Ecotree Lithium Install

[Mrjenben]

We were a lucky winner of the recent 50% discount offer from Ecotree on one of their 120Ah Lithium batteries. This was great timing, as although our current batteries are still performing OK, they are coming up to 6 years old.

So following a chat with Rob at Ecotree we decided to get the new battery and update our installation ourselves.

We have a Hymer Exsis 578I, and the standard install was a single Varta AGM 95ah battery and an Electroblock EBL29. From new I added a second Varta battery and an Schaudt LRM 1218 MPPT solar regulator with a 150w solar panel. This has worked well, supporting us for long stays off grid when touring in the summer.

The main aim for the update is to save some weight, and freshen up our batteries. Although they were still ok for our use, they must have lost some capacity over time. The last thing we want is for them to fail while were travelling.

After checking our install with Rob he agreed that a simple battery swap would work well.

The capacity of our 2 AGMs was 190ah when new. This would give a useable max of 95ah which is probably now down to 70-80ah max, probably less given the way lead acid batteries charge/discharge. The new 110ah Lithium will easily match or beat this, even if we stick to a conservative 75% discharge use.

The gel setting on the EBL29 would be suitable, and by switching the charge profile on the LRM1218 to AGM2 that would be ok too.

Our van doesn’t have a smart alternator, and as we aren’t too bothered about maxing the charge rate when driving he advised not bothering with a B2B to start with. One can always be added later if needed.

We have a NASA BM1 Compact battery monitor which is ok for basic monitoring but I’ve decided to add a Victron Smart Shunt to better manage our battery usage.

Here’s our current setup.

So plans sorted, battery ordered. More to follow!

 

[Mrjenben]

The battery quickly arrived, and after Storm Eunice passed I got on with the job.

Old batteries out

They’re quite heavy

Compared to the new ones

So 25.5kg *2 = 51kg. Replaced by 13.3kg so a saving of 37.7kg!

Ive removed the extra cables and brackets I used to add the 2nd battery. Then I just need to make a couple of new cables to add the Victron Smartshunt (it uses beefy M10 bolts). Then it can all go back together.

 

[Lenny HB]

Whatever the suppliers say Lithium are not a drop in replacement. If you want to get the best out of them and a long life you really should change your mains charger and solar controller also with Lithium you need to fit a B2B to protect your alternator.

 

[peterc10]

Interested in seeing how this goes because your set up is similar to ours.

We have a 6 year old Hymer A Class with 2 x 95Ah AGMs (ours are Exides), EBL29 and LRM1218. Our battery layout is different to yours though. We are thinking of getting 2 lithiums in a straight swap as we do tend to be off grid a lot.

I am probably going to go for KS batteries as they seem to have a more comprehensive BMS which includes a low temperature cut off. It seems that Lithiums must never be charged at temperatures 0 degrees C or under. OK when we are using the motorhome because the batteries are next to the Alde boiler, but when we are not using it the solars will still be charging. It is for that reason that I am going to fit a Votronic solar regulator which also switches off at zero, Belt and braces.

 

[andy63]

Our van doesn’t have a smart alternator, and as we aren’t too bothered about maxing the charge rate when driving he advised not bothering with a B2B to start with. One can always be added later if needed.

firstly, well done, thats a nice little win...
on the battery to battery charger, have you checked the wiring and the capacity of the existing split charge facility... have they or you confirmed that it is capable of supplying what the lithium could take if its in a discharged state....
at least with a battery to battery you would be getting a proper regulated charge to the lithium, rather than just a alternator voltage for the entire time...
just my initial thoughts
Andy

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[Mrjenben]

Whatever the suppliers say Lithium are not a drop in replacement. If you want to get the best out of them and a long life you really should change your mains charger and solar controller also with Lithium you need to fit a B2B to protect your alternator.

Ive heard lots of opposing views on this, mostly from battery suppliers (it’s ok) or b2b manufacturers (your alternator will explode!) I have found it hard to find an actual example of anyone trying a simple drop in replacement - most like to go the whole hog and change everything.

Given my experience (BSc in Electrical Engineering and Electronics) I’m happy that the recommendation of a straight swap is not crazy. I’m happy to give it a try and post my experiences here for others. I fully realise I won’t get the absolute best in terms of charging or battery life but I fully expect it to massively out perform lead acid, and easily outlast my ownership of the van

 

[Mrjenben]

firstly, well done, thats a nice little win...
on the battery to battery charger, have you checked the wiring and the capacity of the existing split charge facility... have they or you confirmed that it is capable of supplying what the lithium could take if its in a discharged state....
at least with a battery to battery you would be getting a proper regulated charge to the lithium, rather than just a alternator voltage for the entire time...
just my initial thoughts
Andy

Andy

Yes - the existing split charge is capable of handling 50 amps. I understand the discharged lithium’s have a very similar impedance to a discharged lead acid so should draw a similar current (although for a longer time as the impedance of a lead acid rises quite quickly) I obviously plan to check this

I understand I probably won’t get an optimal charge and that it will tail off faster than if I fitted a B2B but I’m happy to give it a go!

 

[Tombola]

as you say, you know it wont be "optimal" but that suits you. I almost "dropped in" one on my 2019 autotrail then realised all the wiring was so weedy, I eneded up adding new runs to get what suited me. That wasnt perfect either but it did the job.
What worried me was getting my head round the alternator charging, and I seen this lol. Fortunately my alternator wasnt "smart" either in the end when I tested it (I had been told it was smart initially)
Look forward to seeing your posts how you do your ste up, more and more are going the lithium route these days.

 

[Mrjenben]

Interested in seeing how this goes because your set up is similar to ours.

We have a 6 year old Hymer A Class with 2 x 95Ah AGMs (ours are Exides), EBL29 and LRM1218. Our battery layout is different to yours though. We are thinking of getting 2 lithiums in a straight swap as we do tend to be off grid a lot.

I am probably going to go for KS batteries as they seem to have a more comprehensive BMS which includes a low temperature cut off. It seems that Lithiums must never be charged at temperatures 0 degrees C or under. OK when we are using the motorhome because the batteries are next to the Alde boiler, but when we are not using it the solars will still be charging. It is for that reason that I am going to fit a Votronic solar regulator which also switches off at zero, Belt and braces.

Peter

We’re off grid a lot but aren’t big power users. We don’t have an inverter. If you’re planning on effectively doubling your useable capacity on a regular basis then I think Lenny HB might be right and adding more solar/B2B and updating your chargers might be required.

I agree the KS BMS gives better peace of mind, but I’m not really worried. Whenever the van is in use they wont drop below zero, and when it’s stored it’s easy enough to disable the solar and just give it an occasional top up when it’s warm enough. If the lithiums are disconnected the low self discharge means they can go months with no problems.

Cheers
Chris

 

[Tombola]

it’s easy enough to disable the solar and just give it an occasional top up when it’s warm enough.

and as you say, your batts will be inside the van, less than zero will be rare inside, and you'd know when its coming

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[Jimbohorlicks]

Peter
I agree the KS BMS gives better peace of mind, but I’m not really worried. Whenever the van is in use they wont drop below zero, and when it’s stored it’s easy enough to disable the solar and just give it an occasional top up when it’s warm enough. If the lithiums are disconnected the low self discharge means they can go months with no problems.

Cheers
Chris

There are some Ecotree Lithiums with smart BMS with built in heaters if you check out thier range They also come with Bluetooth .There are larger capacity Lithiums which would be cheaper than 2 X 100 so worth considering also.

 

[Mrjenben]

What worried me was getting my head round the alternator charging, and I seen this lol. Fortunately my alternator wasnt "smart" either in the end (I had been tod it was smart initially)

Yep I’ve seen that before. I don’t think it’s a fair example though. Their alternator is spinning quite slowly. The one on the van is effectively geared by the size of the pulleys so will be spinning faster than this even at tickover and therefore pulling more cooling air through. Also the van wiring adds to the resistance so I don’t think I’m ever going to see anything like 90 amps - and if I did the split charge relay in the EBL will go up first!

I haven’t see a real world example having these problems - and I have searched a bit However, I’m prepared to be wrong - we’ll soon see!

 

[Mrjenben]

There are some Ecotree Lithiums with smart BMS with built in heaters if you check out thier range They also come with Bluetooth .There are larger capacity Lithiums which would be cheaper than 2 X 100 so worth considering also.

Yep I thought about that. The main draw to this battery was its price

 

[Jimbohorlicks]

Yep I thought about that. The main draw to this battery was its price

Yes it is a good price ,the note was for Peter who was thinking of 2x100ah lithium but with the low temp protection.

 

[mitzimad]

ive had mine that i also "won" in the first wave just dropped in to what we had charger set to gel and solar set to gel weve not really had a chance to put them to a proper test but did five days last year without any problems

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[Mrjenben]

Yes it is a good price ,the note was for Peter who was thinking of 2x100ah lithium but with the low temp protection.

Ah

 

[The Wino]

I'm one of the other winners we've been fine on the original 90ah lead acid that's just expired after 7 1/2 years. We have no need for an inverter and have never had a flat battery. I'm thinking of just swapping the battery and altering the settings to gel or AGM if we have it I know we don't have lithium setting neither do we have a smart alternator. We have a 100 w solar panel that goes on the pre wired circuit through the control panel so I'm thinking of setting it to gel as well so it doesn't supply too high a Voltage to the control panel. I know I won't get the best out of the battery but we never park up for more than 2 days I think that's why we never had a flat battery and the capacity of the lithium should be way more than we had before.

 

[The Wino]

ive had mine that i also "won" in the first wave just dropped in to what we had charger set to gel and solar set to gel weve not really had a chance to put them to a proper test but did five days last year without any problems

I was hoping to get that sort of feedback.

 

[peterc10]

Yes it is a good price ,the note was for Peter who was thinking of 2x100ah lithium but with the low temp protection.

Jimbohorlicks Jim, the problem I have is that I do not have the space for one large battery. I looked at that first but quickly rejected it. KS do a battery which is exactly the same size as my existing batteries, and with the same anode layout and the same holding down arrangement. So it will be a very simple install with no changes to battery leads. Same with the solar regulator which will use all the leads from the LRM to feed in. The B2B will be a bit more difficult, but not much more.

The KS ones are cheaper when compared with the equivalent Ecotree ones with the same output and with frost protection and bluetooth.

 

[RowleyBirkinQC]

Interesting thread, Chris, thanks for posting about your experiences with your lithium install.

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[peterc10]

as you say, you know it wont be "optimal" but that suits you. I almost "dropped in" one on my 2019 autotrail then realised all the wiring was so weedy, I eneded up adding new runs to get what suited me. That wasnt perfect either but it did the job.
What worried me was getting my head round the alternator charging, and I seen this lol. Fortunately my alternator wasnt "smart" either in the end when I tested it (I had been told it was smart initially)
Look forward to seeing your posts how you do your ste up, more and more are going the lithium route these days.

The flaw with that experiment was that it started on the false premise that the alternator runs at the same rpm as the engine. You can see that because the pully diameter on their motor was about the same size as the one on their alternator. But that is not what happens in real life because the alternator's pully diameter is usually smaller than the pully diameter on the engine. Therefore the alternator will be running about 3 times faster than the engine. So the problem that occurred at 1500rpm would mean the engine would have to be running 500rpm, which would be unusual to say the least.

 

[Tombola]

The flaw with that experiment was that it started on the false premise that the alternator runs at the same rpm as the engine. You can see that because the pully diameter on their motor was about the same size as the one on their alternator. But that is not what happens in real life because the alternator's pully diameter is usually smaller than the pully diameter on the engine. Therefore the alternator will be running about 3 times faster than the engine. So the problem that occurred at 1500rpm would mean the engine would have to be running 500rpm, which would be unusual to say the least.

hmmmm, interesting and good point,
So what your saying in reality is as most vans will idle around 800 then alternators will be spinning at 2400 ish at idle.
Makes sense

 

[Raul]

Alternator is designed to deliver a regulated charge for lead acid batteries. The charging profile is not compatible to LiFePo4 charging profile. A B2B not only gives a controlled charge, but also the settings are optimised for LiFePo4 charging profile. A drop in replacement terminology is open for to much interpretation, and most will see it in its own view or what suits them. The charging profile for lead is different to lifepo4 , but it’s the most close match to lead replacement. That, does not mean they charge in the same manner.

 

[Tombola]

exactly.
And although you can use them it isnt ideal and may invaidate battery warranties.

You can use a lead acid charger on a lithium battery if you want, HOWEVER, you must NOT use a lead-acid charger if it has an automatic “equalisation mode” which cannot be permanently turned off. A lead-acid charger that can be set to charge no higher than 14.6v can be used for regular charging and then MUST be disconnected after the battery is fully charged. DO NOT leave the lead-acid charger connected to maintain or store the battery, because most will NOT maintain the proper voltage charge algorithm for lithium batteries and damage will occur to the battery that is not covered under battery warranty.

Ultimately, using a battery charger with a specific Lithium charge algorithm is the best option for maximum performance and lifespan of any lithium battery.

(copied from egerdrive batteries info)

 

[Mrjenben]

Alternator is designed to deliver a regulated charge for lead acid batteries. The charging profile is not compatible to LiFePo4 charging profile. A B2B not only gives a controlled charge, but also the settings are optimised for LiFePo4 charging profile. A drop in replacement terminology is open for to much interpretation, and most will see it in its own view or what suits them. The charging profile for lead is different to lifepo4 , but it’s the most close match to lead replacement. That, does not mean they charge in the same manner.

I don’t quite follow you?

Doesn’t a standard alternator just try to provide current to maintain a constant voltage (albeit temperature regulated) ? It uses the increasing impedance of the charging battery to moderate its output. I accept that for lead acid this means the charge current tails off faster than optimal. I’ll be interested to see how long the lower impedance lithium holds a higher current without the help of a B2B.

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[Raul]

On Lithium you don’t rely on internal resistance to self regulate the flow. Lithium has a simple 2 stage profile charging: CC CV and off. Alternator does not do that. It holds it pined at high voltage longer than necessary, and the ultra low resistance when discharged, is capable of absorbing 3C without proper charger, to limit current flow.

 

[Mrjenben]

On Lithium you don’t rely on internal resistance to self regulate the flow. Lithium has a simple 2 stage profile charging: CC CV and off. Alternator does not do that. It holds it pined at high voltage longer than necessary, and the ultra low resistance when discharged, is capable of absorbing 3C without proper charger, to limit current flow.

Interesting. I understand the standard lithium charge profile. You’re saying the issue is overcharging? Is that a theoretical or real problem. My 110Ah battery is good for 0.5c (55A). Do you think I will exceed that without a B2B?

 

[Raul]

Depends, theoretically can max out the bms. How much flow? Depends on wire resistance path. If resistance path is low, current will flow until bms or alternator maxed out. If wire will limit based on output voltage, ( no regen braking), a lower current will make it to the battery. What you don’t have, is a charger to call it quits when full. The alternator does not know when it’s full, it will trickle if voltage is held high.
LiFePo4 can fully charge even at 13,6v, it’s just a longer process. The 14,4-14-6v it’s just spending up the bulk rate pushing more amps in a shorter time span.

 

[Lenny HB]

Interesting. I understand the standard lithium charge profile. You’re saying the issue is overcharging? Is that a theoretical or real problem. My 110Ah battery is good for 0.5c (55A). Do you think I will exceed that without a B2B?

You have a Hymer Exsis, the cables on the charge circuit are 16mm sq and it is a very short cable run between the starter and the leisure battery without a B2B you will easily exceed 55 amps, I've seen 45 amps into Gel batteries on an Exsis, the Lithium has a much lower internal resistance so is cabable of drawing much more current.

You also stand a high chance of burning out the wiring & relay in the EBL.

 

[Googlebot]

If it helps, I have the same model Motorhome and there is a thread in my signature about how I installed 2 Ecotree lithium.

I couldn’t be happier with them.

If you do decide to go a B2B, it was a very simple 30 minute job to put the Votronic 30amp one in.

Just don’t buy jump leads for cable.

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