Lithium upgrade

[JD Hogg]

Just starting the thought process for lithium upgrades from Lead... We have 2012 Rapido, 2x lead batteries 80amh each. I recently upgraded my solar panel from 100w to 200w and changed the solar controller at the same time.

if i just swap my lead batteries for Li , i believe that everything will still work the same without any changes, except that i will miss out on fast charging because my alternator charger at the moment is limited to 23a ? is that correct ? so if i want to benefit from fast charging i will need to install a B2B unit as well. ( Where, and what is , the device that makes the current limitation of the actual 23A ? On the alternator itself? )

if i add another 200w panel, as long as my solar controller can cope with that, i guess that will help charge my future Li a bit quicker so worth doing because only the cost of a panel? (£200)

I see that some people talk about their inverters. We have just a small one (£80 i think, rated 400w i think) that has a single socket output on it - installed in a cupboard - i guess that looking at some of the big units that people have, that they have "connected" the inverter to the 220v circuit so that they can plug into any 220v socket in the van and then the current automatically comes from the inverter (so the inverter is always "on").. is that correct ? Sorry if I've made a mess of trying to describe that.

thanks for any suggestions....

 

[RogerIvy]

if i just swap my lead batteries for Li , i believe that everything will still work the same without any changes, except that i will miss out on fast charging because my alternator charger at the moment is limited to 23a ? is that correct ? so if i want to benefit from fast charging i will need to install a B2B unit as well. ( Where, and what is , the device that makes the current limitation of the actual 23A ? On the alternator itself? )

What makes you think your alternator charging is limited to 23A?
It’s quite likely that the 23A could be a “limitation” imposed by the batteries themselves. It’s quite common for lead acid batteries to draw (accept) just over 10% of their capacity. That said, some Motorhomes do have a current limiter (like a DC-DC or even a real DC-DC).
In tests that we have done some of the larger lithium batteries (280 and 300ah LiFePO4) can draw close to 60A when connected directly to the starter battery (and therefore alternator).
So your focus should be on two things:
1. Protection of the system (alternator, wiring, EBL etc)
2. How to charge most efficiently (Getting the most out of your battery/system)

if i add another 200w panel, as long as my solar controller can cope with that, i guess that will help charge my future Li a bit quicker so worth doing because only the cost of a panel? (£200)

Correct. Try to match the existing panel (different panel sizes poses some challenges if you want them to work to their max).

I see that some people talk about their inverters. We have just a small one (£80 i think, rated 400w i think) that has a single socket output on it - installed in a cupboard - i guess that looking at some of the big units that people have, that they have "connected" the inverter to the 220v circuit so that they can plug into any 220v socket in the van and then the current automatically comes from the inverter (so the inverter is always "on").. is that correct ? Sorry if I've made a mess of trying to describe that.

Most of our customers want the inverter to provide power to existing sockets. To achieve this we either use a changeover switch or even better install a Multiplus. It’s important to not power the charger from the inverter and same goes for the fridge and heating system. So a bit of skill required.
If installing a changeover switch it should be a decent one, such as a rotary (two pole).
And yes, we leave our inverter on permanently but could switch it off if we wanted to.

 

[JD Hogg]

What makes you think your alternator charging is limited to 23A?

I saw (i think) that most alternators on vans can supply upwards of 50a, maybe 80a..... when we drive along, our Rapido control panel tells me we are charging at 23A , so i just presumed that it was being throttled to protect the LA batteries?

 

[Raul]

The 23A limitation comes from batteries themselves, then the cable from alternator to the batteries. Bigger cable allows for more flow and less voltage drop.

 

[suavecarve]

My question would be why do you think you need lithium ?

2 lead acid batteries give you somewhere around 80 amps of usage and you have doubled your solar input and thinking about more. A reasonable Lithium equivalent would be 100 amps or 400 quiddish (plus cables etc)

What has changed in your electrical output from your van that justifies the price of lithium against new lead acid/gel or have you been running out of electricity ? Or is it just everyone else is going lithium ?

Lithium is a game changer if you use shed loads of electric, but if you have been doing all right (presumably) on 160 ah of lead then I wonder if the jump is beneficial for the finances.

(I am a lithium battery motorhomer but charge our e bikes nightly)

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[RogerIvy]

I saw (i think) that most alternators on vans can supply upwards of 50a, maybe 80a..... when we drive along, our Rapido control panel tells me we are charging at 23A , so i just presumed that it was being throttled to protect the LA batteries?

In that case the limitation comes from the batteries. The cable could also be a limiting factor but in such cases would probably be quite warm.
If you change your battery to a (big) LiFePO4 you would essentially remove (or radically change) the limitation. Putting in a smaller LiFePO4 wouldn’t make sense as you land up with what you have. So assume you would/should install a DC-DC.

 

[RogerIvy]

My question would be why do you think you need lithium ?

That is a valid question, I had assumed that because the OP is asking about wiring in inverters he plans to use more power in future.

 

[JD Hogg]

What has changed in your electrical output from your van that justifies the price of lithium against new lead acid/gel or have you been running out of electricity ? Or is it just everyone else is going lithium ?

We off grid most of the time, stay for 2 or 3 days and then move on. We have ebikes, 500w batteries and do 50-80km rides every day which drains them about 50%. if we get back early enough in the day then we charge one off Lead batteries and one from Ecoflow... But in Spain, this time of year, we are lucky to get 7a from the solar and if its 3 or 4pm then much less, so charging back up is more of a problem. I also work, so when not riding, then laptop is on with all the crap that goes with that .

My thought was a foldable solar panel to stick on the floor and point at the sun to help charge the 700w ecoflow - or a 2nd ecoflow battery and find somewhere to plug in every other day - or a 2nd fixed solar and upgrade the Hab batteries....

Without the e-bikes we have plenty and never need extra umph.

 

[suavecarve]

We off grid most of the time, stay for 2 or 3 days and then move on. We have ebikes, 500w batteries and do 50-80km rides every day which drains them about 50%. if we get back early enough in the day then we charge one off Lead batteries and one from Ecoflow... But in Spain, this time of year, we are lucky to get 7a from the solar and if its 3 or 4pm then much less, so charging back up is more of a problem. I also work, so when not riding, then laptop is on with all the crap that goes with that .

My thought was a foldable solar panel to stick on the floor and point at the sun to help charge the 700w ecoflow - or a 2nd ecoflow battery and find somewhere to plug in every other day - or a 2nd fixed solar and upgrade the Hab batteries....

Without the e-bikes we have plenty and never need extra umph.

That answers my question. You need lithium.

I am quite similar to yourself and got 200ah of lithium for 649 and 370 watts of solar plus B2B and sometimes have fully charge both ebikes. We have shed loads of battery and were in Germany Luxembourg in March moving on every other day about 30 miles if that helps you.