Drop in Lithium Batteries - the basics?

[noelex]

I have not heard of any issues with the more spiky output of alternators causing problems with the BMS or the battery itself. That does not mean it could not occur, but it does not seem to be a practical issue.

DC to DC chargers are used because they are a cheap and easy way to limit the alternator output to (hopefully) a safe level and to ensure the charging voltages are appropriate, while at the same time protecting the alternator from damage should the BMS disconnect.

The ultimate solution is to fit a high output alternator with an external regulator. This is a more involved and expensive solution. It makes the most use of the high charge acceptance of lithium, but is overkill for many boats.

 

[Pete7]

Indeed, the serpentine belt kit for us was 500 USD alone plus import duty. Then add the new alternator and external regulator, just too much for us. However on a powerboat that doesn't want to do solar panels and has lots of power absolutely. LFP would work well here because you don't have to reach 100%, just enough to see the boat through until the next run or plug in to shore power.

 

[Tranona]

Lithium can work better than lead when charging via an alternator. The high acceptance rate of lithium until almost 100% full means more charge can be squeezed into the battery bank with only a short amount of motoring. This is a significant advantage.

The drawback is a more sophisticated and expensive system is needed, although these steps are also used on some larger lead acid systems.

If you want to keep things simple and inexpensive this can be done with lithium, for example by incorporating a battery to battery charger. This can be a good solution, but this generally results in a lower charge rate and a more complicated and expensive system than with a simple lead acid system, leading to the somewhat misleading impression that lithium batteries cannot work well with alternator charging.

I am well aware of that. My post was in response to the suggestion that alternators on marine engines are not sophisticated or powerful enough to be used to charge lithium. Standard specs are indeed geared towards acceptance rates of LA batteries- my Beta 30 has a 75amp (and 14.4v) as standard which is more than adequate for a 3-400Ah LA bank that a typical 30-35 yacht would have, and if you want larger then a 120 amp is optional. Some engines of that size like Volvo have a 115amp unit as standard. Clearly one would not want to run at those high levels for any period of time. When discussing the spec on my new engine with Beta and the installer they said they sell very few upgraded 120amp alternators until they get to 38 and 43hp motors which go in larger boats that may have systems that would benefit from the higher output.

Using a B2B is a sensible way of making use of the high acceptance rate of lithium while protecting the alternator, although the cost (£200plus fittings and cabling) rather hurts the cost of changing to lithium for a simple "weekend" cruising boat.

 

[noelex]

Some engines of that size like Volvo have a 115amp unit as standard. Clearly one would not want to run at those high levels for any period of time. When discussing the spec on my new engine with Beta and the installer they said they sell very few upgraded 120amp alternators until they get to 38 and 43hp motors which go in larger boats that may have systems that would benefit from the higher output.

Standard marine alternators are not great. If you want high output there are much better alternatives. Continuous outputs of over 2kw is usually achievable with aftermarket alternators on reasonable sized yacht engines. The cheapest way of doing this is with one of the large frame industrial (or sometimes called bus) alternators.

It helps to have a 24v system If you want very high levels of electrical energy from the main engine.

Not everyone needs this level of electrical energy, but it is nice to know it is possible.

 

[dgadee]

Well, today is cloudy and we are anchored. Not much solar. I could get out the honda if I needed it for the watermaker or could start the engine for the inverter/watermaker. Lithium would charge more quickly, I presume, while I was using these two options.

But I think a b2b is the easiest solution. Sterling is expensive but Victron suggested something at half the price - Orion 12/12-30A - but I don't know enough to compare these systems.

 

[Tranona]

Standard marine alternators are not great. If you want high output there are much better alternatives. Continuous outputs of over 2kw is usually achievable with aftermarket alternators on reasonable sized yacht engines. The cheapest way of doing this is with one of the large frame industrial (or sometimes called bus) alternators.

It helps to have a 24v system If you want very high levels of electrical energy from the main engine.

Not everyone needs this level of electrical energy, but it is nice to know it is possible.

Of course - but the point that I am making is this is not necessary for modest sized installations (such as the OP's) where the standard alternators are fine. There is a tendency to think that just because more advanced/powerful etc products are available they are appropriate in all situations.

 

[Pete7]

But I think a b2b is the easiest solution. Sterling is expensive but Victron suggested something at half the price - Orion 12/12-30A - but I don't know enough to compare these systems.

Can't comment on the Sterling, but the Victron Smart Orion has Bluetooth to a smart phone which we find useful to switch the Orion on and off. If you want more power, you can stack them so two in parallel works. Make sure its the TR Smart version, not the cheaper converter models.

Just be aware that there is a reason for the big fins on the back. They run hotter than the sun. Ours is mounted on the outside of the nav seat with a 3" hole behind it and this is the temperature after an hour. Small computer fan behind it would be good. Just don't put it in a cupboard or under a berth with no ventilation. In use the Orion actually generates 27A once its warmed up. It can also be switched to a power supply mode if the domestic bank goes pear shaped to run instruments etc.

Overall it was a simple solution that has worked well for us over the past two years.

 

[dgadee]

That is hot.

I have a bluetooth Victron mttp the forum encouraged me to splash out on and it is very handy.

Stackability seems a good idea - I can upgrade rather than buy unused power at the start.

Many thanks all. I think I can envisage the new system. Just need to investigate fusing.

I really knew nothing when I first posted.

 

[lustyd]

Orion 12/12-30A

I fitted this model to our current boat and it's excellent. It will happily supply 20A+ for hours on end but does take probably 20 hours to charge our 300Ah lithium if it's run right down. These can be de-rated in the app so consider getting a bigger one which can do short bursts at higher amps but set lower for longer periods with the motor on.

 

[lustyd]

I'm glad that it now takes until the third page of a thread for this kind of comment to turn up. People are becoming better educated.

I think we're fast approaching the point where such posts should be reported as trolling. Hard to believe people would weigh in on something they know nothing about given how much information is now available. It was excusable a few years ago, but times have really changed and information is literally everywhere now

 

[dgadee]

I fitted this model to our current boat and it's excellent. It will happily supply 20A+ for hours on end but does take probably 20 hours to charge our 300Ah lithium if it's run right down. These can be de-rated in the app so consider getting a bigger one which can do short bursts at higher amps but set lower for longer periods with the motor on.

I think that is the biggest. I would need 4 to get near the 140a which the alternator is supposed to produce.

Maybe the Sterling outputs more? And that explains the cost?

 

[PaulRainbow]

I think that is the biggest. I would need 4 to get near the 140a which the alternator is supposed to produce.

Maybe the Sterling outputs more? And that explains the cost?

The Sterling is quoted as being 120a max, costs over £600. If you really need to make best use of the 140a alternator i would consider a different solution to a B2B.

 

[dgadee]

I ed
The Sterling is quoted as being 120a max, costs over £600. If you really need to make best use of the 140a alternator i would consider a different solution to a B2B.

Tell me what you think i need.

 

[dgadee]

Maybe what I need is a lithium battery with a bms which can do a slow shutdown and integrates with alternators.

 

[Pete7]

Tell me what you think i need.

What sort of alternator belt do you have? a serpentine hopefully, but if it's the traditional fan belt type you may have a problem taking over 100A.

You mentioned fuses, so I am guessing you are starting from scratch. Lots of ways to do this and noting its easy to spend someone else's money, but I bought a Victron Lynx Power In. Its designed to just take power in and distribute it as part of a hugely expensive but nice Victron system around the boat.

However, with 4 bolts and nuts it can be converted to a rather neat stand alone fuse box as well as a junction box. Yes of course there is a cost. However, Nathan makes a good point about buying the items separately. For us once converted all power goes in and out via the Power In unit. Even the inverter uses the large lugs on the side and the bolt holes are the same as a Blue Seas circuit breaker so it bolts straight on.

Not a great photo, but you get the idea.

 

[dgadee]

It is a Yanmar 3ym30 from 6 years ago.

What about:

Yanmar 'Smart Ready' retrofit regulator - RJS Marine

 

[rogerthebodger]

What sort of alternator belt do you have? a serpentine hopefully, but its the traditional fan belt type you may have a problem taking over 100A.

Most Car Vee belts are Z section.

These can be increased to A section or Alpha section belt that will transfer a higher torque..

I have a 120 Vmp alternator driven by an Alpha section Vee belt with out an issue.

 

[Pete7]

Most Car Vee belts are Z section.

Yes of course. I did look at different belts, but to really benefit I would also need to increase the pulley ratio so the alternator ran quicker. Sadly the cost was prohibitive for what we would gain as a secondary charging method, solar being the normal method.

 

[Pete7]

It is a Yanmar 3ym30 from 6 years ago.

What about:

Yanmar 'Smart Ready' retrofit regulator - RJS Marine

Looks like you have a ribbed belt, so that is one thing less to worry about.

Not sure about the Yanmar widget, that's a fall back option. I think Paul is suggesting something like the Wakespeed external alternator regulator. Balmar have something similar too. Make a tea and sit comfortably before you Google the prices.

Wakespeed WS500 - RJS Marine

We will see you in a week after you have worked your way through this lot:

How Wakespeed's WS500 alternator regulator solves complex charging issues, now with NMEA 2000 UPDATE

 

[Kelpie]

I think that is the biggest. I would need 4 to get near the 140a which the alternator is supposed to produce.

Maybe the Sterling outputs more? And that explains the cost?

Do you actually need 140A of charging?
On the past two years I've only used engine charging twice. With a little 18A DC-DC.
You don't have to cover every possibility.