Battery to Battery Charger/ Solar Controller - Motorhome Forums, Motorhome Discussion, Motorhome Chat

User Tag List

LinkBack Thread Tools
post #1 of 5 (permalink) Old 28-06-2020, 10:14 Thread Starter
Junior Member
Join Date: Jun 2020
My Motorhome: I drive...
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Question Battery to Battery Charger/ Solar Controller

Hello, first post, thanks for having me etc. I'm in the process of converting my VW LT to a camper and trying to make my mind up with electrics. As a main power source I'm going to have solar which will be sized to be sufficient the majority of the time. For dark dingy winter days I'd like a back up though, also off-grid.

Relays sound like they can end up being more problems than they are worth, so I've been looking at a battery to battery charger (which can also have an integrated solar controller such as-

Althought they're designed to have minimal impact on battery life, what I'm wondering is if anyone knows how much impact it might have on the starter battery life? Since the solar system will hopefully be sufficient most of the time, would it be better for the starter battery and alternator to have switch the connection to the B2B charger to only use it when its actually needed rather than all the time?

Thanks very much
chrismmmm is offline  
Sponsored Links
post #2 of 5 (permalink) Old 28-06-2020, 23:11
Senior Member
Join Date: Jun 2007
Location: Belfast
My Motorhome: Hymer Exsis-i 504
Posts: 8,619
Thanks: 193
Thanked 463 Times in 439 Posts
Hi Chris, welcome to the forum.

I have a B2B but know nothing about it! I just know it hasn't given me any problems!

So I'm just giving your post a bump cos there are lots of folk on here are experts in these things!

jiwawa is offline  
post #3 of 5 (permalink) Old 29-06-2020, 14:57
Senior Member
shingi's Avatar
Join Date: Apr 2008
Location: Hertfordshire
My Motorhome: Hobby 750ELC on Ducato X244
Posts: 820
Thanks: 67
Thanked 41 Times in 39 Posts

Hi Chris,

Im a bit uncertain from your post what your ultimate aim in your requirements might be as regards usage, how and when, to what extent, what periods of time away, time of the year away from home etc., and of course weather conditions wherever you wild camp.

To try to move your post along a bit Im wondering if what I installed in my motor home is maybe along the lines you are planning. I have a 140w solar panel on the roof, a controller, two 80Ah linked leisure batteries and obviously the vehicle battery. The positive terminals are are linked together via a Victron Cyrix battery combiner ( see photo )( 1st. attempt at posting photo, so sorry its a bit small !!) which shares the output from the solar panel equally between them.

Whilst your MH maybe is not being used in the first Winter months it keeps all batteries fed and whilst away during the Summer with plenty of output from the solar panel it is adequate for battery support plus internal lighting, although one has to be sensible and not push ones luck with other power requirement needs.

What Ive described is maybe not exactly what youre looking for but maybe help you along the way?


P.S. This particular brand, Victron is produced in three versions, 120 / 230 / and 400 amp by the way
Attached Images
File Type: jpeg E9BAD734-8BD5-4682-9878-047472E3F18B.jpeg (1.05 MB, 8 views)

Last edited by shingi; 29-06-2020 at 15:03.
shingi is offline  
post #4 of 5 (permalink) Old 29-06-2020, 15:12
Senior Member
Join Date: May 2009
Location: UK and Katowice, Poland, plus All Europe
My Motorhome: Niesmann+Bischoff Arto 69GL (2003)
Posts: 12,759
Thanks: 886
Thanked 475 Times in 425 Posts
The term 'Battery-to-battery' charger is a bit of a misnomer. It is normally used to describe systems that run from the alternator to charge engine and domestic batteries at high charge rates when the alternator controlled only by a automotive voltage regulator will reduce the charge. They only work when the engine is driving the alternator.

I am not sure if the OP is using the term in this sense.

nicholsong is offline  
post #5 of 5 (permalink) Old 29-06-2020, 15:21
Senior Member
shingi's Avatar
Join Date: Apr 2008
Location: Hertfordshire
My Motorhome: Hobby 750ELC on Ducato X244
Posts: 820
Thanks: 67
Thanked 41 Times in 39 Posts
Im not sure either, but perhaps hell tell us when hes on next. Cheers
shingi is offline  

Quick Reply

Register Now

In order to be able to post messages on the Motorhome Forums, Motorhome Discussion, Motorhome Chat forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome