Cheap battery over winter

[tartan-caravan]

Hi, I'm sure this has been asked before but I couldn't find anything in the forum. I keep my van in storage and the solar panel doesn't keep the battery topped up during winter. Is there any reason why I couldn't by a £50 car battery to use during winter when the van is in storage so I charge my leisure battery at home? Thanks, Mike

 

[Buckman]

Hi, I'm sure this has been asked before but I couldn't find anything in the forum. I keep my van in storage and the solar panel doesn't keep the battery topped up during winter. Is there any reason why I couldn't by a £50 car battery to use during winter when the van is in storage so I charge my leisure battery at home? Thanks, Mike

What size is the solar panel? We have a 100w and no issue with it keeping the battery topped up. Do you have a MPPT controller fitted for the solar panel?

If the current solar panel is not adequate enough to keep a leisure battery topped up, it probably would have issues topping up the car battery. Also if the car battery goes too low, there may be issues recharging it.

 

[Beardy]

I assume that your storage is inside (out of sunlight) otherwise a reasonable sized solar panel would keep it topped up - the battery drain in storage should be negligible.

There's no reason why you couldn't use any 12v battery, but lead acid batteries don't like being fully discharged. A £50 car battery would probably be half the capacity of your leisure battery so would last half as long. Below a certain level the plates begin to 'sulphate' and the battery may not recharge - this applies to your leisure battery as well assuming that it's AGM.

 

[tartan-caravan]

What size is the solar panel? We have a 100w and no issue with it keeping the battery topped up. Do you have a MPPT controller fitted for the solar panel?

If the current solar panel is not adequate enough to keep a leisure battery topped up, it probably would have issues topping up the car battery. Also if the car battery goes too low, there may be issues recharging it.

Hi, It's a 100w panel and the controller is a Sargent 3amp Solar RegulatorProduct no: SSR-3A which I'm guessing is a budget model. The van is booked for a service in a couple of weeks so I'll ask them to check the panel etc are working OK. Will look at the mppt controllers again as they're not exorbitant, compared to a new leisure battery!

 

[tartan-caravan]

I assume that your storage is inside (out of sunlight) otherwise a reasonable sized solar panel would keep it topped up - the battery drain in storage should be negligible.

There's no reason why you couldn't use any 12v battery, but lead acid batteries don't like being fully discharged. A £50 car battery would probably be half the capacity of your leisure battery so would last half as long. Below a certain level the plates begin to 'sulphate' and the battery may not recharge - this applies to your leisure battery as well assuming that it's AGM.

Thanks, it's stored outside so thinking there might be something up with the solar charging system.

 

[Buckman]

Hi, It's a 100w panel and the controller is a Sargent 3amp Solar RegulatorProduct no: SSR-3A which I'm guessing is a budget model. The van is booked for a service in a couple of weeks so I'll ask them to check the panel etc are working OK. Will look at the mppt controllers again as they're not exorbitant, compared to a new leisure battery!

The 100w panel should be more than adequate to keep the 12v battery topped up. As you state there may be an issue with the controller. I have read very good reports about Sargent being very helpful in resolving issues. Give them a ring on Monday and have a chat.

 

[Anseo]

Hi, It's a 100w panel and the controller is a Sargent 3amp Solar RegulatorProduct no: SSR-3A which I'm guessing is a budget model. The van is booked for a service in a couple of weeks so I'll ask them to check the panel etc are working OK. Will look at the mppt controllers again as they're not exorbitant, compared to a new leisure battery!

Firstly, a 12v car battery will be fine for the purposes you have described.

A 3 amp solar charge controller is way undersized for a 100 amp solar panel.

A 10 amp solar charge controller would suffice (theoritecally this is still very slightly undersized but you will rarely if ever see maximum output from your solar panel). Having too large a capacity solar charge controller can have detrimental effects. I would suggest not having anything greater than a 20 amp controller for your 100 watt panel.

It is generally accepted that mppt controllers bring little benefit on small solar arrays such as a 100 watt panel, however an mppt controller would be especially advantageous if you decided to expand your solar array.

With that in mind I link some 20 amp solar charge controller options:

PWM 20 amp solar charge controller

MPPT 20 amp without bluetooth

MPPT 20 amp with bluetooth

 

[Mr Grumpy]

I keep ours hooked up to a 50 watt suitcase panel during storage and the battery is kept fully charged.