Starting battery

[newhaul]

Originally Posted by CaptainRivet

1) If the alternator is temp protected no problem and he if he was charging LFP house already that’s a given fact.

2) LFP is much better in delivering high current without a voltage drop which puts additional stress on the starter. 2000W starter/13V= 153A on LFP while 2000W/9.5V =221A due to voltage sag eG Peukert effect. So windings of starter are under more stress with lead and shorter lifespan. Yes it’s not so much capacity used but that doesn’t matter or is a good backup incase house as an internal issue.

3) LFP got cheaper then lead already in sales price, factor in the massively longer lifespan an LFP starter is a nobrainer. Even better is LTO as starter or bowtruster as delivery up to 30x capacity plus 20000-30000 cycles means it survives the lifespan of your vessel. Your goal of a starter is to have a battery that will always work and the LTO is that battery.

I will stick with my grp78 maintance free Fla I get them for under $75 and they last for 8 years so far in my ford pickup

[Putt-Putt]

Originally Posted by newhaul

I am really dubious of the CCA rating of the 20ah lifepo4
Cca calculation formula is
CCA= 7.2 volts x ah rating
And by that formula the 800 CCA rate wou.d require over 110ah battery
But that formula is for FLA batteries

Even calculating using the sag of lifepo4 cca of 800amps and voltage of 13.0 still is 61ah battery .

The relationship between CCA and Ah is dependant on the design of the battery and you will find that the constant shown above will likely not apply.

Here is a chart showing the average CCA & Ah of many BCI group batteries.

Using the first one listed, an 8D, CCA of 1450/Ah (20 hr. rate?) of 220 = 6.6. Then the Group 24 listed calculates as 11.0, while a YTZ14S (the last one) is 20.9.

Using the values listed on the Rolls Battery site for their S12 24, this formula results in a value of 550/85 = 6.5. If you try this on their 12 HHG 325 battery you get 1069/325 = 3.3.

Clearly 7.2 is not the right number, even for an estimate.
The entire premise is likely wrong as the 7.2 constant as noted by Jackery, Renogy and others including AI is said to be in Volts.

That would mean that Rolls would have had to drive their 200# 12 HHG 325 12 volt battery down to 3.3 volts to get their 1069 CCA. Really?

Likewise, how do you drive the 12 Volt YTZ14S down to just 20.9 volts?

How does that work when the definition of CCA is the amount of current delivered at 0º F. for 30 seconds without the voltage dropping below 7.2 V.

Arriving at a CCA value, I read is done by testing the battery in the specified conditions. It could take many retests to get the right value.


https://www.batteryequivalents.com/h...-hours-ah.html

I hope your wife is improving.

[newhaul]

Originally Posted by Putt-Putt

The relationship between CCA and Ah is dependant on the design of the battery and you will find that the constant shown above will likely not apply.

Here is a chart showing the average CCA & Ah of many BCI group batteries.

Using the first one listed, an 8D, CCA of 1450/Ah (20 hr. rate?) of 220 = 6.6. Then the Group 24 listed calculates as 11.0, while a YTZ14S (the last one) is 20.9.

Using the values listed on the Rolls Battery site for their S12 24, this formula results in a value of 550/85 = 6.5. If you try this on their 12 HHG 325 battery you get 1069/325 = 3.3.

Clearly 7.2 is not the right number, even for an estimate.
The entire premise is likely wrong as the 7.2 constant as noted by Jackery, Renogy and others including AI is said to be in Volts.

That would mean that Rolls would have had to drive their 200# 12 HHG 325 12 volt battery down to 3.3 volts to get their 1069 CCA. Really?

Likewise, how do you drive the 12 Volt YTZ14S down to just 20.9 volts?

How does that work when the definition of CCA is the amount of current delivered at 0º F. for 30 seconds without the voltage dropping below 7.2 V.

Arriving at a CCA value, I read is done by testing the battery in the specified conditions. It could take many retests to get the right value.


https://www.batteryequivalents.com/h...-hours-ah.html

I hope your wife is improving.

Wife is doing fine meds are working

As to the CCA calculation formula I just posted what I read from east Penn.

[CaptainRivet]

Originally Posted by newhaul

Wife is doing fine meds are working

As to the CCA calculation formula I just posted what I read from east Penn.

As explained for lithium just forget any CCA bs and just use the starters wattage for LFP to determine what you need.

[CaptainRivet]

Originally Posted by newhaul

I will stick with my grp78 maintance free Fla I get them for under $75 and they last for 8 years so far in my ford pickup

No maintenance free FLA exists
For 108$ you get 30 years plus real maintenance free 20AH LTO Toshiba SCIB cells with busbars, add 15$ for an active balancer and that’s it. Starters till 2000W work with that, no more needed. And no floating the dreaded lead to keep it alive.
In cars yes I had Fla survive 8 years, boats never more then 5…

[newhaul]

Originally Posted by CaptainRivet

No maintenance free FLA exists
For 108$ you get 30 years plus real maintenance free 20AH LTO Toshiba SCIB cells with busbars, add 15$ for an active balancer and that’s it. Starters till 2000W work with that, no more needed. And no floating the dreaded lead to keep it alive.
In cars yes I had Fla survive 8 years, boats never more then 5…

Really then what maintance do I need to do on my sealed lead acid battery?
Aside from charging just like all batteries need when you use them?

[newhaul]

Originally Posted by CaptainRivet

As explained for lithium just forget any CCA bs and just use the starters wattage for LFP to determine what you need.

That post you quoted was not directed at you nor did it have anything to do with lifepo4.
It was purely about fla cca calculations from the East Penn web page.

[Jef & Marin, Netherlands]

My choice would be a 12V LTO start battery to start our 2 engines and the generator. However, I would prefer to buy an LTO battery with 6 cells instead of assembling something myself out of cells, at this moment. I want something that is engine-room-proof.

Is there already a high quality ready made LTO battery on the market for 12V starting?
I only found dubious batteries for car sound system that say they can do many kW of sound, without mentioning the battery Ah rating.


Advantages:
- Long life
- High starting current
- Temperature tolerance
- Light weight
- Comparable price with 2 LA start batteries of 700CCA

[CaptainRivet]

Originally Posted by Jef & Marin, Netherlands

My choice would be a 12V LTO start battery to start our 2 engines and the generator. However, I would prefer to buy an LTO battery with 6 cells instead of assembling something myself out of cells, at this moment. I want something that is engine-room-proof.

Is there already a high quality ready made LTO battery on the market for 12V starting?
I only found dubious batteries for car sound system that say they can do many kW of sound, without mentioning the battery Ah rating.


Advantages:
- Long life
- High starting current
- Temperature tolerance
- Light weight
- Comparable price with 2 LA start batteries of 700CCA

No lithium battery will ever be engine room proof. Heat is the biggest enemy of lithium and it's lifespan and especially from 35 degrees celcius on suffers significantly. LTO is the best in this case but you don't want them in your engine room and if there is really no other way in a closed and heat isolated box compartment.
But with LTO it's so easy to have the battery out of the engine room right after bulkhead or if eg engine under bed behind some panel next to it but not in the engine room itself.
The Toshiba sciB 20AH are little prismastic cells where 6cells together are size of a tiny bit bigger then a 2x2l tetrapack for eg milk or juice on top of each other
The cylindrical cells from Yinglong or Platanno simply connect the cells with an M12 stud connector and put that 6 cell 40AH Yinglong cells into a 116cm long DN70 composite water pipe and put DN70 endcaps on. There are several mounting fittings for walls or corners avaliable. For the DN70 avaliable at any plumber store or DIY market You can shorten the cell studs by cutting with an anglegeinder 3cm of the 4cm M12 stud per cell away to get 1cm stud which is enough to connect 2 cells with a stud connector together. so you get to approx 1m length pipe.The Platano are shorter as only 24AH but with 30C more powerfull that yinglong so pipe is around 70cm long. That also fits easy behind some panel or cable channels or you can tuck it vertical into a corner of eg bulkhead to hull corner or in mono with engine behind the stairs seperate it into 2 parts and put each one half below a stair step directly at the wall to the stairs step corner. Or below bed in the cabin next to it.

No they are no LTO starter batteries made I know off. The ready made ones are for car stereo for show and shine.

[bcboomer]

Dakota make one: https://dakotalithium.com/product/da...UIhT3-jVLo99Rv

[CaptainRivet]

Originally Posted by bcboomer

Dakota make one: https://dakotalithium.com/product/da...UIhT3-jVLo99Rv

Thanks.
Well 700bucks for 20AH LTO....
Well get 6x20AH LTO Toshiba SCIB from batteryhockup.com for 6x18$, an 5A heltec balancer for 15$ and make or find a box you can fit the tiny cells. Shouldn't cost you more then 150-200$ total.

[Jimbo2010]

Tomorrow I'm installing and testing

LiTime 12V 20Ah 800 CCA Marine Starting Lithium Batter

[newhaul]

Originally Posted by Jimbo2010

Tomorrow I'm installing and testing

LiTime 12V 20Ah 800 CCA Marine Starting Lithium Batter

Great let us know the details like what engine ? How well it works
How well the battery was packaged for shipping and all that kind of stuff

[JustMurph]

Originally Posted by Jimnche

A lithium battery is poorly suited as a starter as it is not suited to deliver high amperages for short periods of time.

Not correct. High C rates are exactly what lithium cells do well, both on charge and discharge. What doesn't do high C rates well are the cheap BMSs and cabling used in most drop ins. Use a decent battery or build one yourself, no issue.

[Nicholson58]

Originally Posted by JustMurph

Not correct. High C rates are exactly what lithium cells do well, both on charge and discharge. What doesn't do high C rates well are the cheap BMSs and cabling used in most drop ins. Use a decent battery or build one yourself, no issue.

I agree. We have all Blue Heron. BMS is accessed by smart phone. I always know what’s up.

Please also refer to my post #60. My LFP main and start banks have no problem with the 6 cylinder 115 hp Westerbeke. LFP has come a long way and has come down in price. Extricate yourself from the dark ages, keep it simple and stop dealing with bad water, sulphanation, rejection of charging at the top 25% and everything else wrong with lead acid.