Battery chemistry choice for the non-lithium battery in the system.

[GILow]

Originally Posted by s/v Jedi

Are Odyssey TPPL AGM batteries available where you are? It’s what I have.

Also, the 70A Orion isn’t a smart unit, i.e. not a charger, just a power supply. I am using two 30A smart Orion’s in parallel.

Mate, you just saved me from a VERY silly mistake. I owe you a beer, or ten.

I thought the 70’s were the smart version, but you are correct, they are not. I was distracted by the adjustable output capability. Had a brain fart and took that to be part of the smart package.

So, yes, a pair of 30s.

And I will see if the Odysseys are available here, I assume from Wotttie’s post that they are.

[Wotname]

^^ They are. I have bought a handful in Hobart, we fit them to a few helicopters.

[Wotname]

https://www.rjbatt.com.au/products/brands/odyssey

[GILow]

Originally Posted by Wotname

https://www.rjbatt.com.au/products/brands/odyssey

You are the goods. I know one of their senior sales guys, I was just discussing batteries with him a few days ago. He’s gonna laugh when I come back and ask for an Odyssey AGM.

[Wotname]

^^ maybe he will look after you dollar wise otherwise you will need deep pockets.

[GILow]

Originally Posted by Wotname

^^ maybe he will look after you dollar wise otherwise you will need deep pockets.

I see what you mean, they don’t give them away.

But he just bailed us out already this week with a super cheap battery for a teenage daughter’s car, we may have used up our battery karma.

[s/v Jedi]

So about Odyssey… I like this specific type, the 31-PC2150. They renamed it to ODX-AGM31. It is a group 31 battery.

There are several variations and that is about the terminal studs. Get that right. Here is some info: https://www.odysseybatteries.com/ody...50_series.html

These are very powerful, can deliver 7kW and the short circuit current is 6kA (that is 6,000 Amps). It is just over $500 in the US.

So your conversion is going to be 24V to 12V? Victron just came out with revolutionary new dc-dc converter design but for now there’s only a 12V to 12V unit, 50A no big heat sink because it is 98.5% efficient. I expect more models next year but as you need two units for redundancy anyway, you simply have to get the current Smart Orions. You can get the non isolated version as you probably share a common negative between 12V and 24V.

[goat]

Another vote for optima. You can bypass a bms if it fails. You just have to know if it failed or if it worked and there is a bigger problem somewhere else.

goat

[SOLAR SUPPORT]

Originally Posted by GILow

As for the LTO cells… no thanks. Another BMS based system is not what I am looking for. I want something a bit more robust for the 12 volt battery.

There is no doubt that; The CCA capacities of LA batteries and the fact that they have been used simply and safely for a very long time are important features. In addition, the fact that they serve as a kind of bms HVC safety for LFP service battery banks prevents us from giving up on them completely.

But problems remain with this cumbersome and outdated technology. They require constant floating charge while waiting to prevent sulphation occurring on the LA battery plates, they contain dangerous acid, decreasing performance in extremely cold and hot environments, and finally their relatively variable high price / number of cycle ratios. The above issues can be considered as reasons for the search for different and more advantageous battery chemistry.

LTO chemistry seems ideal for solving these problems. https://www.evlithium.com/lithium-titanate-battery-lto/

I think the reason why CRivet frequently shares detailed LTO information, which sometimes overwhelms me, is to explain to everyone the advantages of LTO chemistry. coming forward. An expensive chemistry LTO. You can directly charge the 6s LTO with sufficient capacity only with an alternator with thermal protection, without using a BMS, and use it only with the addition of an active balancer. Thanks to the superior cell characteristics that come with LTO chemistry, you no longer need BMS's HVC, LTC, HTC protection functions. With sufficient capacity to meet the CCA required by your engine, it seems possible to accomplish many tasks, including starting the windlass, bow thruster and second engine, with a single LTO 6s. I think the high LTO cost needs to be rethought, is it really high?

[Pete7]

Originally Posted by SOLAR SUPPORT

But problems remain with this cumbersome and outdated technology. They require constant floating charge while waiting to prevent sulphation occurring on the LA battery plates,

When you say outdated, how many 12v batteries do you think are in use at the moment.

[sailorboy1]

Originally Posted by GILow

Alternator is supposedly 120 amp, but since it has a single V belt I’m taking that number with enough salt to make a heart surgeon gibber.

Wow, IMO a 1/2" belt is going dust and wear out pretty fast on a 120A alternator. I had to reduce my 100a to 80% to get mine to stop.

[s/v Jedi]

Originally Posted by sailorboy1

Wow, IMO a 1/2" belt is going dust and wear out pretty fast on a 120A alternator. I had to reduce my 100a to 80% to get mine to stop.

It depends on which belt and on the number of pulleys. If you only run the single alternator on an extra belt then you can do up to 200A on a single belt. The belt needs to engage the pulleys 180 degrees and it needs to be a top end belt like Gates green stripe or the best Napa belt (which is also from Gates).

I had 4 belts incl two who each did 200A+ and I’m happy it’s all gone and I now have a single serpentine belt running the water pump and a single 170A alternator.