7 replies to this topic

[Gaz66]

Im looking at lithium race batteries and it seems you need a special charger to charge these due to the charge voltage. Does this mean a special alternator is required also?

Edited by Gaz66, 07 December 2021 - 06:45 PM.

[Avtovaz]

ive got one in my bmw, i have always used a normal charger, they key is they dont like going flat. Mine has held charge for 1 year with out starting the car and worked " off the key!" My engine has a standard volvo b230 alti on it same idea as a mini one.

[weef]

I believe the normal car alternator will charge a lithium ion cell battery, but substituting these for a lead acid type is not just a plug and play exercise.

Individual cell failure is common if they are not charged properly and unless the lithium battery has its own built in charge circuitry this may be more evident. As it is the integrated charge circuits built in to be tolerant of vehicle charge cycles does not come cheap, I recently replaced a lithium ion battery, fitted as standard to certain 3 series BMW,s, it was almost £800 ( genuine BMW ) and then the car has to be programmed to accept the new unit. I do not know if the aftermarket units have the level of tech required, but looking at the prices I doubt it, maybe OK for the weekend racer but its buyer beware.

[mini-mad-mark]

Have you considered one of these which maybe heavier than a Lithium but no special charger or special circuitry on the car required.

 

https://eu.odysseybattery.com/

 

 

I'm using this specific one on my car (which I saw someone else on here using first but I forget who to credit) and so far so good.

 

https://eu.odysseyba...t/ods-agm16l-2/

[Gaz66]

I really need to lose the weight of the lead acid battery which is why i'm looking at lithium ones.
Ive read the issue with charging is that an alternator wont provide a high enough voltage to charge a lithium battery fully.
If thats the case then an alternator which does provide the correct voltage must be available.....mustn't it? Lol

[Petrol]

I have a lithium battery in my motorhome
From my understanding it goes like this

The alternator will charge the lithium battery but not fully. Maybe 80% This is due to the alternator output voltage.
The problem is that lithium batteries can take a huge charge current.... 50A or more is not uncommon. The alternator will get too hot especially at low revs trying to output such huge current.

 

You need to check the amps the battery will draw before worrying about charging voltage
An 80% charged lithium battery would easily start a car

 

Pete

[Gaz66]

I would think the migs will be running a lithium battery due to weight so what alternator would they be running?
Or the fact that they will be starting with a fully bench charged battery will negate any low amperage topping up from the standard output alternator?

[mini-mad-mark]

A std mini 038 battery weighs in at about 10kg - the Odyssey weighs about 7kg and a Lithium is around 3kg depending what sort you get but I think that is for a suitable replacement 

The first 3kg saved with an Odyssey is relatively simple and its also usefully smaller than an 038 for what I was doing (placing it under bonnet on my project) - as far as I can tell the lithium is roughly a similar size to the Odyssey so no additional space saving but does save another 4kg agreed 

 

Thinking about it more deeply I've saved some more weight by not having a full car length main battery cable, at least 1kg I guess although that may not be a option for everyone? 

 

There is also the cost - I think the price of the Lithium batteries is pretty high whereas an Odyssey is only about twice the price of a cheap 038 or about 20% more than a decent one (I paid about £90 this year for mine) - The Lithium I was thinking of (Varley Li-16) is advertised around £600 (of course you may find it cheaper but I doubt anywhere near 90 quid) however I know also that some people won't worry about the cost either when chasing the ultimate weight saving 

 

If I wanted to save the other 4kg I would have to cut out some pies (probably scope in my case to lose more than 4kg!!!) and it would also save me the cost of the pies!!!

 

No I don't work for Odyssey, just an impressed (so far) user