Lithium Batteries

[roaringgirl]

Who batteries did you buy or did you build your own? If you built your own, which cells?

We bought Victron. The Bluetooth ones with external BMS *not* the 'Superpack' ones.

 

[Zing]

Where is "Zing" when you need him?

You rang sir?

 

[kwb78]

This is all very useful info'. Can I drop in a slight thread drift with an additional question! If I fit two LifePo batteries for house use, what would be the best battery type for engine starting? Also, will my standard 140 amp alternator need any additional regulator to properly charge all three batteries at the same time through VSR's or diodes. Many thanks.

I'd stick with lead acid for starting. It's not worth the extra cost and complexity required to use another battery chemistry when lead acid does the job perfectly well - the battery is used to supply high current for short duration, and lead acid copes fine with that.

If you add LiFePo4 house batteries, don't use a diode or VSR to charge them, because that is quite likely to kill the alternator. Lithium batteries will pull as much current as they can get, and the alternator will overheat and fail. It also won't provide the lithium batteries with the ideal charging voltage. The simplest solution is to use a DC-DC charger sized to match the batteries and alternator. That will properly charge the batteries and also protect the alternator by regulating the current drawn from it. It will also prevent a sudden disconnection by the BMS from killing the diodes in the alternator. The starter battery would be maintained by the alternator directly.

 

[Zing]

After going through a set of AGM batteries in just over 2 1/2 years, I believe the time has come to change over to lithium. My existing system has about 480AH of capacity but I
found this is down to a small fraction of that now following my system giving low voltage alarms after discharging about 50AH.

I have a system with a Victron multiplus inverter charger ( C/12/1600/70). This regulary is used to power mains systems drawing typically 100A and ocasionally more. This summer was typical in that for weeks at a time the battery bank sat at 80% SOC or less. I have about 200W of solar on a partially shaded deck but that is insufficient to recharge the batteries each day when we are aboard. Accordingly I am tempted to switch to lithium as they are claimed to better survive in those situations.

I have looked at the options and have come down to two options


1 Go for quality and buy a single 200AH Victron lithium FE04 with a Smart BMS 12/200 to manage the alternator. This with the neceserry cables costs about £2100. It has the advantag of a single DC31 size battery giving room to expand the bank if needed.
2 Go for a cheaper e.g. Renology probably requiring 3 100 AH units to give the maximum current required for the inverter (150A) with a 60A DC to DC charger costing about £1550. Advantage greater capacity but quality?

There seems a large host of low cost lithium about but not much info about its reliability and the value of any guarentee given most of the companies are relativly new.

Has anyone any views as to the best or other options?

I can say what I did, which may well suit you. I bought individual CALB cells (direct from China and done this way is cheaper long run than lead). I used a GWL BMS, which has all I need. Note it has no cell balancing, which I see as an advantage. On a previous installation I had one balancer fail and it took down the pack. I tried without a balancer and found I didn’t need it, so ran it for years happily like that. If you keep voltages well away from the ends, which you should do anyway to maximise life, cells don’t go out of balance. For example my 8 pack after 16 months is 4mV out highest to lowest and unchanged from the start. Most BMSs will not resolve that difference anyway.

The Mastervolt chargers are standard and I put them on fixed voltage output to suit. Ditto the alternator, but at a lower voltage to not overheat the alt. It goes through a Mastervolt Alpha plus charge controller.

I use the high volt level output to activate a relay to control latching high amp Panasonic relays to disconnect the alternator field and the two DC chargers and solar (to come). There is also a Broyce timer relay to shut down the genset. A buzzer and LED come on with the low volt output and another isolatable timer relay to start the genset. The emergency cut-off volt level output disconnects a BlueSea latching contactor. That’s all I need and probably all anyone needs. If you are in a cold area, you shouldn’t charge, but that can me manually done (or automated easily too). I have never needed to worry about high ambient temperatures.

Lithium batteries are great for engine starting BTW. Here’s a company where I used to get my lead batteries in the day when that’s all the company made. Now they have seen the light and are pushing LFP pretty hard:

Sealed Lead Acid | Lithium Batteries | Powersport | Energy Storage - Power Sonic

 

[DuncanHall]

Victron make excellent kit but last time I looked the BMS was not included in the battery pack. It isn't a true drop-in (and all the better for that, IMO.) I wouldn't buy Winstons from GML. Julia Yu is the person to contact for sale direct from the factory. These are Grade A cells and are very well matched for capacity and internal resistance. I have read of numerous sales through her - although have had no direct contact myself. Everyone seems to have had a good experience and she will talk people through the rather nerve-wracking business of purchasing from the Far East. She is Hong Kong based and ships to all parts of the world. She can be directly messaged on Facebook but there is a more general email address. If using it, I would nevertheless endeavour to deal direct with her ... sales@skypowerintl.com

You are correct that the victron needs additional components external to the battery.

However this link shows that internally it looks very similar to a 123 BMS with some of the cell balancing internal. My original thought was to use the Victron Smart BMS 12/200 as this acts as a current limiter for the alternator and I can tune the alternator output by selecting an approrriate size fuse. I am intrigued that the BMS and limiter is about the same cost of a stirling 60A Battery to Battery Charger.

 

[geem]

I can say what I did, which may well suit you. I bought individual CALB cells (direct from China and done this way is cheaper long run than lead). I used a GWL BMS, which has all I need. Note it has no cell balancing, which I see as an advantage. On a previous installation I had one balancer fail and it took down the pack. I tried without a balancer and found I didn’t need it, so ran it for years happily like that. If you keep voltages well away from the ends, which you should do anyway to maximise life, cells don’t go out of balance. For example my 8 pack after 16 months is 4mV out highest to lowest and unchanged from the start. Most BMSs will not resolve that difference anyway.

The Mastervolt chargers are standard and I put them on fixed voltage output to suit. Ditto the alternator, but at a lower voltage to not overheat the alt. It goes through a Mastervolt Alpha plus charge controller.

I use the high volt level output to activate a relay to control latching high amp Panasonic relays to disconnect the alternator field and the two DC chargers and solar (to come). There is also a Broyce timer relay to shut down the genset. A buzzer and LED come on with the low volt output and another isolatable timer relay to start the genset. The emergency cut-off volt level output disconnects a BlueSea latching contactor. That’s all I need and probably all anyone needs. If you are in a cold area, you shouldn’t charge, but that can me manually done (or automated easily too). I have never needed to worry about high ambient temperatures.

Lithium batteries are great for engine starting BTW. Here’s a company where I used to get my lead batteries in the day when that’s all the company made. Now they have seen the light and are pushing LFP pretty hard:

Sealed Lead Acid | Lithium Batteries | Powersport | Energy Storage - Power Sonic

For motorbikes

 

[PCUK]

I'd stick with lead acid for starting. It's not worth the extra cost and complexity required to use another battery chemistry when lead acid does the job perfectly well - the battery is used to supply high current for short duration, and lead acid copes fine with that.

If you add LiFePo4 house batteries, don't use a diode or VSR to charge them, because that is quite likely to kill the alternator. Lithium batteries will pull as much current as they can get, and the alternator will overheat and fail. It also won't provide the lithium batteries with the ideal charging voltage. The simplest solution is to use a DC-DC charger sized to match the batteries and alternator. That will properly charge the batteries and also protect the alternator by regulating the current drawn from it. It will also prevent a sudden disconnection by the BMS from killing the diodes in the alternator. The starter battery would be maintained by the alternator directly.

Many thanks. I'm getting there!

 

[PCUK]

Having grasped dc-dc chargers is it now OK to use a VSR when charging two house batteries from the dc-dc charger to separate them for use with a 1-2-both switch?

 

[PaulRainbow]

Having grasped dc-dc chargers is it now OK to use a VSR when charging two house batteries from the dc-dc charger to separate them for use with a 1-2-both switch?

Not if you are fitting two Lithium batteries.

Even if fitting lead acid, it isn't a good idea to separate the two batteries, although you could potentially use a VSR.

I would suggest you post exactly what it is you are proposing to do and why you want to keep a pair of domestic batteries separate.

 

[PCUK]

OK. I've always used three batteries. One engine start for two engines and two separate house batteries via 1-2-both switch so I always had a house battery in reserve for when the first one went down. This warned me that I would need to charge the batteries in the near future but still have plenty to finish an evening off before the second one went down.
So my proposal is (and it's not in a tablet of stone so open to other suggestions) is to have a lead acid starter battery and two 105ah house batteries charged from the dc-dc charger but isolated from each other to give two selectable supplies via the 1-2-both switch.

 

[geem]

OK. I've always used three batteries. One engine start for two engines and two separate house batteries via 1-2-both switch so I always had a house battery in reserve for when the first one went down. This warned me that I would need to charge the batteries in the near future but still have plenty to finish an evening off before the second one went down.
So my proposal is (and it's not in a tablet of stone so open to other suggestions) is to have a lead acid starter battery and two 105ah house batteries charged from the dc-dc charger but isolated from each other to give two selectable supplies via the 1-2-both switch.

Separating your house bank into two halves is not a good idea. You effectively double the depth of discharge of your first battery. This has a detrimental effect on battery life. If you joined the two house batteries in parallel permanently your batteries will last longer. In addition you would get more efficient charging from you alternator withe larger domestic bank

 

[Zing]

For motorbikes

And bikes have engines just like boats. The point was they are great for starting engines contrary to what some people said.

Some Harley engines are bigger than many boat engines. Look at the spec sheets. You will see that even a tiny 2kg LFP battery should start most small to med sized diesels. I’d personally get a bigger one though.

 

[geem]

And bikes have engines just like boats. The point was they are great for starting engines contrary to what some people said.

Some Harley engines are bigger than many boat engines. Look at the spec sheets. You will see that even a tiny 2kg LFP battery should start most small to med sized diesels. I’d personally get a bigger one though.

So which battery can I buy at what cost to start my 4.4 litre engine. Hypothetical question since I dont want one and have already replaced the batteries for a shade over £200.
I am not Interested in saving weight or Introducing more electronics into the equation or reengineering my charging system or introducing a smart alternator regulator.
If I go lithium house bank in the future I would still keep my lead acid starter batteries and use a couple B2B chargers to charge from the alternator via the starter batteries if I ever needed to.

 

[PaulRainbow]

OK. I've always used three batteries. One engine start for two engines and two separate house batteries via 1-2-both switch so I always had a house battery in reserve for when the first one went down. This warned me that I would need to charge the batteries in the near future but still have plenty to finish an evening off before the second one went down.
So my proposal is (and it's not in a tablet of stone so open to other suggestions) is to have a lead acid starter battery and two 105ah house batteries charged from the dc-dc charger but isolated from each other to give two selectable supplies via the 1-2-both switch.

Geem is spot on in post #51.

If you are sticking with lead acid i would join the two leisure batteries permanently. If you don't already have an emergency parallel switch between the engine battery and the domestics, use the 1-2-both for that.

A battery monitor with a user selectable low voltage alarm could warn you of impending flat batteries. This would be much kinder to your batteries than running one flat and switching to the other.

I would question why you need a DC-DC converter. From what you have posted here, a VSR would be suitable.

 

[DuncanHall]

I have made a further discovery. in #45 is repeated the asertion that the Victron 200AH battery used Winston cells. Looking at the dimensions of the Winston cells this cannot be so as using Winstone cells would lead to a larger enclosure. Infact the energy density of the victron product is much higher. If my criteria 1 is not critical then it begins to justify the higher price of the victron unit. I have emailed 'sales@skypowerintl.com' to get a quote for 300AH worth of Winston cells delivered to the UK to inform my decision.

 

[PCUK]

Geem is spot on in post #51.

If you are sticking with lead acid i would join the two leisure batteries permanently. If you don't already have an emergency parallel switch between the engine battery and the domestics, use the 1-2-both for that.

A battery monitor with a user selectable low voltage alarm could warn you of impending flat batteries. This would be much kinder to your batteries than running one flat and switching to the other.

I would question why you need a DC-DC converter. From what you have posted here, a VSR would be suitable.

Now I'm getting really confused! Earlier I was told I needed the dc-dc charger to prevent the lithiums killing the alternator by drawing too much current. I believe that the alternator should be connected directly to the lead acid starter battery with the dc-dc charger connected in parallel so that the alternator feeds the starter battery directly and the dc-dc charger feeds the lithium house batteries. Am I correct so far?
If it is better to have one house bank then in that case I would be better off getting a single bigger (say 300ah) house battery.
Does that make sense or am I way off beam?
Thanks by the way so far!!!

 

[PaulRainbow]

Now I'm getting really confused! Earlier I was told I needed the dc-dc charger to prevent the lithiums killing the alternator by drawing too much current. I believe that the alternator should be connected directly to the lead acid starter battery with the dc-dc charger connected in parallel so that the alternator feeds the starter battery directly and the dc-dc charger feeds the lithium house batteries. Am I correct so far?

Apologies, i missed that you were fitting Lithium, in which case, you're correct.

If it is better to have one house bank then in that case I would be better off getting a single bigger (say 300ah) house battery.
Does that make sense or am I way off beam?
Thanks by the way so far!!!

Whichever is more convenient/cost effective.

 

[dankilb]

Correction - I confused the posters. The sentiment re: @PCUK ’s batteries still applies.

After going through a set of AGM batteries in just over 2 1/2 years

I think we’ve found out why…

Separating your house bank into two halves is not a good idea. You effectively double the depth of discharge of your first battery. This has a detrimental effect on battery life. If you joined the two house batteries in parallel permanently your batteries will last longer. In addition you would get more efficient charging from you alternator withe larger domestic bank

 

[PCUK]

Apologies, i missed that you were fitting Lithium, in which case, you're correct.



Whichever is more convenient/cost effective.

Thanks Paul, so is the set-up as mentioned above the right way to go? Obviously if that's the case then I'll go with the single larger house battery.

 

[dankilb]

If I were @PCUK I would (have another) go with AGMs.

This time do the wiring, split charging and monitoring ‘properly’ (no disrespect) as per advice on here.

Look after them and you could get a lot of the performance and life for the fraction of the cost of LiFePO4.