Issues with recent horsebox flattening battery

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Mike Hunter

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Hi All

I own a problematic Stephex 3.5 ton horsebox and I thought I would ask if anyone else has experienced the same problem and how they got round it. The box is only a couple of years old and has had this problem since new, which is that it repeatedly flattens the battery. And I mean flattens it; to get the beast going again we have to physically disconnect the battery which is a pain as its hidden beneath the cabin floor, wait 10 seconds, then reconnect it, and then recharge / or jump it. And before anyone asks, we are not leaving anything on other than the vehicle alarm etc

The reason for this problem, we are told, is that we simply don’t use the box frequently enough. It is only used once or twice a month, and it can go 3/4 weeks idle. During that time, it soaks up all the energy in the battery. They sure don’t build batteries like they used to!

To fix this problem I am about to invest in a solar panel on the roof to trickle charge the battery. (We tried a mains trickle charger but to get that to work you need to connect it directly to the battery which means leaving the floor dismantled which renders the box unusable.)

But before I spend more money on what was a costly purchase, I thought I would check if this is a problem others have experienced.

Thanks
 
My OH has solar trickle charged every horse vehicle I've ever had because of these issues, 7.5 and 3.5t. It's a total solution, so I would just do it.
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Yep I’ve had this issue with both 3.5 ton boxes I’ve had, again due to lack of use.

A battery isolator helps (as long as you remember to use it 🙈)
 
I had a similar problem when I had a 3.5t lorry if I didn't use it regularly. We've now got a motorhome, and it's a common problem.

Where we store our motorhome, the motorhomes that don't have a full solar system use the "briefcase" folding/portable solar panels to trickle charge the batteries.

Modern alarms/tracking systems draw a surprising amount of power from the vehicle's battery. Without solar, and if we didn't use the vehicle, our battery would be probably be flat in 2-3 weeks.
 
Mine has been better with a brand new battery but we also swap it out with the old one in winter & charge them up at home. I also bought a really good jump start set off amazon.
 
You could either get an isolator or disconnect the live battery when not in use. One of my liveries use this on hers as hers keeps not starting even when she taken it out, charges this at home then brings up to yard, very small and compact and she keeps in lorry when driving.


 
Second the isolator. I also run mine for 5 minutes at 2000 revs, every 2 weeks. I'm was told by a petrol head that this helps top up the battery
 
Swap the battery for a lithium one. Your present battery is probably already goosed as lead acid batteries don’t like being discharged for long periods.
 
We've added an isolator and a trickle charge solar panel.

Our lorry has a taco which ticks like a clock constantly if it has power, this is enough to drain the battery's to a point the lorry won't start in a couple of weeks without the solar panel.

I'm terrible at remembering to turn the isolator off - this has reminded me I haven't turned it off after going out on Saturday.
 
If its a newer van, then the solar panel is the right answer - you'll likely have been recommended this over an isolater switch by an auto electirican as all the electronics on newer vechicles/engines don't respond well to be being cut off/unpowered for long period either. Got this on my 2015 van, works really well. My old 2003 van was fine with an isolator switch. Basically, what ever chassis we have as a horsebox, it was designed to be a commercial (delivery) van, so sitting unused for days or weeks wasn't really in the main spec.
 
I have an isolator in mine that works perfectly, haven’t had a flat battery for a couple of years……but it means I can’t lock the cab…..
 
Hi All

Firstly thanks for the many responses. I am already pleased to discover that I am not alone with this problem.

The box is built on a Renault Master chassis and both the chassis and box were new at the end of 2022.

I was aware of the option of an isolator switch but, as Suncat has commented, I am nervous to turn everything off completely. This would kill the alarm, loose all the settings in the entertainment system etc etc Modern vehicles don't come back from no power like older ones.

Leaving the battery disconnected is not an option as it is located below the cabin floor in the left-hand doorway and the floor panel has to be unscrewed and removed to disconnect it, and then replaced and screwed back down again when you reconnect it. I know the procedure well now but it’s not something my daughters are going to be doing every time they go out!

Replacing the battery for a lithium one is certainly an option I will research

So I think the solar panel is indeed the best option.

Thanks all
 
If you go the solar panel route get it wired in professionally by a motor home or caravan specialist, so you can be confident that you won’t get and wiring safety issues. You can connect some portable panels directly to the battery but they need the correct safety wiring.
 
One more question on this thread, if I may.
I have now had the solar panael fitted and it appears to be doing the job. The people who fitted it measured the current from the battery before the panel was fitted, the 'parasitic drain' as it is apparently called, as 0.4 amps. I find this to be a huge amount, but am I out of date - is this typical of modern vehicles?
It was a very sunny day and the freshly fitted panel was pushing 4 amps in the other direction, so it should hopefully be okay now.
Time will tell...
Ta
 
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