Start your engine with 4 eve lifepo4 cells, lead makes no sense for this task!!

[Fuss]

With lead, I need 2 big paralleled batteries , with eve 280ah lifepo4, I only need one. It makes no sense to have lead batteries for this task. As all my batteries are eve cells, I have built in redundancy in case of problems.
Of course this only works for those who build their own batteries.
The eve cells are only supposed to be discharged at 1C, so what will happen when I discharge at 4C…will they explode…will they get badly damaged, will they get out of balance, will they swell up, will they get a much shorter life.??
Yes, they might get a much shorter life, but they are good for 6000 cycles when all rules are obeyed, so who cares about cycles!!
The motor starts perfectly…

[Dockhead]

What kind of motor requires two paralleled lead batteries? Are you running an old Detroit Diesel or something?


My 100hp Yanmar starts perfectly (seems like half a revolution sometimes) with a single lead truck battery, which is obviously more battery than is needed. I have one each of those for main and genset, and they live an easy life since neither is connected to anything else. They last 7 or 8 years and don't require watering. If one of them ran down for any reason (hard to imagine how to do it, however), there are two in the same battery box for simple jumping.



Lithium is certainly better for this application, but why go to the trouble?

[Simi 60]

Originally Posted by Dockhead

What kind of motor requires two paralleled lead batteries? Are you running an old Detroit Diesel or something?

Out nta855m Cummins is a 24v start
2 X 12v truck batts

[CaptainRivet]

Originally Posted by Fuss

With lead, I need 2 big paralleled batteries , with eve 280ah lifepo4, I only need one. It makes no sense to have lead batteries for this task. As all my batteries are eve cells, I have built in redundancy in case of problems.
Of course this only works for those who build their own batteries.
The eve cells are only supposed to be discharged at 1C, so what will happen when I discharge at 4C…will they explode…will they get badly damaged, will they get out of balance, will they swell up, will they get a much shorter life.??
Yes, they might get a much shorter life, but they are good for 6000 cycles when all rules are obeyed, so who cares about cycles!!
The motor starts perfectly…

600Euro for a starter battery that last 2-3years...your choice. Eve are storage cycle battery and no starter battery...sure it’s starts and works great but cells get damaged rapidly as these cells degrade fast if used frequently above 0.5C, additionally you need a regulated alternator.
If you want Lithium take 35-40AH LTO yinglong 6cells with a balancer, they do 10C constant (but if you stay at max 6C they life much longer, that’s why 35-40AH) and forget about your starter battery...that’s 30000cyles or 30years plus x in -30 to 70degrees Celsius environment for 400Euro. B-grade matched are fully ok here, the calendar aging will be the major factor.That makes sense technically and economically.

If you have a hybrid starter/house bank like typical for cats (and have the lead starter of the other hull as backup) with at least 2p4s with Eve that works and makes sense as you are using that capacity and 2p will keep the const current below 0.5c and peak below 1C. Expect 2000 cycles then, if you have 3p or better 4p4s then you get your 3500-6000cycles as they always stay below 0.3C which the EVEs are actually made for.
The reason I have 4p4s 1088AH Lishen cell Hybrid bank, 3p would be enough and 4p are 4 cells working spare.You get what you pay for...
If you want or just have space for a small 100-200AH Hybrid bank or induction cooking I highly recommend the new Winston cells, they do 3C constant and 6C peak and can handle this high loads with ease. Perfect fit for that.

[CaptainRivet]

Originally Posted by Dockhead

Lithium is certainly better for this application, but why go to the trouble?

Lifepo4 is certainly not better as they are not made for high C rates caused by the surge of the starter means you need a lot capacity=expensive so the cell gets not damaged. That only makes sense in a hybrid starter/house bank where you use this capacity and simplify your installation.
If you wanna stay close to lifepo4 Winston with 3C const and 6s peak is your choice, a 60AH pack will manage your 2kw starter typically found on engines till 120hp...
Pure starter LTO is the best and most economical fit, 400Euro for 30years plus in -30 till 70 degrees Celsius.in 12V or till 2p6s confit you don‘t need a BMS, an active balancer is highly recommended though and will also monitor your cells.nothing beats that economically,technically and from security as LTO is safest available chemistry.

[ranger58sb]

Originally Posted by Fuss

With lead, I need 2 big paralleled batteries , with eve 280ah lifepo4, I only need one. It makes no sense to have lead batteries for this task. As all my batteries are eve cells, I have built in redundancy in case of problems.
Of course this only works for those who build their own batteries.
The eve cells are only supposed to be discharged at 1C, so what will happen when I discharge at 4C…will they explode…will they get badly damaged, will they get out of balance, will they swell up, will they get a much shorter life.??
Yes, they might get a much shorter life, but they are good for 6000 cycles when all rules are obeyed, so who cares about cycles!!
The motor starts perfectly…

Depends on your engine (I'm guessing relatively small?), so it doesn't work as a blanket statement true for all situations.

-Chris

[s/v Jedi]

If in the real world (not lalaland) then the start battery is always 100% charged. The only chemistry loving that and suitable for starting is AGM.

Now if this thread was about LTO cells then it would have had merit

[Statistical]

Most sailboat aux motors can be started with one battery and in fact most of them with one relatively small dirt cheap plain lead acid battery (no marine specific or dual purpose nonsense).

Starters for most marine aux motors are around 1200W that is 100A although for a few milliseconds it will spike to around 500A but still 500 cranking amps for a starter battery is as pedestrian as you can get.

[CaptainRivet]

Originally Posted by Statistical

Most sailboat aux motors can be started with one battery and in fact most of them with one relatively small dirt cheap plain lead acid battery (no marine specific or dual purpose nonsense).

Starters for most marine aux motors are around 1200W that is 100A although for a few milliseconds it will spike to around 500A but still 500 cranking amps for a starter battery is as pedestrian as you can get.

Volvos starter for D1 and D2 Series is 2kw one, Same Yanmar which majority of mass production boats have.
So we are talking about 150-180A and surge of around 600A.
I agree A dirt cheap 100A FLA starter for below 100bucks will do it all 5-7years new or 35AH LTO for 400Euro for 30years...

[Fuss]

The motor is 6 liter and won’t start on 1 12v lead acid, but there is no lala Land as it’s already done and working. Look at the advantages, for me I’ve got 24 of these cells onboard, when my start battery breaks, I guess I just go and get one of the other cells and use as a replacement….
The alternative is to have 2 big, so old fashioned, emotionally dependant , low capacity batteries that demand that I keep them fully charged at all times. They also demand that I only give them one task. They only want to start the motor and run the motor instruments. If I was to give them other tasks they would complain and use this as an excuse for not starting at some later very inconvenient time.
Thats the problem, they only want to start the motor and they have successfully been convincing us that this is all they have to do, just sit there and do nothing the rest of the time!!. Well these days are over. Lifepo4 is here to upstage these lazy batteries from the past.

[CaptainRivet]

Originally Posted by s/v Jedi

If in the real world (not lalaland) then the start battery is always 100% charged. The only chemistry loving that and suitable for starting is AGM

As long as your regulator works fine...but if it breaks, which is the major failure in alternators...AGM runs dry and you get a thermal runaway that Burns your boat down. After several incidences with AGM in runaway in cars (eg 3month old BMW)and boat the most dangerous chemistry in a boat for me, to be avoided at all costs
Prefer cheap FLA that can withstand substantial abuse and eg survive regulator failure (just refill water) and change it more often if necessary, moneywise equal or cheaper compared to AGM.
Or If you have LFP house and a regulated alternator get an LTO as starter and be done for good for the life of the boat.

[Statistical]

Originally Posted by Fuss

The motor is 6 liter and won’t start on 1 12v lead acid, but there is no lala Land as it’s already done and working. Look at the advantages, for me I’ve got 24 of these cells onboard, when my start battery breaks, I guess I just go and get one of the other cells and use as a replacement….
The alternative is to have 2 big, so old fashioned, emotionally dependant , low capacity batteries that demand that I keep them fully charged at all times. They also demand that I only give them one task. They only want to start the motor and run the motor instruments. If I was to give them other tasks they would complain and use this as an excuse for not starting at some later very inconvenient time.
Thats the problem, they only want to start the motor and they have successfully been convincing us that this is all they have to do, just sit there and do nothing the rest of the time!!. Well these days are over. Lifepo4 is here to upstage these lazy batteries from the past.

Well if it is a 24V starter you need eight cells EVE cells. No idea why you would go with 280Ah but if you did that is over $1k in just cells. Now you need a BMS capable of >500A peaks which is also going to be expensive and then abuse them by pull much higher than the rate max discharge rate probably resulting in a short expensive life. All that to avoid a pair of dirt cheap starter batteries (<$300) which will last reliably for the better part of a decade.

If it is 12V you don't need a pair of lead acid in parallel just one with sufficient CCA so your costs are even lower.

[Fuss]

It’s 12v starting so 4 batteries. I never said it was 24v starting. It has no BMS, it doesn’t need one with this capacity as it’s big enough never to run into the knees.
10 years on your start batteries, I’d like to see that… I used to get 7 years with start batteries that were always fully charged and did one job, 10 years for most sailors is impossible.

[Statistical]

Originally Posted by Fuss

It’s 12v starting so 4 batteries, if you get grade B, not costing so much

Still way beyond the rated C limit. They will be dead in a year. What BMS are you using to safely manage 500A+ discharge rate. No BMS? BMS isn't just for balancing. It protects the cells and your boat from overcharging or an over current situation like starter locked.

If someone has a very large lithium house bank and wants to use that as an emergency start sure that can be done but using LFP especially 280Ah cells for a dedicated starter without a BMS is a solution in search of a problem.

If you have a 12V starter you don't "need" a pair of lead acid starter batteries just one with sufficient CCA.

[Fuss]

Originally Posted by Statistical

Still way beyond the rated C limit. They will be dead in a year. What BMS are you using to safely manage 500A+ discharge rate.

If someone has a very large lithium house bank and wants to use that as an emergency start sure that can be done but using LFP especially 280Ah cells for a starter is a solution in search of a problem.

Ok, you might be right, let’s see, I’ll report back in a couple of years. I’ll start another thread later about another advantage …but that’s not for now.