Lithium battery for caravan

Submitted: Tuesday, Oct 16, 2018 at 17:13
ThreadID: 137356 Views:11072 Replies:10 FollowUps:18
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I know this has been asked before but the latest information is 12 months old.
Has anyone successfully installed a Lithium battery into an existing newish caravan. The new Lithium will replace the AGM's
I have 2 x 120A/h AGM batteries, 1 has died after 4 years, Ctek MXS25 mains charger and a 30amp DC-DC ABR charger which does solar and 12V from car charging.
I understand the existing charge voltage may not be quite enough for the Lithium battery as it requires 14.6V to fully charge to 100%
I'm thinking of going with a 150A/H which has a BMS attached from Ozimall. I have a quote from a recommend SA company but over $6000,00 is a little out of my league.
Has anyone done this?
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Reply By: Keith B2 - Tuesday, Oct 16, 2018 at 18:06

Tuesday, Oct 16, 2018 at 18:06
Here is a recent thread on the subject.
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Reply By: Greg J1 - Tuesday, Oct 16, 2018 at 19:03

Tuesday, Oct 16, 2018 at 19:03
Seems to be a fair debate on lithium caravan batteries on here about a week ago. You may need to double click the search button, dunno.

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Reply By: David G (WA) - Tuesday, Oct 16, 2018 at 19:07

Tuesday, Oct 16, 2018 at 19:07
Check the following link to some lithium batteries that do not require a special charger.

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Reply By: RMD - Tuesday, Oct 16, 2018 at 19:14

Tuesday, Oct 16, 2018 at 19:14
From discussions I thought a 150ah Lithium would cost a little over $2000, charging systems excluded. The onboard BMS is a control for equalising cell charge levels and not the actual charging supply. $6000 seems to be a long way above reality. Probably best to shop/ask around to verify you aren’t’ being dudded by a recommended company.
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Follow Up By: Geoff K4 - Tuesday, Oct 16, 2018 at 21:44

Tuesday, Oct 16, 2018 at 21:44
RMD yes over $6K is way to much, I've been quoted $1700 for a 150A/H buy and drop in with existing electronics albeit the battery will not deliver the full power due to lower charging volts. A Lithium charger may arrive when funds permit.
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Reply By: Keith B2 - Tuesday, Oct 16, 2018 at 20:15

Tuesday, Oct 16, 2018 at 20:15
I just took delivery of two 200AH lithiums complete with BMS delivered for $3,891 inc GST and freight. The supplier says that my AGM settings of 14.4 charge and 13.6 float will be fine. It's worth shopping around as prices are all over the place with these things.
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Follow Up By: Geoff K4 - Tuesday, Oct 16, 2018 at 21:41

Tuesday, Oct 16, 2018 at 21:41
Thanks Keith, most recent info is dated Oct 2017. But I guess it's relevant. The BMS included in battery that I'm looking at is to protect the battery from over charge and low discharge. My battery-mate cuts discharge at 11.5V. And yes charge to 14.4 is fine the battery just won't get to 100%
The $6K+ quote was virtually rewiring the van and supplying all new electronics which I had. Battery in the quote was for only 160A/H. I was quoted for 200A/H Lithium for around $2K, 150A/H is $1700.
Thank you to the other responses.
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Follow Up By: Malcom M - Wednesday, Oct 17, 2018 at 07:16

Wednesday, Oct 17, 2018 at 07:16
You don't float Lithiums!
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Follow Up By: HKB Electronics - Wednesday, Oct 17, 2018 at 13:55

Wednesday, Oct 17, 2018 at 13:55
I have had a Lithium setup for around three ears now. I have 2X100Ah Lithiums in my setup, these have cell balancers on the cells but to date I have not needed them. I generally charge these with the A/C charger set to power supply mode which is 13.8V, there is no need to charge them any higher as they will charge to very close to 100% charge at this level. If I increase the charge voltage to 14.2V or higher once the Lithiums stop taking charge they will only resume charging for a few minutes them stop again.

Once charged I turn the charger off if not using the batteries. Off car charging is via DC/DC Lithium capable charger which I have set to max charge voltage of 14.2V (minimise recharge times) it them then turns off. It will resume charging when batteries drop to around the 90% SOC, or the car is restarted.

As far as I can see most suppliers who recommend higher charge voltages are also recommending you buy one of their cell balancing systems, or their batteries have integrated cell balancers/BMS. Generally these require around 14.6V or higher for them to allow them to function, if the cells aren't out of balance you don't need to cell balance. I have been using my system for around three years now, discharge the Lithiums generally to a max of 50% SOC but have gone to 20% at times, I have had no issues with cell balance and have not needed to raise charge voltage to 14.6V for the cell balance system.

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Follow Up By: Geoff K4 - Wednesday, Oct 17, 2018 at 14:14

Wednesday, Oct 17, 2018 at 14:14
Thanks for that info HKB
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Reply By: PhilD - Tuesday, Oct 16, 2018 at 23:32

Tuesday, Oct 16, 2018 at 23:32
In my view, many of the offerings in the market place are overpriced. If you have even basic 12v knowledge look at building your own using 4 3.2v cells, BMS, connections, wiring, etc which are all readily available. You should match the charger, both BCDC and 240v to the chemistry of the cells. Some are recommended at 14.2v, others at 14.4 and some at 14.6v. I have a home built 400 Ahr system that works fantastically, runs my air conditioner, coffee machine, microwave when needed, hair dryer, 3 fridges/freezer and every other gizmo one might need to live in luxury on the road. I would not go back to AGM when you have the choice of going Lithium.
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Follow Up By: Geoff K4 - Wednesday, Oct 17, 2018 at 08:30

Wednesday, Oct 17, 2018 at 08:30
Thanks Phil, Perhaps you could share your knowledge on how to build up a Lithium? I have an electrical background and some 12V knowledge but the Lithium has been made to appear a very different beast requiring different attention.
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Follow Up By: PhilD - Wednesday, Oct 17, 2018 at 11:54

Wednesday, Oct 17, 2018 at 11:54
Geoff, have a look at EV Works or EV Power for the cells of the size you want. You need 4 for a 12v system. Then the braided connections, BMS, possibly a relay depending on how you want to control the BMS, and then the wiring is reasonably straightforward. You need to ascertain the best charge rate for the cells you use, and match the charging of your solar controller, BCDC charger, and 240v charger accordingly. The solar will depend on the size of your panels (I have used GSL), and I have used a Sterling BCDC charger as it has 9 settings built into it. I have a Tortech Inverter/Charger with multiple settings for the 240v side. I think the Enerdrive chargers can be custom programmed so that is worth looking at. Someone like EV Works can help you set the system up on the battery/BMS side. Obviously, size the cable to match the currents. I have used midi fuses as appropriate, as much better than the 2 pin fuses.
For my Winston cells I charge at 14.2v and float at 13.5v. The wiring is conventional. It is the BMS and charging that can be different to AGM/LA setups.
The BMS /relay is really an overlay over the 4 cells that are in series to cut the draw/charging off when thresholds are exceeded. I hope this makes sense. If not please call me on 0407976872.
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Follow Up By: RMD - Wednesday, Oct 17, 2018 at 15:18

Wednesday, Oct 17, 2018 at 15:18
Thanks to PHILD.
That info is the first real usable info anyone has supplied or presented, even after reading the caravan forum reference in the next reply.
I guess much time and research has been done by Phil to arrive at a system which can be fitted by a skilled/competent person.
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Follow Up By: PhilD - Wednesday, Oct 17, 2018 at 15:27

Wednesday, Oct 17, 2018 at 15:27
It is not that hard! I am an accountant, and can build a great system! You just need to know there is positive and negative, and current flows from its source to its destination, and how to size cables appropriately, crimp and solder properly, etc but practice makes perfect. If you fuse correctly, not much can go wrong.
Give it a go! If needed, I am happy to answer any questions.
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Follow Up By: Allan B (Sunshine Coast) - Wednesday, Oct 17, 2018 at 16:16

Wednesday, Oct 17, 2018 at 16:16
No Phil, It is not like a cash flow, "flowing from its source to its destination".
Electric current flow is much better.... the electrons all come back to the source!

No wonder accountants and engineers never see eye-to-eye. lol

EDIT: Saturday, Oct 20. I'm uncertain of their sense of humour too!

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Reply By: Member - wicket - Wednesday, Oct 17, 2018 at 11:43

Wednesday, Oct 17, 2018 at 11:43
Most of what you are looking for will probably be found here, discussion is about 10 pages long so you might need to settle in with a coffee.
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Reply By: Bill R5 - Friday, Oct 19, 2018 at 17:27

Friday, Oct 19, 2018 at 17:27
I've juts been through this exercise TWICE.

Firstly I replaced the three 100ah AGMs in the Chevy's canopy with a single 120ah Lithium from Itechworld @ $849-. Although they said my existing charging regime would be okay (I had a Redarc SBI-12 and a CTech 25amp 240v and a Steca solar regulator), I decided to upgrade anyway. I installed a 20 amp Enerdrive EN31220 240v charger and a Redarc BCDC1225D to do the solar and the engine powering. I've also installed a Victron BMV700 monitor because voltmeters are not worth anything with lithiums. The voltage just stays around 13.2 virtually all the time. It's the % state of charge that is what you need to monitor.

Secondly, I've just ripped out four 100ah AGMs from the caravan and installed three Solar King 100ah Lithiums @ $760- each.

I'm still using the Projecta 50amp 240v charger and the Morningstar 60amp solar gizmo. The caravan didn't previously have a DC-DC charger, so I'm fitting a Enerdrive DC2DC 40+ amp charger using the existing Anderson plug wiring.
Weight saving is enormous: 220kg out and about 50kg back in.

I couldn't be happier with how these units are performing, but it is early days.

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Follow Up By: Bill R5 - Friday, Oct 19, 2018 at 19:54

Friday, Oct 19, 2018 at 19:54
I've just been reading on the caravaners forum, and I'm now concerned that perhaps I've made a rash decision that could come back and bite me;

Have a look at this video:

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Follow Up By: HKB Electronics - Friday, Oct 19, 2018 at 20:14

Friday, Oct 19, 2018 at 20:14
Personally I avoided the drop in solutions for some of the reasons raised in the video. I went with built up batteries, 2X100Ah units that have cell balancers on each cell and the BMS that monitors all cells of both batteries. The isolation solenoid is rated 240A.

The video though is rather misleading, the BMS as pointed out will disconnect the batteries when they reach a critically low level, in my unit from memory is 10.5V, it is a last line of defence, if your running the batteries down to that level your asking for trouble, in a well designed system you will have a low voltage cut out installed that will isolate the batteries well before that level is reached.
Same applies for overvoltage, the BMS is a last line of defence, having another protection device would be a good idea.

Most good quality BMS's like the Victron units will also have overvoltage and under voltage alarms which can be used to trigger protection devices.

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Follow Up By: Member - shane r1 - Friday, Oct 19, 2018 at 22:08

Friday, Oct 19, 2018 at 22:08
Thanks Roachie
Great info, makes sense , good on enerdrive for putting it out there.
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Follow Up By: PhilD - Friday, Oct 19, 2018 at 22:41

Friday, Oct 19, 2018 at 22:41
My Zeva BMS cuts out at 11.4v, which is much more suited to my Winston cells.
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Follow Up By: HKB Electronics - Saturday, Oct 20, 2018 at 09:47

Saturday, Oct 20, 2018 at 09:47
To me the other issue here is the terminology used, most I believe if you mention BMS one thinks of something like a Victron or the Enerdrive Epro series of battery management systems that monitor current/voltage/wattage/SOC etc.

This not the case with Lithium BMS's, these systems as battery protection systems rather than battery management systems and are required to prevent catastrophic battery fail. They may also include cell balancing devices. These battery protection devices are the last line of defence to protect the battery and shouldn't be depended on for normal under and over voltage protection as they are not designed for this. All systems should have a separate under and over voltage protection devices that will operate before the batteries fail safes do.

The bottom line is if you intend to install a Lithium system yourself you need to do some research and find out what is actually required and how the systems operate. Don't take everything the suppliers say as gospel, do your own research. For instance one of the suppliers mentioned here insists that a cell balancing system must be installed to protect the battery, they also state that a charger set to GEL setting ie14.2V will be fine to charge the battery, funny thing is if you read up on their cell balancing system you'll find it requires a charge voltage of at least 14.6V from memory for it to be able to do its thing.

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Follow Up By: PhilD - Saturday, Oct 20, 2018 at 23:13

Saturday, Oct 20, 2018 at 23:13
I have under and over voltage cut out using the Zeva board, and have monitoring of the voltage of the individual cells. They do not automatically rebalance, but in the past 4 years the cells have stayed perfectly balanced, so the extra electronics would be a wasted cost. This is with Winston cells.
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Follow Up By: HKB Electronics - Sunday, Oct 21, 2018 at 11:15

Sunday, Oct 21, 2018 at 11:15
Same here, three years no balance issues, the video from Enerdrive is rather vague, it implies they are having warranty issues due to the low voltage cutouts failing in their batteries, this appears to be caused by the cut outs operating at currents higher than the batteries rated current which they indicate rather vaguely was 100A for their 100Ah battery.

Now that's rather odd as if the battery is tripping due to low voltage and generally the low voltage cutout limit is very low way under what one would consider 0% SOC, how is the battery able to supply more than its rated current at such a low voltage?

They then allude to cell balance issues caused by the batteries being in parallel the cause of the problem. I and many others are running batteries in parallel and have no such issues?

It would therefore seem they have two issues:

1/ Cell balance issues in their batteries, maybe they need to look at the quality of their cells?

2/ Their low voltage cuts might not be up to the job. This would not surprise me, if you look at a built up 100Ah Lithium battery its physical size is around the same size as a equivalent AGM battery, the protection module on my batteries is rated at 240A and is around a third the size of one of the batteries, cramping suitable circuit into a drop in replacement type unit that can handle the currents involved would not be an easy thing to do.

They also imply other brands would have similar issue, do they? Personally I suspect that all similar looking units are probably made by the same company and branded as per the buyers requirements so maybe they are correct in that regard?

They then go on to say buy a bigger battery rather than two smaller ones, hmmm I wonder how much the bigger unit cost compared to the smaller ones and who's to say you won't get the same cell balance issues with the bigger battery? Also if you have two 100Ah batteries there is a reason for it as one 200Ah would cost less, you most likely have two batteries due to space constraints, at least that is why I have two batteries. Maybe they should have just been up front and advise customers buying two of their batteries that they don't work well together?

Also they then go on to say if you require higher capacity and load handling ability go for their larger battery or their system that uses built up batteries and separate control units. This again implies the BMS units in the smaller batteries and possibly cells aren't up to the job, but then as I have already written you shouldn't be relying on the batteries low voltage cutout for this function.

When I looked at the drop in solutions three years back I decided not to go that path though it would have been the more elegant and the simplest solution. My concerns were those now being raised by Enerdrive and I'm glad I went with built up battery packs and separate control units.

I'm also rather surprised that company that claims to have such a deep knowledge of Lithium batteries made no mention of not relying on the batteries protection device for normal day to day operation as that is not what it is intended for and most likely will fail if used as the only low voltage cutout. The company I purchased my batteries from made it very clear that the batteries protection system is the last line of defence and separate protection devices must be installed that operate prior to the batteries own device under normal conditions.

I had a quick look at an Enerdrive battery on Ebay and it doesn't appear to have any internal cell balancing system, if this is the case it is another good reason to steer clear of this type of battery as ceell balance issues will result in them being a rubbish bin job, though as I written above, my personal as yours is that good quality cells don't go out of balance.

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Reply By: Allan B (Sunshine Coast) - Saturday, Oct 20, 2018 at 20:56

Saturday, Oct 20, 2018 at 20:56
I hope you guys have got this Lithium thing under your belt before I need to replace my AGM's in a couple of years. I can see that I will need assistance from your experience. lol

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Follow Up By: Member - Blue M - Monday, Oct 22, 2018 at 06:07

Monday, Oct 22, 2018 at 06:07
Same here Allan, I will be looking to renew/replace in a couple of years as well.
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Reply By: Dean K3 - Thursday, Oct 25, 2018 at 18:01

Thursday, Oct 25, 2018 at 18:01
Plenty of various opions out there to point its bewildering.

Anywhoo few weeks abck had a 2 week jaunt through goldfields kal-menzies- lenoroa sandstone then back down to big smoke.

whilst locked in a leonora due to wet roads and nasty wether spoke to bloke from up Derby who had one of the those odd looking hybrid KK units that looks more like a horse float with a few windows.

he mentioned he had attended a KK owners meet up down Margaret river way and a local bloke manufactured LiFePO4 batteries and charge controls etc and sells systems suiatble from powering a caravan upto a electric car and full RAPS using solar paenls batteries and back up gennie

Might be worth following up have a conversation see what they suggest

I admit would take fair bit of convincing for me to spend $800 + on one battery but if they cost came down then I'd consider my options

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