Extra Battery Dilemma.

Ballynoes

Pedelecer
Jul 13, 2017
243
140
Perthshire Scotland
So here is my dilemma.

I have been trying to locate a Bosch 12v Travel charger for my ebike, so I can charge the battery when in the campervan.

Sadly I cannot find one anywhere, as they appear to be no longer available, why I don’t know.

So I was thinking about a second bike battery, so I head off with two fully charged batteries for say 2 days cycling, back to the camper at night new battery for the next day.

The other option is an inverter in the Camper to plug in my mains charger, but I think it would drain the leisure batteries (and I have 3 off them) as it needs to be on for 5-6 hours, and the inverter option is not that efficient, ie, convert 12v batteries to mains back to 48v to charge the bike battery

Anyone else have any ideas, just think the second battery is the best option, and charge both before I go. ??
 

flecc

Member
Oct 25, 2006
45,239
21,808
I'd say second battery, but then keep both in use by rotation even when not using the camper to keep both in good equal condition.
.
 
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kangooroo

Pedelecer
Aug 24, 2015
185
136
Wye Valley
I've had a similar dilemma myself but concluded that it wouldn't be practical to charge an e-bike via leisure battery and inverter. The demand would be too high and risk draining the leisure battery. Maybe it would be possible if driving for the entire duration of the charging but this isn't always practical either. I opted for a second battery instead.
 

Ballynoes

Pedelecer
Jul 13, 2017
243
140
Perthshire Scotland
I guess the second battery will always come in handy if I want to go "beyond the range" of one battery.. so a second battery looks the way to go, also I suppose if I am at a caravan site and have hook up, I can recharge till my heart is content :)
 

bikey850

Pedelecer
Aug 22, 2016
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UK
Yoda says ... "Hmmm, think outside the box, you must"

Get a 4 amp charger then after a hard days riding pop into a local pub or restaurant and ask them to charge it up for you whilst you relax (only costs them 30 pence).

Just leave enough time for a few beers or pudding and pick it up again when settling the bill.
 
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Ballynoes

Pedelecer
Jul 13, 2017
243
140
Perthshire Scotland
Yoda says ... "Hmmm, think outside the box, you must"

Get a 4 amp charger then after a hard days riding pop into a local pub or restaurant and ask them to charge it up for you whilst you relax (only costs them 30 pence).

Just leave enough time for a few beers or pudding and pick it up again when settling the bill.
Only one small problem there Bikey,

some of the places I park..... are miles from anywhere, and in the middle of nowhere. ;)
 

bikey850

Pedelecer
Aug 22, 2016
97
15
120
UK
I know ... I know... ;)

Always wanted a camper van but always thought they go hand in hand with an external petrol generator - something like a Honda EU10i.

Honda seem to make a good motor so always though they would be handy to have if touring.
 
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Steve Dyson

Pedelecer
Oct 13, 2018
72
13
How about using a DC-DC buck/boost converter should be more efficient than turning to AC then back to DC

i have 2 that turn 1-35v upto 7amps into variable 1-35v at 5amps they CC/CV so charge my 2 24V batteries up which i then series up to get my full power
 

chris_n

Esteemed Pedelecer
Apr 29, 2016
574
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Austria , Niederau or NE England
There are 1200Wh in a 12v 100ah (typical leisure battery size) battery. I can't see a solar system charging a Bosch battery. I'm pretty sure it will have to handshake with the charger before it will work.
 

GLJoe

Esteemed Pedelecer
May 21, 2017
466
208
UK
I have been trying to locate a Bosch 12v Travel charger for my ebike, so I can charge the battery when in the campervan.
...
The other option is an inverter in the Camper to plug in my mains charger, but I think it would drain the leisure batteries
I'm curious as to why you think the inverter option will drain your leisure batteries, but the 12v travel charger won't ?

You need to pump 400/500wh into the battery regardless of what's doing it.

??
 

Ballynoes

Pedelecer
Jul 13, 2017
243
140
Perthshire Scotland
Hi GLJoe,

what you say is perfectly correct, in that I will have to put that amount back into a battery no matter how I do it.

However as nothing is 100% efficient, if I were to take the 12V from the batteries and through an inverter change this to 240V AC, for my mains charger, I would loose a percentage right there, as inverters are quoted as typically 85% efficient.

Then the charger would loose a small percentage again changing it back to the, I think 48V, to charge the bike battery, again not 100% efficient.

So inevitably I would use more power from my battery bank than necessary, and having a limited supply, as these batteries are required for everything else 12V, you run the risk of... say having no lights.

A mains inverter is a big drain on 12V batteries what ever you are running from it.

I was hoping to get the 12V charger, so I can go direct from 12V to charging the bike, with lower losses.

In hindsight, a second battery will probably be the best option, as I could even charge both at the same time, if I were to plug my campervan into the mains - hook up as they say.
 

Ballynoes

Pedelecer
Jul 13, 2017
243
140
Perthshire Scotland
Looks good soundwave.... until you do the calculations ;)

It says it's 434Wh (watt Hours) and at 12V thats only 36Ah (amp hours)

My camper van will have at least 350Ah, when it's finished.

Anyway have you tried to carry a leisure battery with one hand :)
 

soundwave

Esteemed Pedelecer
May 23, 2015
10,229
4,228
yeah but i bet no one else can run a tumble dryer and a power shower :D