Which B2B?

Phantom

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My next upgrade will be a B2B but for the layman there is just no concise info out there, unless gleaned from various sources it seems, so I was at first in a kind of dilemma whether a 30A B2B would be okay for my lead/calcium batteries totalling <215Ah on a good day. It's more about the maximum battery charge rate and for lead acid that seems to generally be about 20-25%, but FLA batteries can cope much better with abuse than other types anyway. So it looks like 30A will be just fine to take them to about 80% charge after which the current will steadily reduce. So a 30A unit it will be and this should suit my Bosch 90A alternator quite well it seems. So then the question is which one to go for? Well it seems that the ones with a fan generate excess heat and can be noisy, so I'd much prefer a more efficient solid state device and reliability is a major factor. The better ones generally seem in the price range of about £20 difference, so not much in it. Some are simpler to wire up. I don't see any advantage of having Bluetooth connection to an App as it will just do it's three stage thing anyway when set to battery type, so may as well just fit and forget. It's looks are not so important as it will be hidden away from sight but still don't want a fugly one! I generally have the Victron Orion TR 12/12 30 in mind but am quite open to any other suggestions? Just my own thinking aloud thoughts but any others are most welcome. 😶
 
goog post timing, Id be interested what the thoughts are as Im in a similar boat.
Im getting rid of my lead acids, upgrading to Lithium, and a b2b at the same time
 
I am just about to go down the B2B route and it came down to the Ablemail or the Victron. I have decided on Victron for a different reason to @Phantom .

I had looked long and hard at Ablemail, British, very configurable and great support. I had ideas on instrumentation as it has RS232 (I think) data out which I could feed to my own logging / UI system.

Everyone knows Victron, 5 year warranty and reliable. Unfortunately the Orion TR-Smart doesn't have much in the way of data out, but it does have a nice Bluetooth phone app which although doesn't tell you much allows easy set up. The Ablemail on the other hand requires a Windows PC, a lead and some software.

I'm not a Windows user and don't own a Windows PC. Writing the code so my Raspberry Pi or D1 Mini's can talk over RS232 is a faff when they can talk to Victron using humanly readable code at 3v3 or 5v.

So for me it will be Victron. Set it up for AGM with my phone and when I change to Lithium the settings can be changed in less time than Windows could even start to boot.
 
I just wanted the b2b, wasn’t bothered about any logging so I went for the Votronic 30A unit. If I had the budget I would have gone bigger but like everything it’s a compromise, prices jump a lot when looking more than 30A.
Real easy fit with an EBL as well, i needed very little cable, mainly cut into exiting before EBL. A year on I would still go with Votronic, small unit, no noise and does what it says on the tin same as their mppt solar controller 👍
 
I have an old Sterling 50a b2b, and it works well but when the fans are on, its noisy.
Also just helped fit a new Sterling 60a b2b to a friends new Ducato.
Both are very easy to wire up but all settings are done via switches and led,s on the front panel (which suits me).
UK Factory support is excellent, and very responsive.
Forgot to add that they have the 60a ones at £100 off on their website for refurbished.
 
Looking around at 30A dc-dc chargers they seem to start from about £125 with Voltronic £150, Victron £215, Ablemail £220. Renogy do a 20A for £116 and a 40A for £158.
But for ease of fitment, set up and reliability the Victron unit is looking a good buy with member discount at £183 so it looks like I'll get one of those.
30A seems a good compromise of not over stressing your batteries or frying your alternator. 🙂
 
Looking around at 30A dc-dc chargers they seem to start from about £125 with Voltronic £150, Victron £215, Ablemail £220. Renogy do a 20A for £116 and a 40A for £158.
But for ease of fitment, set up and reliability the Victron unit is looking a good buy with member discount at £183 so it looks like I'll get one of those.
30A seems a good compromise of not over stressing your batteries or frying your alternator. 🙂

I don't think you can go far wrong with Victron stuff (or Votronic for that matter). I've used both makes and got good results, never had a B2B though, I seem to be doing okay without one at the moment.

Regards,
Del
 
Just remember, and this is assuming.
I. A 90ah charge will take 3 hours from a 30amp charger at best.
2. This is assuming your batteries will take it.
 
I am just about to go down the B2B route and it came down to the Ablemail or the Victron. I have decided on Victron for a different reason to @Phantom .

I had looked long and hard at Ablemail, British, very configurable and great support. I had ideas on instrumentation as it has RS232 (I think) data out which I could feed to my own logging / UI system.

Everyone knows Victron, 5 year warranty and reliable. Unfortunately the Orion TR-Smart doesn't have much in the way of data out, but it does have a nice Bluetooth phone app which although doesn't tell you much allows easy set up. The Ablemail on the other hand requires a Windows PC, a lead and some software.

I'm not a Windows user and don't own a Windows PC. Writing the code so my Raspberry Pi or D1 Mini's can talk over RS232 is a faff when they can talk to Victron using humanly readable code at 3v3 or 5v.

So for me it will be Victron. Set it up for AGM with my phone and when I change to Lithium the settings can be changed in less time than Windows could even start to boot.
The Bluetooth module for the AMC should be out before Christmas ;).
PS. If you have not bought your Victron B2B already, I have a 30A one I used for my testing that I can do you a fair bit cheaper then anyone else :)
 
Just remember, and this is assuming.
I. A 90ah charge will take 3 hours from a 30amp charger at best.
2. This is assuming your batteries will take it.
This is why I developed my B2B/VSR Combo setup when using bigger banks, as at lower states of charge the B2B can actually be a fair old bottleneck for large banks.

General rule of thumb to sizing charger ...
Wet Cell - around 10% - so 1A worth of charge for each 10Ah of Capacity. e.g. 100AH Battery would suit a 10A Charger. got 200AH of Battery ... a 20A charger would be about right.
AGM - around 20% - so 2A per 10Ah - so a 100AH AGM Battery could use a 20A Charger
Lead Carbon AGM - around 30% - so a 100AH Lead Acid Battery would suit a 30A Charger
Lithium - tends to be around 50% recommended (but varies by maker).
Those charge rates recommendations do vary by battery model and make, so check the battery spec sheets for actual rates, both recommended and maximum.
 
The ring seems quite good and incorporates a mppt. Which of course you don't have to use...
 
The ring seems quite good and incorporates a mppt. Which of course you don't have to use...
Ring unit is well priced, but I must say I have heard more reports of issues with the Ring than any other B2B make. No experience of it personally, so that comment is purely hearsay :unsure:
 
I have the ring rsdc30 it has a fan but not noisier than the engine or fridge when stopped. I got it because it acts as an mppt solar controller for up to 360 w of panels as well. It is a similar price to the victron. I am happy with it. It has occasionally not noticed engine start up though and the sun symbol stayed on with no charging when it should have used the alternator . After sleep mode it reset itself and was fine. Apparently it will work with lithium when I get one. Whether it will be efficient and charge at bulk rate for much longer than it does now with AGM battery I do not know.
 
Ring unit is well priced, but I must say I have heard more reports of issues with the Ring than any other B2B make. No experience of it personally, so that comment is purely hearsay :unsure:
I have used the ring rdc30 and changed it to a victron mppt solar controller and a sterling b2b charger. The problem with the ring was that it sometimes did not ’wake up‘ when the engine was running, and after a two hour drive, the battery had not been charging. I found that if I disconnected the leisure battery momentarily it re set the charge regime. Since changing my charge set up I have found that it performs better than the Ring ever did
 
So with 200ah of lifep04 then are we saying 100a b2b is recommended.
Im thinking maybe this
As Phantom says, what about your Alternator?
Some people fit 2nd alternators specifically for House/Hab/Leisure battery charging.

Its all about balancing requirements. If you have 200Ah of Lithium, how much and how quickly do you need to recharge?
For example, my Motorhome comes with a 10A charger (mains or B2B). for the typical 100Ah Wet Battery motorhomes are fitted with, that's about right. I have fitted 300Ah of Lead Carbon which can charge at a rate of upto 90A. So a charger bigger than 90A would be pointless. At the same time, a charger putting out 10A is way too small, so fitted a 70A Mains Charger and a 60A B2B Charger. (a smaller Mains Charger would be fine if you tended to recharge overnight, but big is good if you want to use a Generator if low and off-grid as it minimizes the running time)
 
As Phantom says, what about your Alternator?
Some people fit 2nd alternators specifically for House/Hab/Leisure battery charging.

Its all about balancing requirements. If you have 200Ah of Lithium, how much and how quickly do you need to recharge?
For example, my Motorhome comes with a 10A charger (mains or B2B). for the typical 100Ah Wet Battery motorhomes are fitted with, that's about right. I have fitted 300Ah of Lead Carbon which can charge at a rate of upto 90A. So a charger bigger than 90A would be pointless. At the same time, a charger putting out 10A is way too small, so fitted a 70A Mains Charger and a 60A B2B Charger. (a smaller Mains Charger would be fine if you tended to recharge overnight, but big is good if you want to use a Generator if low and off-grid as it minimizes the running time)
Good advice yeah, I have a decent victron mains charger and victron mppt, 300w solar so was leaning toward sticking with the Victron 30A b2b as they dont seem to do any bigger .
 
Good advice yeah, I have a decent victron mains charger and victron mppt, 300w solar so was leaning toward sticking with the Victron 30A b2b as they dont seem to do any bigger .
They do state you can parallel them if you want more capacity. That is always an option for the future. (y)
My 60A Ablemail B2B is actually a pair of 30A B2Bs that are mounted in a larger enclosure and share a common external connection. That approach is relatively common with the more programmable kit.
 
And not forgetting Lithium can charge twice as quick as lead, so 30a can = 60a charge time
 

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