I'm using a Optima D34M bluetop deep cycle battery in my solar generator and it has a reserve capacity of 120 mins. I've read that you should only deplete a deep cycle battery down to 80% but I've seen videos where people talked about going do to 50%. That will give me more than 120 mins but how quickly will it ruin my battery?
battery depletion
- Thread starter Greentea
- Start date
It depends.
How quickly will it COMPLETELY be recharged?
How are you determining 80% vs. 50%?
How quickly will it COMPLETELY be recharged?
How are you determining 80% vs. 50%?
In terms of how I'm determining 80% vs 50% I have been using a volt meter that i have attached and I try and not let it get below 10 volts. Is that a good to measure?
as for how quickly I have the battery recharge, its set up on a trickle charger right now but I have 4- 100 watt panels set up to charge if the power goes out.
as for how quickly I have the battery recharge, its set up on a trickle charger right now but I have 4- 100 watt panels set up to charge if the power goes out.
mikefitz
Solar Wizard
- Joined
- May 28, 2020
- Messages
- 2,979
Voltage is not an accurate measure of battery capacity, for a rested battery under no load or charge it gives some idea. You should try to stay in the green region.
From this you can see that at 10v rested, the battery is completely flat.
As for charging this are the recommended values ,
When the battery is loaded the terminal voltage will fall, the bigger the load the greater the voltage drop, for your battery the C value is 55. For example if you had a 5.5 amp load, C/10, at 50% capacity the voltage would be 12 volts. These charts and graphs are approximate and will vary with different types of LA batteries.
Mike
From this you can see that at 10v rested, the battery is completely flat.
As for charging this are the recommended values ,
When the battery is loaded the terminal voltage will fall, the bigger the load the greater the voltage drop, for your battery the C value is 55. For example if you had a 5.5 amp load, C/10, at 50% capacity the voltage would be 12 volts. These charts and graphs are approximate and will vary with different types of LA batteries.
Mike
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,681
Battery charge voltage should be temperature compensated, or else charged while kept at the nominal temperature matching charger voltage settings.
I haven't used Optima blue top.
I have a red top 6V on a vintage car, which has fared pretty well.
I have yellow top series 34/78 in my truck, seems to crank weakly now that it is over 9 years old.
Same series in Sable faded early.
Smaller yellow top in Civic, went through 3 batteries in a row, average of 20 months each.
There is talk of optima forgetting quality with change of ownership and move to low-cost region.
But maybe, different charging and standby drain in various applications is a key factor.
10V is awfully low except for high current draw. What is your intended discharge rate?
I haven't used Optima blue top.
I have a red top 6V on a vintage car, which has fared pretty well.
I have yellow top series 34/78 in my truck, seems to crank weakly now that it is over 9 years old.
Same series in Sable faded early.
Smaller yellow top in Civic, went through 3 batteries in a row, average of 20 months each.
There is talk of optima forgetting quality with change of ownership and move to low-cost region.
But maybe, different charging and standby drain in various applications is a key factor.
10V is awfully low except for high current draw. What is your intended discharge rate?
I dont see how they could be worse than the US made ones of 20 years ago for over discharge tolerance. I went thru 4 optimas in 2 years in my C4 corvette in the late 90s. Two yellows, a red, a blue. The official Optima dealer flat out refused to warranty any of them. Theyd put it on a charger blast charge it for 2 days and declare them good. Next morning they wouldnt start a moped.
C4 corvettes have a stupid feature, underhood lights that stay on when the hood is open. If the repair goes past minutes into many hours even days, and that happens lot with those lemons, it kills the battery. After a few years I added a switch but even though I conspicuously labelled it most mechanics failed to use it.
Had a 2000 watt stereo that cost well into 5 figures, that didnt help.
Optimas are well known for intolerance to over discharge. The best battery I had in 27 years of owning that car was the OEM AC Delco. Lasted 10 years but when it died the case split which is a tragedy as GM wisely (lol)put the battery directly above the main wire harness as it enters the firewall, and its thru wall connection terminals.
Overdischarge is the terrorist murdering bastard of lead acid batteries.
There is a cheap device you can use for small loads up to 30 amp. The Havis Charge Guard think the model i use is CM-MP, heres one on ebay.
HAVIS CG-MP / CGMP (USED TESTED CLEANED) | eBay
The product is used surplus. Radwell is not an authorized surplus dealer or affiliate for the Manufacturer of this product. The product may have older date codes or be an older series than that available direct from the factory or authorized dealers.
www.ebay.com
Cuts the power at 11v. Lower than ideal but prevents really bad abuse. Resets itself most of the time, if it doesnt theres a manual reset.
FYI... the hood light unplugs easily...I dont see how they could be worse than the US made ones of 20 years ago for over discharge tolerance. I went thru 4 optimas in 2 years in my C4 corvette in the late 90s. Two yellows, a red, a blue. The official Optima dealer flat out refused to warranty any of them. Theyd put it on a charger blast charge it for 2 days and declare them good. Next morning they wouldnt start a moped.
C4 corvettes have a stupid feature, underhood lights that stay on when the hood is open. If the repair goes past minutes into many hours even days, and that happens lot with those lemons, it kills the battery. After a few years I added a switch but even though I conspicuously labelled it most mechanics failed to use it.
Had a 2000 watt stereo that cost well into 5 figures, that didnt help.
Optimas are well known for intolerance to over discharge. The best battery I had in 27 years of owning that car was the OEM AC Delco. Lasted 10 years but when it died the case split which is a tragedy as GM wisely (lol)put the battery directly above the main wire harness as it enters the firewall, and its thru wall connection terminals.
Overdischarge is the terrorist murdering bastard of lead acid batteries.
There is a cheap device you can use for small loads up to 30 amp. The Havis Charge Guard think the model i use is CM-MP, heres one on ebay.
HAVIS CG-MP / CGMP (USED TESTED CLEANED) | eBay
The product is used surplus. Radwell is not an authorized surplus dealer or affiliate for the Manufacturer of this product. The product may have older date codes or be an older series than that available direct from the factory or authorized dealers.www.ebay.com
Cuts the power at 11v. Lower than ideal but prevents really bad abuse. Resets itself most of the time, if it doesnt theres a manual reset.
I've used Optimas in various formats and have never had those problems, and even today use them for solar at times because I can hammer them being pure-lead.
While I don't discount anyone's experience, after decades of using them, some of my associates who have problems bring them to me. What I've found from some of my friends who don't really care about batteries in general are:
1) They aren't the original owner
2) They wanted to scam the warranty / free Optima for life club by purposely using the wrong type (red starter when they really needed yellow or blue)
3) The semi discharged battery from the store was simply swapped in the parking lot or at home, without *EVER* getting a full charge. That's really important to charge it fully when you first get it. But they just put it in the vehicle and did nothing but short trips.
4) Fell victim to cheaters cleaning and selling used beaters to look like new from the back of some guys van down by the river. And then scream about Optima not honoring a warantee to a non original owner.
These are the types of things that shorten the warranty.
That being said, here are some fun facts for anyone wanting to use one for solar:
1 - Said before. Charge it FULLY before first use. Saves a lot of pain down the road. Helps ensure you can revive it if you kill it.
2 - All Optimas are basically built the same internally except for terminal arrangements. Some have side terminals, some don't depending on your application.
3 - Optimas in a BLACK cases are SLI (Starter, Lights, Ignition). Not what you want for power storage / solar.
4 - What determines whether it is an SLI or the so-called deep-cycle is how acidic the electrolyte is. Red-tops (and one series of blue tops with the black case) have a higher concentration of acid than the other gray-cased versions, like the Yellow or Blue tops.
5 - So what's the deal with Yellow and Blue tops? NOTHING, except for terminal connections. Like Yellows sometimes having side terminals, whereas the Blues have additional wing-nuts for connecting things like fish-finders, radios, etc.
6 - Just be aware that there is ONE Blue-Top with a black-case to act as a starter for your race-boat. Again, this one is not desirable for solar storage.
WARNING: Some using a parallel connection of Blue-Tops may try to do so using only the wing-nut connections! DO NOT USE THE WINGNUTS for paralleling them, or making your major solar connections to them! Only light-duty connections go to the blue-top's wingnut.
Did I mention to properly charge it before putting it into use the first time? Yes.
I've had great luck using Optimas in both vehicles and solar, but sure there are always exceptions. Then again, I've read through a lot of FUD about Optimas for decades, typically in 4WD forums, so I'm not unfamiliar with all those angry posts about nationalism, not being the original owner, undiagnosed parasitic loads, shortened warranty's and the like.
I've also run Odyssey's. Excellent. Some of my buddies who tried to scam them like they did to Optima got told where to shove it.
So no doubt these things happen. I'm just lucky I guess.
While I don't discount anyone's experience, after decades of using them, some of my associates who have problems bring them to me. What I've found from some of my friends who don't really care about batteries in general are:
1) They aren't the original owner
2) They wanted to scam the warranty / free Optima for life club by purposely using the wrong type (red starter when they really needed yellow or blue)
3) The semi discharged battery from the store was simply swapped in the parking lot or at home, without *EVER* getting a full charge. That's really important to charge it fully when you first get it. But they just put it in the vehicle and did nothing but short trips.
4) Fell victim to cheaters cleaning and selling used beaters to look like new from the back of some guys van down by the river. And then scream about Optima not honoring a warantee to a non original owner.
These are the types of things that shorten the warranty.
That being said, here are some fun facts for anyone wanting to use one for solar:
1 - Said before. Charge it FULLY before first use. Saves a lot of pain down the road. Helps ensure you can revive it if you kill it.
2 - All Optimas are basically built the same internally except for terminal arrangements. Some have side terminals, some don't depending on your application.
3 - Optimas in a BLACK cases are SLI (Starter, Lights, Ignition). Not what you want for power storage / solar.
4 - What determines whether it is an SLI or the so-called deep-cycle is how acidic the electrolyte is. Red-tops (and one series of blue tops with the black case) have a higher concentration of acid than the other gray-cased versions, like the Yellow or Blue tops.
5 - So what's the deal with Yellow and Blue tops? NOTHING, except for terminal connections. Like Yellows sometimes having side terminals, whereas the Blues have additional wing-nuts for connecting things like fish-finders, radios, etc.
6 - Just be aware that there is ONE Blue-Top with a black-case to act as a starter for your race-boat. Again, this one is not desirable for solar storage.
WARNING: Some using a parallel connection of Blue-Tops may try to do so using only the wing-nut connections! DO NOT USE THE WINGNUTS for paralleling them, or making your major solar connections to them! Only light-duty connections go to the blue-top's wingnut.
Did I mention to properly charge it before putting it into use the first time? Yes.
I've had great luck using Optimas in both vehicles and solar, but sure there are always exceptions. Then again, I've read through a lot of FUD about Optimas for decades, typically in 4WD forums, so I'm not unfamiliar with all those angry posts about nationalism, not being the original owner, undiagnosed parasitic loads, shortened warranty's and the like.
I've also run Odyssey's. Excellent. Some of my buddies who tried to scam them like they did to Optima got told where to shove it.
So no doubt these things happen. I'm just lucky I guess.
@Greentea - sorry I lost focus there.
Re: the 50% vs 80% dod issue:
In the old days, when pure-lead AGM tech was vying in competition to nickel-metal-hydride for powering EV's, to look real good, they touted an 80% DOD. It excited us early EV'ers when that meant stripping out a small decrepid pickup truck and stuffing the bed with Optimas or even Enersys Hawkers.
That looked good on paper, but in reality, it had to be cut back to 50% because the cycle life was just too short at 80.
But is it possible without damage? Yes it is for a pure-lead. Is it advisable? - not for cycle life.
So THAT is what the true meaning of deep-cycle is for these batteries. NOT cycle-life, but the ability to be deeply discharged without harm, as compared to "conventional" non pure-lead agm's where doing so takes them to the grave early.
Re: the 50% vs 80% dod issue:
In the old days, when pure-lead AGM tech was vying in competition to nickel-metal-hydride for powering EV's, to look real good, they touted an 80% DOD. It excited us early EV'ers when that meant stripping out a small decrepid pickup truck and stuffing the bed with Optimas or even Enersys Hawkers.
That looked good on paper, but in reality, it had to be cut back to 50% because the cycle life was just too short at 80.
But is it possible without damage? Yes it is for a pure-lead. Is it advisable? - not for cycle life.
So THAT is what the true meaning of deep-cycle is for these batteries. NOT cycle-life, but the ability to be deeply discharged without harm, as compared to "conventional" non pure-lead agm's where doing so takes them to the grave early.
