Lithuim AND Lead acid in same bank?

[Fendell]

Trawling YT last night and came across an interesting Vid that I would like to put to the brains trust, has this been discussed yet? sorry if so.

The fella makes good points about the way his hybrid system works, and in theory it should work well as long as all the parameters he speaks about are met. With modern systems and the monitoring available would this be enough to stop any damage with mixing chemistry?

I will say though, from an engineering point of view any one trying this needs to heed the warning about making sure the voltages are the same before linking the two batteries, as that could get very ugly...

Thoughts?

https://www.youtube.com/watch?v=tAuPfgZgXec

[Dockhead]

Been discussed a few times over the years.



https://www.cruisersforum.com/forums...rs-244279.html


https://www.cruisersforum.com/forums...id-206572.html


https://www.cruisersforum.com/forums...en-206424.html

[Adelie]

I didn’t watch and am not going to but am curious if he’s actually put them in a system and used them for an extended period, say 3-12mo?0

[Fendell]

Originally Posted by Dockhead

Been discussed a few times over the years.



https://www.cruisersforum.com/forums...rs-244279.html


https://www.cruisersforum.com/forums...id-206572.html


https://www.cruisersforum.com/forums...en-206424.html

Cheers Dockhead, I searched but struggled with what to search for prob should have keep trying haha

Originally Posted by Adelie

I didn’t watch and am not going to but am curious if he’s actually put them in a system and used them for an extended period, say 3-12mo?0

I think he mentions its been in for 12 months? Its a really good vid, very clear delivery.

[ikanode]

I mix both Li & Pb but I use a Victron DC-DC converter in between and I charge them separately.

https://www.victronenergy.com/dc-dc-converters

When my current Pb bank dies, I'll probably switch to all Lithium.

[MJH]

Originally Posted by Fendell

Trawling YT last night and came across an interesting Vid that I would like to put to the brains trust, has this been discussed yet? sorry if so.

The fella makes good points about the way his hybrid system works, and in theory it should work well as long as all the parameters he speaks about are met. With modern systems and the monitoring available would this be enough to stop any damage with mixing chemistry?

I will say though, from an engineering point of view any one trying this needs to heed the warning about making sure the voltages are the same before linking the two batteries, as that could get very ugly...

Thoughts?

This is not for me; to begin with I don't need all the power that this guy apparently does. I don't want to stifle progress and will let others get the bugs out of any new idea before I think of putting it into my boat. I will stick with the rule of using all batteries of the same chemistry.

~ ~ _/) ~ ~ MJH

[noelex 77]

A combined lithium and lead acid battery bank is not unusual and has been advocated on many occasions.

However, normally the lead acid is aimed at eliminating the problems if the lithium BMS disconnects the system. The lithium bank is large and the lead acid battery is small.

The video proposes a different combination where the lead acid bank is much larger than the lithium bank and serves a different role.

Whether or not this is a good idea is not clear, but I don’t think the concept should be judged as the same as the more conventional lithium/lead acid hybrid bank that has a large lithium bank with a small lead acid battery.

[Fendell]

Originally Posted by noelex 77

A combined lithium and lead acid battery bank is not unusual and has been advocated on many occasions.

However, normally the lead acid is aimed at eliminating the problems if the lithium BMS disconnects the system. The lithium bank is large and the lead acid battery is small.

The video proposes a different combination where the lead acid bank is much larger than the lithium bank and serves a different role.

Whether or not this is a good idea is not clear, but I don’t think the concept should be judged as the same as the more conventional lithium/lead acid hybrid bank that has a large lithium bank with a small lead acid battery.

My thoughts exactly, its a different way than most of the combinations i have read on here, and online in general. it is in theory a cost effective means of having a large AH bank, with the robust reliability of FLA as redundancy.

[Cpt Mark]

I saw this last night too. Very nice video, very clear and if you want more info you join his patreon at the top tier and he'll talk to you.

Batteries, no matter what their chemistry, have to be charged at specific voltages for specific lengths of time to get fully charged. He does not do this. He also states that with lithium you can deplete it 100% and recharge it but with FLA you can only deplete the 80%. yes, you could do that with either but you will vastly shorten their lifespans. His claim of 15 years cruising, on the hook, with the same FLA battery setup I find difficult to believe.

[tedowens]

I have been using LiFePO4 and AGM together in the same bank for almost a year. I am a full time live aboard. I have 400 Ahr of AGM and 400 Ahr of Li. I charge them from a 10 year old battery charger on a Gel Cell cycle with 14.1 max volts, alternator using a DC/DC charger on a Li cycle (14.2 V), and Solar panels with a Li cycle (14.2 V). I have been on the hook for months at a time and in marinas for months also. Everything works great and I am loving them. I have run them down to 20% SOC, with no problems. At first I checking their temperatures and I haven't found any heat build up. The reason that I put them in the AGMs is to provide a "shock absorber" in the system incase the Li BMS shuts them down suddenly. Watching this video, I see that their are other advantages. Also, I will still have some batteries to use if the Li shuts down, so it gives a backup if needed.

[johnn33]

Interested and listening
John

[jhulmer]

I watched the other night also and found his explanation reasonable! He has been using/testing this system for over a year with no issues and good results.

Looking forward to further comments from others qualified in this field. I would love to install two liPo4 batteries.

Jim

[Rocketpilot]

Perhaps this link is of interest. Just got to know it recently. A major German RV company (Hymer) uses their system meanwhile also.
https://www.bos-ag.com/products/le300/



Regards Klaus (based in Munich)

[Isba]

Hello Klaus I have my sailing boat in Nea Peramos near Kavala.

[Isba]

http://nordkyndesign.com/electrical-design-for-a-marine-lithium-battery-bank/
This is not rocket technic it is cheap and it works ith less electronic systems see this page for advanteges and disadvantages.