battery for charging ebike batteries

jonathan.agnew

Esteemed Pedelecer
Dec 27, 2018
2,383
3,372
dear all, this is a bit heath Robinson. but i'm about to go touring Europe in a camper and had an idea - how would it be IF i built a say 3 or 4kw battery (that weighed around 20kg's in say an aluminium trolley case that disguised it) with a reasonably rapid charger (say around 2kw) to charge in cafes (while using wifi and having the obligatory two hour daily fix of green tea and people watching). This would probably be complex and expensive, BUT would allow me to use a microwave, OH's hairdryer, TV, laptop and charge our ebikes and loads of other creature comforts without worrying about lpg. Id be most grateful for advice, or any members experience of doing this (or if you think its a mad idea with reasons).
 

sjpt

Esteemed Pedelecer
Jun 8, 2018
3,679
2,675
Winchester

 
  • Like
Reactions: jonathan.agnew

jonathan.agnew

Esteemed Pedelecer
Dec 27, 2018
2,383
3,372
Expensive, for sure. Here is a 3kw one for example


Not exactly convinced your average cafe will

1. want you to wheel in what amounts to a home power wall and then

3. be happy to charge it for you for price of a cuppa or two


 

jonathan.agnew

Esteemed Pedelecer
Dec 27, 2018
2,383
3,372
thanks - I was thinking of building it myself - hypothetically, if safety wasn't a concern - 20 20ah 6s hobby kings would theoretically give one around 3kwh I think 9without knackering the cells through over charge/discharge) and (I think) weigh around 10kg's. it would cost about £2k - but off course involve all the risks that come with hobby king packs
as for the ethics - I wouldn't be taking 3kwh in exchange for the cuppa, we'd hardly ever use that much. but I think a larger battery would have a much longer life.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,130
8,230
60
West Sx RH
For all bar the bikes how about considering solar charging on the move and when stationery, using deep cycle SLA batteries ?
 
Last edited:
  • Like
Reactions: jonathan.agnew

jonathan.agnew

Esteemed Pedelecer
Dec 27, 2018
2,383
3,372
Thanks, hadn't thought of that for some reason, will have to do some more back of the envelope about energy budget and what solar panels could realistically provide. It would be less of a faff and safer and probably cheaper
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,130
8,230
60
West Sx RH
Covering the whole camper roof with panels for on the move and if needed some more to plug in when camped up ?
As you say you will have to do the math to see if the batteries can supply the demand you require for your camper van needs.
The deep cycle batteries opposed to Lithium prefer to stand at full charge.
 
  • Informative
Reactions: jonathan.agnew

Danidl

Esteemed Pedelecer
Sep 29, 2016
8,610
12,256
73
Ireland
I think it is a mad idea. Sorry.
In my younger days we did tour the continent..well France and once a bit of Spain with a caravan. The campsites were virtually all equipped with 5 amp outlets . Even if using a camper van, I would expect that one will be going to sites every second or third day. ..showers are nice!. .
Sticking solar PV on the roof of the camper makes more sense and a 200 watt panel will make 1kw over a day.
While the camper van is traveling it will be able to power the fridge and a microwave only takes 1Kw for 20 minutes to cook the chicken, so letting the motor idle if needs be sorts that out.
For real Heath Robinson, think about diverting heat from the radiator to warm water for the tea...
 

kangooroo

Esteemed Pedelecer
Aug 24, 2015
268
183
Wye Valley
I think it would be easier to simply use a campsite for the night with EHU!

As a dedicated wildcamper myself, I can understand you might not want to take this route but I think it's going to be the most practical if you're wanting to use a microwave, hairdryer and charge e-bikes.
 
  • Agree
Reactions: jonathan.agnew

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
thanks - I was thinking of building it myself - hypothetically, if safety wasn't a concern - 20 20ah 6s hobby kings would theoretically give one around 3kwh I think 9without knackering the cells through over charge/discharge) and (I think) weigh around 10kg's. it would cost about £2k - but off course involve all the risks that come with hobby king packs
as for the ethics - I wouldn't be taking 3kwh in exchange for the cuppa, we'd hardly ever use that much. but I think a larger battery would have a much longer life.
It wasnt the ethics particularly but practicalities of dragging a large lithium pack into cafes and back. How often will your camper be right outside a cafe?

And whilst they tend not to mind if you plug in laptop. The look and size this option seems likely to prompt questions?

And you are braver than me! The idea of 10kg of lipo in my bag or near my bed when I'm sleeping scares the bejesus out of me!!
 

jonathan.agnew

Esteemed Pedelecer
Dec 27, 2018
2,383
3,372
I think it is a mad idea. Sorry.
In my younger days we did tour the continent..well France and once a bit of Spain with a caravan. The campsites were virtually all equipped with 5 amp outlets . Even if using a camper van, I would expect that one will be going to sites every second or third day. ..showers are nice!. .
Sticking solar PV on the roof of the camper makes more sense and a 200 watt panel will make 1kw over a day.
While the camper van is traveling it will be able to power the fridge and a microwave only takes 1Kw for 20 minutes to cook the chicken, so letting the motor idle if needs be sorts that out.
For real Heath Robinson, think about diverting heat from the radiator to warm water for the tea...
I can see where you're coming from. Our camper is smallish and our idea is more wilderness and a hotel for a few nights every week (were not crazy about campsites to be honest)
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
My brother has a camper van business (conversion, repair, interiors, canvas work and so forth)

As well as his beloved super old and rare vw splitty panel van he has a more modern and larger vw to take his wife and 2 kids. He hates campsites but runs off lpg and deep cycle leisure batts with a solar array and a small wind turbine when conditions are right.

However, I have successfully charged a totally dead land rover overfinch on a campsite using a couple of 5ah 3s turnigy packs and an accucel 6 charger. Lipo bricks being the power source a d set the charger to sla (it can charge lipo, nicsd, Sla)

So my long winded idea is this

Buy that charger or similar plus a few lipo bricks. Easy charged in a hotel and can charge your sla batts in a bind?

Cheap and easy emergency backup should you run out of lpg And have depleted sla at the same time? Just a thought really

And a long winded one to boot!
 
  • Like
Reactions: jonathan.agnew

Woosh

Trade Member
May 19, 2012
19,525
16,464
Southend on Sea
wooshbikes.co.uk
I have a dozen generators (mostly 1kw, 1.5kw and 2kw) - brand new, still in original cartons, that I can let go for about half street prices (£100 for 1kw + £15 for courier).
They run on petrol, 4-stroke engine, very low noise, 3 UK output sockets for 220V sinewave. Perfect to charge your batteries.
1 year warranty.
I bought them for a project which is now abandoned.
 

jonathan.agnew

Esteemed Pedelecer
Dec 27, 2018
2,383
3,372
I have a dozen generators (mostly 1kw, 1.5kw and 2kw) - brand new, still in original cartons, that I can let go for about half street prices (£100 for 1kw + £15 for courier).
They run on petrol, 4-stroke engine, very low noise, 3 UK output sockets for 220V sinewave. Perfect to charge your batteries.
1 year warranty.
I bought them for a project which is now abandoned.
thanks for the offer, but our smallish camper wouldn't have space, I think in the end solar panels, deep cycle pb and as Kirstin suggest a few turnigy bricks might be sufficient