Question to Battery Gurus...

[TonyP]

It's more expensive but it also has potentially 5x the cycles of a standard AGM. Buy once, ry once. Plus all the other positives that come with a Lithium.

Where are you seeing reports of issues? I had no issues with my Battle Born battery. Though I was using a BCDC1225. But it wasn't required as the BBs are advertised as drop in replacements.

Goal Zero is insanely overprice for what you get.

 

[indycole]

I believe the diode "solution" is misdirected, and we're addressing a symptom of a larger issue that the diode actually exacerbates.

The root issue here is that AGM's are fundamentally not compatible with the vehicles charging system. To charge and maintain an AGM, requires a different charging "profile". The alternator voltage regulators onboard vehicles are tailored for flooded cell batts, period. Any other architecture of battery is going to be compromised.

This is not really about deep cycle/starting amps/capacity/charge level. It's also not about the low charge level you experience on a trip, and you need more charge, and bigger batts. This is because the batt has already been compromised and cannot effectively hold charge any longer.

Specifically, AGMs and other sealed batts, cannot handle the higher peak voltages from the alternator after initial startup. Flooded cells like this for a quick recovery. And they have much more abilities to handle extraneous voltage and current. Sealed batts, when exposed to this, can quickly overheat and boil. Add the hot underhood temps, with higher than AGM compatible peak voltages... They don't deal with this well as they can't really "out-gas" effectively, without permanent impacts like premature failure of internal cells.

Get yourself some solid normal flooded batts. They don't have to be super duper extra large group 31s either. There's nothing inherently crazy with running small fridges, winches, lights, electronics, etc. With some of these (e.g. winch), you'll want the engine running anyways. And you have a nice generator in the form of the engine to top off for longer stretches. My 2x normal group 27 flooded batts last at least 2 days for a full blown camper with all the house amenities. Lots of lights, water pumps, furnace, electronics. And these lasts many many years in this type of use.

Normal flooded cell batts for the win here because its the right type of battery for the application.

Now if you can isolate the AGM/Gel/Lithium batt cicuit, and have a BMS/solar charger, set to the right profile... that's the trick!

Exactly. I have an ongoing exchange with Redarc on this exact topic and there currently is no technology-based solution for this use case. You can either stick with a traditional starting battery or use an AGM and hit with a charger every so often.

 

[TeCKis300]

Where are you seeing reports of issues? I had no issues with my Battle Born battery. Though I was using a BCDC1225. But it wasn't required as the BBs are advertised as drop in replacements.

It's prob not a concern for our modern cars. But there were some reports of alternators not putting out enough voltage over time as they overheat trying to charge at higher the higher currents the BB is capable of accepting.

 

[mcgaskins]

I believe the diode "solution" is misdirected, and we're addressing a symptom of a larger issue that the diode actually exacerbates.

The root issue here is that AGM's are fundamentally not compatible with the vehicles charging system. To charge and maintain an AGM, requires a different charging "profile". The alternator voltage regulators onboard vehicles are tailored for flooded cell batts, period. Any other architecture of battery is going to be compromised.

This is not really about deep cycle/starting amps/capacity/charge level. It's also not about the low charge level you experience on a trip, and you need more charge, and bigger batts. This is because the batt has already been compromised and cannot effectively hold charge any longer.

Specifically, AGMs and other sealed batts, cannot handle the higher peak voltages from the alternator after initial startup. Flooded cells like this for a quick recovery. And they have much more abilities to handle extraneous voltage and current. Sealed batts, when exposed to this, can quickly overheat and boil. Add the hot underhood temps, with higher than AGM compatible peak voltages... They don't deal with this well as they can't really "out-gas" effectively, without permanent impacts like premature failure of internal cells.

Get yourself some solid normal flooded batts. They don't have to be super duper extra large group 31s either. There's nothing inherently crazy with running small fridges, winches, lights, electronics, etc. With some of these (e.g. winch), you'll want the engine running anyways. And you have a nice generator in the form of the engine to top off for longer stretches. My 2x normal group 27 flooded batts last at least 2 days for a full blown camper with all the house amenities. Lots of lights, water pumps, furnace, electronics. And these lasts many many years in this type of use.

Normal flooded cell batts for the win here because its the right type of battery for the application.

Now if you can isolate the AGM/Gel/Lithium batt cicuit, and have a BMS/solar charger, set to the right profile... that's the trick!

But...but..a flooded battery (or two) isn't expo enough! After running both flooded and sealed AGM in several trucks over several years, I tend to agree with you and @TonyP . A healthy flooded and/or isolated lithium would suit most needs, and the boring flooded batteries are super cheap to boot. I wonder if my AGM failure and Mark's were related to the constraints of the technology. I think we both got bad batteries, but there might be an element of the wrong tool for the task. I will continue to use the AGM specific conditioner / charger I have at least once a month to ensure it's getting what it needs periodically.

 

[TeCKis300]

Goal Zero is insanely overprice for what you get.

It's not when you consider they have integrated inverter, charger, solar charger, USB outlets.....

 

[TeCKis300]

But...but..a flooded battery (or two) isn't expo enough! After running both flooded and sealed AGM in several trucks over several years, I tend to agree with you and @TonyP . A healthy flooded and/or isolated lithium would suit most needs, and the boring flooded batteries are super cheap to boot. I wonder if my AGM failure and Mark's were related to the constraints of the technology. I think we both got bad batteries, but there might be an element of the wrong tool for the task. I will continue to use the AGM specific conditioner / charger I have at least once a month to ensure it's getting what it needs periodically.

"Not expo enough"... Love it.

As an engineer and an enthusiast, I'm often conflicted. So many desirable things, but when you look at it from a system perspective... The balance of considerations and compromises...

 

[TonyP]

It's prob not a concern for our modern cars. But there were some reports of alternators not putting out enough voltage over time as they overheat trying to charge at higher the higher currents the BB is capable of accepting.

Which overheating? The alternator or the battery? The BB battery has built in cut in charge and discharge if it overheats. Ideal bulk/absorption is 14.2v-14.6v. It also has overcurrent protection for out of range charge voltage.

Specs here
https://battlebornbatteries.com/wp-content/uploads/2018/03/Battle-Born-Manual.pdf

 

[TeCKis300]

I'm pretty familiar with the Battle Born products.

Alternator, specifically regulator. But again, prob not a concern for our platform.

What is a concern is for people that live or visit cold weather regions. There's real constraints with this technology in the cold. Which is why it's not an option for me.

Other than that, the BB LiFePO4 is really a game changer for weight/capacity. Just gotta wait for the prices to come down.

BTW, I work on multi-million dollar platforms for serious hardcore use. Guess what we use. Plain boring technology batts.

 

[Markuson]

Exactly. I have an ongoing exchange with Redarc on this exact topic and there currently is no technology-based solution for this use case. You can either stick with a traditional starting battery or use an AGM and hit with a charger every so often.

Can you expand on the redarc exchange? They market to just such solutions (or at least their proponents do), so I’m curious.

 

[TonyP]

Cool. I work on multimillion dollar missile systems. Know what they use? 3.5 inch floppy disks and 1990 era pcmcia cards. Doesn't mean it's the most efficient.

 

[TeCKis300]

The platform I work on is state of the art. Money is happily spent for better. But better doesn't currently have the right performance requirements, yet.

The enemy of good enough, is better.

 

[Markuson]

The platform I work on is state of the art. Money is happily spent for better. But better doesn't currently have the right performance requirements, yet.

The enemy of good enough, is better.

On the other hand... state of the art, 82” 4K flat screen TVs still come with crappy AAA batteries so light they almost float away...


(Ya I know... utterly meaningless comment. It’s just funny how companies will save 3 cents whenever they can...even if it means handing you crappy batteries).

 

[TeCKis300]

This is really all anyone needs for extended off-grid travel.

So expo:
https://www.amazon.com/Renogy-Monoc...35652153&sr=8-17&keywords=100w+portable+solar

 

[TonyP]

The enemy of good enough, is better.

Tell that to the military industrial complex.

 

[linuxgod]

+1 @TeCKis300, very good explanation.

The alternator is designed to charge at a lower voltage once the engine warms up to compensate for temperature as well as floating the battery vs bulk/absorption charging. The higher voltage helps with the bulk charge to make up for the starter motor drain, and the voltage drop works fine with floating. Great for a flooded battery, bad for an AGM which has different voltage parameters.

I've spent a lot of time dealing with and researching various batteries for my RV. Despite having 350W of solar available in Texas I still killed a 100Ah AGM overnight. Still not positive what happened but I believe the solar controller switched to float too soon and so the battery wasn't really fully charged, then running a couple fans (which used maybe 30-40Ah total) drew the battery too far down overnight. Or maybe a cell just went bad on me. Disappointing because I had been running off the battery for 2 weeks and it seemed to be getting a full recharge every day from the sun (constant 175-180W @ 10am, switching to float by early afternoon). Moral being, don't think just 'cause you have a solar panel it'll solve all your battery issues!

I looked around for a replacement battery and ended up just getting a $100 Duracell deep cycle flooded battery from Sams Club. 110Ah group 31, and if I kill it I'm only out $100. Since my RV battery sits outside I don't have to worry about ventilation and off-gassing, just checking the SG and topping it off as required. Next purchase will be a $65 automatic battery cut-off, so if I do drop below 12.1V it won't kill the battery again.

I looked at the LiFePO4 options but at $900+ it was hard to make the jump, even to effectively double my capacity and cut the weight in half. In part I balked because my charge controller isn't designed for Lithium, as if the Li battery gets discharged and shuts down, they require the ability for the controller to "surge" the power to the battery to trigger them to turn back on, otherwise they will look dead and never charge.

 

[TonyP]

Well you'd only need a 50ah Lithium ($575) to directly replace a 100aH AGM. Or another way to look at it, two 100aH AGM (at something like 160lbs) to equate a 100aH Lithium at 29lbs.

 

[Markuson]

One thing I have discovered is how massively important it is to make sure your terminals are CLEAN (like scraped to perfect lead surface) and that your terminal connectors are SUPER tight.

I know this is basic stuff, but more often than not, I’ve discovered that various shops have put them back on poorly...and before you know it...you think you have a battery problem that is really just a half-assed connection.

 

[linuxgod]

Well you'd only need a 50ah Lithium ($575) to directly replace a 100aH AGM. Or another way to look at it, two 100aH AGM (at something like 160lbs) to equate a 100aH Lithium at 29lbs.

Yeah I did that math too. A $900 lithium @ 28# was the equivalent of 2 AGMs @ 132# which are about $360. (Actually slightly off since you can drain a Li to 90% but only 50% for an AGM, but I couldn't find pricing on a 92Ah LiFePO4)

Pretty sure whatever happened to my AGM it gave me far under 50Ah the night it died even.

I opted for the $100 flooded Duracell primarily because I'm not quite sure how I killed my battery yet. If the solar charge controller isn't measuring correctly or my propane fridge igniter isn't shutting off (for instance) I'd rather kill a $100 battery right now than a $900 one. Once I'm confident in the setup again I may consider lithium... though again I'm committing to another $300 to replace the solar charge controller. Bah! Stupid incompatible technology.

 

[Markuson]

I’m waiting to hear back from IBS re their DC/DC add on...

 

[RET2]

One of the reasons and perhaps the over riding one for me is the AGM's ability to resist damage from vibration and the pounding we are susceptible to on the trails. Nothing quite like a broken plate or two to ruin a run.