Simplest Solution for off-grid (starter) trickle charging

[Suncat]

Hi all,

Forgive the pun, but I could do with a jump start (in direction!). I’ve recently bought a new horsebox conversation on a 2015 Citroen Relay chassis and I’m looking for the best solution (cost and ease of use) to keep the starter battery topped up as its not in daily use. And I thought that the Motorhome community would likely have solved this issue many times? The horsey community aren't too sure

My previous box was a lot older, so a straightforward battery isolator worked a treat, but I think that isolating the battery won’t do this van and all its electronics much good. Plus it’s a real fiddle to lock all the doors with no power! So I think my options are either:

A Solar trickle charger (Photonic Universe 20w perhaps?) – my battery is a 95Ah so I fear a 10W set up might not be powerful enough in the winter months? I’ve had a (good) quote to fully fit a roof mounted 60W system, but its £600 I don’t have yet sadly.

Or is there a type of trickle charger/controller which runs from a leisure battery only? Though the box doesn’t have a leisure battery system I do have a good one to hand, but all the systems I see seems to be set up to charge leisure firstly and only when they are full and there solar or mains input coming in, then charge the starter battery. Am I missing something? I don’t have a mains supply near the van’s parking, but can recharge a leisure battery overnight easily.

Any advice, links to resources to read or things to consider, all gratefully received!

Many thanks for reading

 

[wildebus]

Hi all,

Forgive the pun, but I could do with a jump start (in direction!). I’ve recently bought a new horsebox conversation on a 2015 Citroen Relay chassis and I’m looking for the best solution (cost and ease of use) to keep the starter battery topped up as its not in daily use. And I thought that the Motorhome community would likely have solved this issue many times? The horsey community aren't too sure

My previous box was a lot older, so a straightforward battery isolator worked a treat, but I think that isolating the battery won’t do this van and all its electronics much good. Plus it’s a real fiddle to lock all the doors with no power! So I think my options are either:

A Solar trickle charger (Photonic Universe 20w perhaps?) – my battery is a 95Ah so I fear a 10W set up might not be powerful enough in the winter months? I’ve had a (good) quote to fully fit a roof mounted 60W system, but its £600 I don’t have yet sadly.

Or is there a type of trickle charger/controller which runs from a leisure battery only? Though the box doesn’t have a leisure battery system I do have a good one to hand, but all the systems I see seems to be set up to charge leisure firstly and only when they are full and there solar or mains input coming in, then charge the starter battery. Am I missing something? I don’t have a mains supply near the van’s parking, but can recharge a leisure battery overnight easily.

Any advice, links to resources to read or things to consider, all gratefully received!

Many thanks for reading

This "set up to charge leisure firstly and only when they are full and there solar or mains input coming in, then charge the starter battery" is a common fallacy. It is down to voltages and when the primary/main/leisure battery is at a certain threshold, the battery maintainer activates. It rarely coincides with the main battery being full - but WOULD usually require charging to be active for a proper maintainer.

Anyway, that is a separate subject and not relevant to your requirement. I read you post as saying you can recharge a leisure battery away fromthe vehicle and then take it over to it?
All you need to do is get a lead from the starter battery to an suitable connector. Then connect the leisure battery you have carried in to that plug and away you go. Loads of different ways to have these leads connected - the key thing is make sure each end has fuse protection.

 

[Squiffy]

Are you suggesting that the starter battery is piggy backing off the liesure battery Dave? If that's the case the cable between the starter and liesure battery would have to be capable of taking a very high current and the fuses would have to be hefty indeed unless I've mis understood your reasoning. It seems to me that Suncat is concerned with the starter battery going flat over a period of time, to be honest if the battery is in good condition and there is no unusual drain going on I.e. alarm system then the starter battery should be good to start after 2 months of lying dormant, certainly my Ducato over the two coldest months of the year alway springs to life with no need to jump start or charge the starter battery.
I could see that the liesure battery might keep the voltage level on the starter battery up but the liesure battery would have to be disconnected before starting if the cable size between the starter and liesure battery was of small cross section as when the starter engages it could possibly draw 180amps from the liesure battery if there was a problem with the starter battery plates. Phil

 

[wildebus]

Are you suggesting that the starter battery is piggy backing off the liesure battery Dave? If that's the case the cable between the starter and liesure battery would have to be capable of taking a very high current and the fuses would have to be hefty indeed unless I've mis understood your reasoning. It seems to me that Suncat is concerned with the starter battery going flat over a period of time, to be honest if the battery is in good condition and there is no unusual drain going on I.e. alarm system then the starter battery should be good to start after 2 months of lying dormant, certainly my Ducato over the two coldest months of the year alway springs to life with no need to jump start or charge the starter battery.
I could see that the liesure battery might keep the voltage level on the starter battery up but the liesure battery would have to be disconnected before starting if the cable size between the starter and liesure battery was of small cross section as when the starter engages it could possibly draw 180amps from the liesure battery if there was a problem with the starter battery plates. Phil

He wants to trickle charge the starter battery from a second battery, not start the vehicle from it.

Some vehicles have a higher residual drain than others. I had a RAV4 which would have a flat starter if stood for 2 weeks.

 

[SquirrellCook]

Orion.

 

[Squiffy]

If the liesure battery is connected to the starter battery as stated, unless it is disconnected before attempting to start the engine the liesure battery becomes not a trickle charge but that of a jump start battery, in which case the leads must be capable of carrying the starter motor ampage, especially if the starter battery has an internal fault or is in poor condition. At the very least one fuse or the other will blow each time an attempt at starting the vehicle is made. I think that Suncat should be aware of this.

 

[Nabsim]

Yes for what David is suggesting it just needs a fuse pulling or isolator switch in line. Cheapest and probably easiest way to extend starter battery while stood. OP has already pointed out they don’t have the spare cash to put ‘proper’ solutions in at present.

 

[wildebus]

If the liesure battery is connected to the starter battery as stated, unless it is disconnected before attempting to start the engine the liesure battery becomes not a trickle charge but that of a jump start battery, in which case the leads must be capable of carrying the starter motor ampage, especially if the starter battery has an internal fault or is in poor condition. At the very least one fuse or the other will blow each time an attempt at starting the vehicle is made. I think that Suncat should be aware of this.

Sorry, but at no point has he said he wants to jump start from a second battery. You could fill a book with possible "what it's" and things to do and not do.

There was a specific question asked. And a specific answer given. End of.

 

[Squiffy]

You seem to have missed my point Dave, never mind others have realised the omission, maybe you should re read your post. End of as you say. Phil

 

[Millie Master]

The risk of any installation such as the one Dave is suggesting is that in a hurry it is oh so easy to forget to do the obvious!

 

[wildebus]

You seem to have missed my point Dave, never mind others have realised the omission, maybe you should re read your post. End of as you say. Phil

no omission that I can see. Your point is irrelvant to the question asked.

The risk of any installation such as the one Dave is suggesting is that in a hurry it is oh so easy to forget to do the obvious!

There is no risk in what I am suggesting, as if in a hurry and you forget to do the obvious, the fuse blows.
As I posted at the end ... "the key thing is make sure each end has fuse protection."

Why don't people (Phil) ever answer the actual question being asking instead of going off at tangents?

 

[wildebus]

PS. For what it is worth, and a reminder to the ACTUAL QUESTION, the OP wants a way to maintain (not jump start) the starter battery for the next few months in a simple way before he gets round to doing a permanent installation.

My suggestion actually happens to be precisely what I did myself for a few months whilst building my last camper. I just ran a bit of twin-core wire (I think 1.5mm2?) from leisure battery to starter battery to maintain it. The reason I had to do this was the starter battery was on its last legs, but I wanted to wait until the van was going to be in use before replacing the battery - and this was a good way to allow me to keep it charged enough for the occasional start.

Now the "Risky" bit ....

The risk of any installation such as the one Dave is suggesting is that in a hurry it is oh so easy to forget to do the obvious!

Obviously I had a bank of fire extinguishers ready. Oh, no, wait. I remember. The 5A fuse in the holder in the cable blew on the couple of times I forgot to do the obvious. Big deal.

 

[Squiffy]

As you wish Dave, most people (Dave) would be gracious enough to admit that they had forgotten to give a fairly important bit of advise. Phil

P.s. At no stage did I think he wanted a jump start, but in the layout suggested the liesure battery would involuntarily become a jump start battery if not disconnected. Read your post Dave.

 

[wildebus]

As you wish Dave, most people (Dave) would be gracious enough to admit that they had forgotten to give a fairly important bit of advise. Phil

If I knew what I had forgotten, maybe I would. But I have NO idea what I am meant to have forgotten.
Phil, sorry, but you are talking nonsense.

 

[Squiffy]

I am now going to ignore this post in total. Phil

 

[wildebus]

I am now going to ignore this post in total. Phil

good, as you don't understand the question or the answer given so best to do so.

 

[Suncat]

Hi all - and thank you for the replies.

To answer the queries, yes I want to trickle charge/maintain the health of the starter battery as a precaution.

I don't know yet that I have a problem, but the van has an alarm, onboard camera system, roof fan, led lighting, etc so I suspect it will have a higher residual drain than a standard on the road van, plus I only actually drive it weekly/fortnightly, so less chance to charge. I do have daily access to it, so can (and do currently) leave the engine running (with the lights or heating on) for a while every 4/5 days to get it into charging mode. So that's my basic answer, it just costs fuel, my attention, etc.

To trickle charge from my leisure battery, I think I need some sort of charge controller to feed the right level of amps in the right direction when needed and protect both batteries?

Related to the above discussion, my other concern is the easiest connection point (solar or leisure fed) - I was considering the OBD port as its just plug in/out. And the OBD is next to the steering wheel in my van, so easy to see and not miss unplugging The starter battery is in the footwell (good) but the terminals aren't accessible for crocodile clips, so I'd need to cable in some sort of solution. Or be in and out of the engine space using the jump points....

I'm comfortable with undertaking most DIY work, as long as I understand the solution - or exactly what I'm asking a professional for if its complex

Thanks again!

Abby

 

[wildebus]

Once you are setup with a Leisure Battery actually installed, a simplest and most flexible option is a specific purpose Battery Maintainer/Trickle Charger. There are a few different makes around and what is suitable can depend on what battery type you have and what alternator you have. The most flexible one IMO is the Ablemail AMT12-2. It is the only one that supports Lithium Batteries as well as basic Lead Acid.

In terms on making the connections to do trickle charging, it is matter of finding a permanent +Ve line from the Starter Battery. In some vans, that can be very handily found on the Cigarette Lighter in the dash that is sometime always live. Other vans it might only be active with ignition on. So you would need to check if it is suitable in yours (on a 2015 Relay it is usually active on ignition only).

BTW, you mentioned a 20W panel? that would be of very little use generally, let alone in the winter. the 20W would only be generated in the summer in full sun.
If I had your van with your situation of needing a temporary solution for a few months and a non-installed Lesiure battery, I would do precisely what I said in my first reply (and I mean precisely that).
In detail ....

Get a twin-core cable - sizewise maybe 2.5mm2, but no larger. Connect that to the Starter battery as a permanent connection, with the +Ve connection protected via a fuse in a holder - maybe use 10A or 15A one on that one, and run that out to an area by the passenger seat (that way nice and tucked away).
On the exposed end of that cable, have a connector of some type. As I said, there are lots around. As a temporary thing (I am assuming this is temporary until you get the solar and lesiure battery installed and can then fit something like an AMT12), you could even just use a 12V Accessory socket.
Then you kind of replicate that on this Leisure Battery you are taking in and out of the horsebox periodically, and then you just plug the leisure battery via the lead on it to the starter via the lead and socket you added and you have your starter battery maintanance.
The wire gauge I stated is too small to provide any starting current of course, and the purpose of the fuses I clearly stated as needed are there to protect the cables against excessive current (this is the key purpose of a fuse - you fit to protect the cable and size the fuse according to the cable gauge).

You could achieve the above by using the following:

Lead with 12V socket and 12V Plug

Amazon.co.uk

Cut in half and fit the socket end to the starter and the plug end to the leisure

Fuse Holders

https://amzn.to/3H6w4Nk

You need one on each battery +ve between the battery and the Red +ve wire on the cable above. I would use a smaller fuse on the Leisure battery end than the Starter battery so if (more likely WHEN as we all forget sometimes) you don't pull the plug out before starting, it should be the Leisure battery fuse end that pops and will be a lot easier to replace then lifting up the carpet and the battery cover.

Terminals and connectors
You need a selection of suitably sized terminals to connect the wiring to the batteries and join the fuse holders to the cables.

 

[wildebus]

As you wish Dave, most people (Dave) would be gracious enough to admit that they had forgotten to give a fairly important bit of advise. Phil

P.s. At no stage did I think he wanted a jump start, but in the layout suggested the liesure battery would involuntarily become a jump start battery if not disconnected. Read your post Dave.

And the fuse I said was a requiremnt would prevent that from happening. You should not just read the words, but try and understand them.

 

[Squiffy]

I couldn't help but see the reply when I open the app, so I will say this. In all my years of having a commercial MoT testing and repair garage on many occasions more than I remember people have asked me to come out to start their vehicle because the battery has gone flat, when I have arrived in more cases than not the starter battery has gone West ( Internal fault ) the customer invariably says but it was fine yesterday, some ask for it to be charged and refitted only to call one of my blokes out again 1 or 2 days later because the battery has gone flat. So the moral of the story is that duty batteries have a bad habit of failing without warning, a liesure battery in parallel with the starter battery in an instance like this will immediately become the duty battery and the full current will be draw down along what ever cable connects them, all be it that its only there originally to keep the alarm or any other small draw from leaving a supposed good condition starter battery. You ( Dave) only mentioned the fuse blow after my intervention. To say run a LEAD to the starter battery is to my mind at least surmise that the OP is well aware of the dangers of light wiring in a potential 200amp situation. Your advice is correct in principle but potentially dangerous in practicality. So it seems that you do not understand your own answer. Phil

I see that you have updated your post well done.