New issue with swap to gel batteries

[Pablo19]

My new gel batteries have arrived and all of my focus has been on trying to get my main charger set up correctly (another thread) for gel and I've completely overlooked the solar controller. Mine looks quite basic, Solar Technologies and with the absence of any model numbers I think it's the one in this link. Am I going to have issues and do I need to get maybe an MPPT controller like a Victron or Votronic with specific gel settings? Also, I assume it's ok having 2 batteries joined in parallel being recognised as a single battery by tbhe controller?! Thanks

Solar Technologies

 

[Lenny HB]

Yes best to get a decent controller either a Victron or Votronic they will be much kinder to your Gels and give a proper absorbtion phase for Gels which they need to fully charge.

 

[Pablo19]

Yes best to get a decent controller either a Victron or Votronic they will be much kinder to your Gels and give a proper absorbtion phase for Gels which they need to fully charge.

Thanks Lenny, I'm not 100% sure but I think my solar panel is 100w. Is there a particular model of Votronic I should select on that basis? I want to make whatever I choose to be futureproof in case I decide to go Lithium at some point in the future. Thanks

 

[daveandsan]

A Votronic mpp 165 will suffice for 100 watt solar but if you want to future proof it get one that will handle more power.
I have 300 watt of solar but I fitted a Votronic mpp 430 just in case I wanted to fit a bit more solar.
One of the benefits of Votronic is it will also trickle charge your engine battery.

 

[Pablo19]

A Votronic mpp 165 will suffice for 100 watt solar but if you want to future proof it get one that will handle more power.
I have 300 watt of solar but I fitted a Votronic mpp 430 just in case I wanted to fit a bit more solar.
One of the benefits of Votronic is it will also trickle charge your engine battery.

Ok thanks but to be fair, my current controller does that now. If I go with the 165 and add more solar, will it just slow the speed of charging or would it not be able to cope with the power generated? Also, would it be a simple swap wiring wise. I notice on the Votronic that the starter negative terminal doesn't go into the controller and there is only 5 wires to connect to it whereas on mine I have six wires, 2 for the panel and 2 for each of the batteries?

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[Lenny HB]

Thanks Lenny, I'm not 100% sure but I think my solar panel is 100w. Is there a particular model of Votronic I should select on that basis? I want to make whatever I choose to be futureproof in case I decide to go Lithium at some point in the future. Thanks

If you are going to change to Lithium I would fit a Victron Blue Smart Solar as there have been a few problems with Votronic with Lithium.

If you look at the data sheets it tells how much solar (PV) each model can handle.
Also if fitting Lithium you would probably want to fit at least 300-400 watts of solar.

 

[funflair]

Ok thanks but to be fair, my current controller does that now. If I go with the 165 and add more solar, will it just slow the speed of charging or would it not be able to cope with the power generated? Also, would it be a simple swap wiring wise. I notice on the Votronic that the starter negative terminal doesn't go into the controller and there is only 5 wires to connect to it whereas on mine I have six wires, 2 for the panel and 2 for each of the batteries?

You only need one -ve as both batteries share a common earth connection. And I like Lenny's suggestion of Victron not only because of the issue to we and others have had with Votronic and LiFePO4 but also because you can then add more stuff like Victron shunt and temperature monitoring on you LiFePO4 and everything is viewable in one app, the custom charging profiles through the app are far more advanced in the Victron, and finally I think they harvest a bit more power than the Votronic ever did.

 

[headlight]

Another vote for Victron blue smart controller.
The app let's you see what your solar is doing, settings can be altered in the app and MPPT controlers are up to 30% more efficient than your present PWM controller.
Last time I looked the Victron blue smart 75/15, which can handle 220 watts of solar were about £100.

 

[headlight]

Victron Energy Smart Solar MPPT 75V/15A - (12/24V) - Sunshine Solar - Sunshine Solar Limited

At Sunshine Solar you can Purchase the Victron Energy Smart Solar MPPT 75V/15A - (12/24V) from certified providers of Victron products UK wide.

www.sunshinesolar.co.uk

 

[Revolvor]

The Victron will only charge your leisure batteries. You will also need something like either of these
[Broken Link Removed] or AMT12-2 to keep your Cab battery charged .

Edit: or one of these:
Votronic

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[TrudeandDall]

If you are going to change to Lithium I would fit a Victron Blue Smart Solar as there have been a few problems with Votronic with Lithium.

If you look at the data sheets it tells how much solar (PV) each model can handle.
Also if fitting Lithium you would probably want to fit at least 300-400 watts of solar.

What are the problems with Votronic solar Lenny ? I ask because I have a Votronic MPPT, which works brilliantly with my current AGM batteries, but when they die I will replace them with Lithium.

 

[Lenny HB]

What are the problems with Votronic solar Lenny ? I ask because I have a Votronic MPPT, which works brilliantly with my current AGM batteries, but when they die I will replace them with Lithium.

It appears to be mainly with the 430 MPP, when the sun comes up in the morning it often doesn't start charging unless you pull the fuse and replace it, it then it works OK the rest of the day.
I use a 350 MPP with my Gels and really like is especially the AES function but I wouldn't risk it with Lithium.

 

[TrudeandDall]

Thanks Lenny. Mine is the 350 and is not any problem at all with the AGM. As and whenever I change to Lithium I will keep an eye on the charging. If it doesn't charge correctly, then it will go back as faulty under warranty.

 

[Jackd]

It appears to be mainly with the 430 MPP, when the sun comes up in the morning it often doesn't start charging unless you pull the fuse and replace it, it then it works OK the rest of the day.
I use a 350 MPP with my Gels and really like is especially the AES function but I wouldn't risk it with Lithium.

That’s good news Lenny.
I fitted my 430 yesterday which I purchased from a slippery Yorkshire funster, who likes Harley Davidsons & go anywhere “toilet trucks”.

You wait til he gets back from the caravan salon!

 

[Pablo19]

You only need one -ve as both batteries share a common earth connection. And I like Lenny's suggestion of Victron not only because of the issue to we and others have had with Votronic and LiFePO4 but also because you can then add more stuff like Victron shunt and temperature monitoring on you LiFePO4 and everything is viewable in one app, the custom charging profiles through the app are far more advanced in the Victron, and finally I think they harvest a bit more power than the Votronic ever did.

When I said only one battery -ve I mean for the starter battery. My current charger has 3 -ve, one for the solar panels and one for each of the batteries. So assuming Battery 1 is the leisure batteries the -VE will be for both my gel batteries but what about the -VE for the starter? I assume that's what is there currently, it does get a charge from the solar for sure. (Edit - also included an image of the Votronic showing just a + for starter battery)

If I use this for a while is it likely to damage the gel batteries? Not sure I will have time to sort a replacement for afew weeks unless it really is a simple swap like for like. All of this researching is time consuming! Also, for info this is currently only a 10A charger so would this struggle to charge a 2 battery combo?

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[funflair]

When I said only one battery -ve I mean for the starter battery. My current charger has 3 -ve, one for the solar panels and one for each of the batteries. So assuming Battery 1 is the leisure batteries the -VE will be for both my gel batteries but what about the -VE for the starter? I assume that's what is there currently, it does get a charge from the solar for sure. (Edit - also included an image of the Votronic showing just a + for starter battery)

If I use this for a while is it likely to damage the gel batteries? Not sure I will have time to sort a replacement for afew weeks unless it really is a simple swap like for like. All of this researching is time consuming! Also, for info this is currently only a 10A charger so would this struggle to charge a 2 battery combo?


View attachment 803249View attachment 803261

You can just put the existing -ve for batteries 1 and 2 into the same connection on the Votronic, a 10 amp charger will just take twice as long to charge 2 batteries vs 1, hopefully I have understood your concern’s correctly.

 

[Pablo19]

You can just put the existing -ve for batteries 1 and 2 into the same connection on the Votronic, a 10 amp charger will just take twice as long to charge 2 batteries vs 1, hopefully I have understood your concern’s correctly.

Hi funflair. Sorry, I'm not making myself very clear! If you look at my existing controller I have 6 connections wired in and there are 3 -ve connections, one for the solar, one for the leisure battery and one for the starter battery. On the Voltronic there are only 2 -ve connections, one for the solar panel and one for both leisure batteries but what about the starter -ve. Apologies if I'm being a bit dim, electrics are not my strong point!

 

[funflair]

Hi funflair. Sorry, I'm not making myself very clear! If you look at my existing controller I have 6 connections wired in and there are 3 -ve connections, one for the solar, one for the leisure battery and one for the starter battery. On the Voltronic there are only 2 -ve connections, one for the solar panel and one for both leisure batteries but what about the starter -ve. Apologies if I'm being a bit dim, electrics are not my strong point!

Leisure and starter -ve can go in together on one terminal on your Votronic, the solar needs it's own -ve to the contoller.

 

[autorouter]

If you look at my existing controller I have 6 connections wired in and there are 3 -ve connections, one for the solar, one for the leisure battery and one for the starter battery. On the Voltronic there are only 2 -ve connections, one for the solar panel and one for both leisure batteries but what about the starter -ve.

In almost every vehicle, the starter battery negative is connected to the vehicle chassis, which is a good solid conductor. The alternator negative is connected to the metal engine, which is in turn connected to the chassis buy a thick wire earth strap. So there is a very good connection between the starter battery negative and the alternator negative.

In a motorhome the leisure battery negative is also connected to the chassis. When the alternator charges the leisure battery, there is a good return path from the leisure battery negative to the alternator through the metal chassis.

Both the solar controllers have a negative wire to the leisure battery. It could go to the chassis, but motorhome bodywork is usually wood, fibreglass etc, so no convenient solid bodywork connection to take the negative return to the battery. The usual advice is just to run a negative wire straight to the battery. The solar current to the leisure battery is usually several amps, and the continuous fairly thick wire avoids the possibility of voltage drop along a maybe poor connection to a thin bit of bodywork.

The solar controller output to the starter battery is only a trickle charge, a couple of amps at most usually, so voltage drop is not really a problem. Because of that, it's possible to send the starter battery negative through the main battery negative wire. The starter battery current goes along the common negative wire, to the leisure battery negative, down to the chassis and then to the starter battery. The current is very low, and it won't cause any problems.

As for what to actually do with the two negative wires, you could attach them both to the solar controller battery negative. Or not use the starter battery negative at all, just put some tape round the end and tie it up out of the way somewhere.

There are some situations where separate negatives for the batteries are a good idea, on a boat for example, but in a motorhome it's completely unnecessary.

 

[Pablo19]

In almost every vehicle, the starter battery negative is connected to the vehicle chassis, which is a good solid conductor. The alternator negative is connected to the metal engine, which is in turn connected to the chassis buy a thick wire earth strap. So there is a very good connection between the starter battery negative and the alternator negative.

In a motorhome the leisure battery negative is also connected to the chassis. When the alternator charges the leisure battery, there is a good return path from the leisure battery negative to the alternator through the metal chassis.

Both the solar controllers have a negative wire to the leisure battery. It could go to the chassis, but motorhome bodywork is usually wood, fibreglass etc, so no convenient solid bodywork connection to take the negative return to the battery. The usual advice is just to run a negative wire straight to the battery. The solar current to the leisure battery is usually several amps, and the continuous fairly thick wire avoids the possibility of voltage drop along a maybe poor connection to a thin bit of bodywork.

The solar controller output to the starter battery is only a trickle charge, a couple of amps at most usually, so voltage drop is not really a problem. Because of that, it's possible to send the starter battery negative through the main battery negative wire. The starter battery current goes along the common negative wire, to the leisure battery negative, down to the chassis and then to the starter battery. The current is very low, and it won't cause any problems.

As for what to actually do with the two negative wires, you could attach them both to the solar controller battery negative. Or not use the starter battery negative at all, just put some tape round the end and tie it up out of the way somewhere.

There are some situations where separate negatives for the batteries are a good idea, on a boat for example, but in a motorhome it's completely unnecessary.

That's superb info autorouter, thank you. I now feel confident doing the job myself!

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