Places to look for Hymer starter battery connection for 30 amp B2B

[LithiumConvert]

As the title says, I am looking for a 30amp connection for a lithium battery B2B on a 2022 Hymer Exsis.

The EBL diagram shows a full battery connection (via a 50 amp fuse) on the back of the EBL , but that connector is empty. The split charge relay is wired somewhere else and I have removed the 80 amp fuse on the now lithium leisure battery to protect the alternator.

The only starter battery connector on the EBL is the one on pin 1 block 2 but that is fused at only 20 amps and not accessible without cutting wires and is needed for the solar panel and the EHU charger.

I can not see any other way to connect the B2B to the starter battery, other than a wire direct to the starter battery which is difficult to get at.

See https://www.motorhomefun.co.uk/forum/attachments/1700919272432-png.837591/ for EBL wiring diagram (Acknowledgment to LennyHB for posting the diagram). Ignore Lenny's red marking in this context.

 

[Googlebot]

Hi.

Are you sure you don’t already have a B2B?

That might be why the connector isn’t there. Modern vans have smart alternators and some manufacturers already fit a B2B at factory due to this.

 

[LithiumConvert]

Are you sure you don’t already have a B2B?

100% sure, No. But, probably 98+

But, if there is one, I can not find it and I would need to change its settings for Lithium.

I will be quite happy to accept suggestions as to where a B2B might be. The leisure battery is in the external hatch next to the heater and the only other thing in there is the EBL and the solar controller (and some leisure battery wiring and fuses for Hymer's very expensive Lithium option which is not fitted.

The vehicle does have a smart alternator.

 

[Googlebot]

I would be tempted to ring someone like Travelworld and ask.

Alternatively if you have a clamp meter, see how much current a low leisure battery is getting. I never saw more than 15 amps before the B2B was fitted.

 

[LithiumConvert]

I would be tempted to ring someone like Travelworld and ask.

Thanks for that suggestiion.

Alternatively if you have a clamp meter, see how much current a low leisure battery is getting. I never saw more than 15 amps before the B2B was fitted.

The original leisure battery engine charging is now disconnected. (80 amp fuse on (lithium) leisure battery removed). So that idea is no longer available, but probably would have been good before I started.

My NDS Energy Meter would also have given the same reading but I only fitted it together with the new lithium battery.

With only short winter trips from home we are managing very well with only EHU and very weak winter solar energy and 200 Ah of lithium.

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[Googlebot]

It won’t harm the lithium to see what a quick charge is doing when the engine is running.

Make sure it’s been used so it will take some charge and start the engine. See what’s going in.

Just make sure it’s warm enough in case it hasn’t got temperature protection.

 

[LithiumConvert]

It won’t harm the lithium to see what a quick charge is doing when the engine is running.

It is the alternator (and warranty) which I am protecting by disconnecting the battery from the alternator. And I am not sure how a "quick charge" would conclusively differentiate between a B2B charge and an alternator charge.

Also, I would like to use the Sterling Power B2B as it is all set up. I have had it working with a temprorary fused wire across the floor to the starter battery. It just needs a neat solution.

But thanks for the suggestion.

 

[MichaelT]

Lenny HB may be able to help once he's woken up

 

[LithiumConvert]

I have also been thinking about Hymer's very expensive Lithium Battery Option.

That comes complete with a B2B (They call it a Booser). Why would thay do that if there is already a B2B installed with the basic AGM battery.

Conclusion: My Hymer Exsis does not have a factory fitted B2B and there is no full starter battery connection in the leisure battery compartment. The Hymer Lithium Booster takes its input from the AGM leisure battery.

There is the fused 20amp connection used by the EHU and solar panel, but I need 30amps.

 

[LithiumConvert]

Are you sure you don’t already have a B2B?

To which I said:

100% sure, No. But, probably 98+

But, if there is one, I can not find it and I would need to change its settings for Lithium.

The update, today (3 months later) is that I have found the B2B. So, You were right.

A Schaudt WA 121545 hidden under a well concealed hatch under a bit of carpet I have never had completely out.

The reason that I never saw any sign of the B2B working is that the 12v power lead, from the starter battery, on the back of the unit had fallen out! (or, perhaps, never put in at the factory!)

So much for the PDI inspection of a new Hymer! But to be fair to the guy who did the PDI inspection, there is nothing on the dealer's PDI tick list to say the engine leisure battery charging should to be checked!

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[TheBig1]

sadly there is a big problem with hymer electrics, with cutting corners to save money so it would not surprise me if it was never wired at the factory. I manufacture and sell upgraded headlight looms for the hymers as the factory wiring is absolute rubbish and the wires snap internally. I have dissected several on my work bench and they have used the thinnest and cheapest quality wires available

 

[LithiumConvert]

Sadly, there is a big problem with Hymer electrics.

{They] have used the thinnest and cheapest quality wires available

I am inclined to agree. Some of wires are thinner than I used to have on my model railway.