Upgrading Charger and Solar Controller.

[Tony68000]

Second post in as many minutes, hope you don't mind..

Got a few questions on my battery charger and solar setup that I hope you might be able to help with.

1. My new MH has a decent size solar panel, but I'm unsure of the actual capacity.. is there anyway of finding out?

2. I have this solar charge controller... any thoughts as to the make?

3. If I replace the battery charger with an all-in-one B2B Charger and MPPT, does the amperage matter? Say I have a leisure battery that can only handle a 20amp charge, will it matter if I get a 60amp B2B charger? Is there an adjustment I can make, or do I need to match them at the point of buying one?

4. My current leisure battery is a 'MONBAT XLM85E C20 - 75Ah'. Looks a cheap one and I've no idea of it's health. I'm not sure what 'type' this battery is, or it's charge current. If I swap if for something a little better can I just drop in a replacement, or do I need to 'adjust' the charger/solar controller? Or will my new B2B+MPPT 'just work'.

For ref, the Renogy DCC50S looks like it might be a good option for me?

Thanks!

 

[Jim]

Can anyone help Tony?

 

[Phill D]

Hi Tony.
Q1. its a bit hit and miss without knowing any details of the panel measurements, number of cells etc. clutching at straws i would say that there should be a label on the underside of the panel maybe you can get a mirror on an arm and get some info off it.
Q2, remove the white cover and post a new photo that may help people help you, that is just a generic cover.
Q3. sorry cant help withB2B's
Q4. 75 ah is quite low and i am almost certain a lead acid battery. what you can replace it with will depend on how much space you have and if your charger unit and solar can be adjusted to charge other types of battery.

hope some of this helps until others come along with better info for you.

 

[Conal]

Tony68000 If you search BtoB or B2B on here you will find a lot of info. I was going down that route (in my head) until I got a quote from RoadPro that scared me. A lot of original not too old stuff would have to be replaced, and I thought that, as most of our overnights are spent at campsites with electricity, it was not economic viable.
I asked for an additional larger solar panel but the size of the original limits what you get from the larger one if on the same system, so I would have had to replace the original.

 

[Tony68000]

Hi Tony.
Q1. its a bit hit and miss without knowing any details of the panel measurements, number of cells etc. clutching at straws i would say that there should be a label on the underside of the panel maybe you can get a mirror on an arm and get some info off it.
Q2, remove the white cover and post a new photo that may help people help you, that is just a generic cover.
Q3. sorry cant help withB2B's
Q4. 75 ah is quite low and i am almost certain a lead acid battery. what you can replace it with will depend on how much space you have and if your charger unit and solar can be adjusted to charge other types of battery.

hope some of this helps until others come along with better info for you.

No, this is a great help thanks. I’ll pull the cover off tomorrow and see what’s there.

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[autorouter]

3. If I replace the battery charger with an all-in-one B2B Charger and MPPT, does the amperage matter? Say I have a leisure battery that can only handle a 20amp charge, will it matter if I get a 60amp B2B charger? Is there an adjustment I can make, or do I need to match them at the point of buying one?

Yes it does matter. In the first stage of charging, the B2B sends out its full amps value, as in the spec. A 60A B2B will send out 60A. This continues until the battery voltage rises to about 14.4V (often several hours) until it is about 80% charged.

Some B2Bs, for example Sterling, have a half power setting, so will send out only half the spec amps value. But most others don't have that option. Another possibility is, some B2Bs such as Victron can be combined together in parallel. So if you get more batteries you can wire up an extra B2B.

1. My new MH has a decent size solar panel, but I'm unsure of the actual capacity.. is there anyway of finding out?

Panel power depends on the panel area. Measure the panel dimensions. Calculate the area. Compare with advertised panels. That should allow you to estimate if it's say 100W, 150W, 200W etc.

Other methods include taping your phone on a stick and doing a video of the label on the panel underside.

 

[Tony68000]

Tony68000 If you search BtoB or B2B on here you will find a lot of info. I was going down that route (in my head) until I got a quote from RoadPro that scared me. A lot of original not too old stuff would have to be replaced, and I thought that, as most of our overnights are spent at campsites with electricity, it was not economic viable.
I asked for an additional larger solar panel but the size of the original limits what you get from the larger one if on the same system, so I would have had to replace the original.

The existing solar panel ‘looks‘ big enough, I know the battery is quite small, and of unknown health, so would probably look to replace the battery with a 110ah one. I (currently) don’t know if the existing charger will be a match and I strongly suspect the solar controller wont be as good as a decent MPPT, so hence looking at the Renogy one. For £200 + new battery this is fairly reasonable. I’m just in the process of picking the new van apart and figuring out what I’ve got... and indeed, a lot of this is in my head too, reality might kick in and I’ll end up sticking with what I have for the time being!

 

[Tony68000]

Yes it does matter. In the first stage of charging, the B2B sends out its full amps value, as in the spec. A 60A B2B will send out 60A. This continues until the battery voltage rises to about 14.4V (often several hours) until it is about 80% charged.

Some B2Bs, for example Sterling, have a half power setting, so will send out only half the spec amps value. But most others don't have that option. Another possibility is, some B2Bs such as Victron can be combined together in parallel. So if you get more batteries you can wire up an extra B2B.

Ah, that’s useful info, thanks. Looks like it’s not that straight forward then.

So, would I start with the battery… and select a B2B to match that? What about the split charge..would that need to match the vehicle battery too? If I read the specs right, the Renogy 50amp charger splits its charge 25amp to the leisure battery and 25 to the vehicle battery. So does that mean I also need a match for the vehicle battery too? Perhaps I need to read a little more! Definitely before I spend any mohey.

As a (mostly computer) techie, I’ve loving this new ’hobby’.

 

[Lenny HB]

Measure the size of the solar panel then compare with ones for sale most ebay listing have the sizes.

The type of battery you fit will depend on what the mains charger can handle but the existing one being 75ah probably a standard wet cell lead acid.

If you fit a 100ah battery you don't want to be charging at 60 amps ideally not more than 20 amp. Some of the Votronic B2B's are adjustable for output, I don't think the renogy is.

Certainly worth replacing that solar regulator looks like it came from Poundland.

 

[Lenny HB]

Ah, that’s useful info, thanks. Looks like it’s not that straight forward then.

So, would I start with the battery… and select a B2B to match that? What about the split charge..would that need to match the vehicle battery too? If I read the specs right, the Renogy 50amp charger splits its charge 25amp to the leisure battery and 25 to the vehicle battery. So does that mean I also need a match for the vehicle battery too? Perhaps I need to read a little more! Definitely before I spend any mohey.

As a (mostly computer) techie, I’ve loving this new ’hobby’.

Yes you are reading it wrong the B2B replaces the split charge relay and connects between the starter battery and the leisure battery.

The Votronic 50amp B2B that can be adjusted is about £400 and solar regulator depending on size £120 to £200.

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[Tony68000]

Thanks for the helpful tips and guidance everyone.

I think I’m going to continue to map out everything I have installed and then decide what, if anything, I replace and when. Definitely not as straight forward as I initially thought.

 

[autorouter]

What about the split charge..would that need to match the vehicle battery too? If I read the specs right, the Renogy 50amp charger splits its charge 25amp to the leisure battery and 25 to the vehicle battery.

Is this the Renogy unit that is a combined 50A B2B and MPPT solar controller? In that case the MPPT controller will charge both leisure and vehicle batteries, splitting the charge between them. I think the percentage splitting is adjustable, but might be wrong about that. Some of them wait until the leisure battery is full before sending charge to the vehicle battery.

The B2B is different. As Lenny HB says, the B2B only charges the leisure battery, and doesn't charge the vehicle battery. The alternator charges the vehicle battery, and supplies power to the B2B for the leisure battery.

 

[Bessy765]

Put your mobile phone on video and slide it round underneath the panel. Should see the label

 

[Raul]

Before you upgrade anything, saving to do it twice, make sure you are realistic with YOUR needs. How much reserve capacity you need, how you use your van, and then start designing a system that works for YOU. Generic items are just that, some are suitable for most, some just don’t cut it.
First start with your capacity
Secondly you look how you going to replenish/charge back. This depends on your use: off grid, driving or hook up. If any activity are more often than others, then is worth concentrating in that area most. You will need to cover all scenarios to a certain extent.

Solar, it’s fairly handy, in some cases it can be main source of charging, allowing longer stays in one spot, less driving, and less hookup. Apart of solar on the roof, it can be portable solar to. A decent controller is a must if you need reliable charging. Buy once, cry once.

B2B, if you drive a fair bit, this option, in some cases can cover all you charging. Some have a solid B2B charging and no solar; works for some. This option is very important in winter use, when solar is almost non existent. So, if winter use is on the cards, B2B is essential.

EHU, if most outing is on sites, a reliable ehu charger will be used most, and will be your primary source. Some vans have a 15-18a charger with very little settings. On the other hand, if not used often, that’s more than enough. But, there are charger out there with ability to dial in settings, that can support different types of batteries. Victron do some great gear.
Finally, but not last, the leisure battery: the larger the capacity, the longer will last. Even if you don’t use all you available power, the shallow cycle can give a very long service. This is valid for ALL types. The charge and discharge rate reduces, putting less stress on the battery. This single item is the most important choice for a reliable system, then the charging sources follows. Buy the best you can afford. If you hold back in one area, you will forever upgrade, or learn to leave with compromises.
Start with your energy needs, then storage, then charging according to your use.
Hope this helps.

 

[Revolvor]

I have got an earlier version of THIS. It is a combined solar charger and B2B and can handle 300 Watts of solar, and the B2B is 20 Amps max. It has a 5 step charging profile.
Mine is only suitable for lead- acid, but it's worked well for 5 years. With 200W solar and 200 Ah batteries we rarely use the on-board charger, even when on EHU.

From the link above:

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[cyberyacht]

B2B really come into their own with lithium batteries which will swallow virtually all the amps you can chuck at them. Whether lithium is the route and expense for you will depend on how much and how long you are off mains hookup.

 

[Tony68000]

B2B really come into their own with lithium batteries which will swallow virtually all the amps you can chuck at them. Whether lithium is the route and expense for you will depend on how much and how long you are off mains hookup.

Useful info. I'm not going down the lithium route. I think at best I'll fit a new 110ah battery.