E bike charging when off grid (1 Viewer)

Jan 27, 2019
173
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Teesside
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58,248
MH
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Since 2016
For those who have e bikes and stay off grid for some days, are you using an inverter and the regular bike charger and if so how is it working out? My e bike battery is 36v and 13.5 Ah And I need to rig something this winter for next years euro travels. Cheers.
 

68c

Oct 22, 2019
1,840
2,848
Southampton
Funster No
65,959
MH
2001 Pilote 270
Exp
Since 2004
Look into DC-DC converters, they are an adjustable electronic device that can either step up or step down a DC supply. We use one that supplies 42v at 3amp from our 12v leisure battery to charge our e-bikes. Loads on Ebay. Look at your charger to see what voltage and current needed to adjust it to. More efficient than 12v DC to 240vAC to 36v DC.
 
OP
OP
C
Jan 27, 2019
173
147
Teesside
Funster No
58,248
MH
VAN CONVERSION
Exp
Since 2016
Now this method is interesting, thanks 68c, another question is there any risk of the lithium bike battery overcharging? Or does the dc-dc charger detect full capacity?
 
OP
OP
C
Jan 27, 2019
173
147
Teesside
Funster No
58,248
MH
VAN CONVERSION
Exp
Since 2016
And to add, if you have time do you have the detailed product description as I am not finding on eBay what you describe, thanks
 

Two on Tour

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Sep 16, 2016
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We charge ours with the supplied 240v charger via our inverter which does not cane our leisure battery.
If we know that we are going to be travelling before we next use our E-bikes, then we charge the batteries again via the inverter as our B2B then plays its part while we are driving.

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Jan 26, 2017
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Eight Years and 28,000 Miles.
For those who have e bikes and stay off grid for some days, are you using an inverter and the regular bike charger and if so how is it working out? My e bike battery is 36v and 13.5 Ah And I need to rig something this winter for next years euro travels. Cheers.
I use a 12v-36v plug in charger to top up our 36v 17ah batteries.

Loads on ebay, make sure it's good quality.

Search the forum, lots of info to be found.
 
OP
OP
C
Jan 27, 2019
173
147
Teesside
Funster No
58,248
MH
VAN CONVERSION
Exp
Since 2016
Currently I have no inverter and if i can I would like to avoid buying one as its only the e bike charging that is the issue. Thanks to all for the replies, I will into these small dc chargers.

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68c

Oct 22, 2019
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Southampton
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Now this method is interesting, thanks 68c, another question is there any risk of the lithium bike battery overcharging? Or does the dc-dc charger detect full capacity?
It just stops supplying any current once the selected voltage is achieved, you could set it a half volt lower if you wish, will make very little difference to the charge. Unless you have a very expensive charger it is unlikely it switches off when charged, just does not supply any current. Your charger probably has a green light showing when fully charged, I fitted a dual volt/amps LED meter, just turn it off when it shows less than 0.1amp. I do not leave it charging unattended.
 

Kannon Fodda

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Feb 26, 2019
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Whether the DC to DC step up charger will work may depend on compatibility with the ebike battery electronics.

You also need to understand the capacity of the charging source. My Bosch 500 battery if almost discharged will take some 30+Ah out of the leisure battery. Remember lead acid type batteries should discharge to only 50% for longevity, and you also need to be mindful of the discharge rate. Gel and lithium can be used more heavily.

If you use the manufacturer supplied ebike mains charger use a pure sine wave inverter off your leisure battery.
 
Sep 17, 2017
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The energy stored in an ebike battery tends to be a very large chunk of the capacity of a boggo motorhome hab battery. You need a lot of surplus storage (e.g. lithium battery) or a lot of generation (lots of solar or regular driving with a strong B2B).

Or you just plan to charge when you're on hookup.
 

68c

Oct 22, 2019
1,840
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Southampton
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2001 Pilote 270
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Since 2004
A 42volt 15Ah e-bike batery is 630Wh. A 12v 100Ah leisure battery is 1200Wh. Of course you would never drop the leisure battery below 50% (600wh) and the bike battery us unlikely to be completely flat as it's BMS will prevent that. We have two 100Ah lead acids with 240Ah solar panels. During the summer we can charge two e-bikes each day, both being on about 50% charge, around 25miles. The annoying thing is we are riding during the day so have to let the solar charge the leisure batts then charge the bikes in the evening. We rarely stop anywhere more than three days so our 120amp altenator tops the batts up then, do not have a B2B just a 100amp charge relay and thicker cables.

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Feb 14, 2021
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Milton Keynes, UK
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Burstner Lyseo 727G
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19 month year 18000 miles UK, Ireland, France, Spain, Germany, Italy. Campsites and off Grid.
The energy stored in an ebike battery tends to be a very large chunk of the capacity of a boggo motorhome hab battery. You need a lot of surplus storage (e.g. lithium battery) or a lot of generation (lots of solar or regular driving with a strong B2B).

Or you just plan to charge when you're on hookup.

I charge up my electric motorbike from my leisure batteries (via inverter). Being a proper motorbike (albeit 50cc moped equivalent) it has a much bigger battery than a typical E bike.

I have 3 batteries -270ah but being AGM's only 50% of that is usable. I tried to charge in 'bits' Put it on for an hour. Let the solar regenerate the batteries. Put it on whilst driving. Another hour the next day. etc etc. It will take 8 hours from 0% to 100% so straight out recharge is not possible but if I don't allow it to drop too low and don't charge to maximum I can manage it.

Annoyingly I cannot find the specs on the battery. Not sure the capacity of it actually is.
 

Lenny HB

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Oct 18, 2007
54,147
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I use a 1000 watt pure sine inverter, I have 3 x 78 ah Gel batteries and 300 watts of solar. I can charge both batteries at the same time but I don't. I try to top them up rather than charge from flat.
If I was to charge both from flat even in June with max solar available it would take at least two days to recharge the leisure batteries.
 
Apr 27, 2016
6,954
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Manchester
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42,762
MH
A class Hymer
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Since the 80s
My e bike battery is 36v and 13.5 Ah
That's 36 x 13.5 = 486Wh, so from a 12V battery it will take 486 / 12 = 40.5Ah. So your leisure battery bank needs to be big enough to give that out a few times if you are staying in one place for a few days.

For comparison, a 100W solar panel will give you 40Ah of (12v) energy on a good summer day, more like 30Ah on an average day.
 
Jul 10, 2017
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Newbie
Cycle to vineyard , whilst wine tasting ask if you can plug in your bike / battery , taste more wine , buy wine and put in panniers ( 8 bottles is easily doable ) , cycle back to motorhome and repeat , simples .
 
Dec 24, 2014
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Ever since lighting was by Calor gas.
Cycle to vineyard , whilst wine tasting ask if you can plug in your bike / battery , taste more wine , buy wine and put in panniers ( 8 bottles is easily doable ) , cycle back to motorhome and repeat , simples .
Or just charge the bike and don't buy any wine. (Repeat as necessary).
;)

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