Confused about batteries and charging

[Tony68000]

The more I learn, the more I realise I don’t know. Would anyone be able to answer some basic questions for me please?

I have an engine/starter battery and a leisure battery.
I have a solar panel and a basic solar regulator (Voltronic SR 130 Duo).

Here goes…
1. Does my leisure battery charge when I’m driving, like my starter battery, or does this only charge via solar?
2. Do either battery charge when I’m on EHU?

edit: Rapido 999m

 

[monzer]

In theory, when your engine is running, both batteries should be getting a charge. Of course sometimes things go wrong that will stop this. A faulty split relay for example.

Usually it's only the leisure battery that will get charged via EHU although there are some setups and devices that people can add to charge the engine battery from EHU at the same time.

 

[Cush]

For me
yes / both

for me I have to select which battery to charge on ehu. I normally change to vehicle battery once the leisure indicates a float charge going in (I don’t have a very complex system) the but solar will do both at same time

hope this helps until someone that knows your van model comes along

 

[Tombola]

1. Does my leisure battery charge when I’m driving, like my starter battery, or does this only charge via solar?

Only if you have a split charge relay or a b2b (dc charger) set up which is quite likely if you have a recent Rapido. You can tell if the leisure battery is being charged by the engine, by starting it and checking if the control panel shows it is being charged either by lights or showing the voltage going in the battery.
Or you can do it with a simple volt meter onto the battery terminals and it would read above 14 v. Or even a cigarette insert that shows the charge, by plugging it into a 12v (cigarette style) socket in the hab area if you have one like this that shows Volts

2. Do either battery charge when I’m on EHU?

Depends on your control panel again, look for 2 different battery images to indicate if you have 2, it will show one in the cab and one in the hab on the panel. The same method as above can be used to check either charge when on hook up.

If you dont have one that charges the cabaswell when on hookup then a battery master from vanbitz, can be bought cheap enough which trickle charges from the leisure to the cab if needed.
A volt meter is a vital piece of kit that will help you track down many problems.

 

[Abacist]

You need to tell us more! Make, model, year for a start. Did you buy new or s/h? Who knows who did what to your van before you?

The alternator charges the cab battery. There is normally a split charge relay to pass current from cab to hab battery. Solar should be wired to charge hab battery but we have heard of cases where it charges the cab battery instead! Where do the wires from the solar controller go? Which battery do they go to? Hab or Cab? EHU powers 240 volts and charges hab battery. You can get a VanBitz battery master to pass current back to the cab battery to keep that topped up. That’s a starter for you.

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[autorouter]

Every motorhome I've seen has an arrangement to charge the leisure battery from the alternator when the engine is running. Most of them have a simple relay (electrically operated switch) that automatically connects the leisure battery to the starter battery when the engine is running, so that the alternator can charge both of them. When the engine stops, the relay automatically disconnects them so they are separate batteries again.

The latest motorhomes have a smart alternator, and have a special charger that runs from the alternator to charge the leisure battery. The special charger, called a Battery-to Battery (B2B) charger or charge booster, can also work with a standard alternator instead of that relay, and is a popular upgrade.

Your Votronic Duo solar controller has two separate outputs, and charges both the leisure battery and the starter battery. Most solar controllers only have one output, to the leisure battery, so you are lucky on that one.

When connected to EHU, there will be a mains-powered charger somewhere, probably built into the 12V distribution/fusebox. It will certainly charge the leisure battery. However some of them charge the starter battery, and some of them don't. If you tell us the make and model of that box I'm sure someone will know. For example Schaudt EBL, Reich, Nordelettronica, CBE.

 

[Tony68000]

This is really handy info. I'll wait until it's dark now, as the solar will confuse things, and check the battery voltages with the engine running and then on hookup.

I guess I just thought that everything charged everything, but slowly realised this wasn't the case.

For ref, it's a Rapido 999M, 2007, and has had the Solar added by a previous owner. Not sure of any other additions.

 

[GeoffnDee]

Tony68000 If , after you have done your checks you find you need more information , as autorouter has said , it is the make and model of your PSU / habitation fuse box that is needed to be able to help with information regarding the normal operation of the charging system that is fitted to your Rapido Motorhome .

 

[Tony68000]

Tony68000 If , after you have done your checks you find you need more information , as autorouter has said , it is the make and model of your PSU / habitation fuse box that is needed to be able to help with information regarding the normal operation of the charging system that is fitted to your Rapido Motorhome .

Right, I'll do this, thanks.

 

[Jev88]

If the previous van owner has changed things then knowing the original set up or someone else with the same van is irrelevant.
Measure voltage of each battery with everything turned OFF (including solar if you can).
Now start engine and wait a couple of minutes - engine battery most definitely getting charge, but measuring your leisure battery will tell you if a relay is allowing charge to trickle to them too (often very slow though!)
My old Coach-built had a rocker switch on control panel - centre - OFF, Up to use engine battery to power 12v circuit and allow it to be charged by EHU and finally Down to select leisure battery (to power 12v circuit and also receive charge from EHU).

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[Tony68000]

If the previous van owner has changed things then knowing the original set up or someone else with the same van is irrelevant.
Measure voltage of each battery with everything turned OFF (including solar if you can).
Now start engine and wait a couple of minutes - engine battery most definitely getting charge, but measuring your leisure battery will tell you if a relay is allowing charge to trickle to them too (often very slow though!)
My old Coach-built had a rocker switch on control panel - centre - OFF, Up to use engine battery to power 12v circuit and allow it to be charged by EHU and finally Down to select leisure battery (to power 12v circuit and also receive charge from EHU).

Can I use the control panel to do this? It shows both batteries... or do I need a meter directly on each battery?

 

[TrudeandDall]

As autorouter says in #6, the votronic solar controller has the functionality to charge the hab and starter batteries. Two points though - the bulk of the solar energy goes to the hab battery with approximately 1 amp to the starter battery and this only works if your particular van has been wired up for this function. Best to check if the right hand side small positive connection for the starter battery is wired (or not).

 

[Jimbohorlicks]

Both batteries should charge when your driving.When on ehu ,generally only the leisure battery will charge up unless you haveca battery master connected between the leisure and starter batteries.
When off grid your solar will only charge your leisure battery unless you have a dual battery controller that is connected to the starter or a battery master.
If you check your batteries whilst hooked up or with solar on you will only see the charging rate,,but that will indicate what's being charged. If you want to check the state of the batteries disconnect the ehu and solar.( Check the batteries at the terminals) And the battery master to starter battery if you have one.
I find that the plug in cigarette type battery indicators are useful, but not always accurate.

 

[Jev88]

Can I use the control panel to do this? It shows both batteries... or do I need a meter directly on each battery?

I don't trust onboard readouts. They can be flakey and you can't see connection problems between the clever box and the batteries without a multimeter direct to battery. e.g. my old bus said fridge was fine, multimeter at either end of the wires that go to supply 12V showed several VOLTS difference - tracked down to a crumbling connector block near fridge. Screen onboard didn't see a problem but the fridge at the other end did, enough for power supply but insufficient under load (spark). You can't argue with a direct voltage measurement

 

[autorouter]

Can I use the control panel to do this? It shows both batteries... or do I need a meter directly on each battery?

There's some wiring and fuses between the actual battery terminals and the control panel, so potentially there can be problems, and the control panel may be misleading. But if you check the control panel agrees with a voltmeter directly on the batteries, then yes, you can use that instead.

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[VXman]

autorouter said that your Voltronic duo solar controller has 2 outputs so that it can charge both batteries. Probably worth checking that both outputs are connected up and where they are going to. Sometimes the starter battery is not connected to the solar output as it's more difficult to route the cables.

 

[Tony68000]

autorouter said that your Voltronic duo solar controller has 2 outputs so that it can charge both batteries. Probably worth checking that both outputs are connected up and where they are going to. Sometimes the starter battery is not connected to the solar output as it's more difficult to route the cables.

Ah, there are wires coming from the solar regulator's starter battery terminals, so I presume it's connected.

If I read it right, it delivers a trickle (0.8amp) to the starter battery at all times (when solar is active).

Oddly, the solar regulator is in the middle of the van, in one of the top cupboards... sort of half-way between the starter battery and the leisure battery. I've read it's best to be as close to the leisure battery as possible, so no idea why it's actually there. Not sure where the cables route or where the cables for the solar go yet.

 

[autorouter]

Oddly, the solar regulator is in the middle of the van, in one of the top cupboards... sort of half-way between the starter battery and the leisure battery. I've read it's best to be as close to the leisure battery as possible, so no idea why it's actually there. Not sure where the cables route or where the cables for the solar go yet.

Probably the wires were pre-installed when the MH was manufactured, so the wires through the roof were conveniently placed. The reason for installing it near the battery is that if there is any voltage drop along the battery cables, the controller gets the wrong battery voltage and doesn't charge it optimally. One way round this - Victron units do this - is to stick a small Bluetooth module on the battery to relay the accurate voltage and temperature. The other option, a pair of thin voltage sensing wires, is probably a real pain to install, easier to just move the controller next to the battery.

If I read it right, it delivers a trickle (0.8amp) to the starter battery at all times (when solar is active).

Usually the starter battery is fully charged when you arrive - to the camp site or back home - so it only needs a trickle charge to keep it topped up.