Lithium v AGM

[Adrianp 137]

These are the LiFePO4 cells that we have just got for Lady Nada -  8 x Winston 300ah cells to give 600ah @12V. They get some pretty good abuse in this video without catastrophic failure.

 

[CarpeDiem 539]

11 hours ago, erice said:

so the lithium iron phosphate batteries you speak of are not the lithium ion batteries that thermally ran away and caused these problems 4 years ago?

No, different chemistry.  The hoverboards and the Samsung batteries, (and the batteries in the fatal battery glider story, mentioned above), were Lithium Polymer batteries or more correctly lithium-ion polymer (abbreviated as LIP, LiPo, Li-poly, lithium-poly and otherways) - the hoverboard chemistry was specifically LiCoO2 - Samsung was probably the same chemistry as are most small electronics.

Lithium Polymer is, (generally), no good on boat cause the nominal voltage is too high (3.6v - 3.9v depending on chemistry) and all of our electronics is designed to run at 12/24/48v and LiPo doesn't fit very well into that range.

Lithium iron phosphate batteries, abbreviated LFP, (generally), have the chemistry LiFePO4 and these are what you will find on boats and household solar installations, the nominal voltage is 3.3v which fits better with a 12v system and all the parts/things available that come for 12volts.

A new, (relatively speaking), player in town is the Lithium iron yttrium phosphate battery LiFeYPO4 - this is (according to the people that make them) superior to LiFePO4 but still has all the safety benefits.

[CarpeDiem 539]

50 minutes ago, Adrianp said:

These are the LiFePO4 cells that we have just got for Lady Nada -  8 x Winston 300ah cells to give 600ah @12V. 

If they are new, then they will be LiFeYPO4 - lithium iron yttrium phosphate - a very safe battery from a reputable manufacturer.

[erice 732]

Thanks, very educational

[waikiore 501]

Still dont understand the cost versus what you really get with lithium types versus AGM, particularly when I have had a great run with AGM and comparatively safe also not requiring a specialised charging regime.

[Island Time 1,313]

1 hour ago, waikiore said:

Still dont understand the cost versus what you really get with lithium types versus AGM, particularly when I have had a great run with AGM and comparatively safe also not requiring a specialised charging regime.

Well, thats pretty easy. Very basically - and please read the PDS for any you may consider using, but:

WAY more cycles.

Use of complete battery capacity (use till voltage drops, then recharge)

WAY WAY faster recharge - full charge source output until full, no charge tapering. 

[CarpeDiem 539]

1 hour ago, waikiore said:

Still dont understand the cost versus what you really get with lithium types versus AGM, particularly when I have had a great run with AGM and comparatively safe also not requiring a specialised charging regime.

The only true benefit is a weight/space saving.

Every battery has a special/optimal charging regime so this is kind of moot.  It's just that your very used to your current charging regime and don't even see it as a regime any more.

Lots of factors to consider. In a nutshell, if you have enough power and charging to meet your needs then why change?  If you want to add more power reserves then lithium might be a cost effective way to do this over the long term. 

There are lots of benefits, but if they are worth it to you is always going to be a personal choice.

For us it's a no brainer, we need to install an electric fridge, there is no room for another AGM battery and I hate putting hours on the engine to just charge the battery. Your mileage will vary based on your needs. 

In summary, if someone wants more power and they want to be able charge faster, then lithium should be seriously considered, especially so if the existing AGM Bank is due to be replaced.