hawk, so think everything is original.

It’s riding on a 2021 Tundra Limited with Firestone airbags.

I think my batteries need replacing. When we wake up in the morning, the fridge compressor is cycling through the low voltage protection, zamp controller is reading 10V. When the sun comes up the controller reading climbs, fridge cycles less, and in full sun we are back to 13v plus. Run the water pump and lights flicker a little during this time. My impression is that the 4-5 year old batteries are done.

With that said, I can’t decide between AGM and Lithium. AGM would be an easy swap. Lithium is intriguing for longevity and weight. With Lithium I have absolutely no idea if I need to update more of the electrical components (Iota 30/IQ4, Battery Link ACR, etc). I have no idea if I need new components.

What I really need is for a non technical summary of going Lithium and what if any I need to add and/or replace.

Help!

 

[rando]

Your first step should be to install a battery monitor like the Victron BMV-712 or Victron Smart Shunt so you can see what is actually going on with your batteries. It sounds like the batteries aren't doing well, but it also may be that they just aren't getting enough charge. Depending on your usage, and the size of the solar panel, you may not be harvesting enough solar power to charge the batteries enough to get through the night. You can get some idea about this by leaving the camper plugged into shore power overnight (which will fully charge the batteries), and then seeing how long the battery lasts with your normal loads.

Once you have figured out what the real problem is, you can decide on replacing the batteries.

 

[Vic Harder]

+1 on what rando said. Get a shunt based monitor as he suggested so you can get a good reading on what is going on. Voltage readings are almost useless.

 

[ckent323]

+2 with what Rando suggested

You did not say how much capacity your group 24 battery has.

I think that group 24 batteries have a capacity ranging from about 70 - 85 Amp hours. (Edit: per battery)

Conservatively that gives you about 35 to 45 useable amp hours (maybe a bit more). (Edit: per battery so 70 to 90 Ah total)

Some things to consider:

You said you have a large refrigerator non - propane so I assume it is AC/DC compressor refrigerator. You said it is a large refrigerator some of the larger models can pull upwards of 3 amps/hr on average depending on the outside temperature. For exmple here is the info for the the Isotherm 130

• Current Draw:
  Compressor Running: 4.7 - 5.0 Amp @ 12 Volt DC (half at 24 Volt DC)
• Average: 1.2 Amp @ 12 Volt DC (measured at 43°F in refrigerator, 72°F ambient temperature)

I have seen average numbers for Dometic refrigerators in the 2+ amp range. If you are using the refrigerator in temperatures higher than 72 degrees it will probably draw more current on average.

Also if you are using the ceiling fan or heater or other powered items that will also up your power consumption.

Conservatively assuming your solar system produces neglegble power from 5 PM to 8 AM and your refrigerator will comsume 2 amps an hour on average then 15 hours * 2 amps/hour your battery must provide around 30 Amps overnight. Edit: That would leave enough capacity to power the system for one subsequent night unless the weather or shade prevents the solar system from recharging your battery during the subsequent daytime.

I did not see the size of your solar panel in your post but it will need to be big enough to produce at least 30 amps during the day. How much power your panel will produce depends on a number of things but first order is full sun and no shade or clouds. If you have clouds or shade your panel will produce less power.

But as rando and Vic have commented you need to measure your power consiumption and then determine how much power your solar system is producing.

I hope this is helpful (as well as correct - sometimes I make mistakes in in my posts).

Edit: I checked the FWC website for the largest refrigerator. I noted the following information:

From the FWC website:

"The Isotherm 130 Liter Refrigerator/Freezer is a compressor style refrigerator unit that runs on either 12 volt battery power or 120 volt shore power electricity. This refrigerator does NOT run on propane.

The benefits to a compressor refrigerator like this, is that is does not need to be level to work properly, once you turn it on, it works, and it usually will cool more efficiently in hot weather. But you will need a dual battery system and a roof mounted solar panel to keep up with the power it uses.

Without dual batteries and a good solar system, this style of refrigerator will drain your camper battery down in about 1 day."

(so with your two battery system you should be able to go two nights without a full recharge but if you do not get much charging during the day, due to clouds or shade, your battery bank may only last 24 to 36 hours).

Regards,

Craig

 

[CougarCouple]

Hello BryanToyFWC
Yes listen to those above. I also read a lot here and elsewhere. Keep educating yourself on what it would take to go Lithium. We got our ATC with 2 AGM’s in 2017 and they just started failing. There can be a lot to going lithium and I’m glad I had the time to get the knowledge.
My guess is it’s about 3x more to go lithium vs the replacement AGM. Hope this helps.

Congratulations on your Hawk [emoji16]

Russ

 

[JHanson]

Lithium technology has awesome potential, but it is far from a plug-and-play proposition at this point. Please read this for some background information.

 

[Jon R]

The rough cost for my lithium battery and solar power system:
200 Ah battery $1250 ahipped
Victron Orion Smart 12/12-30 isolated dc to dc charger $265
Victron Smart MPPT 100/30 solar charger $220
Victron Battery monitor BMV-712 $210
Blue Seas bus bars and fuse block $120
6awg wire, lugs, wiring incidentals $150
Renogy 200watt solar panels (two) $600

Never worrying about having enough electrical energy: priceless

If I was doing it again I’d probably do a single 320 watt panel instead.

 

[Wandering Sagebrush]

Lithium technology has awesome potential, but it is far from a plug-and-play proposition at this point. Please read this for some background information.

Jon, interesting. Please do continue to keep us updated on your experience. I’m a bit of a retro-grouch, so it will be good to learn a little more.

 

[BryanToyFWC]

Your first step should be to install a battery monitor like the Victron BMV-712 or Victron Smart Shunt so you can see what is actually going on with your batteries. It sounds like the batteries aren't doing well, but it also may be that they just aren't getting enough charge. Depending on your usage, and the size of the solar panel, you may not be harvesting enough solar power to charge the batteries enough to get through the night. You can get some idea about this by leaving the camper plugged into shore power overnight (which will fully charge the batteries), and then seeing how long the battery lasts with your normal loads.

Once you have figured out what the real problem is, you can decide on replacing the batteries.

Thank you very much for the thoughtful response! I'm very much a novice on this.

I would assume that after driving for several hours plugged into the truck, or directly leaving shore power to go off camping would also mean that I'm starting the night with a full charge. Just my naive assumption. Last weekend we went straight from shore power/home to camping, fridge was low volt protection cycling by early morning (also a 3am propane false alarm, but a different problem I'm reading about here). By afternoon in full CO sun the voltage reading (understand now this isn't the best way to evaluate batteries, thanks Vic) was 13.5 and everything was running as normal. Nothing but the fridge running all night (Isotherm 130L compressor).

Batteries are 75 Ah each. Not sure the size of the solar panel, that wasn't in my paperwork!

I will look into a battery monitor. Something to learn about and install, hopefully without breaking stuff.

 

[BryanToyFWC]

Hello BryanToyFWC
Yes listen to those above. I also read a lot here and elsewhere. Keep educating yourself on what it would take to go Lithium. We got our ATC with 2 AGM’s in 2017 and they just started failing. There can be a lot to going lithium and I’m glad I had the time to get the knowledge.
My guess is it’s about 3x more to go lithium vs the replacement AGM. Hope this helps.

Congratulations on your Hawk [emoji16]

Russ

Thanks Russ, the Hawk is so fun! Lithium definitely sounds like a big investment/change.

 

[BryanToyFWC]

The rough cost for my lithium battery and solar power system:
200 Ah battery $1250 ahipped
Victron Orion Smart 12/12-30 isolated dc to dc charger $265
Victron Smart MPPT 100/30 solar charger $220
Victron Battery monitor BMV-712 $210
Blue Seas bus bars and fuse block $120
6awg wire, lugs, wiring incidentals $150
Renogy 200watt solar panels (two) $600

Never worrying about having enough electrical energy: priceless

If I was doing it again I’d probably do a single 320 watt panel instead.

Wowza! I may go AGM while I learn more and save my pennies for this change later down the road.

 

[rando]

Jon has a very nice system! If you do decide you need a new battery, you can get started with lithium for a lot less. But figure out what is going on first, and see if you have a problem before you throw money at it.

 

[Wallowa]

Lithium technology has awesome potential, but it is far from a plug-and-play proposition at this point. Please read this for some background information.

Thanks for the link, I get Overland Journal but missed that info, what really caught my eye was all the Bluetooth data that each battery monitors and transmits...excellent; beats my Victron 712 monitor...might mention that BB currently does have a built in heating element for cold weather use...wish BB also had the built-in Bluetooth monitoring that the Anti-Gravity has...I also have carried the small Li Antigravity on my motorcycles for several years..

 

[Beach]

If you want to keep it simple and minimize cost, stay with AGM batteries, but be sure to get true deep cycle type, DO NOT get dual purpose type, like Optima etc. 2 new healthy 24 series batteries might cure your ills, but if you need more capacity, consider moving up to a 27 or 31 series battery, unless weight is an issue. Good advice given in above posts, you absolutely need enough panel output to recharge fully during the day. Last year I replaced my Optima with a Renogy 100ah AGM deep cycle last year, it is a big improvement.

 

[goinoregon]

myself, i would go lithium. if u stay with agm, i would purchase from local FWC dealer, and have them evaluate your setup, and see what they recommend. they could install a controller, shunt , etc., for not too much $.
u can then spend your time and effort on operating and monitoring system, vs trying to determine each and every component. i have a victron solar controller, and it is nice to just connect via bluetooth with your phone, and see what is going on with both solar and battery.
go

 

[BryanToyFWC]

myself, i would go lithium. if u stay with agm, i would purchase from local FWC dealer, and have them evaluate your setup, and see what they recommend. they could install a controller, shunt , etc., for not too much $.
u can then spend your time and effort on operating and monitoring system, vs trying to determine each and every component. i have a victron solar controller, and it is nice to just connect via bluetooth with your phone, and see what is going on with both solar and battery.
go

Thanks!!! Would love to do that, except my local FWC dealer has been totally unresponsive to requests to do just that. I’ve reached out on at least three occasions and heard crickets. It’s sort of crazy really, but they must have enough business. So I’m on my own to figure it out.

 

[Jon R]

Bryan,

Do you know what your usage of the camper is going to be in terms of overall trip duration, how much driving typically each day, and typical weather and shade conditions relevant to solar charging? It may be that a less expensive approach could be identified based on your usage, with the ability to expand your system later.

For example, if you only did weekend trips of 3 days or less, you could use a 100 to 200 ah lithium battery and just charge it at home before each trip. Or maybe only do a dc to dc charger and do solar later.

 

[BryanToyFWC]

Bryan,

Do you know what your usage of the camper is going to be in terms of overall trip duration, how much driving typically each day, and typical weather and shade conditions relevant to solar charging? It may be that a less expensive approach could be identified based on your usage, with the ability to expand your system later.

For example, if you only did weekend trips of 3 days or less, you could use a 100 to 200 ah lithium battery and just charge it at home before each trip. Or maybe only do a dc to dc charger and do solar later.

Thanks Jon, just getting back to this forum.

We use the camper for both 1 night quick camps to 6-8 night mostly off grid adventures. We have an additional portable solar panel that we haven't used yet but will be bringing that with on the next longer trip. We do a lot in sunny CO and UT, but want to extend out further west where we know there are more clouds (or smoke clouds).

Seeing as though my fully charged batteries won't last even one night, I know I need new ones. Went to order similar AGMs for simplicity, I found most of the good ones in the right size sold out....go figure inventory issues. Lithium batteries are all in stock, ugh...back to square zero.

 

[Wallowa]

Bryan,

Yes, we are also smoked in up here in NE Oregon, surrounded by fires and smoke coming from 800+ miles away....going to be a long Summer!

Lots of information on Li vs AGMs...I went to Li after my FWC AGMs faded into the sunset....in the Winter on a ski trip....not much heat without electricity and in below zero...OK why did I go Li..

#1 They have at least 3-4X the life expectance of AGM...
#2 Putting pencil to paper and the cost of Li becomes less than AGM over the years..
#3 You can draw down, get usable Watts, out of them to zero and then recharge them without damage...50% draw down for AGM and below that you cut into the lifetime of the AGM.
#4 You can recharge Li batteries faster than AGM...they will handle more incoming amps.
#5 Lastly for me the most important, the dependability along with longevity sealed the deal...as they say, the BB will probably outlast me..

I went the full Monty: 160 & 170w Zamp panels, Victron MPPT 100/30, Victron IP67 25 amp 100v charger, Victron BMV-712 w/battery temp sensor, Victron Orion DC/DC 30 amp charger [4 awg] and a 100ah, heated, Battle Born.

No more worries about running out of juice on the White Rim or anywhere in BFE; just the way I went and of course I could be wrong!

Honestly, transitioning from carrying my gear on my back or in my sea kayak to the Hawk....well, do you really need electricity? Yes, but only to start the Tundra...


Good luck,
Phil

 

[BryanToyFWC]

Bryan,

Yes, we are also smoked in up here in NE Oregon, surrounded by fires and smoke coming from 800+ miles away....going to be a long Summer!

Lots of information on Li vs AGMs...I went to Li after my FWC AGMs faded into the sunset....in the Winter on a ski trip....not much heat without electricity and in below zero...OK why did I go Li..

#1 They have at least 3-4X the life expectance of AGM...
#2 Putting pencil to paper and the cost of Li becomes less than AGM over the years..
#3 You can draw down, get usable Watts, out of them to zero and then recharge them without damage...50% draw down for AGM and below that you cut into the lifetime of the AGM.
#4 You can recharge Li batteries faster than AGM...they will handle more incoming amps.
#5 Lastly for me the most important, the dependability along with longevity sealed the deal...as they say, the BB will probably outlast me..

I went the full Monty: 160 & 170w Zamp panels, Victron MPPT 100/30, Victron IP67 25 amp 100v charger, Victron BMV-712 w/battery temp sensor, Victron Orion DC/DC 30 amp charger [4 awg] and a 100ah, heated, Battle Born.

No more worries about running out of juice on the White Rim or anywhere in BFE; just the way I went and of course I could be wrong!

Honestly, transitioning from carrying my gear on my back or in my sea kayak to the Hawk....well, do you really need electricity? Yes, but only to start the Tundra...


Good luck,
Phil

Thanks Phil (and everyone else),

Reviewing my setup and comparing to the Li setups above, it seems that the only piece I'm universally missing for the Li setup is the DC-DC charger. I really have no technical understanding of what this does, something about the truck battery/alternator/FWC batteries. I have a brand new truck (2021 Tundra), so would hate to break something important (alternator/battery). Can someone give me the dummy version for why this is in the Li setups?

May not be a perfect solution to start with Li, but the IOTA battery charger can add the LiFEPO charge controller for $18, my Zamp solar controller (while not MPPT) does say it works with LIFEPO. So the missing piece is DC/DC and I have no idea where this would even be installed let alone what it does. Am I thinking about this correctly? Add the DC/DC and the IOTA LIFEPO controller, slam in a new 100ah LI battery and all is well? Or will I burn down my rig or truck?