Is a Voltage of 11.8 Dangerously Low for My AGM Battery?
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- เผยแพร่เมื่อ 21 ธ.ค. 2020
- Richard asks, "When I've discharged my AGM (L16) house batteries to anywhere near 50% SOC the voltage reads about 12.1VDC. If I were to take the bank down to 30% SOC, for example, wouldn't voltage drop dangerously low to 11.8 range? Or maybe (once or twice a season) 11.8 isn't so bad? What say you Jeff! "
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Good advice, I feel more confident about my solar setup now
Thank you for being correct with your recommendation. The DOD is important however the AGM battery data sheet shows the lowest voltage at .2c as 10.8v. At higher currents you can go lower preferably only being below 10.8 for seconds.
Awesome guy! Short and simple
Glad you liked it!
I'm glad I watched this ! I have 2 AGM deep cycle batteries and 1 lead on a gauge and always switch them over ar 12.3 volts ! Now I will use them until 11.8 volts ..Thanks I can do longer trolling 👌
Glad it helped
Thank you for this video. I bought an agm battery 12v 35Ah for my fish finder consuming 2Ah at 13.8v
I was worried about articles saying I'll lose cycles. I fish on a minimum of 9 - 12 hrs a day if I'm out on the water. I feel better now.
Good info thanks. Greetings from sunny Jamaica.
Thanks for watching!
What a beautiful explaination..
Glad our explanation resonated with you.
Great video, as usual, ty.
Glad you enjoyed it
awesome advice
Great sanity check video. Batteries are a consumable! :)
Thanks Hans.
That made me smile; "people who cut those corners, those people that drive us crazy"...most of humanity Jeff. Pleasant surprise when it's not the case, I take it as a given.
"I ran outtov red cable, so I used black for a third of the positve runs!"
Totally agree. Sometimes, I'm just shaking my head, what were they thinking?
A: they were "being clever"
B: they weren't...at the very least not about the legacy anyway.
Then comes the ironic dawning realisation that doing it right would have been easier and quicker too.
I often catch myself about to dofer and force myself to stop and wait for the appropriate materials to be sourced.
Hi Jeff
Thanks, this is a great video, not many guys explain it this well.
I have a question though.
I have deepcycle bateries 12v system
I can manually set the discharge voltage protection value.
What is the actual voltages on
20% discharge
30 % discharge
40% discharge
50% discharge
60% discharge
Want do you find to be a still safe % value for discharging gell bateries and still avoid damaging the battery
Thanks
Blessings to you
Jeff, thanks for the great video! Another good reason to bring you battery down to 50% or 60% is that when your alternator charges, it will charge at a load (higher amps) that is much closer to its capacity, so you will put more amp-hours back into the battery much quicker. I suppose some people will run their engine at anchor to get the battery from 90% to 100%, not realizing that their alternator is only going to put out something like 10 amps instead of 60 amps with an 80 amp alternator.
Capt Randy, bang on, as a battery get near to full, i.e. the absorption phase, the batteries ability to take a charge is diminished and battery charges slowly at the point.
Thank you for all you do Jeff. Your videos are awesome. I just donated. No to advertisements lol
Aloha from Hawaii.
Wow, thank you!
Aloha to you as well
I agree with you. The difference between 30% and 50% is while 50% might save you few $$ the 30% DOD will save your time as 30% will have bigger fast bulk charging window which is what you want if you don't wanna spend lot of time babysitting a 🔋☺️
I like the way you said it is OK to deep discharge deep cycle batteries. This does not damage or destroy the battery, although it does decrease service life. I also agree that what alternative? If you are running an engine or PV panels, small wind turbine, obviously you're already charging your batteries; if none is the case , the obvious choice is to run a genset, but at times that's inconvenient. Absolutely. Use your batteries. For some reason, the average boat owner seems to think a boat is a toy; NOT when it comes to bad crimps and undersized wire runs. On water a fire is a disaster, with a hull to hold heavy fumes like a bowl and you can't walk away. Also as little as 2 stray volts can be deadly in salt water under the right conditions. Be safe, do it to code and then some. Happy sailing. :)
Well said Ta04409. Thanks for sharing.
@@PacificYachtSystems My pleasure. "Alternative" energy is my hobby since the mid 70s; lived on an island with no utilities for a while. I'll say this: Recent technologies and methods have been wonderful in this area. Keep sailin'. Merry Christmas. :)
Jeff, Thanks for another great video! I have a question. It's time for new batteries. I currently have 1 bank in 2 separate locations of 12v Gel batteries. 4 in the engine compartment, and 3 that are in the bow area for the bow thruster & Windlass. All 7 batteries are connected together and serviced by a single inverter charger.
I would like to switch to 6V batteries. I have the space for large AH 6V (Something like a Rolls S6 L16) in the engine compartment, but space is limited in the forward compartment. (would need 6V's roughly the same size as a Group 31 12v battery) Can I mix battery sizing? I assume the batteries up front would be much less AH, or should I use the same sized batteries everywhere?
Hi Chris, if you batteries are at two ends of the boat, perhaps it's worth considering having two battery banks instead of one battery bank. This is hard, but try to have one battery bank in one place and one place only.
Does this apply to GEL batteries too? I discovered mine yesterday at 11.9 volts in my RV and got worried.
My agm battery was not running my chart plotter or. I checked the voltage. Reading 9.6 volts with volt ohm meter. Hooked up to agm charger. After 1 minute it says the battery is fully charged. I checked it, showing 11.1 volts. Got another agm charger showing the same thing. This battery usually strarts up my 9.9 outboard which usually charges the battery. My outboard was putting out 16.8 volts. Appreciate the help. Thanks
Hey Jeff. I have a question. Just replaced my BMW E60 battery in january (old one Banner Raging Bull 92Ah 750CCA WET - lasted 8 years). Got a Varta SIlver Dynamic G14 AGM 95Ah 850CCA), i've registered and coded to the car corectly. The issue is that after a month, while with multimeter on battery terminal, it shows 11.9v-12.1v before starting the car in the morning, then after starting the engine it goes from 14.5v to 15.3v while alternator charging it. I am doing 4 times/week, short journeys to work, so 30 miles every day for 4 days. The voltage each morning is the same 11.9v -12.1v. Is this normal? I am not receiving any errors in dash or with testers. Let me know if you have a clue. Thanks
I really don't understand much, but my toyota runx car battery discharges slowly with the load of an alarm system and parking sensors and folding mirrors for security, and starts with 11.80 volts. Though I have 2 batteries of 12 volts and 45 amps capacity. Does the capacity drop with voltage drop? Can these 2 batteries with these security loads start my car everytime or do I have to charge my batteries in the weekend?
I agree! They have an estimated amount of "cycles" so use them! If it fails, warranty gives you a new one.
Thanks for sharing.
I love your videos! They are helping me so much. Big THANK YOU.
You are so welcome!
I have two Yuasa sealed 12v 36Ah batteries. I put them away in low voltage state 2 years ago and now one is showing 7.4v and the other 8.4v. I put them on a basic charger over night (as the smart charger couldn't see them) and got one to 11.5v and then the smart charger saw it and started charging. A short time later, it said fully charged and stopped charging. The charger said 13.5v but my DVM said 11.5v and the battery has almost no ability to even turn over the motor it should be turning.
Have I trashed my nice expensive Yuasa batteries or can they be saved?
Thanks.
Hey Jeff! Thanks for all of your great videos! I have a question regarding depth of discharge. I have a bank of 5 G31 Firefly batteries. If I understand correctly, at full charge the voltage should be 12.7v which it seems to be. How do I determine what my depth of discharge is at any given time? The lowest they have been run down to is 11v which is when my inverter starts low voltage chirping. How low CAN they be run down to? Thank You!
Hi Don, you'll need a battery monitor installed on your bank, some suggestions are the Victron or Xantrex models.
I bough 12v 95ah AGM battery to my car but there was module issues and 3-4 times my battery went to about 9.5 volt, so fully discharged/ I tried to recharge them after 4 days of staying discharged but I was wondering if my battery is damaged you think? When I go inside my car after 72 hours, it only shows around 11.9volt 12.1volt when ignotion is on. I was expecting to see 12.6-12.8 volt at least
Hey, I have a 48v (12*4)AGM or Gel Battery , My battery, is fully charged at 53.7v,
I use it for about 13km in an ebike and it drop to 51.7v. How much D.O.D my battery use?
What is the lowest voltage you would go to using one battery I have 2 I use one is led acid sealed and the other is AGM I mainly use with my electric trolling motor , and charging cell phone and go pro ECT how low in volts should I go
Currently my 320AH AGM bank is 11.4v under 8A load and the datasheet says fully discharged is 10.8V. Its night and I can't run my generator right now...
If i have 2 12v 200ah batteries hooked in parallel, would i still find my battery at 11.8v in the morning or would that stop my issue?
The number one killer (and to make sick) is charging with amps. The cause of heat and sulphation. The trade off being time. Trickle is best BUT High voltage spikes with a tiny bit of baseline current and your battery may actually increase in capacity. The whole point of Bedini energizers - which easily run from solar. The trade off being when charging the charge battery must be completely disconnected from your system.
I have a xs d4800 battery in my car and it reads 12.3 volts with car off, is this battery bad?
Good stuff… related question, I’m running 300ah bank on a multi plus 3000 inverter… having a hard time deciding on settings, I can set a shut off at voltage but that’s under load… with the AC running I’m pulling 110 amps roughly so if I auto shit off at 11.8 I’m not really at 80% discharge
Once it disconnects at 11.8 the voltage goes back up to say 12.5
My question is what’s a good shut off voltage under load that would get me in 11.8-12 v range? It’s a very short run from battery bank to inverter with 4-0 wire
That's a tough question, normally we set the low voltage disconnect at 10.5 / 11 volts. If you set too high, all too often the inverter will kick out. Remember it's normal for a full battery to run a large inverter load and be hovering around 11 volts. Similarly a starter load from an engine will bring the voltage to 11 volts. Remember large loads means large voltage drop.
💯 used the power
Exactly.
Ok, I'm not a boater, but i have a general battery question related to battery voltage... I've seen a project on TH-cam, done with rechargeable batteries, specifically Milwaukee 18v drill batteries, whereby it powers lights in an enclosed trailer, and they say that if you go below a certain voltage, it can harm your batteries, or their lifespan or something I'm not sure which. These rechargeable batteries have a programmable cut-off circuit added to the build to cut power at something like .4v over their maximum usage level, which, if i understand correctly, means that a Milwaukee 18v rechargeable drill battery should be cut off at around something like 16.4 volts.
Ok, now that the background information is out of the way, is there such a thing as a "safe" cutoff voltage in any kind of 12v or similar store bought batteries? It doesn't matter if it's deep cycle or not, although i guess deep cycle (or other specific voltage rechargeable batteries) would be best for the specific purpose of being rechargeable, and I'm just wondering if, say i build something that requires a battery, be it a lawn tractor battery, fish finder battery, 12v battery, or what have you, if there's a reason to include an automatic power cut-off, based on minimum programmed voltage???
cool thanks
Hi Jeff I had this AGM in my car for about a year now, I checked the Voltage and it was reading 12.24 with no load so I charged it and in about a minute or less it went to 14.40v, does this mean that my AGM is shorted or bad?
A resting voltage of 12.24 VDC (i.e. no charge or discharge for about 1 day), is simply too low and probably means you have a weak battery. A resting voltage should be about 12.6 to 12.8. Charging your battery and bringing the voltage to 14.4 is just a surface voltage after charging.
My battery voltage (AGM) drops below 8 volts when cranking my car in the morning sometimes.
How do you know what percentage of capacity the current battery level are?
Good question, you have to install a battery monitor on the house batteries.
Thanks for the video I have a question about these 4 used 12v 78ah AGM batteries I just bought yesterday they seem to drop pretty quick from over 13 volts to about 12.5v when I disconnect my solar panels only running around a 115 watts is that normal how long is a person supposed to actually get on a battery before you get down that far at 100 or 200 watts of even 300 watts it's not much but dang I'm barely getting any time
A 300 amp-hour battery bank should give you about 15 amps of discharge over a 20 hour timeframe, if your load is smaller then the C20 rating of 15 amps, you'll get more useable amp-hours.
@@PacificYachtSystems yesterday and today they seem to be holding a little better the guy told me they were very good batteries but been sitting for a while in the enclosed environment he has a whole pallet of these batteries
How many volts do I set to turn off when the battery is 50% thanks💖
Need to check the manufacturers datasheet to work that out. I would say 12.1V or 12V is a good starting point. I go way below that to 11.5V under moderate load.
Agreed. People freak out taking an AGM below 50%. Silly. Use it. Accept it.
Do agm batteries take a charge slower as they age? Do they build resistance as they age?
Yep, AGM like other lead acid batteries are harder to charge as the batteries get older.
@@PacificYachtSystems Thank you
I run a 3amp fridge..
I ran the 2 × 100 amp GEL in parallel down to 11.4..
Would this definitely damage the batteries..
With no solar I am getting around 1,1/2 to maybe 2 days run time down to 12v with no sun...
The deeper you discharge a battery, the less battery life you'll get. Suggest you stop discharging the battery around 12 volts and not let it do down to 11.4 volts.
It's okay to bring it down to very low once a while. Like times when sun is not doing it's job. But to do it very often means you are reducing the lifespan of the battery. Alternative would be adding battery and possibly adding solar panel. Weighting on alternative, you look at the cost of getting 2 replacement batteries vs getting another battery (and solar panel) which one is more cost effective. If the math makes more sense to just use the batteries at 11.4v then continue doing it. Like what Jeff said, it is a matter of choice and knowing what you are doing. Thanks Jeff, this is the kind of advice that make sense.
i like what has being told here ! Let's use our batteries damned !!! :)
What if you bought a new battery and it's at 11.8 because you didn't charge it until a year after you bought it?
Low voltages sometimes do happen, for various reasons, including not being charged.
Hi Jeff.
I bought my 100AH battery (connected to solar charger and panels of course) 2 months ago.
I only discharge it to 50% but now when im connecting my 2 small (5Wx2) fans and 20W bigger one in the evening the voltage under load is showing 12.2V !! (Rested volt.: 12.8V)
When I tried to connect my PC (13A) my inverter just switched off showing not enough of voltage.
What happened ? How can i fix it ?
Sounds like your battery has gone bad if a 3 amp load is dropping it from 12.8v to 12.2v. I would plug it onto an AC charger for 24h and try again. Is it an AGM or flooded battery?
@@PacificYachtSystems Its AGM. Its connected to my solar charger all the time. It always has. And when not used it was trickle charged. I tried my 50W fan yesterday. Run it for 2 hours and after 2 hours it showed 12.1V underload. WHen i turned it off however it showed 12.6V....weird stuff.
This is a confusing subject for us non-electricians. Based on what you are saying in the video can I assume that occasionally bringing down your battery voltage to around 11,8 V will not drastically shorten your batteries lifespan or damage the batteries. Thanks in advance for your help.
Yep, exactly.
If an AGM battery is kept fully charged on shore power, and never cycled, is it like new?
Yes, as long as the charger is set to the correct voltage setting recommended by the battery manfucturer.
In terms of a off-grid solar setup, what would be best, AGM or efb?
What's an efb?
@@PacificYachtSystems it appears to be the replacement for AGM, but I'm not sure what the difference is and which is better for solar storage
@@PacificYachtSystems stands for enhanced flooded battery. Not quite as many ccas as a AGM.
Go lithium you can get lithium lipo4 cells for same price as AGM and those can be discharged to 100% so for the same AH you get more since for AGMs its not recommended to fully discharge as they suffer cycle loss. Also lithium handles temperature drop much better than lead acid.
I got 10.8 on my gel battery from china in my ev motorcycle with no problem. (The battery indicator shown red and almost empty but I can go home safely)
Yeah, it's about battery life. A year in, I consistently find my battery at 11.8v in the morning. Not expecting to get more than 2 years of life out of it, but I'm okay with that.. price of running a fridge and ventilation off a 12v battery.
Thanks for sharing.
If you go to 30%, I think it might be a bad idea to leave it there for long periods of time. Isn’t it true that if you go down that low you should get it charged back up at least above 50% in a reasonable amount of time?
What if my AGM is completely discharged? Is it a goner?
Once you bring an AGM battery to complete empty, you've certainly taken away some of the capacity, like a 1-2 percent. What makes the damage worst is how long you leave the battery in a complete discharge state. For instance, leaving an AGM or even a flooded lead acid battery completely empty for a month or two would be a disaster and probably a major drop in battery capacity.
AGM are good batteries but they have a major drawback, they can be very difficult to recharge when dead.
Yep, dead batteries are rarely the same capacity after a recovery charge.
So the damage that they are saying when an AGM battery is discharged more than 50% is just it lowers the recharge cycles?
Correct, with batteries, it's a trade-off how deeply you discharge a battery affects the number of battery cycles you get.
@@PacificYachtSystems Sorry for the follow up question. But can you still top up the battery and holds its charge?
Don't worry about reducing your cycles. Just use a cheap pulse repair battery charger every month, and it will recover it's state of health almost back to normal
I have an AGM battery in my brand new Honda Odyssey and it is at 14.1V when the vehicle is on. Immediately after shutting off it goes to 12.3V and my radio lasts 10 to 15 minutes. Honda stealership says that's normal sir. I call @*#*(@*@*it!!!!!!!!!!!!!!!!!!!!!!!
Don't do any of these, just turn the battery upside down. Because the electrolyte settles down due to usage thumps and gravity. 🤘.
Really, thanks for sharing.