Deep cycle batteries

[inthepines]

Originally Posted by Tightwadted

If I remember correctly, I've heard that most batteries are made by just a few companies, I have used the Walmart Everstart grp 29 deep cycle batteries rated at 110 Ah (less than $100) for 4 years to boondock, running LED lights,etc and the big draw my DW's O2 concentrator that draws about 10 amps per hour (tested) when i did my initial test 1 battery ran the inverter and O2 machine for 6 hours before stopping. We used 4 batteries for our trip to Alaska in 19, and many weeklong boondocking trips since then. but we did run the genny to charge them up during the day, since she runs the O2 24/7. 2 batteries new in 17, 2 new in 19, I also swap them into my boat for the trolling motor. Still going fine when i pulled them to put in LifePo's last month. i ran them a lot of cycles, YMMV. ted

This is true, East Penn, Clarios (former Johnson Controls) and Exide.
Clarios makes the interstate brand. AtlasBX (hankook) is a new player on the scene as well with a plant in Tenn. but don't be surprised to see a battery from them made in Korea.

Lifepos really are the best bang for buck though.

I'm dealing with this issue right now myself. The TT I just bought has a battery that is fried. I want to go Lithium but it's too late in the season for me to justify dropping the money on them so I'm just going get some cheap marine FLA.s to get by this season and buy fresh Lithiums for next year.
Than I get to replace my power center to handle the charging profile..
1 Lithium can do the work of 2 lead acids. No you can't charge them in freezing weather unless you keep them warm but they still will discharge just fine in freezing temps. I use lithiums in my trail cam because of that.

[Gearjunkie]

Originally Posted by Bowtie Jim

Thanks for the info Guys. After thinking about it we probably wouldn't be doing more than 1 or 2 nights off grid. I always try for full hookups but these days , well you know.
I think I'm going with the NAPA group 31.
It's actually $20 less than the link i posted so that better.
I'm thinking about a small solar charger to help keep it charged. There are so many kits for around $100-150 I think I can come up with something easy enough.
Thanks again for your help

I'm sure that battery will do exactly what you want.

Someone mentioned it not being a true Deep Cell, which is true. Marine Deep Cell batteries have cranking capabilities for starting outboard motors. I believe they are less money than a true deep cell and you can't drain them as much as a true deep cell.

Having said that, most (if not all) new units come with Marine Deep Cell batteries.

[garywilson]

I'd check the ratings... not many of them.
Might check Harbor Freight or another seller on Amazon?
100 watts isn't much.

[QUOTE=Bowtie Jim;5821765]Hmmmm....

[BobinICT]

I've been using these and we boondock mostly. So far the lowest SOC we've experienced has been about 76%. They are heavy but for me I feel worth it.

[Dave Pelletier]

Originally Posted by inthepines

Lifepos really are the best bang for buck though.

1 Lithium can do the work of 2 lead acids.

Actually LiFePO4 batteries have advantages but "bang for the buck" isn't one of them. Even though they can do a 100% dischage vs. the 50% of a lead acid at 3X the cost they are a poor choice from a cost vs. power perspective. Where they shine is weight, which is why I use them on my motorcycles.

Battleborn Lithium = $12.79 per amp hour

Interstate GC-2 = $1.96/12v amp hour.......X2 as you only have half the useable amp hours = $3.92/ amp hour.

Or to put it another way, for the cost of one 100AH BB lithium, I can buy almost 6 GC-2's for a total of 675 AH which divided in half for the 50% maximum discharge = 337 AH's

Unless you don't have the space or can't haul the weight, the cost benefit for Lithiums just isn't there yet.


Dave

[twinboat]

Originally Posted by Dave Pelletier

Actually LiFePO4 batteries have advantages but "bang for the buck" isn't one of them. Even though they can do a 100% dischage vs. the 50% of a lead acid at 3X the cost they are a poor choice from a cost vs. power perspective. Where they shine is weight, which is why I use them on my motorcycles.



Battleborn Lithium = $12.79 per amp hour



Interstate GC-2 = $1.96/12v amp hour.......X2 as you only have half the useable amp hours = $3.92/ amp hour.



Or to put it another way, for the cost of one 100AH BB lithium, I can buy almost 6 GC-2's for a total of 675 AH which divided in half for the 50% maximum discharge = 337 AH's



Unless you don't have the space or can't haul the weight, the cost benefit for Lithiums just isn't there yet.





Dave

The 1/2 usable AH is a myth. You can safely draw flooded batteries down to 20%.

You can't draw 100% out of lithium. 90% maybe but at 100% they shut off. Most inverter/chargers will not charge them.

That blows up your math calculations.

Here are some grafics showing it.

[Dave Pelletier]

Originally Posted by twinboat

The 1/2 usable AH is a myth. You can safely draw flooded batteries down to 20%.

You can't draw 100% out of lithium. 90% maybe but at 100% they shut off. Most inverter/chargers will not charge them.

That blows up your math calculations.

Here are some grafics showing it.Attachment 335687Attachment 335688

Pehaps; I was giving the lithiums as much benefit as possible, but all your figures do is make the cost benefit calc for the LiFePo batteries much WORSE.......making my point even more valid




Dave

[inthepines]

Originally Posted by twinboat

The 1/2 usable AH is a myth. You can safely draw flooded batteries down to 20%.

You can't draw 100% out of lithium. 90% maybe but at 100% they shut off. Most inverter/chargers will not charge them.

That blows up your math calculations.

Here are some grafics showing it.Attachment 335687Attachment 335688

absolutely correct, how long do you think they are going to last?
I'd bet not as long as the manufacturer recommends.
I've been thru many SLA's in UPS's; that I definitely believe and have experienced SLA's not lasting 2 years when DOD is consistently below 50%.
I don't think it's good practice to completely discharge your lithiums. I try around 40% for the ones I play around with.

battleborne are about the most expensive battery to run numbers off of. They also are not the only good battery available. battleborne claims 10-15 years AGM is stated 5-7.
So you're still getting twice the battery from a battleborne than lead acid.
If you follow the recommended usage.

[Dave Pelletier]

Originally Posted by inthepines

absolutely correct, how long do you think they are going to last?
I'd bet not as long as the manufacturer recommends.
I've been thru many SLA's in UPS's; that I definitely believe and have experienced SLA's not lasting 2 years when DOD is consistently below 50%.
I don't think it's good practice to completely discharge your lithiums. I try around 40% for the ones I play around with.

battleborne are about the most expensive battery to run numbers off of. They also are not the only good battery available. battleborne claims 10-15 years AGM is stated 5-7.
So you're still getting twice the battery from a battleborne than lead acid.
If you follow the recommended usage.

Sure the BB's may be more expensive than most but at 3-4X the cost compared to lead acid, even cheaper brands aren't going to get there. Even using the very conservative comparison numbers regarding discharge rates, the cost per AH of lithiums is far, far higher......so even if you found Lithium batteries at half the cost of BB's, they are still going to cost twice the cost of lead acid.

......go ahead and do your own battery pricing and AH analysis but you won't be able to come out ahead with the lithiums when it comes to $$'s per AH.

Using my own example, I have 4 Interstate GC2 ETL UCL 225 AH batteries giving me 450 AH's at 12V. My cost was around $800.....how much do you have to spend on Lithiums to get that much power?

Dave

[CRV2]

Keep in mind that the cost needs to consider the number of cycles each type of battery has over its life. For example, it is common for a lead acid battery to provide 2~300 cycles over its life and a Lifepo4 battery to provide 2~3000 cycles over its lifetime. So, you may find that over the years you have to purchase 10 lead acid batteries for each comparable Lifepo4 batteries. Certainly the upfront cost of Lifepo4 is very high compared to Lead Acid batteries. ~CA

[Dave Pelletier]

Originally Posted by craigav

Keep in mind that the cost needs to consider the number of cycles each type of battery has over its life. For example, it is common for a lead acid battery to provide 2~300 cycles over its life and a Lifepo4 battery to provide 2~3000 cycles over its lifetime. So, you may find that over the years you have to purchase 10 lead acid batteries for each comparable Lifepo4 batteries. Certainly the upfront cost of Lifepo4 is very high compared to Lead Acid batteries. ~CA

a valid point though I was just talking about cost/AH. I'm not sure that a 10:1 lifespan is realistic but I typically get 5-10 years from my GC batteries so I'm not sure I'd live long enough to see a savings from Lithium.

I'm not anti-Lithium; as I've said, I use them exclusively on my motorcycles but I just think they are too expensive currently to be considered a good "bang for the buck".....hopefully the cost will come down; I'm sure it will. Maybe when my disposable lead acids pack it in in 7 years, the cost for the lithiums will be more reasonable.


Dave

[twinboat]

Originally Posted by inthepines

I've been thru many SLA's in UPS's; that I definitely believe and have experienced SLA's not lasting 2 years when DOD is consistently below 50%.

.

And 4 years with 50% DOD cycle life ?

Pay now, pay later.

[twinboat]

Originally Posted by craigav

Keep in mind that the cost needs to consider the number of cycles each type of battery has over its life. For example, it is common for a lead acid battery to provide 2~300 cycles over its life . ~CA

I just posted a cycle life chart showing 1000 cycles at 50% DOD and a cycle life of 500 cycles at 90% DOD.

That's 50% more cycles then your non fact based example.

[jrollf]

It gets complicated.

Using your chart

Lead acid, 100 a/h drawn down to 80% to get a round 550 cycles means you have 80 a/h useable per cycle.

LifePO4, 100 a/h, drawn down to 80% to get around 3,000 cycles means you have 80 a/h useable per cycle.

So for 3,000 cycles from the LifePO4 you would in theory go through around 5.5 lead acid batteries for every LifePO4.

To be fair, the vast majority of lead acid "deep cycle" batteries are actually hybrid, you'll never get 500 cycles at 90% discharge. True deep cycle batteries are good deal more expensive than the $90 Marine "deep cycle" from Walmart, and harder to find. The easiest route is to usually by two 100 a/h 6 volt golf cart batteries wired in series to provide 12v 100 a/h capacity.

Individual usage habbits play a huge roll in which battery make finacial sense.

Lead Acid makes perfect sense for a weekend warrior, especially one that generally seeks out camp sites with electricity as it will take a many years to use up the cycles, especially since they likely won't deeply discharge the batteries.

LifePO4 makes a lot of sense for fulltimers/ long term campers that exclusively boondock and use solar as they will be cyclying batteries on a nearly daily basis. Then factor in for big battery banks in the 500 to 1,000 a/h or higher range many of these campers have and lead acid weight does become a big concern.

So the real answer is "It depends" [emoji16]