Lithium battery , charger , Honda 2000i generator

[wchancey]

We are new to the van dwelling scene , and wont have our maiden voyage until spring.
 We are going to be living in an e450 box van and solar on top is our eventual goal.
 But to start I would like to buy a 100w lithium battery , that can be charged , with a charger powered by a Honda 2000i generator.
 Question is this something that can be done rather quickly or does the charging process take hours.

 

[John TF]

Generally speaking , fast charging most chemistries can / or will shorten the batteries life .
When looking at lithium types , you should be much more informed than most other types , the issues can be a much bigger deal , than most other chemistries .
With the number of different lithium types , they are a number of things that make them more useable , again generally up to a point , they can be charged fast , they can be partially charged etc. without shortening there life .
I would suggest learning more , maybe with the smallest / cheapest components 1st to get feel for what the numbers are , the last thing you should do , is to just buy this & that without doing the math to design / build system .
With most any lithium , you want to make sure there is a BMS - Battery Management System , not all lithium batteries with have them built in .

 

[John61CT]

LFP is fine up to 3-4C charge rate, no harm done at all by high amps, just letting volts going too high or continuing to charge after trailing amps drops past .02C.

Don't buy a "drop-in" 12V but a pack of four bare cells, the internal BMS will limit charge rate.

Then you can charge from empty (actually 8-10%) up to your definition of Full - mine is 13.8V

in well under an hour.

In reality you will be limited by the amp rate of your charge sources.

80A is likely the most you can drive with that genny.

Sterling ProCharge Ultra and ProMariner Pronautic P are user adjustable wrt voltage setpoints, and I'm pretty sure both cab be derated if the full current output bogs the Honda down too much.

Note the "companion" version of the genny can output a bit more power without tripping the fuse, and two of them can be paralleled if you need higher output for some reason in the future.

You will need LVD and OVD protection, and ensure you van't charge in freezing temps.

You probably will never get around to getting solar, no need really

 

[John61CT]

Do not consider using NMC or LiPo chemistries, LiFePO4 only is safe for a van or boat House bank.

And prismatic bare cells only, not packs salvaged from EV or assembled from the 18650 cylinder cells.

 

[John61CT]

Here's my "boilerplate" LFP summary

Any and all feedback is welcome!

____
Bare cells: ​Winston/Voltronix, CALB, GBS, A123 & Sinopoly

Systems: OceanPlanet (Lithionics), Victron, MasterVolt, Redarc (Oz specific?)

Note nearly **every** vendor, also those of ancillary hardware touted as "LFP ready", gives charging voltages **way too high** for longevity.

My (conspiracy) theory is that manufacturers would prefer their cells get burned out in under 10 years.

EV usage is very different from much gentler House bank cycling. Most EV people talking "lithium-ion" mean other chemistries not as safe as LFP, much shorter lifetimes, and with completely different setpoints and behaviors.

My charge settings for LFP: 3.45Vpc which = 13.8V max for "12V".

Either stop when voltage is hit, or if you want another couple % SoC capacity, stop when tailing amps hits endAmps of .02C, or 2A per 100AH. Note even at the "low" max charge voltage, letting the charge source continue to "push" even low currents long past the endAmps point is **over-charging, and will** greatly reduce lifecycles.

If you can't then "just stop", set Float at 13.1V, but that is a compromise, and *may* shorten life cycles.

With LFP, you don't need to fill up all the way at all, as far as the cells are concerned, in fact it is bad for them to sit there more than a few minutes. Therefore only "fill up" if loads are present, ready to start discharging, ideally right away.

Store the bank as cool as possible and at 10-20% SoC, or maybe higher to compensate for self-discharge, if not getting topped up regularly (I would at least monthly). Letting the batts go "dead flat" = instant **permanent unrecoverable** damage. 

Same with charging in below 32°F / 0°C freezing temps.

Persistent high temps also drastically shortens life.

Charging at 1C or even higher is no problem, as long as your wiring is that robust, vendors may spec lower out of legal caution.

Going above 14V won't add much AH capacity, but will shorten life cycles dramatically.

The point is to look at the SoC vs Voltage chart, and avoid the "shoulders" at both ends, stay in the smooth parts of the curve. And of course, we're taling about gentle "partial C" House bank discharge rates, size appropriately and be careful feeding heavy loads like a winch or windlass.

Following these tips, letting the BMS do active balancing is unnecessary and potentially harmful, just look for LVD / OVD and temp protection. Multiple layers of protection are advised if it is a very expensive bank, don't rely on any one device to work.

Check cell-level voltage balance say monthly to start, then quarterly, finally every six months if there are no imbalance issues, but only if that seems safe to you.

This thread is long but informative
LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks , make sure to give both Maine Sail and Ocean Planet your close attention.

Also MS' summary notes here
http://www.pbase.com/mainecruising/lifepo4_on_boats

**Everything** at that site is worth reading, very valuable. He also has great articles in Practical Sailor. His new site under development transitioning the pbase content is here

https://marinehowto.com/support , feel free to make a donation to help with those expenses.

Best of luck and do please report back here.

 

[frater secessus]

But to start I would like to buy a 100w lithium battery , that can be charged , with a charger powered by a Honda 2000i generator.
 Question is this something that can be done rather quickly or does the charging process take hours.

I assume you mean 100Ah (amp-hours) lithium battery.

In practice Li charges faster than lead-acid because the latter slow down significantly after Bulk. Li keeps taking big current right up to your stopping point.

Li + a generator is a good fit. I don't have either one but your described use sounds fine.

 

[29chico]

Here's my "boilerplate" LFP summary

Any and all feedback is welcome!

____
Bare cells: Winston/Voltronix, CALB, GBS, A123 & Sinopoly

Systems: OceanPlanet (Lithionics), Victron, MasterVolt, Redarc (Oz specific?)

Note nearly **every** vendor, also those of ancillary hardware touted as "LFP ready", gives charging voltages **way too high** for longevity.

My (conspiracy) theory is that manufacturers would prefer their cells get burned out in under 10 years.

EV usage is very different from much gentler House bank cycling. Most EV people talking "lithium-ion" mean other chemistries not as safe as LFP, much shorter lifetimes, and with completely different setpoints and behaviors.

My charge settings for LFP: 3.45Vpc which = 13.8V max for "12V".

Either stop when voltage is hit, or if you want another couple % SoC capacity, stop when tailing amps hits endAmps of .02C, or 2A per 100AH. Note even at the "low" max charge voltage, letting the charge source continue to "push" even low currents long past the endAmps point is **over-charging, and will** greatly reduce lifecycles.

If you can't then "just stop", set Float at 13.1V, but that is a compromise, and *may* shorten life cycles.

With LFP, you don't need to fill up all the way at all, as far as the cells are concerned, in fact it is bad for them to sit there more than a few minutes. Therefore only "fill up" if loads are present, ready to start discharging, ideally right away.

Store the bank as cool as possible and at 10-20% SoC, or maybe higher to compensate for self-discharge, if not getting topped up regularly (I would at least monthly). Letting the batts go "dead flat" = instant **permanent unrecoverable** damage. 

Same with charging in below 32°F / 0°C freezing temps.

Persistent high temps also drastically shortens life.

Charging at 1C or even higher is no problem, as long as your wiring is that robust, vendors may spec lower out of legal caution.

Going above 14V won't add much AH capacity, but will shorten life cycles dramatically.

The point is to look at the SoC vs Voltage chart, and avoid the "shoulders" at both ends, stay in the smooth parts of the curve. And of course, we're taling about gentle "partial C" House bank discharge rates, size appropriately and be careful feeding heavy loads like a winch or windlass.

Following these tips, letting the BMS do active balancing is unnecessary and potentially harmful, just look for LVD / OVD and temp protection. Multiple layers of protection are advised if it is a very expensive bank, don't rely on any one device to work.

Check cell-level voltage balance say monthly to start, then quarterly, finally every six months if there are no imbalance issues, but only if that seems safe to you.

This thread is long but informative
LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks , make sure to give both Maine Sail and Ocean Planet your close attention.

Also MS' summary notes here
http://www.pbase.com/mainecruising/lifepo4_on_boats

**Everything** at that site is worth reading, very valuable. He also has great articles in Practical Sailor. His new site under development transitioning the pbase content is here

https://marinehowto.com/support , feel free to make a donation to help with those expenses.

Best of luck and do please report back here.

Wow, someone who has got it together on properly using LFP for a house bank.  Especially agree on the 13.45Vpc and not using a BMS.  

Anyone thinking about going with LFP needs to be both very knowledgeable and consistently dedicated to doing the right thing for their house battery bank or loads of $$$ will probably be flushed down the drain.

 

[John61CT]

(Blush) why thank you!

If you have corrections or additions do please let us know.

And BTW good form here to trim long quotes

 

[jonyjoe303]

[font=Verdana, Arial, sans-serif]Question is this something that can be done rather quickly or does the charging process take hours.[/font]

[font=Verdana, Arial, sans-serif]100ah lifepo4 you buy most can be charge at 100 amps, those batteries are all what is called 4S type of lithium packs, 4 rows of 3.2 volt cells to get 12.8 volts.[/font]

[font=Verdana, Arial, sans-serif]When you fast charge them, they charge at maximum amps until one row of batteries reaches 3.65 volts then the bms starts draining the high cell or cutsoff the charging. If the battery is severely out of balance you will never get a full charge but it will be close enough.[/font]

[font=Verdana, Arial, sans-serif]This is a picture of my lifepo4, I monitor overall voltage and each roll of cells voltage, its the only way I know for sure if the battery has got a full charge. If all 4 LEDs on the right read 3.65 volts its fully charge and I never see that unless its connected to a balance charger.[/font]

 

[John61CT]

Sorry but all that may be true for some specific make or model, but none of it applies to the usual prismatics used for House banks.

No matter the AH capacity, if you have a big enough charge source you can safely recharge a completely depleted LFP bank back to Full in under an hour.

Period.

If your BMS prevents you from doing that when you want to, you bought the wrong product.

 

[blars]

If you charge at over 1/2 C (two hours to full charge) you need to worry about balancing, overheating, and cell swell. So I recommend not doing so, just charge at less than 1/2 C. If you keep the charge and discharge rates less than 1/2 C, anecdotal evidence shows auto-balancing boards are about as likely to cause a failure as to prevent one. Selling means lost capacity, so you need pressure plates to compress the sides to prevent it when fast charging.

 

[John61CT]

No, long as you keep voltage down charging at high amps won't cause problems.

Even at low amps, going up above 3.5 will.

Can go for years with House usage without any rebalancing, no per-cell hardware needed while cycling normally, causes more harm than good.

And of course about needing plates.

 

[frater secessus]

Whether or not it's required, I plan to follow blar's sub-C approach when I go LFP. Probably a non-issue since I don't plan to have any big charging sources or giant loads. haha

 

[John61CT]

Yes I'll go along with that.

Once you get over 800AH or so, pretty hard to get past .5C anyway.

 

[scottorious]

Do not consider using NMC or LiPo chemistries,  LiFePO4 only is safe for a van or boat House bank.

And prismatic bare cells only,  not packs salvaged from EV or assembled from the 18650 cylinder cells.

Why not? I recognize that a boat might not be the best place but I put immense load on my EV batteries every time I hit the accelerator and when I put the Volt in mountain mode the internal generator dumps huge amounts of power into the battery all while I'm sitting just inches away. With conservative charging and useage the salvaged volt cells that everyone is using are staying incredibly balanced without a BMS. With a BMS it seems like they are pretty solid sells. Several folks are thrashing the Volt cells in homebuilt electric cars and they seem to be operating just fine.

 

[John61CT]

Why not? I recognize that a boat might not be the best place but I put immense load on my EV batteries every time I hit the accelerator and when I put the Volt in mountain mode the internal generator dumps huge amounts of power into the battery all while I'm sitting just inches away. With conservative charging and useage the salvaged volt cells that everyone is using are staying incredibly balanced without a BMS. With a BMS it seems like they are pretty solid sells. Several folks are thrashing the Volt cells in homebuilt electric cars and they seem to be operating just fine.

Yes I was not talking about EV usage, I have no interest getting into that at this point.

My statement applies to House usage, building protective electronics around LFP prismatics is proven, safer and (at least more) familiar for knowledgeable DIY.

Trying to replicate all the protective systems used by the professional engineers in commercial EV is way too far out of my comfort zone, and the more I learn about it the more that is true.

Read about the Dunning-Kruger effect and try to avoid getting trapped by it.