Must I have DCtoDC Charging to use lithium? (1 Viewer)

[Ed Scratcher]

Want a very modest off grid capability for the odd night or two, looking at 100W solar (minimal space), mppt, potentially direct to 100ah lithium leisure battery. SARGENT tell me I must have dc to dc charging - I have a Sargent EC400 PSU.
If that’s so probably go with AGM.
What do you experienced users think? Bear in mind this ignoramus needs simple positive suggestions please, I will be using a professional fitter.

 

[andysam]

I have a Sargent EC400 PSU.

How old's the van? Smart Alternator? If the EC400 charges AGMs then it will sufficiently charge Lifepo4s but will never fully charge them due to differing charge profiles (voltage) but if occasional and not heavy use it will be fine. I ran a van like that for a couple of years. It really depends on the alternator.

 

[Lenny HB]

Although some Lithium battery suppliers say they area drop in replacement you will never get the best out of them. Two reasons for fitting a B2B (DC to DC) charger to make sure the Lithium gets a proper charge at the correct voltage and to protect the alternator.
AGM is about the worst choice for a leisure battery and if you do fit one only do it if your charger has the correct charging profile for the type fitted.

 

[Ed Scratcher]

Thanks for the replies, our Peugot autocruise/Swift PVC is 2013. Sargent reckon it’s EC400psu will only handle 100W max solar, and seemed to suggest wiring not being up to handling more plus lithium. Current 95ah lead acid battery is 9+ year old, as we are doing a month long trip to Spain and Portugal thought a ‘simple‘ power update was due. Considering 100ah Lithium, cost within reason not a problem, but no idea how much extra work and complication B to B would be?
Dont laugh - had no idea b to b = dc to dc!

 

[Ed Scratcher]

Andy Sam, Not sure about the alternator, but suspect at euro V 2013 it’s not as powerful as later models.

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[andysam]

A relatively straight forward fit. Shouldn't cost much to have done. Running the wiring will be the biggest part of the job. If you need more solar (and have the room) an MPPT charge controller is quite cheap.

 

[Lenny HB]

The Sargent unit just has a cheap PWM solar controller in the back of the case it is best to bypass it and fit a decent MPPT controller.
If you are going to fit Lithium you will probably want to fit more solar as one of the big advantage of Lithium is their fast charge capability.

 

[jumar]

Recently gone Lithium....having a Victron DC2DC is a marriage that's made all the difference...

 

[Ed Scratcher]

Thanks everyone, appreciate the responses. Already decided on MPPT, solar is limited by space - 5.4m van with lots of stuff on the roof (had hoped to go with vanbitz, but their solar panel dimensions are a problem) pity because I favour victron kit. Concerned about enough solar to charge lithium - maybe that’s another plus for b2b?
Any suggestions where to get it all fitted very welcome? Based near Telford so midlands would be good, but best fitters vital!

 

[Jim]

Hot Swap Lead Acid For Lithium

EDDIE ‘VANBITZ’ JONES DISCUSSES LITHIUM LOTS OF OPINIONS ON THIS ONE SO WE THOUGHT WE’D ASK EDDIE JONES OF VANBITZ, FIRST, WHAT HE MADE OF THE RUSH TO INSTALL LIFEP04 […]

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[Bobby-gg]

Yes, is my answer.

I've got 175w solar, and 110ah lithium and conducted an experiment this weekend when I knew that the weather was poor, and my solar charge would be minimal.
Used my 12v system as normal, so, lighting, phone charging, TV, Internet, water pump etc, fridge and kettle were on hook up, but they would be on gas when "off-grid" and over 4 nights I dropped the battery down to 32%.
On leaving site Tuesday morning, my B2B was putting in almost 700watts and after less than 10minutes driving to our next stop the battery had gone up to 41%



So yes, a big B2B if you are limited on your solar

 

[Bobby-gg]

What can do you have?
I managed to squeeze in a victron 175w panel, across a ducato panel van, and in between skylights as its only 668mm wide iirc

 

[jongood]

Want a very modest off grid capability for the odd night or two, looking at 100W solar (minimal space), mppt, potentially direct to 100ah lithium leisure battery. SARGENT tell me I must have dc to dc charging - I have a Sargent EC400 PSU.
If that’s so probably go with AGM.
What do you experienced users think? Bear in mind this ignoramus needs simple positive suggestions please, I will be using a professional fitter.

imo. inless you have a very compelling reason for 5.4m then buy a bigger motorhome, with a proper shower and a made up bed, I see so many guys sat out in the cold morning waiting for their wives to get up so they can get at the kettle etc.
its then worth spending the money fitting it out correctly, if you buy it right you might it already has some of the components mentioned, like a decent solar array with Mppt regs etc.

 

[Ed Scratcher]

What can do you have?
I managed to squeeze in a victron 175w panel, across a ducato panel van, and in between skylights as its only 668mm wide iirc

Had to smile at the typo, it is a tin-can, but we call it a van. The only free space anywhere near that @ 660mm wide is right across the roof front, and may foul the opening skylight, or stick out forwards slightly. In fairness to Vanbitz they said ‘let’s have a look’, but I would really rather not have the panel there.

 

[Bobby-gg]

No, I definitely meant can!

Here's mine squeezed between my skylights

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[mitzimad]

ours lithium is just chared from a split charger and solar and it been fine for the last 4 years everyone tells me i need B2B but everything works so i will soldier on .Is it working to its full potential PROBABLY NOT BUT IVE GOT BETTER THINGS TO DO THAN WHAT A MONITOR 24 7

 

[wfdTamar]

I googled the Sargent EC400 and it says to use lead acid or 'some AGM'. Given your requirements, I'd just put in a decent one that will work with what you have (plus the solar). I'd try to squeeze in the biggest solar panel you can find. A Yuasa L36-EFB would be fine. With the solar I'd be surprised if that didn't work unless you have some high power consumption devices (compressor fridge?).

 

[RM_Marine]

I googled the Sargent EC400 and it says to use lead acid or 'some AGM'. Given your requirements, I'd just put in a decent one that will work with what you have (plus the solar). I'd try to squeeze in the biggest solar panel you can find. A Yuasa L36-EFB would be fine. With the solar I'd be surprised if that didn't work unless you have some high power consumption devices (compressor fridge?).

I've got two of these in my autotrail apache 700 and they charge well, currently on float after the van has been used for ten days with just solar to recharge and never drop below 60%.

Yes, I do have to press the isolation bottom on the Sargent unit or I get a persistent drain, it has taken a few days of no use of the van for the solar to charge but its free and not being used and is currently parked up gathering dust waiting for its next outing.

 

[wfdTamar]

My Yuasa L36-EFB was fine in storage through 3 winters (Sep 2019 to May 2022) during Covid when I couldn’t get back to the UK. The 200 watts of solar kept it and the starter battery in good condition right through.

 

[Bolti]

Thanks everyone, appreciate the responses. Already decided on MPPT, solar is limited by space - 5.4m van with lots of stuff on the roof (had hoped to go with vanbitz, but their solar panel dimensions are a problem) pity because I favour victron kit. Concerned about enough solar to charge lithium - maybe that’s another plus for b2b?
Any suggestions where to get it all fitted very welcome? Based near Telford so midlands would be good, but best fitters vital!

This is my 5.4m van and that is a 200w panel as you can see a larger on would have fitted its just finding the correct length and width.
View attachment 727531View attachment 727531

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[wfdTamar]

I think you’ve done the photos incorrectly.

 

[Bolti]

 

[AshVanBitz]

Good afternoon Ed Scratcher, I remember speaking with Nick about your vehicle (and also viewing your photos and dimensions of the roof). The available space on your roof is very limiting due to the positioning of your existing rooflights and vents. There were two areas that were potential options (one across the front of the vehicle and one on the rear nearside). The rear nearside area was reduced due to a vent that is positioned right in the centre. Even though on paper it shows that our long/thin 100W panel would fit in this area we have to allow additional space for the mounting feet. We also have to position the panel so the feet can be secured level either in or out of the ridges. It made more sense to have the panel situated at the front of the vehicle (widthways) as this provides the largest area. I know that you were not overly happy with this solution as you were worried about whistling when you were driving. This is not something that I have encountered before but at the same time I could also not 100% guarantee that it would not happen. It is highly unlikely though.
This is why we recommended that you bring the vehicle to us and let us go on the roof where we can physically try all our panels to see if there is an option that you would be happy with. The offer of course still stands and if you do plan a trip/holiday down to the Southwest moving forward, please give me a call and we can discuss what date(s) suit you best.
Kindest regards
Ash

 

[Ed Scratcher]

Good afternoon Ed Scratcher, I remember speaking with Nick about your vehicle (and also viewing your photos and dimensions of the roof). The available space on your roof is very limiting due to the positioning of your existing rooflights and vents. There were two areas that were potential options (one across the front of the vehicle and one on the rear nearside). The rear nearside area was reduced due to a vent that is positioned right in the centre. Even though on paper it shows that our long/thin 100W panel would fit in this area we have to allow additional space for the mounting feet. We also have to position the panel so the feet can be secured level either in or out of the ridges. It made more sense to have the panel situated at the front of the vehicle (widthways) as this provides the largest area. I know that you were not overly happy with this solution as you were worried about whistling when you were driving. This is not something that I have encountered before but at the same time I could also not 100% guarantee that it would not happen. It is highly unlikely though.
This is why we recommended that you bring the vehicle to us and let us go on the roof where we can physically try all our panels to see if there is an option that you would be happy with. The offer of course still stands and if you do plan a trip/holiday down to the Southwest moving forward, please give me a call and we can discuss what date(s) suit you best.
Kindest regards
Ash

Hi Ash, Thanks for your interest and follow up. Nick did explain everything very clearly, it may be irrational, but I still prefer not to use the front space. However I am considering removing the mushroom vent altogether, and this will give a more useable area On the back quarter. I note that both pvc’s shown on this thread do not have such vents, and I think I will have sufficient air circulation without it. But I am back to the drawing board re which leisure battery and b2b requirement - leaning towards b2b at the same time as solar fitting just to future poof. Thanks all for your input it all helps ( except for buying a bigger van).

 

[AshVanBitz]

Hi Ash, Thanks for your interest and follow up. Nick did explain everything very clearly, it may be irrational, but I still prefer not to use the front space. However I am considering removing the mushroom vent altogether, and this will give a more useable area On the back quarter. I note that both pvc’s shown on this thread do not have such vents, and I think I will have sufficient air circulation without it. But I am back to the drawing board re which leisure battery and b2b requirement - leaning towards b2b at the same time as solar fitting just to future poof. Thanks all for your input it all helps ( except for buying a bigger van).

A b2b would be a very good upgrade regardless of when leisure battery you choose. We have customers that do not have the real estate on the roof to allow any form of solar and purely get their power from the b2b without any issues whatsoever. Happy to talk more if you want some advice.

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[jumar]

B2B or DC2DC works in Sunny, Cloudy. Rainy or whatever climatic conditions prevail.... incredible piece of kit...makes our Motorhoming usage more versatile...