Help! Converting a 2008 Gary Fisher HiFi Plus 29

[kripski]

I need your help...I'm a newbie and looking to convert my full-suspension 2008 Gary Fisher Hifi Plus 29er a clean looking yet powerful all-terrain ebike. This is the conversion kit I have picked out: https://www.aliexpress.com/item/32937069426.html?spm=2114.12010612.8148356.8.dbf36b47AuoRSu

Yet I am facing a few challenges:

1. The frame triangle is small and will only allow for a battery max height 3.5 inches. There is another water bottle attachment under the down tube but the battery will get more exposed to the elements. Is this an issue?
2. I plan to use the pedal assist function yet I live in a area some decent hills, plus I plan to take it on off-road trails. What performance can I expect with the 1500w motor and 52v 14.4ah battery? Will I burn it out?
3. I have little to no room to mount a controller I was exploring kits that have a built-in controller in either the hub or battery. I think it will make the bike look better but is overheating a concern? Are you aware of any kits like this that would work for me?

If you have any other affordable conversion kit suggestions PLEASE send them! I'm excited to get it setup this summer.

Need your help...Thanks!

Adam

 

[J.R.]

If it were me, I'd consider either a geared hub or a mid drive. A 1500 watt direct drive will be very heavy, stated weight 40+ pound kit.

My first bike was a 500 watt DD hub. It is very heavy and not the best for trails. With a 40 lb kit, I think when all is done you'll have a 70 lb mtb.

Love the bike you have. Should be fun when all is sorted. Good luck!

 

[kripski]

I've avoided looking at mid drives because the install seems to be way more technical. BUT if it's lighter and can provide similar or more power maybe I will open up that can of worms and see whats available. I'll post pix when its done! It should be a great finished product.

 

[WilliamT]

If your going to use it for technical climbs, then definitely go mid-drive, otherwise its not as critical in my opinion.

You might be able to get away with a slim 13 ah battery on the downtube where the water bottle bolts are. But having 2 small (4) ah batteries may be easier to attach. Then it will fit in your frame and on the outside downtube. Luna Cycles sells small batteries called Luna Pups. Just make sure you get on the email list and buy when you get it. Those batteries sell out in less than 12 hours.

1500 watt won't hurt the battery if the battery can provide the current needed to produce that kind of power. Any 52v/48v battery that can handle 30 amps continuous will be fine. Those pup batteries can handle 35 amps.

Running it at 1500 watts will quickly drain the battery. A 52v 4ah battery (208 watts) running at 1500 watts continuous will probably drain your battery in 5 minutes. If your doing that w/throttle only, then BBSHD is safer to get vs a BBS02. If you pedal with assist, then it doesn't matter

 

[tomjasz]

Luna warranty.
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[indianajo]

1. plan to use the pedal assist function yet I live in a area some decent hills, plus I plan to take it on off-road trails. What performance can I expect with the 1500w motor and 52v 14.4ah battery? Will I burn it out?
2. I have little to no room to mount a controller I was exploring kits that have a built-in controller in either the hub or battery. I think it will make the bike look better but is overheating a concern? Are you aware of any kits like this that would work for me?

52 v & hills are a bad combination. Most US vendors have stopped selling anything above 36 v on hill climbing bikes. I climb 77 hills with my 48 v geared hub motor, but they are short and overall rise is 200'.
As JR said, direct drive hub motors are bad news at slow speeds on hills. they will do it, but chew up a lot of battery wh because the slip is so high. Geared hub motors go 5 x as fast due to the gears, so I use about half the wh on my 30 mile commute geared hub versus DD. I got mine at ebikeling.com but he quit selling 48 v geared hub motors, only 36 now. Luna had a mac 12 I bought, for slower speeds than the Mac 10.
Geared hub motors will not shed heat fast enough to climb 1000' in 15 minutes. Full power at low speeds for 15 minutes burns them up. My hills are rollers, up to 15%, but short enough I haven't damaged my motor in 4000 miles. DD like crystal will shed the heat, but you can't afford enough battery to climb 1000 ft of 15%.
I've gotten 2 trash batteries, 1 btrbattery via amazon, 1 sun ebike via ebay. Got my money back from Amazon. I got one good battery from luna. ebikeling has a good reputation too, but his controllers are very basic.
You have room to put a shark or dolphin battery above the top rail. You'll have to use clamps to keep it above the rail instead of hanging below. I make clamps out of 1" strips of sheet metal I cut out of box fan shells. Then I clamp them with #10-32 stainless screws & elastic stop nuts. Mcmaster, grainger, or fastenal for real hardware that won't fracture or strip. ebay/amazon for hardware that looks just like the real thing, but isn't.
You have room to hang a controller under the frame cylinder. I hung my controller with spam can lids & #10-32 screws. You can see it under my seat out of the rain. Rains every day, now. My battery is in a 3/4" al angle frame, with wires pointed down, and wrapped in packing foam under a green pvc bag. Hasn't shorted out in 4000 miles 2 1/2 years.
Controllers in the motor or battery are bad news. No good way to get the heat out, and when the battery dies, the new one is not compatible with the old one. You want a battery that has 4 wires, red black to controller, red black to charger. Nothing else. Unless you want to spend $$$$ when the battery dies.

 

[tomjasz]

52 v & hills are a bad combination.

Good land, what in the world does battery voltage have to do with hills!

Geared hub motors will not shed heat fast enough to climb 1000' in 15 minutes.

That's just not accurate. What speeds are you talking about maintaining?

put a shark or dolphin battery above the top rail.

Do you mean the top tube? For that mounting there are several options. 1 from a member here, JRA, to relocate the bottle mounts, the Bottle Bob.

Thanks for sharing your usual creativity in solving problems!

 

[indianajo]

Good land, what in the world does battery voltage have to do with hills!

That's just not accurate. What speeds are you talking about maintaining?

You are the one that told me MAC limits full power at slow speeds to 15 minutes, else they burn.
Slip is higher at low speeds. Slip turns into self heating. More voltage, more wasted current.
Electricbikes.com cancelled my order for a 48 v Mac12 when he found out we have 15% grades in southern indiana. My uphill speeds average 10 mph due to coast energy from downhill, so I don't burn up motor. electricbikes.com recommended I order a crystal DD motor instead of a MAC12. I was sick of dragging a $189 1000 w DD motor along with my feet unpowered, wasn't about to buy a $750 crystal. Bought a 48 v Mac12 from luna.
ebikeling.com quit selling 48 v geared hub motors, went to 36 v. Higher voltages ram more current through a dragging motor at slow speed. No back emf at slow speeds as is generated at rated speed. Read audel's motor book. Industrial 3 phase motors limit low speed application to 50% of rated speed unless current delivery is limited to low percentage rating. (Siemens, yakasaka VFD). Also industrial VFD use chopper drive at speeds below 50%. bike hub motors are 3 phase AC motors with a much cheaper VFD drive than a seimens.

 

[tomjasz]

You are the one that told me MAC limits full power at slow speeds to 15 minutes.

I'm sorry, you misread or I wasn't clear. Using the Grin motor simulator we can plug in different parameters. But there is no one phrase limit.

here's a 15% grade video. This is the grades from the ridges here in SE MN. I didn't realize Indiana had 350-500' bluffs to climb.

 

[AHicks]

I would vote against the direct drive as well. I had a 1500w and ended up swapping it for a MAC 12t geared hub because I found it lacking in the bigger hills. VERY happy with the MAC geared hub, so slightly biased in that regard.

That said, if I had a bike like yours, especially when faced with a lack of room to put "stuff" I would have to vote for a mid drive. Probably a big one (1000w plus). These have all the power you would ever need, AND, the controller is built into the motor - one less thing to find room for.....

I would also insist on a throttle, which is not possible on some, so beware.

 

[geekwithoutacause]

What did you end up doing with this bike? I can buy this bike in size large and am looking to add a mid drive. Will the chainstay give any issues ?

 

[creativepart]

Here's a very similar build to what you're planning. Battery on the bottom of the downtube. I would agree that Mid-Drive is the way to go. Also the controller is built into the motor of the Bafang mid-drive.