BOS LE300 Smart Battery System experience?

[Sixty-nine Chevy]

Hi all. Does anyone here have any experience with the LE300 which apparently is 'a lithium extension for any 12V lead-acid battery, whether AGM, GEL, or wet cell'. As far as I understand it, the thing simply connects to your existing leisure battery with no need to change the charger. Almost sounds too good to be true. Further details at https://www.bos-ag.com/products/le300/.

 

[Buddy1012]

Had this set up to work with 3 x 95ah AGM battery bank for around a year now. MH came with the original dealer spec and I didn't fancy paying out for the £5k upwards for a full conversion to lithium (batteries, new chargers & installation etc). I've added a 4 module extension - took me 30 minutes to fit, neatly under a seat, and seems to work really well. Just done a 2 week winter tour of the Scottish Islands, 4 nights on EHU with the rest 'off grid' and never saw the main battery bank fall below 13v, with the lithium extension doing most, if not all of the work with the AGMs acting as a reserve. It appears to work in exactly the same way as is claimed by the manufacturer.

 

[Sixty-nine Chevy]

Had this set up to work with 3 x 95ah AGM battery bank for around a year now. MH came with the original dealer spec and I didn't fancy paying out for the £5k upwards for a full conversion to lithium (batteries, new chargers & installation etc). I've added a 4 module extension - took me 30 minutes to fit, neatly under a seat, and seems to work really well. Just done a 2 week winter tour of the Scottish Islands, 4 nights on EHU with the rest 'off grid' and never saw the main battery bank fall below 13v, with the lithium extension doing most, if not all of the work with the AGMs acting as a reserve. It appears to work in exactly the same way as is claimed by the manufacturer.



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Your system sounds great. We added just a single unit and it has made a significant difference. Fit and forget.

 

[G1969]

Your system sounds great. We added just a single unit and it has made a significant difference. Fit and forget.

What are the costs, can't see a link on their website?

 

[bigtwin]

Lenny HB, Raul, RogerIvy, eddie, autorouter, et-al, your thoughts on this setup/concept?

Ian

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[Lenny HB]

If you have the factory fit Lithium from Hymer they do similar a couple of Funsters have done it and are pleased with it (no longer members)..

I can't see the point of carrying a heavy lump of lead around I would rather fit more Lithium.

 

[Raul]

I can’t read the link, it opens but no loading. If it’s a gizmo that enables you to join the lead with LFP, then for some will work.
However, a true Lithium system it’s more simple, efficient, light, and robust. As Lenny HB says, What’s the point in carrying another lead?

 

[eddie]

I concur, what’s the point

Your still limited to how quickly the system can charge due to the inadequate charging provided by placing the batteries in parallel (erroneously AKA “split charging“ and one of the primary benefits of lithium is speed of recharging, making power use anxiety a thing of the past

 

[bigtwin]

Your still limited to how quickly the system can charge due to the inadequate charging provided by placing the batteries in parallel

Why does placing them in parallel limit the speed of charging? The current will always take the path of least resistance (i.e. the LiFePO4 path).

The LiFePO4 part of the system will discharge first and will charge first (as fast as the charge source will deliver). The only situation whereby the charge time is extended would be the situation where you have completely drained the LiFePO4 and have partially discharged the leads too. Even in that scenario the LiFePO4 would preferentially charge (quickly) as soon as the charge source was connected.

Ian

 

[eddie]

Why does placing them in parallel limit the speed of charging? The current will always take the path of least resistance (i.e. the LiFePO4 path).

The LiFePO4 part of the system will discharge first and will charge first (as fast as the charge source will deliver). The only situation whereby the charge time is extended would be the situation where you have completely drained the LiFePO4 and have partially discharged the leads too. Even in that scenario the LiFePO4 would preferentially charge (quickly) as soon as the charge source was connected.

Ian

The main point of the system is you change nothing, therefore the original charging relay stays in place and the maximum charge available to the system is governed by the wire gauge, wire length, in line fusing and ultimately the quality of the relay

If your forced to install a B2B again, why keep and drag around a lump of lead?

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[Raul]

Why does placing them in parallel limit the speed of charging? The current will always take the path of least resistance (i.e. the LiFePO4 path).

The LiFePO4 part of the system will discharge first and will charge first (as fast as the charge source will deliver). The only situation whereby the charge time is extended would be the situation where you have completely drained the LiFePO4 and have partially discharged the leads too. Even in that scenario the LiFePO4 would preferentially charge (quickly) as soon as the charge source was connected.

Ian

The LE300 sits in between the lead and LFP, they are not directly in parallel, the gizmo connects them. So you are limited by that device capability, plus the existing wiring etc.
With a true LFP system, the charge is limited by your charging means, and discharge by the bms. Huge difference, as you will wire accordingly, and no other limitations.

 

[bigtwin]

The main point of the system is you change nothing, therefore the original charging relay stays in place and the maximum charge available to the system is governed by the wire gauge, wire length, in line fusing and ultimately the quality of the relay

If your forced to install a B2B again, why keep and drag around a lump of lead?

Ah I understand what you meant now, it’s not the paralleling that that limits the charging, it’s the not fitting a more capable charging system (so not optimising the setup).

Ian

 

[eddie]

Ah I understand what you meant now, it’s not the paralleling that that limits the charging, it’s the not fitting a more capable charging system (so not optimising the setup).

Ian

Yes a standard relay set up simply puts the engine and the leisure batterys in parelell when the engine is running, its a lazy cheap way of doing it and luckily due to smart alternators is slowly becoming obsolete

My posts from 20 years ago we extolling the virtues of a B2B type system explaining how people were being duped with the term "spilt charging"

I was a lone voice in those days, thirty something, thinner, fitter and had more hair lol

 

[RogerIvy]

I was a lone voice in those days, thirty something, thinner, fitter and had more hair lol

I was joking that once I was “young and naive” … problem is I’m now “old and naive”

On a serious note though I agree with what all you guys are saying, would just like to add one thing:
Simple lithium setups are sometimes difficult enough to debug (remember the thread about dual batteries). Complicating the installation potentially makes it much more difficult to debug. If everything is going smoothly it’s ok, but when things go wrong it can become a nightmare. A good old DC-DC (B2B) on a single chemistry with split charge disabled IMO simplifies things and makes it easier to debug should things go wrong.

 

[bigtwin]

I can see that a split-charge arrangement perhaps isn’t the best way to charge a lead acid habitation battery as the similar internal resistances work against effective charging of the habitation battery. However, cable sizing and relay current capacity restrictions aside, a LiFePO4 and lead acid parallel network shouldn't be compromised in the same way as a lead/lead network due to the charging bias towards the LiFePO4 battery due to its lower internal resistance.

Tell me what I’m missing and therefore why I’m wrong.

Ian

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[Sixty-nine Chevy]

What are the costs, can't see a link on their website?

Mine was fitted by a local campervan garage, but I think they sourced from the following link which includes a price. https://www.force4.co.uk/item/BOS/LE300-Lithium-Extension-Battery-System/29WZ

 

[Buddy1012]

What are the costs, can't see a link on their website?

I bought mine from Cactus Navigation - 4 modules giving 100ah useable LifePO4 power. In practice I have found this to be ample for up to 2 days use before the system starts eating away at the AGMs (140ah useable) I went this way as I ended up buying a cancelled order to avoid a long wait and it came with 3 x 95a obviously brand new AGMs - I couldn't face up to the additional £5K to £6K for a full blown lithium swap out on top of the original £160k. The total cost was £1500 for something that behaves like a lithium set-up (almost!). Time will tell whether it was the right way to go. If the AGMs last as long as claimed under this set-up ie 7 years or so then that will be the proof. The additional weight (lead bank) is not an issue for me as plated to 5.5 tonne and even in full touring set-up I've never had less than 250kg to spare. Another bonus is that the LE300 is easily removable and therefore transferable should the need arise.

 

[CutThroatJake]

I have a couple of these for sale if anyone is interested from a HYMER Smart Battery System.

Also I’ve got the AGM battery should that also be of interest.